Advances in jute research 9789385059452, 9789385059964, 9385059963

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Advances in Jute Research

Dr. N. Gokarneshan, M. Maanvizhi and U. Dhatchayani

W New Delhi, India

Published by Woodhead Publishing India Pvt. Ltd. Woodhead Publishing India Pvt. Ltd., 303, Vardaan House, 7/28, Ansari Road, Daryaganj, New Delhi - 110002, India www.woodheadpublishingindia.com First published 2019, Woodhead Publishing India Pvt. Ltd. © Woodhead Publishing India Pvt. Ltd., 2019 This book contains information obtained from authentic and highly regarded sources. Reprinted material is quoted with permission. Reasonable efforts have been made to publish reliable data and information, but the authors and the publishers cannot assume responsibility for the validity of all materials. Neither the authors nor the publishers, nor anyone else associated with this publication, shall be liable for any loss, damage or liability directly or indirectly caused or alleged to be caused by this book. Neither this book nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming and recording, or by any information storage or retrieval system, without permission in writing from Woodhead Publishing India Pvt. Ltd. The consent of Woodhead Publishing India Pvt. Ltd. does not extend to copying for general distribution, for promotion, for creating new works, or for resale. Specific permission must be obtained in writing from Woodhead Publishing India Pvt. Ltd. for such copying. Trademark notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation, without intent to infringe. Woodhead Publishing India Pvt. Ltd. ISBN: 978-93-85059-45-2 Woodhead Publishing India Pvt. Ltd. Master E-ISBN: 978-93-85059-96-4

This book is dedicated to my beloved late father my beloved mother my reverred master my beloved wife and son and last but not the least my beloved readers

Contents

Preface

ix

1.

Colouration of reactive dyed jute fabric using biotechnology

1

1.1

Introduction

1

1.2

Technical details

2

1.3

Determination of optical properties

2

1.4

Effects of treatments

3

1.5

Dye uptake, colour strength, and fastness properties

3

2.

3.

References

5

Studies on wrap-spun jute yarn

7

2.1

Introduction

7

2.2

Technical details

8

2.3

Tensile properties

9

References

12

Biofinishing of jute for enhancement of fabric handle

13

3.1

Introduction

13

3.2

Technical details

14

3.3

Findings of the investigation

15

3.4

Influences of independent variables on different responses

15

3.5

Influence of enzyme treatment on surface appearance

18

3.6

Influence of enzyme treatment on chosen Kawabata evaluation system parameters and jute fabric handle values 19

3.7

Values of primary and total hand

19

viii

Contents

3.8 4.

5.

6.

7.

Influence of enzyme treatment on drape coefficient

21

References

22

Novel approach for jute retting

23

4.1

Introduction

23

4.2

Technical details

24

4.3

Enzymatic activities of isolated fungi

25

4.4

Studies on pH and redox potential

26

4.5

Comparison of the retting methods

26

4.6

Evaluation of fungal dry retting

27

References

28

New treatment for characterization of thermal, surface, and tensile properties of jute

29

5.1

Introduction

29

5.2

Technical details

30

5.3

Tensile tests

31

5.4

Scanning electron microscope (SEM) studies

32

5.5

Fourier-transform infrared spectroscopy (FTIR) studies

33

5.6

Differential scanning calorimetry (DSC) studies

34

5.7

Thermogravimetric analysis (TGA)

35

References

36

Jute dyeing using natural dyes

39

6.1

Introduction

39

6.2

Technical details

40

6.3

Discussion of findings

40

References

42

Influence of thermal treatment on wrap-spun jute yarns

43

7.1

Introduction

43

7.2

Technical details

45

7.3

Influence of dry heating on tensile properties

45

ix

Contents

8.

7.4

Influence of boiling water treatment on tensile properties

50

7.5

Influence of dry heating on residual shrinkage

51

7.6

Influence of thermal treatments on twist liveliness of wrap-spun yarns

51

References

51

An assessment of traditional system jute classification for composite applications

53

8.1

Introduction

53

8.2

Technical details

54

8.3

Thermostability

55

8.4

Alkali-soluble fraction

56

8.5

Degree of fibre damage

57

8.6

Degree of lignification

58

8.7

Degree of whiteness

60

8.8

Parameters rendering a differentiation between TD classes possible

61

Parameters enabling differentiation between upper and lower sections

63

8.9

9.

10.

References

64

Mechanical properties of knitted jute-reinforced composites

67

9.1

Introduction

67

9.2

Technical details

68

9.3

Tensile tests

69

9.4

Flexural tests

70

9.5

Impact tests

71

References

73

Influence of dynamic loading on jute non-woven fabric

75

10.1

Introduction

75

10.2

Technical details

76

x

Contents

10.3 11.

12.

13.

Findings of the study

76

References

80

Yarn pull-out behaviour of jute plain woven fabric

83

11.1

Introduction

83

11.2

Technical details

85

11.3

Findings of the study

85

References

87

Chemically and biochemically modified jute substrate – Thermal and structural characteristics

89

12.1

Introduction

90

12.2

Technical details

91

12.3

Surface morphology investigation

93

12.4

X-ray crystallinity, moisture regain, and copper number

95

12.5

Thermal stability

96

12.6

Investigation by FTIR spectroscopy

99

References

101

Jute non-woven fabric as composite reinforcement

103

13.1

Introduction

103

13.2

Technical details

104

13.3

Jute non-woven properties

105

13.4

Woven jute-reinforced plastics versus needlepunched non-woven jute fabric

106

13.5

Influence of fibre orientation

107

13.6

Influence of needle penetration depth

108

13.7

Influence of needling density

109

13.8

Influence of mass/unit area

110

13.9

Jute non-woven surface modification

110

13.10

Influence of bleaching

111

13.11

Treatment with alkali

111

xi

Contents

13.12 14.

15.

16.

Treatment with enzyme

111

References

112

Influence of some factors on compression behaviour of jute needle-punched non-woven fabric using statistical models

113

14.1

Introduction

114

14.2

Technical details

114

14.3

Findings of the investigation

115

References

119

Water absorbency of jute needle-punched non-woven fabric

121

15.1

Introduction

121

15.2

Technical details

122

15.3

Wettability

122

15.4

Influence on ESC

124

15.5

Influence on ERS

126

15.6

Correlating the bulk density, ESC, and ERS

128

15.7

Confirmation of model

128

References

130

Method for determination of electrical resistance of jute fabric

131

16.1

Introduction

131

16.2

Technical details

132

16.3

Influence of voltage

133

16.4

Influence of fabric type

133

16.5

Influence of gauge length

134

16.6

Influence of moisture

134

16.7

Influence of fibre orientation

135

16.8

Influence of areal density

135

16.9

Influence of heating

136

References

136

xii 17.

18.

19.

20.

Contents

Ternary blended yarns from jute

139

17.1

Introduction

139

17.2

Technical details

140

17.3

Jute, shrinkable acrylic, and hollow polyester blends

140

17.4

Jute, polypropylene, and hollow polyester

142

17.5

Yarn rupture

142

17.6

Jute-based fabric development in handloom

143

17.7

Developed fabric versus commercial fabric

143

17.8

Influence of washing treatment

144

References

144

Developments in instrumentation for testing of jute

147

18.1

Introduction

147

18.2

Technical details

149

18.3

Correction factor caused by contact resistance

154

18.4

Warm-up time for test commencement

154

18.5

Repeatability test

155

References

156

Influence of some factors on the physical properties of jute and hollow polyester yarn

159

19.1

Introduction

160

19.2

Technical details

160

19.3

Statistical interpretation

161

References

170

Newly developed jute geotextiles

173

20.1

Introduction

173

20.2

Technical details

174

20.3

Microbial profile of water and soil

175

20.4

Optimization of chemical treatment

175

20.5

Influence of chemical treatment on water repellency and strength retention

175

xiii

Contents

21.

22.

23.

20.6

Test of compatibility with environment

177

20.7

Prediction of durability

177

20.8

Field tests of treated fabric

178

References

179

Qualitative and quantative assessment of microorganisms relating to piling of jute

181

21.1

Introduction

181

21.2

Technical details

182

21.3

Analysis of microbial populations

183

References

186

Bleaching of sulphonated jute/cotton blended fabric

189

22.1

Introduction

189

22.2

Technical details

190

22.3

Influence of treatment time and temperature

190

22.4

Influence of hydrogen peroxide

191

22.5

Influence of pH

192

22.6

Influence of fabric–liquor ratio

193

22.7

Thermogravimetric analysis

193

References

194

Digital image analysis for evaluation of abrasive damage of jute-based fabric surface

195

23.1

Introduction

196

23.2

Technical details

197

23.3

Choice of texture features

198

23.4

Studies on 100% jute fabric

199

23.5

100% cotton fabric

201

23.6

Jute/cotton fabric

201

23.7

Comparison between 100% jute, 100% cotton, and jute/cotton fabrics

204

References

205

xiv 24.

25.

26.

27.

Contents

Influence of various mordants and dyeing process variables on jute fabric dyeing with extract of natural dye

207

24.1

Introduction

208

24.2

Technical details

209

24.3

Influence of various mordants on mechanical properties

210

24.4

Influence of various mordants on colour yield and colour fastness

210

24.5

Influence of dyeing process variables

211

24.6

Colour strength and related colour interaction parameters 213

24.7

Colour fastness

214

References

216

Thermodynamic aspects and dyeing kinetics of jute fabric dyed with natural dye extract

219

25.1

Introduction

219

25.2

Technical details

220

25.3

Study details

221

References

226

Bleaching of jute with peracetic acid

229

26.1

Introduction

229

26.2

Technical details

231

26.3

Discussion of the findings

231

References

236

Influence of dyeing and finishing on the UV protection of jute/cotton fabrics

237

27.1

Introduction

237

27.2

Technical details

238

27.3

Influence of jute lignin on UV protection

239

27.4

Influence of bleaching

242

27.5

Influence of sun-protective dyes

242

27.6

Performance of simultaneously dyed and finished fabrics in UV protection

244

xv

Contents

27.7 28.

29.

30.

Effect of titanium dioxide

245

References

245

Hybrid jute/HTPET-fibre-reinforced epoxy composites

247

28.1

Introduction

247

28.2

Technical details

249

28.3

Charpy impact properties

251

28.4

Flexural properties

252

References

255

Studies on thermal and mechanical characteristics of jute fibre-reinforced composites

257

29.1

Introduction

257

29.2

Technical details

258

29.3

Investigation of the properties

259

29.4

Thermogravimetric analysis of jute composite

262

29.5

Differential scanning calorimetry

262

29.6

Dynamic mechanical analysis

263

29.7

Storage modulus

263

29.8

Loss modulus

265

29.9

Tan δ

266

References

267

Evaluation of colour performance and dye compatibility in the dyeing of jute with binary of natural dyes

269

30.1

Introduction

270

30.2

Technical details

272

30.3

Findings of the investigation

273

30.4

Compatibility tests

275

References

278

Preface

This book comprehensively reviews significant researches in the area of jute. For over years jute fibre had limited areas of application. But researches over the past decade have proved that newer areas of applications are possible. One interesting aspect of jute research is that India has made major contributions in the area, and more particularly West Bengal. The properties of jute fibre have been well investigated and exploited during recent years. I wish to duly acknowledge the authors whose significant contributions have been included in this book so as to create more awareness among readers regarding the versatility of jute fibre in different areas of applications and also to promote the research interest in jute fibre. Dr. N. Gokarneshan Professor and Head Department of Textile technology Park College of Engineering and Technology Coimbatore, Tamil Nadu, India

Chapter 1 Colouration of Reactive Dyed Jute Fabric Using Biotechnology

Abstract The reactive dyeing on jute fabrics has been compared with regard to sequential treatment based on bioscouring bleaching and alkaline scouring bleaching. Of these, the former method exhibits better dye uptake than the latter one. The easy entry of dye molecules into the fabric is facilitated by the removal of impurities and removal of small amount of jute constituent during biotreatment. With biotreated jute fabric, the shade brightness also gets enhanced. The biotreated bleached dyed jute fabrics show marginal improvement in wash fastness. Good ultraviolet protection properties are also observed in the dyed fabric. There is an improvement in the handle properties of biotreated jute fabric, and also a slight decrease in tensile strength.

1.1

Introduction

Jute fibre is basically lignocellulosic, biodegradable, and renewable. Owing to its high tenacity and low extensibility, it is traditionally being used for producing packaging material. It is also stiff and harsh. The jute industry is facing stringent competition from its synthetic counterparts, which are light in weight and more economical for producing packaging material. In order to sustain the big Indian jute industry and also to protect the farmers engaged in jute cultivation, it is necessary to diversify the product range for effective utilization of jute fibre. Recently, a number of decorative and valueadded items such as upholstery, curtains, furnishing materials, handicraft products, outer garments, and so on, are produced from jute fibres. Hence, in order to overcome the inherent setbacks of the jute fibre, such as stiffness, harshness, and brittleness, and to render the fabric soft and lustrous, the jute fabric is chemically or biochemically modified.1,2 The fabric should also

2

Advances in Jute Research

appear attractive by bleaching and dyeing, besides improvement in feel.3 For making diversified and value-added products, a number of chemical processing methods have been evolved over the past few years. Moreover, jute fabrics have also been dyed with several natural and synthetic dyes to make the fabric attractive. In most of the cases, effluents are produced after pretreatment and bleaching and left-out dye liquors containing dyes and salts produce pollution. It is necessary to reduce the pollution and dye effluent should contain minimum amount of dyes. Hence, efforts have been directed towards the use of biotechnical methods to reduce pollution load. A special reactive dye producing minimum dye effluent and deep colour shade with improved feel has been utilized.

1.2

Technical details

Grey woven jute fabric has been used in the investigation. Chemicals of analytical grade have been used and include hydrogen peroxide, trisodium phosphate, sodium hydroxide, sodium carbonate, sodium silicate, sodium acetate, acetic acid, non-ionic surface active agent and Glauber’s salt. Cellulase enzyme and xylanase enzyme of commercial origin have been used. The reactive dyes of triazinyl type – Procion blue and Procion green have been used.4 The grey jute fabric has been subjected to the processes of chemical scouring, bioscouring, bleaching, and dyeing followed by cold washing and drying under specified conditions.5 Various standards have been used for evaluation of grey chemically scoured, bioscoured, chemically scoured-bleached, bioscoured-bleached, chemically scoured-bleached-dyed and bioscoured-bleached-dyed jute fabrics. These include whiteness index, yellowness index, brightness index, K/S value, L, a, b values (computer colour matching system), wash fastness, lightfastness, handle properties, tensile properties, and ultraviolet (UV) protection factor.

1.3

Determination of optical properties

Jute fibre mainly comprises cellulose, hemicelluloses, and lignin. Based on standard procedure, the optical properties of grey, chemically scoured, bioscoured, chemically scoured-bleached and bioscoured-bleached jute fabrics have been determined. On comparison with only chemically scoured and bioscoured jute fabric, the scoured bleached and bioscoured-bleached jute fabric show marked improvement with regard to whiteness and brightness.6 In the case of bioscoured-bleached jute fabric, these are found to be more. Of the

Colouration of Reactive Dyed Jute Fabric Using Biotechnology

3

two enzymes used, cellulose enzyme acts on the cellulose fibre component, and xylanase acts on the hemicelluloses component of the jute fibre, respectively.7

1.4

Effects of treatments

Jute fibre has a composite structure comprising major and minor components. The major components are cellulose, hemicelluloses, and lignin, while pectin, mineral matter, and a little amount of fats and waxes constitute the minor component. During the fibre processing, it acquires dirt and dust particles as well as batching oil. Hence, the scouring of jute means removal of added and inherent impurities. Enzymolysis results from treatment with cellulose and xylanase enzymes, accompanied by the removal of a small percentage of cellulose and hemicelluloses along with some soluble lignin.8,9 Measures are taken during the treatment to avoid major strength loss and the enzymolysis is stopped through inhibition technique.6 By this process, porosity of jute fibre increases and the non-ionic surface active agent present in the bioscouring liquor helps to remove the added and inherent impurities present in the fibre. Thus, the bioscouring process is effective and results in absorbent fabric. Two types of bis-triazinyl reactive dyes have been used to dye alkali-treated and enzyme-treated fabrics (chemically scoured-bleached and bioscouredbleached jute fabrics) and analysed for properties such as λmax, K/S value, L, a, b values, wash fastness, and lightfastness.10

1.5

Dye uptake, colour strength, and fastness properties

In the case of both dyes, the uptake of dye with regard to colour strength value for bioscoured-bleached-dyed jute fabric is greater compared with chemically scoured-bleached-dyed jute fabrics. It could possibly be attributed to the formation of more number of pores inside the fibre structure during enzyme treatment, leading to easy entry of dye molecules in the fabric.6 Wash fastness in case of bioscoured-bleached-dyed jute fabrics is found to be slightly better in comparison to chemically scoured-bleached-dyed jute fabrics. In the case of both dyed fabrics, the lightfastness ratings are found to be similar. Also, L, a, b values of both the fabrics are as expected.

1.5.1 Handle properties In the case of raw, chemically scoured-bleached, bioscoured-bleached, and their respective dyed fabrics, the handle properties with regard to bending

4

Advances in Jute Research

length, flexural rigidity, bending modulus have been determined.6 In the case of chemically scoured-bleached jute fabric, an adequate decrease in bending length, flexural rigidity, and bending modulus has been observed in comparison with raw jute fabric. However, there is further decrease in these values with bioscoured-bleached jute fabric. The fabric is rendered softer by bioscouring, which involves removal of impurities, removal of a portion of cellulose, and hemicelluloses constituent of fibre, cleavage of ester linkage, and shortening of cellulose. Even after dyeing with both types of procion dyes (blue and green), the bending length, flexural rigidity, and bending modulus values do not change significantly.

1.5.2 Tensile properties A tensile testing machine has been used to determine the tensile properties such as tensile and extension values of grey, chemically scoured-bleached, bioscoured-bleached, and their respective dyed fabrics. There has been a loss in strength for chemically scoured-bleached jute fabric on comparison with grey jute fabric, which could possibly be attributed to more drastic chemical reaction during conventional alkaline scouring process.6 Loss of strength has also been observed in the case of bioscoured-bleached jute fabric, which could be because of enzyme action on the fibre. Very minimum strength loss has been observed during dyeing process than chemically scoured-bleached and bioscoured-bleached jute fabric. 1.5.3 UV properties A Labsphere UV transmittance analyzer has been used in the UV transmission analysis of grey, chemically scoured, bioscoured, chemically scoured-bleached, bioscoured-bleached-dyed, and bioscoured-bleached-dyed fabrics.11,6 Table 1.1 gives the fabric grading, and their corresponding transmitted UV radiation in percentage. Table 1.1 Ultraviolet protection UPF rating Protection grade 15–24 Good 25–39 Very good 10–50+ Excellent

factor (UPF) protection grade Transmitted UV radiation in percentage 6.7–4.2 4.1–2.6 ≤ 2.5

Source: adapted from ref. [6].

An average of nine readings has been considered as the mean UV protection factor. The UV protection properties of undyed jute fabrics are described with

Colouration of Reactive Dyed Jute Fabric Using Biotechnology

5

regard to fibre composition and fabric construction. It has been observed that poor UV protection properties and transmission of solar radiation in the case of UV-A and UV-B are very high. The UPF rating is seen to improve in jute fabric after dyeing with bis-triazinyl reactive dyes and the UV transmission value is less. Hence, good UV protection properties are observed in dyed fabrics.

References 1.

Pan N C, Chattopadhyay S N, Roy A K, Patra K and Khan A (2011), Int Dyer, 196(9), 13.

2.

Pan N C, Chattopadhyay S N, Roy A K, Patra K and Khan A (2009), Melliand Int, 15(3), 100.

3.

Pan N C, Chattopadhyay S N, Roy A K, Patra K and Khan A (2010), Man-Made Text India, 38(8), 288.

4.

Chattopadhyay D P and Chaudhary R (1997), Man-Made Text India, 40(12), 495.

5.

Pan N C, Chattopadhyay S N, Roy A K, Khan A and Patra K (2013), J Text Sci Eng, 3(1), 1.

6.

Pan N C, Chattopadhyay S N and Roy A K (2015), ‘Application of biotechnology in the coloration of jute fabric using bis-triazinyl type of reactive dyes’, Indian J Fibres Text Res, 40, 414.

7.

Vigneswaran C and Jayapriya J (2010), J Text Inst, 101(6), 506.

8.

Chattopadhyay S N, Sanyal S K, Kundu A B, Day A, Pan N and Mitra B C (1997), Indian Text J, 107(10), 14.

9.

Chattopadhyay S N, Sanyal S K, Kundu A B, Day A, Pan N and Mitra B C (1997), Indian Text J, 107(3), 64.

10.

ISI (1982), Handbook of textile testing, New Delhi, India, Bureau of Indian Standards.

11.

Gupta D (2007), Colourage, 55, 75.

Chapter 2 Studies on Wrap-spun Jute Yarn

Abstract In comparison with conventional jute yarns, wrap-spun jute yarns normally exhibit lesser tenacity and greater elongation at break. At higher wrap densities, they give multi-peak breaks, based on the linear density. When compared with wrap-spun jute having two-ply cotton yarn as wrapping element, the tenacity of wrap-spun jute yarn having viscose rayon multifilament yarn as wrapping element, is lower. Compared to the conventional twisted jute yarns, the wrap-spun jute yarns are comparatively better.

2.1

Introduction

Attempts have been made to produce wrap-spun jute yarn using hollow spindle technique. A general model has been proposed to predict the yarn strength from various structural parameters of wrap-spun yarn and the theoretical approach has been confirmed through experimental work on wrap-spun woollen yarn with nylon filament as wrapping element.1,2 The influence of wrapping element, linear density, and wrap density on wrap-spun polyester yarn structure and tenacity has been investigated.3,4 The different properties of wrap-spun jute yarns have been studied by many research workers, using the hollowspindle technology.5–9 However, most of them involved yarns with synthetic multifilament or monofilament yarns as wrapping element, restricting the wrap density to the maximum of 300 wraps/m. Jute fibre core – synthetic filament wrapping yarn combination requires separate treatments during chemical processing, for example, bleaching, dyeing, and so on, for jute and synthetic components. Moreover, these yarns are not fully biodegradable so with the objective to produce fully biodegradable wrap-spun yarn, two-ply cotton yarn was selected as wrapping element as it is compatible with the chemical nature of jute. Certain investigations have been carried out on wrap-spun jute

8

Advances in Jute Research

yarn having viscose rayon multifilament yarn as wrapping element. However, there are no details available regarding wrap-spun jute yarn prepared with cotton yarn as wrapping element in hollow-spindle wrap spinning machine.7 Bhattacharya and Sengupta reported about jute yarn wrapped with cotton yarn, spun in the conventional jute spinning machine.10 In the case of wrapspun jute yarn, the jute fibres produced from hollow-spindle machine have been aligned parallel to yarn axis and have not been subjected to twisting, whereas the jute fibres in the spin-wrapped jute yarns have been twisted as normal spun yarns and therefore have been helically aligned in relation to yarn axis.10 Hence, the structures of these two types of yarns are quite different. It was, therefore, thought worthwhile to engineer a wrap-spun jute yarn with cotton yarn as wrapping element in the high-speed hollow spindle machine at a speed 2.5–3.5 times of that of the conventional jute spinning process with an idea to improve some of the yarn tensile properties to suit weaving on modern high-speed looms. Such yarns, wherein jute fibres are partially covered with cotton yarn, can also improve the aesthetic properties of the finished product. A systematic approach has been done to develop a wide range of wrap-spun jute yarn with cotton yarn as wrapping element. For each count, the wrap-spun yarns have been spun in three different linear densities (276, 190, and 120 tex) with varying wrap density (250–450 wraps/m). The wrapping element is two-ply cotton yarn, being more uniform and reasonably stronger than single yarn of the equivalent linear density. Also, two-ply cotton yarn could possibly provide an aesthetic effect in the wrap-spun yarn. In order to produce a wrap-spun jute yarn of a particular linear density, a viscose rayon multifilament yarn has been used as wrapping element.

2.2

Technical details

Jute fibre of commercial hessian warp batch, 2-ply 10 tex cotton yarn, and viscose rayon multifilament of 13.3 tex (120 denier) have been used. Jute yarns of varying nominal linear densities have been spun on a wrap spinning machine. In total, 100% jute yarns of three different linear densities were also spun with an optimum twist in the conventional apron draft spinning machine from the conventional third drawn sliver.11 Eighteen different wrap-spun jute yarns having cotton/viscose rayon multifilament yarn as wrapping element were prepared, maintaining the draft and delivery speed at 40 and 60 m/min, respectively, at spinning stage. In case of wrap-spun yarns, the fibre was processed through the conventional jute spinning system up to the second drawing stage. The sliver thus obtained was once again processed through the second drawing machine, keeping the doubling and draft same to get a more

Studies on Wrap-spun Jute Yarn

9

regular sliver. The load-elongation properties of all the yarns were tested on an Instron tensile tester at 65% relative humidity and 7°C.

2.3 Tensile properties Figure 2.1 shows the tensile properties of the wrap-spun yarns, two-ply cotton yarn, viscose rayon multifilament yarn, and conventionally spun all jute yarns. In the case of the wrap-spun jute yarns, it is seen that they have lower tenacities and higher extension-at-break in comparison with the conventional all jute yarns of the equivalent linear densities.11 A similar trend has also been seen.7 Figure 2.1 shows that the rupture process of wrap-spun yarns are catastrophic, whereas that of the others exhibited staggered stick-slip failure, leading to many stress peaks during rupture.

Figure 2.1 Load-elongation curves of wrap-spun jute yarns having wrapping element as cotton yarn The ascending and descending portions of the load-elongation curves show stress peaks. In the case of 276-tex yarns, the multiple breaks are at wrap density of 400 wraps/m. Owing to the excessive breakage of the wrapping yarn, the yarn could not be spun beyond this wrap density level (cotton yarn).11 When compared with the filament yarn, the low breaking energy of the cotton yarn is the prime factor for staggered breaks of the aforesaid wrap-spun jute yarns. The simultaneous increase in strain level of the wrapping cotton increases with the increase in wrap density by means of increased lateral pressure and thus the inter-cohesion of jute fibre. Beyond the wrap density of 400 wraps/m, for coarser yarn of 276 tex nominal count, the dynamic strain level was so high that the wrapping cotton yarn ruptured during spinning and

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Advances in Jute Research

consequently the yarns with higher wrap density could not be spun. However, for the finer yarns of 190 and 120 tex nominal count, the wrapping cotton yarns did not attain the dynamic critical strain level during spinning as the diameter of the jute component was smaller, thereby making it possible to spin wrap-spun yarns of higher wrap density (450 wraps/m). However, the yarns have been subjected to static tensile stress during tensile testing. The extension, as well as the collapse of the helically wound wrapping yarn, is caused by the tensile stress along yarn axis. The lateral pressure increases due to the collapse of helical configuration of the wrapping yarn. However, low extensibility of cotton yarn does not allow the wrapping yarn to share the tensile stress built up in the yarn matrix. Consequently, there has been poor elongation balance and the yarns are ruptured. As the wrap density increased, this effect became more pronounced. However, the load-elongation behaviour of the viscose rayon multifilament wrapping yarn is observed to be very different from the cotton wrapping yarn. During tensile failure, there has been asymmetric stretching of the filaments in viscose rayon multifilament yarn, leading to a pronounced yield point at a load level of around 92 and stepwise stick-slip rupture of filament. In the case where viscose rayon multifilament yarn is used as a wrapping element in the wrap-spun jute yarns, a similar trend has been noticed. However, load-elongation behaviour of the viscose rayon multifilament wrapping yarn greatly differs from that of cotton wrapping yarn, as can be seen in Figure 2.2.

Figure 2.2 Load elongation behavior of viscose rayon multifilament wrapping yarn and cotton wrapping yarn

Studies on Wrap-spun Jute Yarn

Figure 2.3

11

Hairiness and appearance of wrap-spun and conventionally spun jute yarns: A – Conventional 100% jute, B – 250 wraps/min, C – 300 wraps/min, D – 400 wraps/min, E – 450 wraps/min

The viscose rayon filament yarn shows asymmetric stretching of its filaments leading to a pronounced yield point at a load level of around 90 g and stepwise stick-slip rupture of filament during tensile failure. Accordingly, when the viscose-rayon-multifilament-wrapped jute yarn has been extended during tensile deformation, the lateral force exerted by the wrapping element is suddenly dropped at the yield point. There has been no contribution of any lateral force by wrapping element, above the yield point. However, the parallellaid jute staple fibres that constituted the core component of the wrap-spun jute yarn started to slip. The wrap-spun jute yarn failed because of the increase in fibre slippage of the core component. Hence, even though the viscose rayon multifilament wrapping yarn showed high elongation of 17.5%, it failed to contribute to building up of lateral force at higher extension level of the wrap-spun yarn. The drastic drop in tenacity of the wrap-spun yarn with the increase in wrap density beyond 300 wraps/m might be explained in the light of quick attainment of the yield point of the viscose rayon multifilament yarn at 350 wraps/m as the wrapping element had already attained higher level of tensile strain during spinning wrap-spun yarn of higher wrap density. It has been found that the tensile strength of wrap-spun yarn with viscose rayon multifilament wrapping yarn reduces as the wrap density increases. However, the trend has been found to be erratic in the case of finer yarns (120 tex nominal count). It could arise from the higher irregularity of the finer jute component. The breaking elongation of these yarns generally increased with the increase in wrap density. However, in the case of 276 tex yarn at 350 wraps/m, a quantum rise in the breaking elongation has been noticed, in comparison with

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300 wraps/m in the case of 190 and 120 tex yarns. Also, with finer yarns, the increase in trend of breaking elongation with the increase in wrap density has not been as smooth as that for coarser yarns of 276 nominal linear density. The appearance of wrap-spun jute yarn with cotton wrapping yarn is comparatively better than that of the conventional all-jute yarn. This is mainly due to the less hairiness of wrap-spun jute yarns as compared to that of conventionally spun yarns. In the case of wrap-spun yarn, the decrease in hairiness has been reported earlier (Fig. 2.3).12,13 The production speed of 120 tex wrap-spun jute yarn with cotton yarn as the wrapping element has been 60 m/min, whereas with all-jute yarn of equivalent density, it was around 17.5 m/min. On the other hand, in comparison with conventional jute yarns, the spinning performance of the wrap-spun jute yarns has been quite satisfactory even with such higher delivery rate.

References 1.

Xie Y, Oxenham W and Grosberg P (1986), J Text Inst, 77(5), 295.

2.

Xie Y, Oxenham W and Grosberg P (1986), J Text Inst, 77(5), 305.

3.

Xie Y, Oxenham W and Grosberg P (1986), J Text Inst, 77(5), 314.

4.

Behery H M, and Nunes M F (1986), J Text Inst, 77(6), 386.

5.

Princz F J (1987), Proc, International Seminar, Golden Jubilee (1937–1987), Indian Jute Industries Research Association Calcutta, India, 91.

6.

Sengupta A K, Chattopadhyaya R S, Sengupta S and Khatua D P (1989), Proc, National Seminar on Jute and Allied Fibres, Jute Technological Research Laboratories, Calcutta, India, March, D1

7.

Khatua D P, Aditya R N, Mukerjee S, Neoji S K and Bhattacharya P K (1990), Proc, National Seminar on R& D, Indian Jute Industries Research Association Calcutta, India, 94

8.

Sengupta A K, Chattopadhyaya R S, Sengupta S and Khatua D P (1993), Indian J Fibre Text Res, 18, 62.

9.

Choudhri A, Mukerjee S, Sharma I C, Khatua D P and Aditya R N (1994), J Inst Eng India Text Eng Div, 75, 12

10.

Bhattacharya G K and Sengupta P (June 1985), J Text Assoc (India), 46, 159.

11.

Roy A. N, Basu and Majumder A (2000), ‘A study on wrap spun jute yarn with cellulosic yarn as wrapping element’, Indian J. Fibre Text Res, 25, 92–96

12.

Barella A and Manich A M (1997), Text Prog, 26(4), 1–29.

13.

Basu G, Roy A N, Majumder A and Ghosh S N (1999), Indian J Fibre Text Res, 24, 177.

Chapter 3 Biofinishing of Jute for Enhancement of Fabric Handle

Abstract The different physical properties of treated jute fabric are considerably influenced by the three processing parameters, namely enzyme concentration, treatment time, and treatment temperature, within the selected zone. Of the three, the concentration of enzyme and treatment duration is more important. The findings of the image analysis for five selected fabrics point out that the enzyme treatment reduces the number of hairs and hair length substantially. The Kawabata evaluation results confirm the improvement in feel of the fabric after enzyme treatment. Treatment with 4% (owf) enzyme at 50°C for 90 min has been found to be the best as it results in more than 15% increase in the total hand value of the fabric.

3.1

Introduction

The natural fibres have again come into limelight owing to the global awareness for eco-friendly products. At one time, jute fibre has been considered a low importance fibre used in packaging only but has subsequently grown as a versatile raw material for varied end uses. In comparison with other natural fibres, it has certain useful characteristics that could be utilized for the production of value-added and innovative jute products such as shawls, blankets, carpets, wall covering, and so forth, since these relatively coarser materials when produced from other natural fibres such as cotton and wool incur increased raw material cost.1 Attempts have also been made to introduce jute in the apparel sector. Some of the leading textile sectors in the country have been producing jute-blended denim either on trial or regular production basis. Drapeability and harsh prickly feel are some of the major setbacks of jute. Hence, to improve feel of jute by chemical processing through eco-friendly

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approach, some of the setbacks of jute need to be minimized. Thus enzyme has been the major focus of researchers. Cellulase enzymes have already been recognized to improve the surface property of cotton. Some of the cellulases being used are Aspergillus niger, Trichorderma longibrachitum, Fusarium solani, and Trocoderma viride.2 Some cellulase enzymes are capable of breaking 1,4 β-glucocidic bonds of cellulose. The enzymes are biomolecules of about 20 amino acids with molecular weight from 12 000 to 150 000 and therefore they are too large to penetrate the interior of a cellulosic fibre are affected.3 It leads to the enhancement of the hand and feel of the fabric due to surface etching. Pierce has been the pioneer in attempting the objective evaluation of the hand of apparel fabrics, which has been subsequently well improvised by Kawabata by providing a feasible instrumental technique to evaluate hand quality. The indentified hand quality attributes (or primary hand qualities) such as fullness, stiffness, and smoothness and the mechanical and surface properties that relate to these attributes have been evaluated. His approach instantaneously provides the exciting opportunities for developing a new generation of apparel fabrics. A good deal of literature is available on the fabric hand and the use of Kawabata’s method in the evaluation of fabric mechanical properties.4–8 A number of industries and research organizations have already used this method for developing new products with superior properties, process optimization, quality control, selecting new raw materials, minimizing manufacturing costs, and so forth. Though the Kawabata evaluation system for fabrics (KES-FB) measures 18 parameters, the fabric properties can often be explained by lesser number of parameters. Even though reasonable data is available on the handle properties of enzyme – treated cotton fabrics, very little information is available on enzyme – treated jute. This chapter focuses on the study of the influence of cellulose enzyme on the properties and feel of 100% jute fabric. In order to evaluate the fabric hand feel, the physical results, image analysis, and KES-FB have been analysed.

3.2

Technical details

About 100% grey jute woven plain fabric has been used. The chemicals used are sodium carbonate, amolan, which is a scouring agent, 10% peracetic acid, 50% hydrogen peroxide, stabilizer SIFA, trisodium pyrophosphate, and cellulose enzyme Biosoft – P. The fabric has been scoured with sodium carbonate and amolan FBOL at 80°C for 45 min9 with a material to liquor ratio of 1:30. It has then been bleached sequentially with peracetic acid and hydrogen peroxide.10 The scoured and bleached fabrics have been treated with cellulase enzyme at pH 4.5 with material to liquor ratio of 1:50 under

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different sets of conditions as per the Box and Behnken response surface design with three independent variable and three levels of each variable. Three independent variables have been chosen – enzyme concentration, treatment time, and treatment temperature. After the enzymatic treatment, the pH of the bath was increased to 9–9.5. The weight loss of the fabric after enzyme treatment has been calculated by measuring the difference in weight of the fabric before and after enzyme treatment. Instron tensile tester has been used to measure the breaking load of the fabrics before and after each treatment. The per cent loss on breaking load has also been calculated in each case. A stiffness tester has been used to measure the bending length, which is a measure of fabric stiffness. The per cent loss in bending length has also been calculated for each treatment. Shirley crease recovery tester has been used for measuring the crease recovery angle for the control and treated samples. An image analyzer has been used to record the images of fabrics. The approximate average number of hairs and their mean length have been measured using a software program. KES-FB has been used to measure the fabric characteristics such as low stress tensile, bending, and surface properties of the fabrics. Six Kawabata evaluation system parameters and four fabric hand descriptions are studied to distinguish the characteristics of different enzyme treated fabrics.

3.3 Findings of the investigation The enzymes obtained from various sources have been tested and the study has been divided into three sections. First, the material has been subjected to certain statistically designed experiments. Second, a few conditions have been chosen for image analysis from the results of the physical testing of these experiments, so as to evaluate the degree of improvement.9 Third, conditions have been further chosen from subsequent results, to objectively evaluate feel adopting the KES-FB method.

3.4

Influences of independent variables on different responses

The influence of treatment conditions on different jute fabric properties has been studied and their respective regression equations obtained. The enzyme concentration has been found to have the maximum effect on all the four responses – weight loss, loss in breaking load, loss in bending length, and gain in crease recovery angle followed by duration of treatment. Both of these independent variables have a positive effect on the four responses.9 The

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various responses against enzyme concentration and treatment temperature for treatment duration of 1.5 h have been determined. It is found that as the enzyme concentration increases, the weight loss, loss in breaking load, loss in bending length, and improvement in crease recovery angle also increase (Figs. 3.1–3.4). The increase in treatment temperature from 45 to 50°C has a positive effect, whereas the treatment temperature beyond 50°C has an adverse effect on different responses.

Figure 3.1 Weight loss versus enzyme concentration and treatment temperature for treatment duration of 90 min Cellulase comprises endoglucanases or endocellulases, cellobiohydrolases or exocellulases and cellobiases or β-glucosidases, endoglucanases, hydrolyse cellulose polymers randomly along the chains. Cellobiohydrolases attack the polymer chain ends and produce primarily cellobiose coupled with the enzyme. The degradation of cellulose can be supported by exocellulases through disruption of the local crystalline cellulose structure. This renders the region most susceptible to subsequent hydrolysis by endoglucanases. Small chain oligomers such as cellobiose are hydrolysed into glucose by β-glucosidases.11 The mechanical agitation easily removes some of the jute hairs and the removal is further enhanced by the enzymatic weakening of the ends. The weight reduction is primarily because of surface hair removal

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Figure 3.2 Loss in breaking load versus enzyme concentration and treatment temperature for treatment duration of 90 min

Figure 3.3 Loss in bending length versus enzyme concentration and treatment temperature for treatment duration of 90 min

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Figure 3.4

Gain in crease recovery angle versus enzyme concentration and treatment temperature for treatment duration of 90 min

and surface etching that consequently decrease the breaking load. The loss in bending length and improvement in crease recovery angle may be attributed to the improvement in softness and feel of the fabric, which is also evident from the KES-FB results. A study has been reported on the improvement in crease recovery angle on cellulase enzyme treatment of polyester viscose fabrics.12

3.5

Influence of enzyme treatment on surface appearance

Based on the physical testing results, five fabrics have been chosen for image analysis. The photograph of image analysis of the control fabric has also been recorded along with that of the treated fabrics. The fabric images have been taken from both vertical and horizontal directions. The approximate number of hairs and hair length has been calculated using software program. The enzyme treatment is found to reduce the surface hairs to a considerable extent, as seen from the top and side views in the figures.9 The number of hairs and hair length show that the order of degree of hair reduction is different in different fabrics tested. The decreasing order of the fabrics is as given below: Fabric 10 > Fabric 7 > Fabric 5 > Fabric 2 > Fabric 14 > Control.

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19

Fabric 10 and fabric 7 have been selected for Kawabata evaluation. The control fabric (untreated) has also been evaluated along with the treated fabric for comparison purpose. It can be seen that the fabric 10 shows the best results, so far as hair reduction is concerned.

3.6

Influence of enzyme treatment on chosen Kawabata evaluation system parameters and jute fabric handle values

KES evaluation results show that fabric 10 is more extensible than fabric 8 and control fabric. Better handle can be related to low energy to extend or compress the fabric. Similar Kawabata results have also been achieved for cellulose enzyme treatment on cotton.13 Because of enzyme treatment there is decrease in tensile resilience and is found to be more with fabric 10. This decrease can be due to the improvement in softness of the material which is clear from the decrease in bending rigidity. The decrease in tensile resilience of cotton knit on cellulose enzyme treatment has already been reported.9 The bending rigidity of a fabric depends upon the bending rigidity of threads and the mobility of warp/weft within the fabric. The degree of decrease in bending rigidity of fabric 10 has been found to be higher than that in fabric 7. In the case of fabric 10, the lower value of hysteresis of bending deformation implies the enhancement of the material softness. The decrease in hysteresis of bending deformation of polyester on caustic treatment has been reported.14 The coefficient of friction and surface roughness are decreased by enzyme treatment and fabric 10 is found to be better in this regard. The image analysis photographs also support the finding that the surface properties of the fabrics are improved by enzyme treatment, which removes surface fibres and reduce protruding fibre length (Fig. 3.5).

3.7

Values of primary and total hand

It has been found that with jute fabrics, biofinishing can improve the softness and fullness (Fukrami) and decrease the stiffness (Koshi) (Fig. 3.6). The effectiveness of enzyme becomes even the more evident by the enhancement of drapeability or decrease in antidrape stiffness (Hari), and smoothness (Numari).9 The cellulose present on the fabric surface is more accessible to the enzyme and gets easily hydrolysed compared to the cellulose present inside. The preferential hydrolysis makes the surface fibrils weak and their breakage from fibre surface causes smoothness and softness to the fabric. Moreover,

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there is a substantial improvement in the total hand value. The biopolishing of cotton showed similar results.15

Figure 3.5

Image analysis of jute test fabrics

Biofinishing of Jute for Enhancement of Fabric Handle

Figure 3.6

3.8

21

Image analysis of jute fabrics

Influence of enzyme treatment on drape coefficient

Matsdaira’s equation is useful for calculation of drape coefficient, based on mechanical characteristics of bending, shear properties, and fabric weight.16 It is to be noted that the drape coefficient is a criterion of static draping behaviour.9 The decrease in drape is a clear indication of the improvement in the softness of the jute fabric on enzyme treatment.

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References 1.

Chattopadhyay D P (1998), Colourage, 5. 23.

2.

Patra A K and Chattopadhyay D P (1998), Text Asia, 29(8), 46.

3.

Wadham M (1994), J Soc Dyers Colour, 110(12), 367.

4.

Kawabata S (1980), The standardization and analysing of hand evaluations, The Textile Machinery Society of Japan, Japan, July.

5.

Kawabata S, Niwa M and Kawai H (1973), J Text Inst, 64(1), 21.

6.

Kawabata S, Niwa M and Kawai H (1973), J Text Inst, 64(2), 47.

7.

Kawabata S (1983), Objective specification of fabric quality, mechanical properties and performance, The Textile Machinery Society of Japan, Japan.

8.

Kawabata S (1982), Objective specification of fabric quality, mechanical properties and performance, The Textile Machinery Society of Japan, Japan.

9.

Chattopadhyay D P and Sharma J K (2000), ‘Improvements in jute fabric handle through biofinishing’, Indian J Fibre Text Res 25, June, 121–129.

10.

Chattopadhyay D P, Sharma J K and Chavan R B (1998), Book of papers, Environmental issues: Technologyoptions for textile industry (IIT, Delhi), 23.

11.

Kumar A, Purtell C and Yoon M (1996), Int Dyer, 181(10), 19.

12.

Sharma I C, Chattopadhyay D P, Chatterjee K N, Mukhopadhyay A and Kumar A (1998), Indian J Fibre Text Res, 23, 44.

13.

Almeida L and Paulo A C (1993), Melliand Textilber, 74, 404.

14.

Datta R K, Shah A M and Patel N C (1995), ATIRA Communiation on Textiles, 29, 146.

15.

Saraf N H (1997), Int Dyer, 182, 24.

16.

Matsudaira M (1992), J Text Mach Soc Japan, 38(92), 39.

Chapter 4 Novel Approach for Jute Retting

Abstract In order to overcome the setbacks of conventional jute retting, eco-friendly, and water-saving technology has been used through pectinolytic fungi adopting dry fermentation. The fungal dry retting has been done by selection of four cultures of fungi. Studies on fungal dry retting of jute have revealed that it is able to reduce water requirement in an eco-friendly way. This enables the production of better quality jute fibre in shorter duration. Moreover, the regular yarn can be produced from such fibres. Fungal dry retting has a number of merits as listed below: •

It is an aerobic process and hence does not produce any harmful smelling gases that could pollute the environment.

•

No possibility of producing methane gas.

•

Quicker fungal retting and does not permit mosquito breeding.

•

Fibre can be extracted on dry land in place of dirty polluted water.

•

Could prove beneficial for combating against anthropogenic factor which causes global warming.

•

Use of the technology could fetch carbon credit for farmers.

4.1

Introduction

Owing to misuse of available water, the world is facing a crisis situation for drinking water and agriculture use. Moreover, there is a steady decline in rivers, lakes, ponds, and so forth, which are natural sources of water. The increased demand of water for cultivation of high yielding crop varieties is rapidly exhausting the groundwater reserve. Another problem is the commencement of global warming which is causing irregular climatic conditions, particularly

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delayed rainfall and scanty rainfall. There is a major dependence of water for extraction of jute fibre from plants. In such a crisis situation, any innovative technique to reduce the water resource has a great influence on the sustenance of jute, which is the highest grown natural lignocellulosic fibre crop. The major cultivation areas of jute are Eastern, and North Eastern India, and Bangladesh. However, jute and kenaf (mesta) is also grown in lesser extent in China, Thailand, Indonesia, Nepal, Mayanmar, and Brazil. In the case of traditional retting practice, all other jute growing countries are facing scarcity of water as in India. The retting is a process involving immersion of harvested jute plants in fresh water that is 20 times the volume of the immersed plants.1–3 Owing to the combined action of the water and retting microorganisms, the jute fibre and sticks get separated. Retting microorganisms attach to the jute plants through entry from water.4,5 The quality of jute fibre is degraded with regard to its color, appearance, and other physical and chemical properties due to poor quality of water, and ultimately reduces its market price.6,7 Therefore, development of a method which requires very little quantity of water for retting purpose is the prime need of the day to help jute farmers and the jute cultivation. It has not been possible to achieve uniform retting despite attempting fungal retting with dry jute ribbon.8,9 The chapter highlights on an innovative water saving and eco-friendly method for extraction of jute fibre from plants adopting dry fermentation method through use of pectinolytic fungi. This new scientific approach is a breakthrough in the retting process, and could be a boon to the farmers and jute cultivation.

4.2

Technical details

Enrichment culture method has been used for isolating fungi from various retting environments and rotten fruits and used for jute retting. Jute pectin has been used for culturing the fungi by using special agar medium. The special fungi that have been sourced include Aspergillus tamarii, Aspergillus flavus, and Aspergillus niger, and Sporotrichum thermophile. Standard procedures have been adopted for assessment of their specific enzyme activities.11–13 Potato dextrose agar slants have been used to maintain the fungal cultures mentioned above for dry retting of jute. For dry retting, defoliated whole jute plant aged between 90 and 120 days. A pH meter with combined electrode has been used to determine the pH before and after fungal retting. Selected fungi cultures have been grown under specified conditions over a period of 7–10 days. Suspension containing grown fungi has been sprayed on the defoliated green jute whole plants.14 After complete fungal growth in the

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plants, the jute fibres have been extracted from the stem by merely pulling with hand. The extracted fibres have been properly washed, dried, and then strength, fineness and fibre grade determined to adopt standard procedures. Using standard procedures, yarn produced from extracted fibres have been determined for various parameters including tenacity, elongation, twists/inch, Unevenness per cent, thick and thin places, work of rupture, tensile strength at break, and hairiness.

4.3

Enzymatic activities of isolated fungi

During jute retting, depectinization occurs, wherein pectinolytic microorganisms play a significant role in the separation of fibres and separate the fibres from the jute stick through consumption of pectin and other gummy substances.4 The four isolated fungi secrete enzymes – exopectinase, pectine lyase, xylanase, and cellulose in various proportions. During the retting process, the enzymes pectinase, and xylanase play a significant role. During the retting process, cellulose enzyme could prove harmful, particularly after the retting process. Generally, pectinase, xylanase, and cellulose are associated enzymes found in retting microorganisms and they act on specific substrates sequentially. First, pectinase enzymes act on pectin. This is followed by xylanase that easily consumes decomposable cellulose, short-chain xylan, and softens the jute fibre.14 After the easily decomposable carbohydrates are consumed, cellulose enzyme becomes active. At this stage, fibre cellulose is attacked by cellulose enzyme which happens during over retting. Hence, microorganism with less cellulose enzyme activity will be more effective for retting purpose. During biopolishing of cellulosic or lignocellulosic fabrics because of removal of protruding fibres (preferable), the role of cellulose enzyme becomes significant.17 It has been found that S. thermophile exhibits maximum amount of exo-pectinase enzyme in culture broth followed by the fungus A. flavus. Highest amount of pectin lyase enzyme is produced by S. thermophile followed by the fungus A. niger. It has been found that all the four fungi producing xylanase enzyme are well matched with each other. No significant difference has been seen in the cellulase enzyme production activity of all the four fungi. Moreover, in the case of S. thermophile the overall enzyme production ability in broth culture, exceeds the other three fungi. As the water retting occurs in submerged condition under anaerobic state, the fungal retting system differs from the conventional retting. On the other hand, fungal retting is carried out in dry and aerobic condition. In most of the jute growing areas, jute retting is normally conducted between the months of July and August, where the average day temperature remains at around 35°C.

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Earlier studies have shown that optimum for jute retting is 34°C18 All three fungi of Aspergillus species have optimum growth temperature at around 32°C. S. thermophile has a different optimum growth temperature of 45°C, but can grow at wider temperature range of 30–50°C. S. thermophile is more effective when the retting is carried out at higher temperature.

4.4

Studies on pH and redox potential

The pH variation and redox potential arising from fungal growth in culture broth and in jute retting beds have been determined. It is clear that all the fungi produce alkaline reaction in culture broth and in dry retting beds. The alkaline reaction is found more intense when these fungi grow in jute plants, which shows that the mechanism of dry retting differs considerably from water retting and requires study. Pectin is known to be a polygalacturonic acid with varying degree of branched methyl esters.19 Hence, galacturonic acid is produced during decomposition of polygalacturonic acid which renders the retting environment acidic under normal water retting system.14 The dissolved oxygen is quickly consumed by the aerobic microflora, during water retting, and renders the water environment anaerobic. Anaerobic bacteria plays key role in anaerobic environment, and the environment gets polluted because of release of reduced obnoxious smelling gases such as ammonia, methane, hydrogen sulphide, butyric acid and so forth.20,21 Considering this aspect, fungal dry retting of jute is far more eco-friendly compared to conventional water retting. The redox potential during dry retting also remains in the oxidized range. Preliminary study has made it clear that all the four above-mentioned fungi perform better retting compared to conventional water retting.

4.5

Comparison of the retting methods

The superiority of fungal dry retting is shown by dry retting carried out on bench scale followed by in farmer’s field. Fungal retting is completed in 3–4 days earlier in comparison to water retting and the fibres are brighter in appearance. In the case of dry jute retting, bench scale trials have been carried out with plants of 90, 110 and 120 days. The fibre evaluation properties including fibre strength, fibre fineness, residual root content in the fibre and the fibre grade, have been determined. In the case of 90 days jute plant, barky root content is found in the jute fibres ranging within 5%. On the other hand with A. flavus, the range falls within 8% for jute fibres of 110 days. In the case of 120 days plant, similar trend is exhibited by all fungi. The fibre

Novel Approach for Jute Retting

27

strength is found uniformly good in 90 and 110 days plant except A. niger of 110 days plant. Perhaps because of its higher cellulase enzyme activity, the strength of A. niger retted jute fibre is seen to be relatively lower. When jute plants retted by individual fungi considered, it seems that the fibre strength is reduced with age of the plant which is not likely. Hence, some other factor may require to be studied. With the increase in the age of the plant, the fibre becomes coarser, with only exception of S. thermophile in case of plant age of 110 days. During tender age, plants are softer and succulent, and as the plant age increases, they become harder with lesser moisture content and also more lignified. Hence, microbial activity becomes slower, leading to coarser fibres.14 Jute retting is supposed to happen as a combined action of physical changes by water and microbial enzyme activity. Fungal enzymes play the key role in fibre separation with little water available, in the case of fungal dry retting. Hence, when the plants dry during fungal dry retting, it is necessary to moisten the plants by spraying water, as living organisms including fungi cannot survive without it. A number of factors determine the fibre grade and in such case the fibre grade remains between TD-4 and TD-5 but mostly closer to TD-4. It can be concluded that A. flavus is the best. The average moisture levels are maintained between 33 and 35%, in such retting trials, during the time of application of fungal inoculum on the jute plant beds and the corresponding average moisture regain is recorded between 50 and 54%. The fungus are able to grow profusely on jute plants for retting, as the Relative humidity (RH) is 78%.

4.6

Evaluation of fungal dry retting

It is carried out in farmers field with the above-mentioned fungi to evaluate the efficacy of the new retting system. Results from specific studies have shown that the fungal growth propagated on jute plants and the jute fibres can just be extracted by the farmers from the fungal dry retted jute plants sitting on land. Both conventional water retting and fungal dry retting have been compared with regard to efficacy. Results obtained from the tests show that on an average most of the fungal dry retting carried out at farmers field exhibit better fibre quality in lesser duration of retting, and the average fibre strength is higher and the fibre is fine14 The root content is less in the fibre for most cases with higher fibre grade except in a particular field with A. flavus. As the retting technology is new to farmers, they require proper training for producing fibre of superior quality. Assessment has been done on the biosafety measure and possibility of any adverse effect of the fungi on preceding rice crop.

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References 1.

Banik S, Basak M K, Paul D, Nayak P, Sardar D, Sil S C, Sanpuii B C and Ghosh A (2003), Ind Crops Prod, 17, 183–190.

2.

Banik S, Basak M K and Sil S C (2007), J Natural Fibres, 4(2), 33.

3.

Das B, Chakraborty K, Ghosh S, Majumdar B, Tripathy S and Chakraborty A (2012), Ind. Crops Prod, 36, 415.

4.

Ray A K, Mandal A K (1967), Jute Bull, July 131.

5.

Bhattacharyya S K (1974), Jute Bull, 194.

6.

Alam A (1998), Retting and extraction of jute – problems and prospects. In Proceedings – International Seminar on Jute and Allied Fibres – Changing Global Scenario, Kolkatta, NIRJAFT, 5.

7.

Basak M K (2006), ‘Microbiological technology for extraction of jute and allied fibres’, in Ray RC, Microbial Biotechnology in Agriculture, Vol. II, Jersey, Plymouth, Science publishers, Enfield, 387.

8.

Haque M S, Akther F, Asaduzzaman M and Eshaque A K M (1992), Bangladesh J Jute Fibre Res, 17, 79.

9.

Ahmed Z, Aktar F and Alamgir M (1999), Bangladesh Sci Res, 17, 107.

10.

Gilman J C (1957), A manual of soil fungi, 2nd revised edition Iowa state college press, 450.

11.

Kobayashi T, Higaki N, Suzumatsu A, Sawada K, Hagihara H, Kawai S and Ito S (2001), Enzyme Microb Technol, 29, 70.

12.

Pitt O (1998), Methods Enzymol, 161, 350.

13.

Bailey M J, Biely P and Poutanen K (1992), J Biotechnol, 23, 257.

14.

Shyamal B, ‘Fungal dry retting – An ecofriendly and water saving technology for retting of jute’, Indian J Fibres Text Res.

15.

Sadasivam S and Manickam A (2008), Cx (1–4) Glucanase Assay (Colorimetric method), 3rd edition New Delhi, New Age international publishers, 116.

16.

Gomes I, Saha R K, Mohiuddin G and Hogg M M (1992), World J Microbiol Biotechnol, 8 589.

17.

Hassan K S, Shah A B, Yang V W, Gharia M M and Jeffries W (1996), J Ferment Eng, 81(1), 18.

18.

Kundu A K (1964), Factors influencing retting of jute, Jute Bull, 27, 225–230.

19.

Das B, Chakraborty A, Ghosh S and Chakraborty K (2011), Turkey J Biol, 35, 671.

20.

Saigal B N, Ghosh A, Datta A K and Chakraborty P K (1975), Indian J Environ Health, 17(1), 318.

21.

Nandan S B (1997), Retting of coconut huska unique case of water pollution on the south west coast of India, Int J Environ Stud, 52(1–4), 335–355.

Chapter 5 New Treatment for Characterization of Thermal, Surface, and Tensile Properties of Jute

Abstract Investigations have been carried out to determine the influence of various treatments such as enzymes, carbon dioxide pulsed infrared laser, ozone and plasma on the tensile, surface and thermal properties of jute fibres. The findings reveal no significant difference in the tensile strength of treated and untreated fibres. There is a change in chemical composition as revealed by Fourier-transform infrared spectroscopy analysis. There is an increase in surface roughness after the treatments, as seen through scanning electron microscope. The thermal stability of fibres shows no significant changes as indicated by differential scanning calorimetry and thermogravimetric analysis studies. Thus, the new methods of treatment chosen hold promise for modification of lignocellulosic plant fibres without significantly altering their tensile strength and thermal stability.

5.1

Introduction

During the recent years environmental issues like global warming, energy consumption, and the trend for making products out of renewable sources in order to partially or completely replace petroleum-based synthetic fibres that are neither biodegradable nor renewable, have prompted an increase in the consumption of the natural fibres.1 Fibres of plant origin (jute, flax, sisal, etc.) offer many advantages like economy, renewable, easy availability, low fossil-fuel energy requirements, considerably good mechanical properties, and lower cost than synthetic fibres.2 Also, these fibres possess certain properties like stiffness, impact resistance, flexibility, and modulus.3–5 Because of such inherent properties, these fibres are useful in various areas of applications like building materials and structural parts for automotives that need light

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weight. However, the lack of compatibility of natural fibres with most of the matrices is a major concern for their application as reinforcement for composites. Weakness in fibre/matrix adhesion results from the poor moisture resistance of natural fibres arising from incompatibility and poor wettability with hydrophobic polymers.6 In order to modify the natural fibres and to optimize the fibre/matrix interface, they can be subjected to physical and chemical treatments.7 In order to deal with the incompatible surface properties of natural fibre and polymer matrix, various types of surface modifications are available and these include alkali, enzyme, plasma, ultrasound, ultraviolet15, and neodymium-doped yttrium aluminium garnet laser.8–14,16 However, the use of some techniques especially CO2 pulsed infrared laser and ozone in such modification processes of plant fibres are less common. In the world production of cellulosic fibres, jute ranks second and is used as reinforcement in natural fibre composites.17,18 Jute comprises a reasonably high proportion of stiff natural cellulose. This chapter highlights the influence of some innovative fibre modification methods like infrared laser and ozone on the tensile, surface, and thermal properties of jute fibres and compares the results obtained from enzyme- and plasma-modified fibres. It is intriguing to note that no research has so far been done relating to the area discussed herein.

5.2

Technical details

Jute woven fabric having following particulars have been produced: Count – 1.5 Ne Material – Tossa jute Weave – 5 end satin GSM – 600 The fabric woven has been washed with 2% of the fabric weight, using non-ionic detergent solution under specified conditions. This has been done to remove any dirt and impurities and dried for a specified time duration, before giving further treatments.19 The fabric has then been subjected to the following treatments a)

Enzyme treatment

b)

Ozone treatment

New Treatment for Characterization of Thermal, Surface, and Tensile

c)

31

Laser treatment

d) Plasma treatment For enzyme treatment, the following chemicals have been used a)

Texazym DLG new

b)

Texazym BFE

c)

Texawet DAF antifoaming agent in distilled water

The above chemicals have been used in suitable proportions under specified conditions and fabric treated with these for prescribed temperature and time duration. The fabric has then been rinsed with fresh water many times and dried at room temperature for 2 days. Ozone treatment has been done in a closed container containing ozone gas under appropriate conditions. Laser treatment has been done by irradiating a laser on the surface of jute fabric under specified conditions. The laser beams interact with fibres causing local evaporation of material, thermal decomposition, or changing the surface roughness.20 The plasma treatment has been carried out on jute fabric using dielectric barrier discharge plasma with suitable conditions. The following techniques have been used for characterization of the jute material a)

Tensile testing

b)

Surface morphology

c)

Attenuated Total Reflection–Fourier Transform Infrared (ATR- FTIR) (spectroscopy) study

d) Thermal analysis

5.3

Tensile tests

As depicted in Figure 5.1, the tensile test has been used to determine the degree to which the tensile strength of the treated jute fabric is affected.19 It has been noticed that there is a small decrease in the breaking strength of enzymetreated jute fibres. This may be due to the partial removal of cementing

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Figure 5.1 Influence of treatments on tensile strength of jute fabrics (Source: adapted from ref [19]) materials binding the individual fibre cells, resulting in a little reduction of tensile strength. It has been found that there is no significant difference in the breaking strength of other fibres as compared with untreated jute fibre.

5.4

Scanning electron microscope (SEM) studies

As depicted in Figure 5.2, the morphological changes arising from the various treatments have been analysed. The surface morphology shows significant changes after the treatments. It has been found that the untreated jute exhibits multicellular nature with a rather smooth surface.19 On the other hand, enzymetreated fibres show a rough and fragmented surface morphology. This may be due to the partial removal of cementing materials from the fibre surface after this treatment. The thermal degradation of surface fibres after laser treatment result in a rough and porous fabric has been determined. It has been found that the jute fibre treated with ozone shows increase in the roughness and cracks on the surface. Plasma treatment causes a minor increase in fibre surface roughness. On the whole, SEM photos strongly point out that the surface morphology of jute fibres undergoes change.

New Treatment for Characterization of Thermal, Surface, and Tensile

Figure 5.2

5.5

33

Morphology of jute fibers (a) untreated (b) enzyme treated (c) laser treated (d) ozone treated and (e) plasma treated [19]

Fourier-transform infrared spectroscopy (FTIR) studies

The FTIR spectra of untreated and treated jute fibres have been analysed. The stretching of the hydrogen-bonded O–H pertaining to cellulose and lignin structure of the fibre indicates a broad and intense spectrum at 3342 cm−1.21 The bands lying between 2750 and 3000 cm−1 correspond to the CH stretching in saturated hydrocarbons.22 The characteristic bands for the C–H stretching vibration of CH and CH2 in cellulose and hemicelluloses components are found to be at peaks of 2922 and 2856 cm−1.23,24 Owing to the stretching vibration of C=O bonds in carboxylic acid, ester components of cellulose and hemicelluloses as well as non-conjugated carbonyls in lignin, the peak arises at 1736 cm−1.23–25 This peak is slightly reduced for enzyme-treated fibres which shows the partial removal of hemicelluloses and lignin components upon treatment. But, by means of ozone and plasma treatments, there is increase in peak height at 1736 cm−1. The aromatic ring vibrations in lignin are related to the peaks at 1599 cm−1 and 1508 cm−1.26,27

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The oxidation of lignin could probably cause increase in the peak intensity at 1736 cm−1, the decrease of peak after plasma treatment, and disappearance of peak after ozone treatment at 1508 cm−1.28 The absorption at ~ 1650 cm−1 is probably associated with absorbed water in crystalline cellulose and the lower intensity of this peak for laser-treated fibre indicates a decrease in the amount of water absorbed. The bending of CH3, CH2, and CH wagging in lignin can probably result in absorption bands at 1456, 1423, 1369, and 1315 cm−1. At about 1238 cm−1 the band arising from the C–O–C asymmetric vibration for cellulose and hemicelluloses can be seen as indicated by some research workers, and is found to be more pronounced in plasma-treated fibres, possibly because of cellulose oxidation. It has been indicated that the C–O–C symmetric glycosidic stretching or ring stretching mode at around 1100 cm−1 arise from the polysaccharide components (large cellulose). The stretching vibration of C–O and O–H belongs to the polysaccharide in cellulose.29 The reduction in shoulder height at 1105 cm−1 and peak height at 1055 cm−1 for infrared laser gives a strong evidence that this treatment can alter the fibre surface structure. Moreover, in the case of ozone and plasma-treated fibres, the increased peak intensity at ~ 3200–3600 cm−1 shows that hydroxyl groups react with the carboxyl group.30,31 Also, the decrease in peak at the same wave number range can be due to the reduction of hydroxyl and carboxyl groups on the surface of laser-treated jute fibre caused by thermal degradation.19 Hence, it is proved that the surface chemistry of jute fibres has been changed by the given treatments.

5.6

Differential scanning calorimetry (DSC) studies

The thermal behaviour of treated and untreated jute fibres have been compared by using DSC. The DSC curves presenting endothermic processes of jute fibres are expressed in terms of heat flow per unit mass of fibres (Fig. 5.3). The results of DSC analysis have been determined. There are large endothermic peaks below 100°C in the DSC curves of all samples and relate to the heat of vaporization of water absorbed in the fibres.32 It can be associated with the loss of water molecules from the surface or interstitial spaces within the fibres.33 At temperature between 160 and 300°C the second small and broad endothermic peaks can be seen.34 At about 200°C the hemicelluloses in lignocellulosic fibres get degraded, whereas at higher temperatures other polysaccharides like cellulose gets degraded. In the case of untreated fibre the degradation temperature of hemicelluloses is seen to decrease from 254°C, and even lower temperatures for all treated specimens. This is particularly

New Treatment for Characterization of Thermal, Surface, and Tensile

Figure 5.3

35

DSC thermograph of treated and untreated jute fibers [19]

so with fibres treated with laser (241.5°C and plasma – 236°C). This may be explained due to decrease in both phenolic and secondary alcoholic groups or oxidation of hemicelluloses by the formation of intermonomeric bonds in them.35 On observation of the third endothermic peaks for cellulose degradation at about 365°C for treated fibres (359–365°C) there is no substantial difference compared to that of untreated jute fibre (366°C) (Fig. 5.3). In the case of enzyme-treated fibres the cellulose decomposition peak is slightly inverted to exothermic and significantly decreased. There has been same kind of reduction/ inversion because of alkali treatment.36,37 It can arise from the partial removal of non-cellulosic constituents like hemicellulose and lignin, resulting in the destruction of chemical linkages between the constituents that could have some effect in decreasing the cellulose degradation peak.38

5.7

Thermogravimetric analysis (TGA)

The thermal stability/decomposition of fibres can be studied by TGA. The thermal degradation behaviour of the material is evaluated by measuring the rate of weight loss of the sample as a function of the temperature. Figure 5.4a,b depicts the thermogravimetry and differential thermogravimetry curves (DTG) of treated and untreated jute fibres. Like DSC curves the peaks below 100°C in the DTG curves are attributed to the loss of moisture absorbed by the fibres, and strong sharp peaks at around 365°C are due to the degradation of cellulose.19 In the case of all treated samples, there is no significant difference

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Figure 5.4 TGA curves (a) TG and (b)DTG [19] noted in the degradation temperature of cellulose. These results are consistent with the above DSC analysis. The weight loss (%) of untreated fibre is found to be higher compared with that of treated jute fibres in the temperature between 30and 450°C.

References 1.

Sinha E, Rout S K and Barhai P K (2008), Appl Phys A, 92, 283–290.

2.

Mishra S, Mohanty A K, Drzal L T, Misra M, Parija S, Nayak S K and Tripathy S S (2003), Compos Sci Technol, 63, 1377–1385.

3.

Sydenstricker T H D, Mochnaz S and Amico S C (2003), Polym Test, 22, 375.

4.

Nair K C M, Diwan S M and Thomas S (1996), J Appl Polym Sci, 60, 1483–1497.

5.

Eichhorn S J, Baillie C A, Zafeiropoulos N, Mwaikambo L Y, Ansell M P, Dufresne A, Entwistle K M, Herrera-Franco P J, Escamilla G C, Groom L, Hughes M, Hill C, Rials T G and Wild P M (2001), J Mater Sci, 36, 2107–2131.

New Treatment for Characterization of Thermal, Surface, and Tensile

37

6.

Rana A K, Mandal A, Mitra B C, Jacobson R, Rowell R and Banerjee A N (1998), J Appl Polym Sci, 69, 329–338.

7.

Bledzki A K and Gassan J (1999), Prog Polym Sci, 24, 221–274.

8.

Bledzki A K, Fink H P and Specht K (2004), J Appl Polym Sci, 93, 2150–2156.

9.

Aziz S H and Ansell M P (2004), Compos Sci Technol, 64, 1219–1230.

10.

Ray D and Sarkar B K (2001), J Appl Polym Sci, 80, 1013–1020.

11.

George M, Mussone P G and Bressler D C (2014), Ind Crop Prod, 53, 365–373.

12.

Sinha E (2009), J Ind Text, 38, 317–339.

13.

Bozaci E, Sever K, Sarikanat M, Seki Y, Demir A, Ozdogan E and Tavman I (2013), Compos Part B: Eng, 45, 565–572.

14.

Laine J E and Goring D A I (1977), Cellul Chem Technol, 9, 561.

15.

Gassan J and Gutowski V S (2000), Compos Sci Technol, 60, 2857.

16.

Botaro V R, Dos Santos C G, Arantes Jr. G and Da Costa A R (2001), Appl Surf Sci, 183, 120.

17.

Corrales F, Vilaseca F, Llop M, Girones J, Mendez J A and Mutje P (2007), J Hazard Mater, 144, 730.

18.

Cai Y, David S K and Pailthorpe M T (2000), Dye Pigm, 45, 161.

19.

Jabbar A, Militk J, Wiener J, Javaid M U and Rwawiire S (2016), ‘Tensile, surface and thermal characterization of jute fibres after novel treatments’, Indian J Fibre Text Res, 41, 249–254

20.

Stepankova M, Wiener J and Dembický J (2010), Fibre Text East Eur, 18, 70.

21.

Brigida A I S, Calado V M A, Gonsalves L R B and Coelho M A Z (2010), Carbohyd Polym, 79, 832.

22.

Spinace M A S, Lambert C S, Fermoselli K K G and De Paoli M A (2009), Carbohyd Polym, 77, 47.

23.

Fiore V, Valenza A and Di Bella G (2011), Compos Sci Technol, 71, 1138.

24.

De Rosa I M, Kenny J M, Maniruzzaman M, Moniruzzaman M, Monti M, Puglia D and Sarasini F (2011), Compos Sci Technol, 71, 246.

25.

Morshed M M, Alam M M and Daniels S M (2010), Plastic Sci Technol, 12, 325.

26.

Hague M M, Hasan M, Islam M S and Ali M E (2009), Biores Technol, 100, 4903.

27.

Tserki V, Zafeiropoulos N E, Simon F and Panayiotou C (2005), Compos Part A: Appl Sci Manuf, 36, 1110.

28.

Gadhe J B, Gupta R B and Elder T (2006), Cellulose 13, 9.

29.

De Rosa I M, Kenny J M, Puglia D, Santulli C and Sarasini F, Compos Sci Technol, 70, 116.

30.

Lu N and Oza S (2013), Compos Part B: Eng, 45, 1651.

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31.

Mwaikambo L Y and Ansell M P (2002), J Appl Polym Sci, 84, 2222.

32.

Silva G G, De Souza D A, Machado J C and Hourston D J (2000), J Appl Polym Sci, 76, 1197.

33.

Belaadi A, Bezazi A, Bourchak M, Scarpa F and Zhu C (2014), Compos Part B: Eng, 67, 481.

34.

Ray D, Sarkar B K, Rana A K and Bose N R (2001), Bull Mater Sci, 24, 129.

35.

Felby C, Nielsen B R, Olesen P O and Skibsted L H (1997), Appl Microbiol Biotechnol, 48, 459.

36.

Mitra B C, Basak R K and Sarkar M (1998), J Appl Polym Sci, 67, 1093.

37.

Sikdar B, Basak R K and Mitra B C (1995), J Appl Polym Sci, 55, 1673.

38.

Ray D, Sarkar B K, Basak R K and Rana A K (2002), J Appl Polym Sci, 85, 2594.

Chapter 6 Jute Dyeing Using Natural Dyes

Abstract When bleached jute fabrics are dyed with aqueous extracts of deodara leaf, jackfruit leaf, and eucalyptus leaf, light brown to light mustard shades are obtained having good wash fastness. Deeper shades with darkening and dulling are obtained using ferrous sulphate mordant in the dyeing of bleached jute fabric with extracts of deodara leaf, jackfruit leaf, and eucalyptus leaf. This has been evident from the significant changes in Colour strength (K/S) values, Colour levelness (L) values and brightness index values. Among the three concentrations of ferrous sulphate mordant, 1% (owf) concentration showed better results with regard to shade and brightness.

6.1

Introduction

There is a steady increase in the use of natural dyes in textile applications.1–4 This follows as a consequence of the problems related to synthetic dyes which are largely being used in textiles. Synthetic dyes pose the problems of toxicity and health hazards. As a result, many countries/organizations around the globe have evolved stringent environmental standards restricting their use. Natural dyes can be extracted from plants, insects, and minerals without any chemical processing and possess many merits, which include renewable resources, no health hazards, no disposal problem, and harmonized with nature.5 However, there are problems related to their use which include number of colours, inadequate degree of fixation, inadequate fastness properties, reproducibility of shades, and so on. Through judicious application of these dyes on substrate, such setbacks can be minimized. In the case of jute, the application of natural dyes is limited. Natural dyes and jute fibre are both eco-friendly. This chapter highlights on the effort taken to dye jute fabric with three natural dyes extracted from deodara leaf, jackfruit leaf, and eucalyptus

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leaf with and without using mordant. These leaves are easily available, costeffective, and the dye extracted from them can be easily dyed on jute fabric.

6.2

Technical details

Jute fabric with plain weave in the grey state has been used. Three types of dyes have been obtained from plant sources, namely, deodara, jackfruit, and eucalyptus, respectively. Hydrated salt of ferrous sulphate has been used as mordant. The chemicals such as hydrogen peroxide, sodium hydroxide, sodium sulphate, trisodium phosphate, Ultravon JU, and acetic acid of analytical grade have been used. The dyestuffs have been obtained in powder form, after suitably processing the leaves of the plants. The grey jute fabric has been bleached with hydrogen peroxide, sodium hydroxide trisodium phosphate, non-ionic detergent, and sodium silicate (ML ratio 1:20, temperature 85°C, time 60 min, and pH 10). Acetic acid has been used as neutralizing agent. The bleached jute fabrics have been dyed under the following conditions: dye used – 8% owf; temperature − 95°C; ML ratio – 1:20; time – 60 min; pH – 5.7 Sodium sulphate has been used as the levelling agent. The bleached jute fabrics has been mordanted under the following conditions: temperature − 90°C; ML ratio – 1:20; time – 30 min; ferrous sulphate of varying concentrations between 1 and 3% has been used. The mordanted jute fabrics have been dyed with the natural dyes mentioned. The whiteness, yellowness, and brightness indices have been determined in the scale grey dyed and bleached jute fabrics using computer colour matching system. The colour strength and wash fastness of the fabrics have been determined and evaluated based on the IS:3361–1979.6

6.3

Discussion of findings

The whiteness, yellowness, and brightness indices of grey and bleached jute fabrics at 10° angle of observation. In order to obtain lighter shades with natural dyes, whiteness, yellowness, and brightness indices of grey jute fabric after bleaching with hydrogen peroxide are found to be satisfactory. The bleached jute fabrics have been individually dyed with deodrara leaf extract, jackfruit leaf extract, and eucalyptus leaf extract without and with ferrous sulphate mordant of various concentrations, respectively. Figure 6.1 shows the diagrammatic flow chart of the total experiment.

Jute Dyeing Using Natural Dyes

Figure 6.1

41

Different processes represented schematically

It has been shown that the bleached jute fabric dyed with deodara leaf extract exhibits lower dye uptake (in terms of K/S value) as compared to pre-mordanted bleached jute fabric dyed with the same natural dye. Thus the dyed shade appears as a light mustard brown shade. The uptake of dye also increases proportionally with the increase in the mordant concentration. At higher mordant concentration the dye uptake has been found to be higher, which can be due to the darkening and dulling of shades caused by the effect of mordant. The jute fabric bleached and dyed with deodara leaf extract exhibits dull dark brown shade after applying 3% (owf) ferrous sulphate as mordant. With the increase in mordant concentration, the dyed fabric became duller in appearance, and so also the brightness index value, whereas the wash fastness was almost same for all the cases. When the bleached jute fabric was dyed with jackfruit leaf extract without applying mordant, the lower dye uptake was achieved and the light brown shade was observed on the fabric. As the mordant concentration increased, the shade of jackfruit leaf extract-dyed jute fabric became darker and duller. After application of 3% (owf) ferrous sulphate mordant before dyeing, a deep brown shade has been developed on the jute fabric. The wash fastness has been satisfactory in all the mordant concentrations. The jute fabric dyed with eucalyptus leaf extract had dyeing characteristics similar to that in the earlier cases. A dark black shade has been achieved on the fabric by the application of 3% (owf) ferrous sulphate mordant. The deeper shade depth was caused by lower L values. About 60% lower L values were obtained as compared to that for fabric dyed without

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mordant. Similarly, the brightness index value was also decreased by about 77% in case of 3% mordant concentration. There has been good wash fastness rating and no change in λmax value.

References 1.

Pan N C, Chattopadyay S N and Day A (2001), Man-Made Text India, 44, 17.

2.

Pan N C, Chattopadyay S N and Day A (2003), J Text Assoc, 63, 243.

3.

Bhattacharya N, Doshi B A and Sahasrabudhe A S (1998), Am Dyest Rep, 87, 26.

4.

Moses J J (1999), Text Dyer Printer, 32, 10.

5.

Gulrajani M L (2001), ‘Present status of natural dyes’, Indian J Fibre Text Res, 26, 191.

6.

IS: 3361-1979 (1982), ISI Handbook of textile testing, New Delhi, Bureau of Indian Standards.

7.

Pan N C, Chattopadhyay S N and Day A (2003), ‘Dyeing of jute with natural dyes’, Indian J Fibre Text Res, 28, 339.

Chapter 7 Influence of Thermal Treatment on Wrap-spun Jute Yarns

Abstract Polyester, nylon, and polypropylene (PP) flat multifilament wrapped when subjected to thermal treatment showed a downward trend in tenacity. In the case of PP-textured multifilament and PP monofilament-wrapped yarns, no definite trend has been seen on the one hand, and on the other hand, the breaking extension of all the wrap-spun yarns increased. The specific work of rupture improved up to 15 min of treatment for nylon wrapped yarn, indicating a maximum value at 10-min treatment time. However, other wrapspun yarns showed a reduction in the work of rupture upon dry heating. The work of rupture of polyester, nylon, and PP flat multifilament-wrapped jute yarns increased at one side and at the other side the work of rupture of PPtextured and PP monofilament-wrapped yarns decreased, with boiling water treatment. Besides polyester-wrapped yarns all the other wrap-spun yarns showed a decrease in the initial and secant modulus, upon dry heating. No clear relationship could be established between the change in the tensile properties of wrapping element and those of wrap-spun yarns after dry heating. By thermal treatment in an aqueous medium, there is a decrease in the twist liveliness of wrap-spun yarns. By increase in treatment time in the dry heat, there has been reduction in residual shrinkage of all wrap-spun jute yarns.

7.1

Introduction

The hollow spindle method is used to produce wrap-spun yarn by wrapping a continuous filament yarn around a staple fibres bundle. The high delivery speed of the machine and the rotational speed of the wrapping element creates a high centrifugal force on the wrapping element. Simultaneously, the wrapping element is subjected to the stresses because of the frictional

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resistance from different machine parts such as thread guides, and so on and bending to a wide angle to the yarn axis during wrapping. Also, the rewinding of wrapping element before spinning leads to the development of considerable amount of internal stresses in the filaments, which result in high curling tendency of wrap-spun yarns and has a deleterious effect on further processing, thus affecting the dimensional stability to the yarn. The setting is a treatment given to the fibre usually after any mechanical stress to improve the dimensional stability. The feasibility of this treatment relates to the stress relaxations that can be achieved by thermal treatments or swelling agents so as to decrease curling tendency and also the tendency to shrink by reheating. Hence, the heat setting of wrap-spun yarn may possibly affect some of its mechanical properties. Studies have indicated that after heat setting, the work of rupture of wrap-spun jute yarn increases significantly.1 The study also involved thermal treatment for 5 min and the wrapping materials used include polyester and nylon multifilament yarns and high-density polyethylene (HDPE) monofilament yarns. Subsequent studies reported on the properties of jute and jute viscose blended wrap-spun yarns using HDPE monofilament and Polypropylene (PP) multifilament yarns as wrapper elements.2 The properties of wrap-spun yarns were evaluated after giving a thermal treatment for 5 min However, the changes in the properties have not been compared with those of parent wrap-spun jute yarns. The influence of thermal treatment on the wrapspun jute yarns has not been reported in the literature. The chapter focuses on the changes in the tensile behaviour of wrap-spun jute yarn subjected to treatments for 5–30 min. The residual shrinkage and curling tendency of the yarn have also been studied. The wrapping materials used are polyester, nylon, and PP-textured filament yarns. Earlier investigations on the tensile responses of wrap-spun jute yarns with various types of continuous filament yarns of varying linear densities as wrapping element has shown that with polyester and nylon wrap-spun yarns the specific work of rupture increased with the increase in the wrap density while increasing the wrap density from 250 to 450 wpm at a step of 50.3 In case of PP, a similar trend of work of rupture was also observed. Among all the PP-wrapped yarns, the specific work of rupture was found to be highest in case of 10 tex flat and textured multifilament-wrapped yarn of 350 wpm. It was also observed that the initial modulus of wrap-spun yarn with any type of wrapping element decreases with the increase in the wrap density. The 9-tex polyester-wrapped yarn showed the lowest value of initial modulus while in case of 8.3 tex nylon-wrapped yarn the modulus decreased with wrap density up to 350 wpm. In order to improve the weaving performance on high-speed weaving machines and also to render jute fabrics more acceptable for different areas of applications, the higher specific work of rupture and low-initial modulus are considered to be

Influence of Thermal Treatment on Wrap-spun Jute Yarns

45

the most desired characteristics of jute yarn.4 The wrap-spun jute yarns with 9 tex polyester, 8.3 tex nylon, and 10 tex PP multifilament yarns as wrapping elements and wrap density of 350 wpm have been chosen to investigate the influence of thermal treatment of the wrap-spun yarns.

7.2

Technical details

Hessian jute fibre for wrap category has been used as the core component of the yarn, and the wrapping elements comprise of multifilament polyester, nylon 6 multifilament, PP multifilament and monofilament.5 The wrap-spun jute yarns have been spun on a wrap spinning machine. The wrap-spun yarn in hank form has been subjected to thermal treatment in an induced draft heating machine with dry hot air at constant length condition. The material and process details are as given below:6–9 Temperature: PP – 135°C; nylon – 185°C; polyester – 185°C Treatment durations: 5, 10, 15, and 30 min The yarn hanks were then allowed to cool at room temperature at constant length condition.5 The wrap-spun yarns were also treated in boiling water for 30 min at constant length condition. The tensile properties of the yarns have been measured using instron tester at 65% relative humidity and 27°C. The gauge length was 500 mm and speed was 500 m/min. The secant modulus has been determined. The wrap-spun yarns were measured for residual shrinkage by treatment with boiling water for 30 min in relaxed condition. Ring loop method has been used to measure the twist liveliness of the yarns.

7.3

Influence of dry heating on tensile properties

The tenacity of polyester-wrapped yarn reduced with the increase in treatment time in dry heat and after 15 min, it regained to some extent (Fig. 7.1).5 Simultaneously, the extensibility has been found to be remarkably high at 15 min and the combined effect of tenacity, breaking extension, and modulus also exhibited a downward trend. The initial modulus decreased with the increase in treatment time up to 15 min and followed by an increase. The yield stress fi rst increased at 5 min, then decreased up to 15 min, and again increased though the lowest value did not come down than that of the parent yarn. The yield strain increased remarkably at 15 min and then decreased rapidly at 30 min. The value of secant modulus was found to be lowest at 15-min treatment (Fig. 7.2). With nylon, the tenacity of wrap-spun yarn was unchanged up to 10-min treatment, while the breaking extension

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Figure 7.1

Influence of treatment duration in dry heat on tenacity, breaking extension, and specific work of rupture of wrap-spun jute yarn with polyester multifilament yarn as wrapping element (Source: adapted from ref [5]).

Figure 7.2

Influence of treatment duration in dry heat on initial modulus, secant modulus, yield stress, and yield strain of wrap-spun jute yarn with polyester multifilament yarn as wrapping element (Source: adapted from ref [5]).

Influence of Thermal Treatment on Wrap-spun Jute Yarns

Figure 7.3

47

Influence of treatment duration in dry heat on tenacity, breaking extension, and specific work of rupture of wrap-spun jute yarn with nylon multifilament yarn as wrapping element (Source: adapted from ref [5]).

increased considerably at 5 min and then reduced with increase in treatment time though it did not come below the breaking extension of the parent yarn (Fig. 7.3). The initial modulus increased up to 10-min treatment, reduced at 15 min and then levelled off (Fig. 7.4). There has been a significant increase (about 30%) in work of rupture up to 10 min of exposure due to the considerable increase in initial modulus and breaking extension. However, there has been reduction in the work of rupture. Both the yield stress and yield strain followed the similar trend showing their highest value at 10-min treatment. The secant modulus first decreased at 5-min treatment. Treatment duration of 5 min exhibited reduction in the secant modulus followed by an upward trend with a marginal rate of change. The findings relating to the change in tenacity and work of rupture of the wrap-spun yarns do not agree with earlier findings, which could be attributed to the difference in the inherent characteristics of the filament wrapper yarns. As depicted in Figure 7.4, during treatment duration of 5 min, an abrupt decrease in tenacity has been seen with PP flat multifilament-wrapped yarn. The tenacity then regained up to 30-min treatment duration. On the other hand, a considerable improvement in breaking extension has been attained, exhibiting the highest value at treatment duration of 10 min.

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Figure 7.4

Advances in Jute Research

Influence of treatment duration in dry heat on initial modulus, secant modulus, yield stress, and yield strain of wrap-spun jute yarn with nylon multifilament yarn as wrapping element (Source: adapted from ref [5]).

The drastic reduction in tenacity and initial modulus ultimately resulted in a considerable loss in work of rupture. Both, the yield initial modulus and the secant modulus were decreased drastically at 5-min treatment and then increased marginally up to 15-min treatment following a similar trend. Also, with yield stress, similar trend has been seen. But, till a treatment duration of up to 10 min, the yield strain value exhibits an upward trend followed by reduction at a lower rate of chance up to 30-min treatment. Depicts that even though similar trend has been seen with PP-textured multifilament-wrapped yarn, but tenacity and breaking extension have been erratic with the treatment in dry heat. The maximum value has been noticed at 10-min treatment, in these cases. After treatment duration of 5 min, the initial modulus drastically reduced and then it was almost levelled off (Fig. 7.5). After treatment duration of 5 min, the abrupt decrease in initial modulus ultimately lead to a drastic decrease in work of rupture. There has been no defined trend in secant modulus values. Both yield stress and yield strain increased with the time of treatment, showing the highest value at 10-min treatment. Figure 7.6 shows that the tenacity of PP monofilament-wrapped yarn first decreased at 5-min treatment and then it increased up to 30-min treatment though the rate of change was marginal. A continuous upward trend has been noticed in the breaking extension with drastic change at treatment duration of 5 min. But, at treatment duration of 5 min, the work of rupture at a very high rate of change then almost levelled

Influence of Thermal Treatment on Wrap-spun Jute Yarns

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Figure 7.5

Influence of treatment duration in dry heat on initial modulus, secant modulus, yield stress, and yield strain of wrap-spun jute yarn with polypropylene (PP)-textured multifilament yarn as wrapping element (Source: adapted from ref [5]).

Figure 7.6

Influence of treatment duration in dry heat on tenacity, breaking extension, and specific work of rupture of wrap-spun jute yarn with PP monofilament yarn as wrapping element (Source: adapted from ref [5]).

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off. A downward trend has been seen in both initial modulus and secant modulus though after treatment duration of 5 min, the rate of change has been marginal. As can be seen from, after treatment duration of 5 min, the yield stress reduced and then increased with the time of treatment marginally, while upward trend has been seen in the yield strain. The reason for the initial increase in the tenacity of polyester and PP-textured wrapped yarns is that due to the shrinkage of filaments on thermal treatment, the radial compressive force exerted by the continuous filaments increases, which makes the fibrous core more compact and results in higher wrapped yarn strength initially. However, a decrease in yarn strength arises after further exposure to heat, where the maximum compactness of the core fibre is achieved, and increase in shrinkage only increases the helix angle of the filament. The maximum compactness has already been attained before thermal treatment, with nylon, PP flat, and PP monofilament. So, the thermal treatment has only increased the obliquity effect of the wrapper element. The increase in helix angle of the filaments caused an increase in the waviness of the resultant yarn. When these yarns are subjected to tensile loading, first the waviness of the yarns gets straightened without any relative displacement between fibre to filament or fibre to fibre, giving lower moduli and higher extension value of the wrapspun yarn. When compared with the PP flat multifilament-wrapped yarn, the PP-textured multifilament-wrapped yarn exhibits different trends in tensile properties. It could arise from varied surface properties of the filaments. It may also be noted that on dry heating, polyester, PP flat, and PP-textured multifilament yarns did not show any appreciable change in tenacity. The nylon multifilament yarn showed an upward trend in tenacity up to 15 min of treatment and then decreased. In case of PP monofilament yarn, a downward trend in tenacity was observed up to 15-min treatment and then the tenacity levelled off. The breaking extension of polyester yarn showed a downward trend up to 15-min treatment then increased to some extent. Till exposure duration of 15 min, the breaking extension of nylon and PP flat multifilament yarns increased, followed by a decrease. On the other hand, PP monofilament yarn exhibits a downward trend up to exposure duration of 30 min. There has been no significant change in breaking extension of PP-textured multifilament yarn. Moreover, the relation between the tensile behaviour of filament yarns used as wrapping elements and wrap-spun jute yarns could not be clearly established.

7.4

Influence of boiling water treatment on tensile properties

Except with PP monofilament-wrapped yarn, the drop in tenacity has been seen in the case of wrap-spun yarn upon thermal treatment with boiling

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water treatment also.5 But, despite the marginal increase with PP-textured multifilament-wrapped yarn, the extensibility of all the wrap-spun yarn increased. The work of rupture of polyester, nylon, and PP flat multifilamentwrapped yarns increased though in case of nylon the increase was marginal. In case of PP-textured multifilament and PP monofilament-wrapped yarns, the work of rupture deteriorated to some extent. The influence of obliquity as discussed previously can account for the decrease in tenacity and increase in breaking extension of wrap-spun yarns.

7.5

Influence of dry heating on residual shrinkage

The lowest residual shrinkage has been noticed in the wrap-spun yarn having polyester as wrapping element treated for 10 min, and on the other hand, it was achieved with nylon as wrapping element in wrap-spun yarn treated for 5 min.5 In case of PP flat and PP-textured filament-wrapped yarns, the residual shrinkage decreased with the increase in treatment time, while in case of PP monofilament-wrapped yarn, the lowest residual shrinkage was obtained at 10 min of treatment. Comparing the lowest value of all the yarns it is revealed that the polyester gave the most stable yarn followed by nylon and PP filaments. The stereoisomeric structure of PP could possibly contribute to the higher value of residual shrinkage of PP filament-wrapped yarn.

7.6

Influence of thermal treatments on twist liveliness of wrap-spun yarns

Treatment of the wrap-spun yarns in dry heat significantly increased the twist liveliness of polyester and nylon-wrapped yarns.5 First, there is a reduction in twist liveliness with PP flat and textured wrapped yarns followed by increase, whereas with PP monofilament the twist liveliness of wrap-spun yarn remained almost unchanged before and after dry heating. Also, there has been remarkable decrease of twist liveliness for wrap-spun yarn under tension, with boiling water treatment. However, the twist liveliness of wrap-spun yarn without any tension did not show encouraging results. In case of polyester, nylon and PP flat multifilament-wrapped yarns, the twist liveliness value reduced to around 29, 28, and 34%, respectively, while in case of PP-textured and PP monofilamentwrapped yarns, no such change was observed. In order to describe the varied behaviour of twist liveliness of the wrap-spun yarns subjected to thermal treatment under length conditions, an elaborate and systematic study is necessary.

References 1.

Sengupta A K, Cattopadhyay R S, Sengupta S and Khatua D P (1991), Indian J Fibre Text Res, 16, 128.

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Choudri A, Mukherjee S, Sharma I C, Khatua D P and Aditya R N (1994), J Inst Eng (India), Text Eng Div, 75, 12.

3.

Roy A N and Basu G (2001), Indian J Fibre Text Res, 26, 246.

4.

Basu G, Roy A N, Majumder A, Ghosh S K, Mukopadhyay M K, Aditay R N and Mukerjee S (1997), J Inst Eng (India), Text Eng Div, 8, 7.

5.

Basu G and Roy A N (2002), ‘Effect of thermal treatment on wrap spun jute yarns’, Indian J Fibres Text Res, 27, 369–375.

6.

Pajgrt O, Reichstadter B and Sevcik F (1983), Textile science and technology, Vol. 6, New York, Elsevier Scientific Publishing Co., 55.

7.

Sbrolli W (1968), In Mark H F, Atlas S N, and Cernia E, Man-Made Fibre Science and Technology, Vol. 2, New York, Interscience Publishers, 288.

8.

Datye K V and Vaidya A A (1984), Chemical processing of synthetic fibres and blends, New York, John Wiley & Sons, 136.

9.

Ludewig H (1971), Polyester fibres – chemistry and technology, London, Wiley-Interscience, 285.

Chapter 8 Assessment of Traditional System Jute Classification for Composite Applications

Abstract The traditional jute classification system has been evaluated to determine its suitability in composite applications. The upper and lower sections of different tossa jute samples have been analysed considering five potentially relevant factors for composites – thermostability, alkali-soluble fraction, degree of fibre damage (degree of polymerization and tensile strength), degree of lignifications (acid-soluble and acid-insoluble lignin), and degree of whiteness. The traditional jute classification is not suitable for composite applications. In the case of composites, the variations between upper and the lower sections are significantly greater than the variations among the different classes of Tossa jute (TD). The largest relative differences exist for thermostability but there is no significant difference among samples analysed. Finally, it is concluded that a new fibre classification system is required for the success application of jute fibres in composites.

8.1

Introduction

There is a global industrial need to clearly identify fibres to manufacture composites for construction, automotive materials, insulation, and varnishes in combination with thermo- and duro-plastics.1–7 At present, this requirement is mainly covered by synthetic or inorganic fibres. Natural fibres are not generally used in industrial applications despite their advantages relating to price, weight, or eco-friendliness. It is necessary to have a quality management system for the entire jute fibre production chain for their effective application in composites in the international market. Consistency in fibre quality is a critical criterion for the industrial application of jute fibres in composites. As a result, there is a need to define the particular quality parameters that characterize the

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suitability of jute fibres. The potentially relevant fibre parameters in the case of composite applications parameters include thermostability, fibre fineness, extent of fibre damage, odour characteristics, degree of lignifications, alkalisoluble fraction (a potential parameter for the retting degree), whiteness (a potential parameter for the degree of contamination), and moistness.8–15 While the Indian market benefits from the special quality assessment procedure for raw uncut jute fibre strands, the European market of flax and hemp fibres has no generally accepted and established quality classification system.16 This standard defines the quality grades of white jute (Corchorus capsularis) and tossa/daisee jute (Corchorus olitorius) based on the measured values for the most important parameters. As a result, fibre strand qualities may be graded as WI—W8 and TOI—T08, respectively, where WI and TDl represent the highest qualities (superior quality). It is almost practically impossible to measure the relevant parameters systematically, despite the basis for such objective grading being available. Hence, the quality grade is mainly based on the grader’s individual experience in judging jute strands by estimation (hand and eye). The chapter highlights on evaluating the suitability of traditional jute classification system for the special requirements of composites applications. Hence, typical samples of various TD grades of tossa jute have been used to determine the fibre parameters potentially relevant for this purpose. Also, it is assumed that the fibre quality varies within individual fibre strands more than that within various TD grades. The upper portions of fibre are finer, whereas the root portions comprise hard and harsh fibres which are more contaminated and heterogeneous.

8.2

Technical details

Jute varieties of tossa and daisee comprising high, medium, and low qualities have been selected. The jute strands have been cut into three portions – upper portion 40 cm, middle portion, and lower portion 40 cm.17 From each grade, the lower and upper sections were separately taken for the analysis and the middle section was discarded. It is expected that a wide variation within a single TD grade might exist.18 Assessments have been done based on the factors such as thermostability, alkali-soluble fraction, degree of fibre damage (degree of polymerization and tensile strength), degree of lignification (acidsoluble and acid-insoluble lignin) and degree of whiteness. Thermostability of the jute fibres has been determined by mass loss per unit area using gravimetric method under the following conditions: Sample weight of 2 g; drying at 105°C for 4 h; under atmospheric air at 210°C for 2 h

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The alkali-soluble fraction has been determined under the following conditions, adopting the same methodology as that for ramie and kenaf fibres14,19 Jute fibres are leached for 4 h with dichloroethane cut into pieces of 1 cm and homogenized. The dried fibres of 1 g were then boiled and stirred for 30 min at 120°C with 1% sodium hydroxide in a nitrogen atmosphere. pH was neutralized by washing with boiling water, 1% acetic acid, and then by cold water. Gravimetric analysis of the dried fibre has been done. The residual alkali fraction was only 2%, starting with 20–30% the use of only 1% sodium hydroxide helped to reduce loss of fibre strength. The degree of fibre damage was determined by measuring degree of polymerization and tensile strength.20 The degree of lignifications was determined by measuring the lignin contents of acid-soluble and acid-insoluble lignin. The degree of whiteness has been determined using CIE colour system. The data of the calculation is based on CIE y and CIE Y since these gave the most significant variations. y stands for standard colour proportional value and Y stands for the coordinate referring the whiteness. For all the parameters, mean values and 95% confidence intervals were calculated. Analyses of variance (ANOVAs) with Tukey’s post hoc test were used to observe the difference between the pairs of single and grouped samples. For the multivariate data analysis, canonical discriminant analysis was applied.21 The first two canonical discriminant functions have been plotted two dimensionally.

8.3

Thermostability

The mean values of mass loss measured at 210°C lie between 2.7 (TD4_down) and 4.6% (TD2_up) (Fig. 8.1). The confidence intervals ranged between ±0.7 and ±1.0% (absolute) in all the samples, and are in the same range as the differences between the samples.17 The average values of lower sections (3.6 and 2.7% for TD2 and TD4, respectively) are less than those of the corresponding upper sections (4.6 and 4.0% for TD2 and TD4, respectively). It has been suggested that at >170°C, the thermal degradation of flax and jute fibres can be detected clearly using the parameters tensile strength, degree of polymerization, and degree of crystallinity. Jute mass loss at 200°C after 1 h is about 5.2% but it increases rapidly at higher temperatures. When jute is processed under elevated pressure, there is dramatic reduction in tensile strength of laminates even at >> jackfruit wood:red sandalwood. Thus, this proposed method of relative compatibility rating system may be useful to identify compatible binary pairs of natural dyes for dyeing jute with binary mixture of natural dyes in various proportions, providing the dyer an option for selecting correct and compatible mixture of natural dyes to match a target compound shade. The investigation provides an easy and simple colorimetric method of relative numerical rating of compatibility to identify and select proper compatible natural dyes to get different compound shades with improved wash and light fastness for jute products.

30.1

Introduction

Chemically jute has the following composition: Cellulose – 54–60% Hemicellulose – 20–24%, and Lignin – 12–14% In addition to the primary and secondary –OH groups of cellulose present in cotton and jute, there are some –CHO and –COOH groups in jute, as well as some –C=C unsaturations and phenolic –OH groups in the lignin component. Thus the receptivity, affinity, and absorption characteristics of any dye including of any dye including natural dyes will be different for jute and cotton due to their varying chemical composition and chemical functionality pattern. Hence, it is felt essential to study the compatibility of mixture of selective natural dyes and their colour fastness properties for both jute and cotton separately. The study of dyeing of jute with the binary mixture of jackfruit wood and various natural dyes has been carried out.

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With worldwide growing consciousness of environmental and chemical hazards of some of the synthetic dyes, the use of eco-friendly natural dyes particularly for natural fibre products such as jute and cotton textiles are being preferred. However, all the natural dyes may not be essentially eco-friendly. Dyeing with natural dyes has not achieved wide acceptability in the organized sector due to their limited availability, limited shades, and lack of standard procedures of dyeing, difficulty in reproducibility and matching as well as lack of scientific knowledge on compatibility and chemistry of such dyes. There are only a few and discrete studies available in the literature describing the application of mixture of natural dyes on cotton textiles, reporting the colour interaction, resultant colour strength, and metameric effects.1,2 Some studies on the compatibility of binary and ternary mixtures of synthetic dyes are widely available in the literature, whereas such studies with mixture of natural dyes on jute or cotton or on any other textiles are scanty and sporadic.3–8 Compatibility of a pair of dyes can be judged by different methods, such as a)

Subjective visual assessment of the degree of o-tone build-up by a series of dyeing

b)

Theoretical prediction of compatibility by comparison of rates of dyeing (time of half dyeing) and dyeing kinetics (diffusion coefficients) for each individual dye to derive V numbers of Z values, which are usually specific to the textile substrate and dyeing conditions

c)

Quantitative assessment of change in hue angle (ΔH)

d) Comparing and plotting ΔC versus ΔL or K/S versus ΔL values for two sets of progressive shades (20–100% with 10–20 point differences) obtained by dyeing with varying dye concentration and also with varying profile of dyeing time and temperature, and e)

Quantitative compatibility rating for the mixtures of more than two dyes by calorimetric analysis of actual colour strength developed (not on the basis of dye absorbed).

The method of plotting ΔC versus ΔL or K/S versus ΔL values has been used in the discussion considered. A newer empirical index called colour difference index has also been proposed for the assessment of relative compatibility rating to judge the degree of compatibility of different pairs of natural dyes applied on jute. Some studies on improving colour fastness behaviour after the application of natural dyes are available in the literature.9 Most of the natural dyes show

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inadequate wash or light fastness behaviour.10 Three types of cationic fixing agents and an ultraviolet (UV) absorber have been applied to dyed jute to improve the fastness to washing and light, respectively.

30.2

Technical details

Hessian jute fabric of decorative type and having plain weave has been bleached with hydrogen peroxide. The following chemicals have been used. Laboratory reagent grade aluminium sulphate has been used as the chemical mordant. The natural mordant myrobolan has been used in powder form. The natural dyes chosen for the investigation are as follows: a)

Jackfruit wood

b)

Red sandalwood

c)

Sappan wood or redwood

d) Manjistha or madder e)

Marigold

f)

Babool10–16

Commercial grade sodium chloride, acetic acid, sodium carbonate, sod iu m hyd rox ide a nd LR g r a de 1,2 ,3 ben z t r ia zole, cet r i m ide (tetradecyltrimethylammonium bromide) and CTAB (n-cetyl N-trimethyl ammonium bromide) and textile auxiliaries grade Sandofix-HCF liquid have been used. The following procedures have been followed. a)

Extraction and purification of colorant from natural dyes

b)

Mordanting

c)

Dyeing

d) Application of cationic dye fixing agents and UV absorber e)

Measurement of colour strength and related colour interaction parameters

f)

Compatibility tests for selected binary pairs of natural dyes

g) Colour fastness17–20

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273

Findings of the investigation

The study deals with the following three major objectives for the colouration of jute fabrics with selected binary pairs of natural dyes: a)

Colour strength and related parameters

b)

Colour fastness of dyed jute fabrics, and compatibility of selected binary pairs of dyes

It has been reported earlier that the premordanting using 20% myrobolan followed by 20% aluminium sulphate is the most suitable system for dyeing bleached jute fabric with red sandalwood dye.21 Hence, the same system of premordanting of jute fabric has been used for the study.

30.3.1 Colour strength and related parameters The observed and calculated surface colour strength for premordanted jute fabrics dyed with binary pairs of dyes. It is found that the differences in the observed and calculated K/S values are minimum for jackfruit wood:babool.21 The order of increase in the differences between the observed and calculated K/S values for the various pairs of dyes applied are: Jackfruit wood:babool < jackfruit wood:manjistha < jackfruit wood:marigold ≤ jackfruit wood:red sandalwood < jackfruit wood:sappan wood. The metameric effect, considering the differences in the K/S values measured at ƛmax for dye A and ƛmax for dye B for each pair of natural dyes is also found to be minimum for the mixture of jackfruit wood and babool. The order of increasing differences between the two sets of observed K/S values at two different ƛmax values for each pair of natural dyes is as given below: Jackfruit wood:babool ≤ jackfruit wood:manjistha < jackfruit wood:marigold < jackfruit wood:red sandalwood < jackfruit wood:sappan wood The K/S values at a common wavelength (420 nm) for premordanted jute fabrics dyed with selected binary pairs of dyes in different proportions (75:25, 50:50, and 25:75) have been determined. Data are also given for total colour differences (ΔE), changes in hue (ΔH), changes in chroma (ΔC), metamerism index (MI) and brightness index (BI). The data for total colour difference show the minimum ΔE values for the combination Jackfruit wood: Babool, irrespective of the proportions of the mixture of each selected pair of dyes. Comparison of the negative values for change in chroma (ΔC) shows that the changes in chroma values for the combination jackfruit wood:sappan

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wood are always lower or minimum, while a maximum change in the same is observed for jackfruit wood:babool for all the dye proportions studied. The values for change in hue angle (ΔH) are found to be positive for the combinations jackfruit wood:manjistha, jackfruit wood:red sandalwood, and jackfruit wood:sappan wood but negative for jackfruit wood:marigold and jackfruit wood:babool. Irrespective of negative or positive signs, the increasing orders of magnitude for ΔC and ΔH values for each binary pairs of dyes in equal proportion (50:50) are: ΔC – jackfruit wood:sappan wood< jackfruit wood:marigold < jackfruit wood:manjistha < jackfruit wood:red sandalwood < jackfruit wood:babool. ΔH – jackfruit wood: marigold < jackfruit wood:sappan wood < jackfruit wood:babool < jackfruit wood:red sandalwood < jackfruit wood:manjistha. The minimum MI values are observed for the combination jackfruit wood:marigold for all the three proportions of dyes mixture. Irrespective of the proportions of pair of dyes, the order of increasing MI is as follows: Jackfruit wood: marigold < jackfruit wood:sappan wood < jackfruit wood:babool < jackfruit wood:red sandalwood < jackfruit wood:manjistha. BI is another important colour parameter for dyed fabrics, being considerably dependent on surface lustre and specular reflectance. BI values for these binary pairs of dyes (50:50) are found to increase in the following order Jackfruit wood:marigold < jackfruit wood:manjistha < jackfruit wood:babool < jackfruit wood:red sandalwood < jackfruit wood:sappan wood. The use of other two proportions of selected pair of dyes also shows similar results.

30.3.2 Colour fastness The colour fastness data for selected binary pairs of dyes applied in different proportions (75:25, 50:50, 25:75) to premordanted jute fabrics after treated with one of the three cationic fixing agents or a UV absorber. The binary pair jackfruit wood:babool shows satisfactory fastness to washing fastness without after treatment and the ratings of LOD 4 and ST 4–5 remain unchanged after treating them with any of the three cationic fixing agents used.21 Binary pair jackfruit wood:marigold also gives a similar result showing satisfactory fastness to washing if proportions of jackfruit wood are above 50. For 25:75 jackfruit wood:marigold, the fastness to washing for both LOD and ST is one unit lower and may be improved to a measurable extent by the use of any one of the cationic fixing agents. Dyeing of the binary

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pair jackfruit wood:manjistha, is to some extent, unsatisfactory before any after treatment but gives satisfactory wash fastness after the treatment with any one of cationic fixing agents. With the binary pairs jackfruit wood:red sandalwood and jackfruit wood:sappan wood, however, the fastness to washing is generally unsatisfactory with or without after treatment except in the case of jackfruit wood:sappan wood after treated with sandofix-HCF, irrespective of the proportion of binary pairs of dyes. The data for fastness to light indicate that the after treatment with 1% benzitrizole generally increases the fastness rating by one point for all the binary pairs of dyes, irrespective of their proportion. The presence of UV absorber in the dyed jute fibre enhances the light fastness by preferred absorption of the UV radiation. This reduces the attack on the natural dyes and the lignin component of the jute fibres that results in more rapid fading and decolouration respectively in the absence of benzotriazole. In all the cases, the fastness to dry and wet rubbing between 4 and 4–5 need no special treatment for its further improvement. Good rub fastness in all these cases indicates that there are no unfixed dyes left on the fibre surface after soaping and washing and that these dyes have penetrated well inside the fibre voids and probably got fixed well by ionic interaction or hydrogen bonding or coordinated complex formation with the mordants or with the functional groups of jute fibre, as the case may be.

30.4 Compatibility tests Binary pairs of dyes vary considerably in their response to dyeing processes. A given pair of dyes may exhibit compatibility under one set of dyeing conditions but prove to be incompatible under another set of condition. Regular build-up of the individual dye on a particular fibre does not always guarantee similar behaviour when applied together. Two methods of test for compatibility of binary pairs of dyes have been used. In the conventional method, the closeness and degree of overlap have been compared between two sets of curves in the plots ΔC versus ΔL or K/S versus ΔL for two sets of progressive depths of shade produced using two sets of dyeing methods.3–6,17 However, it is felt highly essential to test the compatibility of different pairs of natural dyes by some form of quantitative term expressed as relative compatibility rating for the various pairs that will help the dyer by providing options for selecting dyes to match a target shade. Therefore, an easy method of determining relative compatibility rating between any pair of natural dyes has been proposed by postulating a new colour difference index as mentioned previously.21

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The closer the CDI values for dyeing with different proportions (75:25, 50:50, 25:75) of the dyes in binary pairs under the same dyeing conditions, the higher is the compatibility rating for that pair of dyes. To test the degree of fitness of this proposed method, the result of compatibility between the two methods (conventional and proposed) have been proposed. Figure 30.1 shows the plots of K/S versus ΔL (plots a–e) and ΔC versus ΔL (plots aʹ–bʹ) for two sets of dyed materials for five separate pairs (jackfruit and other dye proportions) of natural dyes. • •

First method of dyeing Second method of dyeing

In case of binary pair jackfruit wood:manjistha, plots of K/S versus ΔL show that the two curves for the two dyeing methods studied, run similarly with only slight separation, whereas plots ΔC versus ΔL show that the curves for

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Figure 30.1 Plots of K/S against ΔL (a–e) and ΔC versus ΔL (aʹ–eʹ) for dyeing of five binary pairs of natural dyes on pre-mordanted jute fabrics of natural dyes on premordanted jute fabrics (a) Jackfruit wood:manjistha – a and aʹ, (b) Jackfruit wood:marigold – b and bʹ, (c) Jackfruit wood:red sandalwood – c and cʹ, (d) Jackfruit wood:babool – d and dʹ, (e) Jackfruit wood:sandalwood – e and eʹ (Source: adapted from ref [21]) both dyeing methods are widely spaced and do not approach one another. In the proposed RCR system, the pairs of dyes exhibit grade 3 (average) relative compatibility rating, showing predominantly closer similarity with the behaviour in the K/S versus ΔL plots. In case of binary plots jackfruit wood:marigold the two curves for two dyeing methods do not show similar build-up behaviour in both the plots (b and bʹ). This is indicative of ‘poor’ to ‘worst’ compatibility for this binary pair of dyes. In the RCR system, this binary pair also exhibits grade 1 (worst) relative compatibility rating. Thus, the conventional and the proposed methods show very similar results. In case of binary pair jackfruit wood:red sandalwood, the plots of K/S versus ΔL show that the two curves for two dyeing methods partially and

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only a minor deviation from one another is observed, indicating a moderate degree of compatibility.21 However, plots ΔC versus ΔL shows that the curves for the two dyeing methods are widely spaced, indicating a low degree (fair to poor) of compatibility between these dyes. In the proposed RCR system, this binary pair of dyes exhibits grade 3–4 (moderate) relative compatibility rating. In case of binary pair, jackfruit wood:babool, the plots of K/S versus ΔL show that the two curves for both methods of dyeing partially overlap with only slight deviation, indicating a good degree of compatibility. In the corresponding plots of ΔC versus ΔL, however, the curves for both dyeing methods show a significant separation from one another, indicating an average to moderate degree of compatibility. In the proposed RCR method, this pair of dyes exhibits grade 3–4 (moderate) relative compatibility rating. In case of binary pair jackfruit wood:sandalwood, the two curves for both dyeing methods, the plots show a wide separation without any systematic buildup behaviour with either increasing concentrations (second dyeing method) or increasing dyeing time and temperature (first dyeing method). Thus, these two dyes are totally incompatible with one another when applied as a binary pair by any method. In the proposed RCR system, this pair exhibits the Grade 0 (non-compatible) relative compatibility rating.

References 1.

Samanta A K, Singhee D and Sethia M (2001), ‘Proceedings, conventional on natural dyes’, in Gupta D and Gulrajani M L, Delhi, Department of Textile Technology, Indian Institute of Technology, 20.

2.

Samanta A K, Singhee D and Sethia M (2003), Colourage, 50(10), 29.

3.

Datye K V and Mishra S (1984), J Soc Dyers Colour, 100, 334.

4.

Shukla S R and Dhuri S S (1993), J Soc Dyers Colour, 109, 402.

5.

Shukla S R and Dhuri S S (1992), J Soc Dyers Colour, 108, 395.

6.

Shukla S R and Dhuri S S (1992), J Soc Dyers Colour, 108, 139.

7.

Blackburn D and Gallagher V C (1980), J Soc Dyers Colour, 96, 237.

8.

McLaren K (1976), J Soc Dyers Colour, 92, 317.

9.

Cristea D (2006), Dyes Pigm, 70, 238.

10.

Gulrajani M L and Gupta D (1992), Natural dyes and their application to textiles, Delhi, Department of Textile Technology, Indian Institute of Technology, 25.

11.

Samanta A K, Aggarwal P and Datta S (2007), Indian J Fibres Text Res, 32, 446.

12.

Samanta A K, Aggarwal P and Datta S (2006), J Inst Eng India, Text Eng, 87, 16.

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13.

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