THE EFFECT OF CEEMICAL TREATMENTS ON THE ABRASION RESISTANCE OF WOOLFABRICS A Thesis submitted in fulfilment of the requirements for the degree of DOCTOR OF PHILOSOPHY by ATHANASIOS PEPPAS It, LIBRARY Being an account of work carried out under the supervision I of Dr. ' I. Holme l I The Department of Textile Industries, The University of Leeds, Leeds, LS2 9JT. February, 1981 Tttýýý T, ý oý 4 DEDICATED TO HAZEL ACKNOWLEDGEMENTS I would like to express my sincere gratitude to the late Professor A. Robson, Ph. D., C. -Chem., A. R. I. C., C. Text., F. T. I. in initiating this research and to Dr. I. Holme, B. Sc., Ph. D., C. Text., F. T. I., C. Col., F. S'D. C., for his constant guidance, invaluable advise and sustained interest throughout the preparation of the work. I am particularly indebted to the International Wool Secretariat for financing this research and to Professor P. Grosberg M. Sc., Ph. D., M. I. Mech. E., C. Text., F. T. I., for the opportunity to work in this department. I also wish to thank : Dr. T. Shaw and Dr. M. A. Ruahforth for helpful discussions. I. W.S. Technical Centre for technical assistance at various stages of the work. Dr. D. J. Johnson and Dr. M. G. Dobb and the Textile Physics Laboratory for provision of x-ray diffraction and SEM pictures. Mrs. V. Whitehead and the staff of the Clothworkers' Library for helpful assistance and to Mrs. J. Caiger and Miss H. A. Greenwood for typing this thesis. Finally, I would like to express my deep appreciation for the help and encouragement received over a long period of time from my parents who sacrificed much to ensure my education. LIBAgy Preface The low abrasion resistance of wool fabrics compared with many man-made fibre fabrics is known to be a frequent cause of consumer dissatisfaction particularly in pure wool suiting fabrics. Accordingly this project was undertaken to attempt to improve the abrasion resistance in order to maintain the quality image associated with wool fabrics and improve their market competitiveness vis-ä-vis other fabrics. - Although several workers have discussed the effects of particular finishes on specific fabrics, very little systematic investigation of the effects of chemical treatments on the abrasion resistance of wool fabrics has been carried out. In the current study the difference in abrasion rates of woven wool fabrics composed of different structures have been studied in relation to the abrasion resistance and other relevant physical properties. The work carried out in this thesis is divided into two parts. A review of the literature is followed by a description of the experimental work carried out. The review of the literature summarises current views on the general mechanisms and factors involved in abrasion processes for textile fabrics and the effects of selective finishing treatments on the abrasion resistance of wool fabrics. In addition details of the abrasion testing conditions used in this work for determining fabric abrasion resistance have been described. The' experimental work is concerned with the changes in wool fabric abrasion resistance produced by the following treatments: (i) Application of polymer shrink-resist finishes by padding and by exhaustion treatments, (ii) Treatment with organic solvents, (iii) Treatment with ethylene glycol at-1500C, (iv) Deamination and esterification, (v) High temperature steaming (130°C), (vi) Dyeing, (vii), Wet abrasion. Because of the great commercial importance of polymer shrink- resist finishes for wool fabrics, the main objects of the experimental work were to establish the effects of a range of polymer shrink-resist finishes applied by conventional padding and exhaustion techniques on the abrasion resistance of wool fabrics and the mechanisms by which the abrasion resistance is improved. CONTENTS Page CHAPTER 1 THE ABRASION RESISTANCE OF TEXTILE FABRICS 1 1.1. Fabric Abrasion Mechanisms 6 1.2. Morphological Changes in Wool Fibres during Fabric Wear and Abrasion testing 9 1.3. Abrasion Testing 17 1.3.1. The Martindale Abrasion Tester 19 1.3.2. Factors Affecting the Abrasion Resistance of Fabrics 23 1.3.3. Assessment of Abrasion Damage (end-point) 28 1.4. Factors Determining Fabric Abrasion Resistance 29 1.4.1. Fibre Properties 29 1.4.1.1. Fibre dimensions and morphological characteristics 29 1.4.1.2. Mechanical properties of Fibres in Relation to Abrasion Resistance 30 1.4.1.2.1. Tensile Properties 32 1.4.1.2.2. Flexural properties 39 1.4.1.2.3. Shear Properties 39 1.5. Yarn Structure 40 1.5.1. Yarn Twist 42 1.5.2. Yarn Crimp 43 1.6. Fabric Structure 45 1.6.1. Threads per Centimetre 45 1.6.2. Weave Structure 46 1.6.3. Crown Height 48 1.7. Fibre Blending 49 1.8. The Effects of Selective Finishing Treatments on the Abrasion Resistance of Wool Fabrics 51 1.8.1. Binding Agents and Lubricants 51 1.8.2. Moisture Regain 52 1.8.3. The Effect of Heat 53 Page 1.8.4. The Effect of pH 57 1.8.5. The Effect of Shrink-resist Treatments 59 1.8.5.1. Subtractive processes 59 1.8.5.2. Additive processes 63 1.8.5.2.1. Monomer Processes 64 1.8.5.2.2. Prepolymer Processes 68 1.8.6. The Effects of Steam Treatments on the Abrasion Resistance of Wool Fabrics 77 1.9. The Effects of Dyeing. Processes on the Abrasion Resistance of Wool Fabrics 81 CHAPTER 2 The Effects of Polymer Shrink-resist treatments on the Abrasion resistance of woven wool'Fabrics 95 2.1. Introduction and Objectives 95 2.2. Shrinkage in Wool Fabrics 95 2.2.1. Relaxation shrinkage 96 2.2.2. Felting shrinkage-Mechanisms and Theories 97 2.3. The Control of Felting Shrinkage 99 2.4. Preliminary Studies of Polymer shrink-resist treatments 101 2.4.1. Introduction and Objectives 101 2.4.2. Experimental 102 2.4.3" Results and Discussion 116 2.4.3.1" Martindale Abrasion Resistance (MAR) 116- 2.4.3.2. Rate of fabric weight loss during abrasion testing 128 " 2.4.3.3. Fabric Bending Properties 142 2.4.3.4" Fabric Tensile Properties 151 2.4.4" Conclusions 151 2.5. Method of Polymer Application 159 2.5.1. Introduction and Objectives 159 2.5.2. Experimental 159 Page 2.5.3. Results and Discussion 162' 2.5.3.1. Martindale Abrasion Resistance (MAR) 162 f 2.5.3.2. Rate of Fabric weight loss during Abrasion testing 169 2.5.3.3. S. E. M. Studies of Polymer-treated fabrics 181 2.5.3.4. Fabric pilling-mechanism of fabric wear 185 2.5.3.5. Fabric Bending Properties 189 2.5.3.6. Fabric Tensile Properties 197 2.5.4. Conclusi ons 203` 2.6. Synergism in Abrasion resistance and Shrink-resistance 205 2.6.1. Introduction and Objectives 205 2.6.2. Experimental 206 2.6.3. Results and Discussion 208- 2.6.3.1. Abrasion Resistance 208, E 2.6.3.2. Rate of Fabric weight loss 212 ' 2.6.3.3. ' Fabric Pilling 215 2.6.3.4. Fabric Tensile Properties 217 2.6.3.5. Fabric Bending Properties 220 2.6.3.6. Shrink-Resist Effectiveness and Abrasion Resistance 223 2.6.3.7. Flex Abrasion Resistance 228 2.6.4. Conclusions 231---- 2.7. The Effects of Cubex Testing 233 2.7.1. Introduction and Objectives 233 2.7.2. Experimental 234 2.7.3. Results and Discussion 235 2.7.3.1. Shrink-resist Effectiveness 235 2.7.3.2. Martindale Abrasion Resistance (MAR) 238---- 2.7-3-3. Changes in Fabric Properties as a result of 3 hour washing test 242 2.7.3.4. The effects of blowing on the abrasion resistance and pilling of woollen flannel 250 2.7.3.5. Crease Recovery Angle 250 Page 2.7.4. Conclusions 259 2.8. The effects of Polyacrylate shrink-resist treatments 262 2.8.1. Introduction and Objectives 262 2.8.2. Experimental 263 2.8.3. Results and Discussion 266 2.8.3.1. Fabric Area Felting Shrinkage 266 2.8.3.?. Martindale Abrasion Resistance (MAR) 270 2.8.3.3. Fabric Tensile Properties 274 2.8.3.4. Flex Abrasion Resistance 277 2.8.3.5. Fabric Bending Properties 277 2.8.4. Conclusions 282 CHAPTER 3 The Effects of Organic Solvents on the Abrasion Resistance of Woven Wool Fabrics 285 3.1. Introduction and Objectives 285 Section 3.2.287 3.2.1. Experimental 287 3.2.2. Results and Discussion 290 3.2.2.1. Martindale Abrasion Resistance (MAR) 290 3.2.2.2. Fabric Tensile Properties 299 3.2.2.3. Cyclic Stress-strain Properties 304 3.2.2.4. Fabric Bending Properties 308 Section 3.3. 310 3.3.1. Introduction 310 3.3.2. Experimental 310 3.3.3. Results and Discussion 312 3.3.3.1. Martindale . abrasion resistance 312 Section 3.4. 329 3.4.1" Experimental. 329 3.4.2. Results and Discussion 333 3.4.2.1. Flex Abrasion Resistance 333 3.4.2.2. Fabric Surface Frictional Properties 336 Page 3.4.2.3. Fabric Area Felting Shrinkage (F. A. F. S. ) 341 . 3.4.2.4. Crease Recovery Angle (CRA) 345 3.4: 2.5" X-ray diffraction studies 354 3.5" Conclusions 354 CHAPTER 4 The Effects of Ethylene Glycol at 1500C on the Abrasion Resi stance of Woven Wool Fabrics 357 4.1. Introduction and Objectives 357 4.2. Experimental 358 4.3. Results and Discussion 359 4.3.1. Cyclic Stress-strain Properties 359 4.3.2.