INFLUENCE OF ADDITIVES IN SPINNING DOPE AND SPIN BATH TEMPERATURES ON STRUCTURE AND PROPERTIES OF ACRYLONITRILE TERPOLYMER FIBERS

Transcription

1 INFLUENCE OF ADDITIVES IN SPINNING DOPE AND SPIN BATH TEMPERATURES ON STRUCTURE AND PROPERTIES OF ACRYLONITRILE TERPOLYMER FIBERS by M. SURYA KUMARI DEPARTMENT OF TEXTILE TECHNOLOGY Submitted in fulfilment of the requirements of degree of DOCTOR OF PHILOSOPHY INDIAN INSTITUTE OF TECHNOLOGY, DELHI November, 1987

2 CERTIFICATE This is to certify that the thesis entitled "INFLUENCE OF ADDITIVES IN SPINNING DOPE AND SPIN BATH TEMPERATURES ON STRUCTURE AND PROPERTIES OF ACRYLONITRILE TERPOLYMER FIBERS", being submitted by Ms. M. Surya Kumari, to the Indian Institute of Technology,Delhi, for the award of the degree of Doctor of Philosophy in the Department of Textile Technology, is a record of bonafide research work carried out by her. Ms. Surya has worked under my guidance and supervision and has fulfilled the requirements for the submission of the thesis. The results obtained in this thesis have not been submitted, in part or in full, to any other University or Institute for the award of any degree or diploma. Prof. (Miss) P. Bajaj,. Thesis Supervisor

3 ACKNOWLEDGEMENTS I wish to extend my sincerest thanks to my research adviser Prof. (Miss) P. Bajaj, for her personal attention and painstaking efforts to complete this thesis. She helped me in removing the inner ignorance and bestowed the light of real knowledge by being the sole guide and well wisher. I am thankful to Prof. M.L. Gulrajani, Head of Textile Technology Department, for extending the necessary facilities. I am grateful to Dr. A.A. Vaidya and Dr. N.D. Sharma of Sir Padampat Research Centre (SPRC), J.K. Synthetics, Kota, for providing me with wet-spinning facility and for their helpful attitude. My special thanks are due to Dr. D.C. Gupta and Mr. B.V. Rao for their kind concern and constant encouragement. Appreciation is extended to Council for Scientific and Industrial Research (CSIR), for the financial support. I also wish to acknowledge the debt owed to my colleagues and friends; specially Vankatraj, Anand, Ramarao, Patti, Dhara, Padmanaban, Ramesh, Manjeet, Rajeev, Sarita, Sunil Kumar, Ranjana, Sangeeta, Rekha, Ratna, Preeti and Reshmi, who generously extended their help and cooperation whenever it was needed. I would like to thank Mr. Rajesh K. Arora for the patience and care with which he typed my thesis, and Mr. N.L. Arora, and Mr. K.G. Padam for the expert tracings.

4 11 I am indebted to Sunil for his patience and constant encouragement and my family members for their kind concern and love. To them, I dedicate this thesis. S "/"1 4 L ma.a,:. (v) (M. Sdya Kumari)

5 ABSTRACT Fiber forming acrylonitrile terpolymers having acrylonitrile, vinyl acetate or methyl acrylate, and sodium methallyl sulfonate as a third comonomer, were hydrolysed employing sulfuric acid and sodium hydroxide as hydrolysing agents. The extent of hydrolysis was restricted to DMAc solubility so that the hydrolysed products could be used as an additive in the spinning dope in order to study their effect on moisture sorption and dyeability of the fibers. FT-IR, NMR and X-ray techniques have been used to establish the mode of hydrolysis of the acrylonitrile terpolymers, and the effect of comonomer on the extent of hydrolysis. Hydrolysed products of AN-VA-sodium methallyl sulfonate with a degree of hydrolysis "i0.104, and and the polar materials such as secondary cellulose acetate, polyvinyl acetate, polyvinyl pyrrolidone and glycerol were used as spinning dope additives in the wet-spinning of the AN-VA-Sodium methallyl sulfonate spinning dopes. Spinning has been carried out on a laboratory scale unit, using dimethyl acetamide:water mixture (45:50 v/v) in the coagulation bath with temperatures ranging from 10 to 60 C. Density, X-ray orientation, X-ray crystallinity, sonic modulus, moisture sorption, water retention and tensile properties of these fibers were measured. The physico-mechanical properties of these fibers are related to the gel-fiber structure and the fracture morphology of the fibers.

6 ii Thermal properties of the blend fibers have been studied through DSC, TGA and TMA techniques. Thermal stabilization of the fibers has been carried out to establish the structural changes occurring during the oligomerization of blend fibers. FT-IR spectroscopy was employed to detect the structural changes. The dyeability of the fibers has been studied using three basic dyes, i.e., Basacryl Golden Yellow XGFL, Panacryl Brilliant Red 2B and Methylene Blue 2B. The rate of dyeing was determined and the diffusion coefficients have been related to the molecular size of the dye molecules as well as to the structure of the blend fibers. The light-and color-fastness data of the dyed fibers have also been presented.

7 CONTENTS Page No. ABSTRACT CHAPTER 1 INTRODUCTION AND LITERATURE SURVEY 1 GENERAL INTRODUCTION ON ACRYLIC FIBERS 1.1 Modification Through Copolymerization Acrylic Fibers with Improved Hydrophilicity and Dyeability Basic Dyeable Acrylic Fibers Acid Dyeable Acrylic Fibers Antistatic Acrylic Fibers Acrylic Fibers with Improved Flameretardancy and Heat-stability Intrinsically Colored Fibers 1.2 Modification of Fiber Forming Acrylonitrile Copolymers 1.3 Variation of Spinning Parameters 1.4 Use of modifiers in Spinning Dope For Improving Hydrophilicity and Dyeability Antistatic Acrylic Fibers Flame-retardant Acrylic Fibers 1.5 Use of Modifiers in Spinning Bath 1.6 Surface Modification of Acrylic Fibers Enhancing Hydrophilic and Antistatic Properties Fibers with Improved Dyeability Imparting Flame-retardancy Ion-exchange Acrylic Fibers 1.7 Objective of the Present Work

8 Page No. CHAPTER 2 HYDROLYSIS OF ACRYLONITRILE TERPOLYMERS AND THEIR STRUCTURAL INVESTIGATIONS 2.1 INTRODUCTION Hydrolysis of Acrylonitrile Based Polymers Structural Investigations of Acrylic Polymers by IR, NMR and X-ray Techniques EXPERIMENTAL Materials Hydrolysis Procedure Elemental Analysis Infrared Spectra NMR X-ray Diffraction RESULTS AND DISCUSSION Infrared Spectral Studies NMR of Hydrolysed Acrylonitrile Terpolymers X-ray Diffraction Studies 65 CHAPTER 3 WET SPINNING OF BLENDS OF ACRYLONITRILE TERPOLYMER AND ITS HYDROLYSED PRODUCTS 3.1 INTRODUCTION EXPERIMENTAL Preparation of Spinning Dope Determination of Dope Viscosity Wet-spinning Freeze Drying of Samples Microscopy of Gel Fibers Structural Properties Mechanical Properties 76

9 Moisture Regain Wicking Height Water Retention Values Fracture Morphology Page No RESULTS AND DISCUSSION Dope Viscosity Spinnability of the Blends Effect of Coagulation Bath Temperature and Blending with Hydrolysed Terpolymers on Gel Fiber Structure Effect of Spin Bath Temperature on Properties of the Final Parent and Blend Fibers Fracture Morphology 89 CHAPTER 4 INFLUENCE OF SPINNING DOPE ADDITIVES ON THE STRUCTURE AND PROPERTIES OF ACRYLIC FIBERS 4.1 INTRODUCTION EXPERIMENTAL Materials Preparation of the Spinning Dopes Wet-spinning and Fiber Properties RESULTS AND DISCUSSION Dope Viscosity Spinnability of the Dope Effect of Spinning Dope Additives on Gel Fiber Structure Effect of Spinning Dope Additives on Final Fiber Properties Fracture Morphology 109

10 Page No. CHAPTER 5 THERMAL STUDIES ON ACRYLONITRILE TERPOLYMER BLEND FIBERS 5.1 INTRODUCTION EXPERIMENTAL Sample Preparation Thermal Analysis Isothermal Studies Thermo-mechanical Analysis RESULTS AND DISCUSSION Thermo-oxidative Degradation Differential Scanning Calorimetry FT-IR of the Isothermally Heat Treated 124 Fibers Shrinkage 126 CHAPTER 6 DYEING BEHAVIOR OF THE ACRYLONITRILE TERPOLYMER BLEND FIBERS 6.1 INTRODUCTION EXPERIMENTAL Materials Dyeing Dye-uptake Calculation Diffusion Coefficient Fastness Properties RESULTS AND DISCUSSION Dye-uptake as a Function of Dyebath 135 Temperature

11 Page No Dye Diffusion Effect of Dope Additives on Equilibrium 137 Dye-uptake Values Energy of Activation Light-f astness of Dyed Fibers Wash-fastness 143 CHAPTER 7 SUMMARY AND CONCLUSIONS SUMMARY AND CONCLUSIONS SCOPE FOR FURTHER RESEARCH 150 REFERENCES 151 LIST OF PUBLICATIONS