TXL 712Polymer and Fibre Physics

B L Deopura

bdeopura@gmail.com

Introduction

• Fibers are a unique class of materials: large extension & recovery, flexibility

• First man made fibers- Viscose rayon 1986• First synthetic polymer/fiber Carothers

1929 at DuPonts, long chain molecules• Nylon Socks 4 million in 1940 and….• No crease trousers 50’s and 60’s

Contd.• A range of properties of a given

fiber type like cellulose, cotton , viscose rayon, jute, lyocell

• Range of properties of say nylon6

Cotton fibers in a longitudinal view

Cotton &Lyocell fibres

S S curves of cellulosic fibres

Strain(%)

Stress(gm/f)

Stress–strain curves of lyocell (Tencel), modal and regular viscose rayoncompared with cotton

S S Curves of Wool, Silk Nylon

Typical stress–strain curves of HM–HT fibres

Course Content

1. Physical state of polymers: Conformation of polymer molecules , Glass

transition temperature, Rubber elasticity, crystallization in polymers, melting, Polymer in solutions, Fiber forming polymers

2. Structure of fibers and its determination: Models of fiber structure, X-ray diffraction,

Thermal methods: DSC, TMA, DMA,TGA , Optical microscopy

3. Physical properties of fibers Moisture regain, Mechanical properties, optical

properties, thermal properties

BOOKS RECOMMENDED

1. Physical properties of textile fibres by

W.E.Morton and JWS Hearle. 4th Edition

2. Introduction of polymers by R.J.Young

3. Polymer physics by W. Gedde

4. Physical polymer science by H. Spherling

Polymeric Materials: Uniqueness

• Ductility, Low density, Shapeable in any form at relatively low temperatures, coloured

• Fibers are an example of polymers in terms of shape and uniaxial properties, fibers in turn can be made in any shape, woven/ nonwoven etc.

• Variability of fibers-cellulosics-cotton,jute, viscous rayon, lyocell, chemical/physical state of materials

The objective• The course deals in understanding

the physical state of polymeric /fibrous materials.

• Methods of fiber structure determination

• Physical properties and their relationship with the structure

Evaluation

• Minor 1 25• Minor 2 25• Major 40• Sup. Exam/ Presentation 10

Chemical Structure of Fibre Forming Polymers:

Repeat units

Polyethylene Polypropylene

Nylon 6,6 PET

Polystyrene (Not a Fiber forming polymers ?)

PAN CELLULOSE

Polyaramids (KEVLAR) Silk R= 1- 4 Wool R= 1-18