Fibre Science — DU B.Sc. Polymer Science Previous Year Question Papers

Attempt four questions in all: Draw a neat and labelled diagram, wherever necessary. 1. (a) List major difference between natural and synthetic fibres. (b) Homopolymer PAN is a precursor of carbon fibres but not ideal one. (e) Why should tensile strength of fibre increase with increase in molecular weight? - (d) What attributes of fibre are affected by crystalline and amorphous regions ? (e) Mercerized cotton is lustrous. Explain. 5x3 2: (0)- Discuss the preparation of a dope. (b) Polymer concentration plays crucial role in the spinning of aramid fibres. Explain in detail. (c) Discuss properties of cellulose acetate fibres. 5,5,5 3. Write notes on the following : 5,5,5 (a) "silk fibres (b) Carbon fibres Glass fibres. 4. (a) How do properties of nylon 6 'fibres differ from nylon 66 fibres ? Also comment on physical and chemical properties of nylon fibres. (b) Discuss chemistry of wool fibres. (e) Discuss primary and secondary variables of imelt spinning. 5,5,5 5. (a) Discuss necessity of modification of fibre with a suitable example. (b): Illustrate Dry-Jet wet spinning technique with a neat schematic. (c) Comment on structural changes taking place during fibre spinning.