Chemistry and Engineering of Polymer Reactions (CEPR) — DU B.Sc. Polymer Science Previous Year Question Papers

2. Draw a neat and labelled diagram wherever necessary. i. iii. vi. Why is no initiator required in plasma polymerizatioii? ii. W]]at js redor.initiation? Explain Reactor js called as heart of polymerization process. Explain iv. Define kinetic chain length. v. Give schematic representation of batch and semi-batch reactor Explain why bulk polymerization is generally more suited for step-growth polymerization than for chain-vii. viii. ix. x. growth polymerization. IIlustrate retardation on chain growth polymerization with suitable example How would you achieve cross]in king in step growl polymerization? What is reactivity ratio? Give the necessary condition of reactivity ratio to obtain an altemating polymer Distinguish radical chain growth and ionic polymerization. (10 x 3) a) Give two examples of plasma pol}Jmerisation along with tl]eir significant properties and [Ises. b) Describe the step\`Jise mechanism (Initiation, Propagation, and Termin<ation) for the formation of c) Describe how NMP is used to synthesize a block copolymer of styrene and 4-vinylpyridine. (5 × 3) a) Discuss kinetics for cationic polymerisation and derive an equation for the degree of polymerisation b) Solvent plays a crucial role in ionic chain polymerisation. Justify it. c) Discuss photochemical initiators with suitable reaction examples and suggest the class of compounds a) What are batch reactors? Discuss their merits and applications. b) For the polymerization of pure (undiluted) styrene with benzoyl peroxide at 60°C, the number-average degree of polymerization, Xn, is given by the general expression: For a rate of polymerization of 10- mol/l-s and monomer concentration of 8.35 mol/l calculate: i. The value of the transfer constant to the monomer ii. Number-average degree of polymerization, Xn iii. Xi assuming there is no transfer (normal termination) (5,10) a) Derive an expression for a polymerization for rate and percent conversion carried in a batch reactor. Q.G a) Derive an expression for rate for chain growth polymerization b) Discuss the methods to control molecular weight in step growth polymerization. c) Illustrate the role of reactor in polymerization. (5x3) Q.7 Write a note on the following (Any three) a) Suspension polymerization b) Alfrey Price scheme c) CSTR d) Ceiling Temperature (5x3)