1. Answer ALL parts. (a) Answer BOTH parts (i) and (ii) of this question. (i) For the homopolymer of propene (CH2=CHMe) with the aid of suitable diagrams, explain the following terms: isotactic polymer; syndiotactic polymer; atactic polymer. (6 marks) (ii) Explain why syndiotactic placement is favoured in an anionic polymerization of styrene conducted at low temperatures in polar solvents. (6 marks) (b) Answer ALL parts (i) (iii) of this question. (i) Using the Carothers equation, calculate the number-average molecular weight of Nylon 4,6 prepared by the polymerization of an equimolar mixture of adipic acid (HO2C(CH2)4CO2H) and tetramethylene diamine (H2N(CH2)4NH2) for functional group conversions of 0.500 and 0.995. Comment on when in the polymerization reaction the concentrations of adipic acid and tetramethylene diamine approach zero. (5 marks) (ii) In the formation of Nylon 4,6 in the preceding question, 1b(i), describe the effect on polymer molecular weight if 5 mol% of acetic acid was added to the starting mixture and the reaction was run to complete conversion of functional groups. (4 marks) Question 1 continued (iii) Calculate the expected degree of polymerization (xn) for a step growth polymerization with an equilibrium constant of 81 in a closed reaction vessel. Explain changes to the conditions which may allow a high molecular weight polymer (Xn > 100) to be obtained from this reaction. (3 marks) (c) The polymerization of a THF solution of styrene (0.5 M) was initiated by: (i) sodium naphthalide (0.01 moles) under rigorous exclusion of air and moisture and (ii) sulfuric acid (0.01 moles) at -78 C. Explain why the polystyrene isolated from (i) has twice the number average molecular weight of the polymer isolated from reaction (ii) and draw the structures of the isolated polymers from (i) and (ii) including the expected end groups. (6 marks)