Abstract: The molecular weight distribution of polyalpha-methylstyrene prepared by anionic polymerization, with n-butyllithium as initiator was investigated. The influences of ether additives, ratios of ether to initiator and polymerization temperature on the molecular weight distribution of polymers were studied.Thereactivity of reactive species and rate of interchange between the reactive species were considered as the main factors effecting the molecular weight distribution of the polymer.With increasing polymerization temperature and by using more strong and concentrated ether additive the molecular weight distribution of the polymer became more narrow.

Key words: anionic polymerization, alpha-methylstyrene, molecular weight distribution