MSE 430 Fall 2015 Problem Set
Write down a reaction scheme for polymerization of styrene (CH2=CHPh) initiated by thermolysis of azobisisobutyronitrile (AIBN), including both combination and disproportionation as possible modes of termination.A sample of polystyrene prepared by bulk polymerization at 60°C using radioactive (14C) AIBN as initiator, was found to have Mn average = 1000 kg mol-1 and a radioactivity of 6 x 103counts s-1 g-1 (measured using a liquid-scintillation counter). Given that the AIBN has a radioactivity of 6 x 109 counts s-1 mol-1, determine the mode of termination which operated in the preparation of the polystyrene sample