Copolymerization of styrene and norbornene with β-diketiminato nickel/methylaluminoxane catalytic system

Styrenenorbornene (S-N) copolymerizations were carried out using beta-diketiminato nickel complexes CH{C(CF3)NAr}2NiBr (Ar?=?2,6-iPr2C6H3, 1; Ar?=?2,6-Me2C6H3, 2) in the presence of methylaluminoxane. The influence of the comonomer feed content and polymerization temperature on the conversion and composition of the copolymers with the catalytic system was investigated. An increase in the feed ratio of S/N led to an increase in the incorporated styrene content of the resulting copolymer. NMR characterization of the copolymers generated with the catalytic systems showed that the random S-N copolymers are produced. Differential scanning calorimetric determination of the copolymers shows higher Tg values than polystyrene, and gel permeation chromatographic measurements have shown that the copolymers possess rather narrow molecular weight distributions, suggesting that the copolymerization take place at a single active site. Copyright (c) 2012 John Wiley & Sons, Ltd.