Reversible addition-fragmentation chain transfer polymerization of vinyl acetate under high pressure

Abstract

In this work, high molecular weight polyvinyl acetate (PVAc) (Mn,GPC = 123,000 g/mol, Mw/Mn = 1.28) was synthesized by reversible addition-fragmentation chain transfer polymerization (RAFT) under high pressure (5 kbar), using benzoyl peroxide and N,N-dimethylaniline as initiator mediated by (S)-2-(ethyl propionate)-(O-ethyl xanthate) (X1) at 35 C. Polymerization kinetic study with RAFT agent showed pseudo-first order kinetics. Additionally, the polymerization rate of VAc under high pressure increased greatly than that under atmospheric pressure. The "living" feature of the resultant PVAc was confirmed by 1H NMR spectroscopy and chain extension experiments. Well-defined PVAc with high molecular weight and narrow molecular weight distribution can be obtained relatively fast by using RAFT polymerization at 5 kbar.