Preparation and characterisation of branched poly (styrene-co-acrylonitrile) via atom transfer radical polymerisation using β-bromoethyl benzene as initiator

Abstract

Branched poly (styrene-co-acrylonitrile) was prepared by atom transfer radical polymerisation (ATRP) of styrene (St) and acrylonitrile (AN) with the feed composition of 0·5 using β-bromoethyl benzene (BEB) as the initiator and divinylbenzene (DVB) as the branching agent. The polymerisation kinetics and the development of branching were studied by gas chromatography (GC), triple detection size exclusion chromatography (TD-SEC) and proton nuclear magnetic resonance (1H-NMR) spectroscopy. The primary chains with the pendent vinyl groups were formed dominantly at a monomer conversion of less than 50%. The pendent vinyl group participated in the polymerisation, which resulted in the formation of branching structure accompanied by a rapid increase in molecular weight and a broadening in its distribution. The branching chains developed gradually as the molecular weight increased. The copolymers of higher molecular weights had higher branching degree than those of lower molecular weights.