Thermal degradation and flammability characteristics of some polystyrenes and poly(methyl methacrylate)s chemically modified with silicon-containing groups

Several Si-containing methacrylates and acrylates have been free radically copolymerised with methyl methacrylate and with styrene. The copolymers have been examined by DSC to determine glass transition temperatures (T-g), by TGA to determine thermal stabilities, and by measurements of limiting oxygen index (LOI) to determine ignitability/flame retardance. The copolymers are found to have T(g)s similar to those of the parent homopolymers suggesting that the mechanical properties are little affected by the incorporation of the Si-containing groups and to have slightly improved flame retardance. LOI and char yields suggest that the mechanism of flame retardance, i.e. whether vapour phase or condensed phase, depends upon the nature of the Si-containing substituent. (C) 2003 Elsevier Ltd. All rights reserved.