THERMOGRAVIMETRIC ANALYSIS OF POLY(ALKYL METHACRYLATES) AND POLY(METHYLMETHACRYLATE-G-DIMETHYL SILOXANE) GRAFT-COPOLYMERS

The thermal stabilities of various poly (alkyl methacrylate) homopolym ers and poly (methyl methacrylate-g-dimethyl siloxane) (PMMA-g-PSX) gr aft copolymers have been determined by thermogravimetric analysis (TGA ). As expected, the thermal stabilities of poly(alkyl methacrylates) w ere a function of the ester alkyl group, and polymerization mechanism. In particular, thermally labile linkages, which result from terminati on during free radical or nonliving polymerization mechanisms, decreas e the ultimate thermal stabilities of the polymers. However, graft cop olymers, which were prepared by the macromonomer technique with free r adical initiators, exhibited enhanced thermal stability compared to ho mopolymer controls. A more complex free radical polymerization mechani sm for the macromonomer modified polymerization may account for this r esult. (C) 1994 John Wiley & Sons, Inc.