EFFECTS OF VARIOUS ESTER GROUPS IN GAMMA-RADIATION DEGRADATION OF SYNDIOTACTIC POLY(METHACRYLATE)S

The gamma irradiation of poly(methacrylate)s with various ester groups at room temperature was investigated by gel permeation chromatography and NMR techniques. The G values for scission and crosslinking for ea ch of the polymers were estimated from the changes in the molecular we ights and molecular weight distributions. The new structures formed du ring gamma irradiation were examined by H-1-NMR spectroscopy. All of t he investigated poly(alkane methacrylate)s were found to produce the a lkane formates during gamma irradiation, and for poly(2-methyl heptyl methacrylate) G(S) was less than 4G(X), indicating gel formation in th is polymer. In the investigation of poly(benzyl methacrylate), no form ate ester was found, but some small molecule compounds formed from the benzyl radical were detected. The benzyl group was also found to stab ilize the polymer against radiation damage. (C) 1996 John Wiley & Sons , Inc.