CONTROL OF MOLECULAR-WEIGHT AND END GROUP OF POLYMER BY ADDITION-FRAGMENTATION REACTION WITH ALPHA-(BROMOMETHYL)ACRYLATE AND ALLYL BROMIDE

Allyl bromide as well as methyl alpha-(bromomethyl)acrylate functioned as an effective chain transfer agent through addition-fragmentation reaction in the radical polymerization of methyl methacrylate and methyl acrylate. The H-1 NMR spectra of the polymers revealed that the end groups of the polymer with the controlled molecular weight arise from addition of the polymer radical to the carbon-carbon double bond of the transfer agent accompanying subsequent scission of the carbon-bromine bond and reinitiation with bromine atom. However, allyl bromide was found to be almost ineffective in styrene polymerization, because of a low reactivity of the carbon-carbon double bond toward poly(styrene) radical.