Free radical chain transfer to allyl monomers at low polymerization temperatures

Abstract

AbstractAlkylboron–oxygen, an active, low‐temperature free radical initiator, has been employed to investigate the effects of very low polymerization temperatures on the free radical homopolymerization and copolymerization of allyl monomers. Unlike some polymerizations which have been reported to undergo dramatic changes in polymerization rates at very low polymerization temperatures, the allyl systems behaved in a like manner at high and low temperatures. Similar, low values of reduced viscosities were obtained for homopolymers of allyl monomers prepared over a 300°C. temperature range. An almost identical effect of allyl chloride concentration on the molecular weight of ethyl acrylate/allyl chloride copolymers was also observed for copolymerizations performed over a 100°C. temperature range. For solution homopolymerizations and copolymerizations the activation energy for free radical abstraction from the allyl monomer is, therefore, nearly equal to the activation energy for addition of that radical to the allyl double bond, even at temperatures down to the melting points of the monomers.