PHOTOINITIATING CAPABILITIES OF VINYL POLYPEROXIDES AND METAMORPHOSISOF BLOCK-INTO-BLOCK COPOLYMER

This article describes the first comprehensive study on the use of a v inyl polyperoxide, namely poly(styrene peroxide) (PSP), an equimolar a lternating copolymer of oxygen and styrene, as a photoinitiator for fr ee radical polymerization of vinyl monomers like styrene. The molecula r weight, yield, structure and thermal stability of polystyrene (PS) t hus obtained are compared with PS made using a simple peroxide like di -t-butyl peroxide. Interestingly, the PS prepared using PSP contained PSP segments attached to its backbone preferably at the chain ends. Th is PSP-PS-PSP was further used as a thermal macroinitiator for the pre paration of another block copolymer PS-b-PMMA by reacting PSP-PS-PSP w ith methyl methacrylate (MMA). The mechanism of block copolymerization has been discussed. (C) 1996 John Wiley & Sons, Inc.