Poly(styrene-b-butyl acrylate-b-styrene)copolymers prepared by iodine transfer bulk polymerization:Kinetics,structure and properties
Iodine-terminated poly(butyl acrylate)(I-PBA-I)was prepared by iodine transfer bulk polymerization using iodoform chain transfer agent and azo-initiator,and further applied as a macro-chain transfer agent in the chain extension polymerization of styrene to synthesize poly(styrene-b-butyl acrylate-b-styrene)(PS-b-PBA-b-PS)copolymers.The polymerization kinetics,structure and properties of PS-b-PBA-b-PS were characterized.The results show that both homopolymerization of butyl acrylate and block copolymerization of styrene exhibit the characteristics of"living radical polymerization".The number average molecular weight of I-PBA-I was increased from 15 000 to 134 500 as the feed molar ratio of BA to CHI3(nBA,0/nCHI3,0)increased from 100/1 to 1 000/1.PS-b-PBA-b-PS copolymers with the number average molecular weight of 46 000,69 000,97 500 and 127 000 were obtained at nBA,0/nSt,0 ratios of 1/1,1/2,1/3 and 1/4,respectively.Micro-phase separation was observed in PS-b-PBA-b-PS copolymers,and block copolymers exhibited certain transparency and improved toughness.The impact strength of PS-b-PBA-b-PS copolymer with nPS/nPBA of 3.85/1 was similar to that of commercial styrene-butadiene block copolymer prepared by anion living polymerization.
polystyrenepoly(butyl acrylate)iodine transfer polymerizationkineticsblock copolymer
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