活性自由基聚合反应合成苯乙烯与丙烯酸酯嵌段共聚物及相关共聚物

用Cu(phen) 2 Br/1 PEBr催化引发体系合成了分子量为 50 0 0左右的溴端基聚苯乙烯 (PS Br) .以后者为大分子引发剂 ,在Cu( phen) 2 Br存在下引发甲基丙烯酸甲酯 (MMA)或丙烯酸丁酯 (BA)聚合 ,合成了二嵌段共聚物PS b PMMA和PS b PBA ,并通过GPC、IR、1H NMR及DSC等进行了表征 .实验发现 ,丙烯酸甲酯(MA)在Phen/CuCl/CCl4 催化引发下发生爆聚反应 ,仅当和异丁基乙烯基醚 (IBVE)才发生可控的自由基共聚合反应 .当MA和IBVE的投料摩尔比为 1∶1时 ,所得共聚物中两种单体链节的组成比为 1∶1 7左右 .

SYNTHESIS AND CHARACTERIZATION OF P(St-b-MMA),P(St-b-BA) AND POLY(MA-co-IBVE) BY USING PHEN-ATRP SYSTEMS

A bromine capped polystyrene (PS-Br) with an M n of around 5,000 was synthesized by using Cu(phen)-2Br/1-PEBr as catalyst and initiator to polymerize styrene (St) according to atom transfer radical polymerization (ATRP) mechanism.Then, by using such a PS-Br as a macro-initiator,some block copolymers P(St-b-MMA) and P(St-b-BA)] were also prepared through phen-ATRP.These block copolymers have been characterized by means of GPC,IR, 1H-NMR and DSC,respectively. It was found that there were no any homopolymers in these block copolymer systems and P(St-b-BA) exhibited a compatible system due to the short length of both blocks,although the miscibility between these two blcoks was poor. By using phen/CuCl/RCl as catalyst and initiator, the explosive polymerization phenomenon of methacrylate (MA) was observed. However,the copolymerization of MA and iso-butyl vinyl ether (IBVE) could be controlled in ATRP.The obtained poly(MA-co-IBVE) was characterized and discussed by using DSC and 1H-NMR.