【摘要】 以α-溴代异丁酸叔丁酯为引发剂,CuBr/2,2′-联二吡啶为催化体系,双甲基丙烯酸乙二醇酯为支化单体,在80℃经原子转移自由基聚合反应合成了支化聚苯乙烯。用1H-NMR、GC、GPC、MALLS和DSC分别对聚合反应过程及聚合物进行了表征和分析。研究表明,聚合反应初期主要生成带有悬垂双键的线型齐聚物,支化结构主要在反应中后期通过悬垂双键的聚合偶联形成;在单体转化率高达87%的情况下合成了质均分子量高达7.9×105的支化聚苯乙烯,其玻璃化转变温度在100℃左右,略低于线型聚苯乙烯。更多还原

【Abstract】 Branched polystyrenes have been prepared from styrene and ethylene glycol dimethacrylate by atom transfer radical polymerization(ATRP) at 80 ℃.The polymerization catalyzed by the complex of CuBr/2,2′-bipyridyl was proceeded by one step without solvent.The structures and the properties of polymers were characterized by 1H-NMR,GC,MALLS,GPC and DSC.It is proved that the formation of highly branched structure only occurs at the middle stage of polymerization by the coupling of linear oligomers formed at the early stage.The molecular weight determined by MALLS is 7.9×105 and its Tg is slightly lower than that of linear polystyrenes.更多还原