以α-溴代异丁酸叔丁酯(t-BBiB)为引发剂,二乙烯苯(DVB)为支化单体,经原子转移自由基聚合(ATRP)合成支化苯乙烯/丙烯腈共聚物.用核磁共振(~1H-NMR)、凝胶渗透色谱-多角激光散射(GPC-MALLS)和黏度测试方法对聚合反应过程和聚合物进行表征和分析.结果表明,反应初期生成带有悬垂双键的初级链,在单体转化率达到40%后悬垂双键参加反应生成支化聚合物;随着单体转化率的提高,支化结构更为完善,聚合产物Zimm支化因子变小;同一聚合物样品中,分子质量较高的组分具有相对较高的史化程度,表现出相对更小的Zimm支化因子.
Branched copolymer of styrene and acrylonitrile was prepared by atom transfer radical polymerization (ATRP). Proton nuclear magnetic resonance(~1H-NMR), gel permeation chromatography(GPC)coupled with multi-angle laser light scattering(MALLS)and viscosity measurement were used to clarify the polymerization process and characterize the prepared copolymers. It is proved again that the polymerization generates primary chains bearing pendent vinyl groups at the early stage, branching occurs mainly after monomer conversion reached 40%. As the polymerization proceeding, the content of the branched polymer increases, and the branched polymer possesses some high and perfect branched architecture, resulting in decreased values of Zimm branching factor. As regarding to the same polymer sample, fraction of high molecular weight also possesses some high and perfect branched architecture comparing with that of low molecular weight.
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