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以α-溴代异丁酸叔丁酯(t-BBiB)为引发剂,CuBr/联二吡啶为催化体系,二乙烯苯(DVB)为支化单体,采用原子转移自由基聚合反应(ATRP)经过一步加料方法和先臂后核方法分别合成不同支化结构类型的支化聚合物,同时以四官能度引发剂经ATRP合成臂数确定的星形聚合物为参照。采用三检测体积排除色谱(TD-SEC)得到Zimm相对支化因子g′与g和表征聚合物支化结构类型的指数因子ε(g′=gε)。结果表明:随支化结构类型的不同,支化结构指数因子ε表现出不同的分子量依赖特性。星状支化聚合物的ε平均值<1,而且随分子量的变化保持相对恒定;无规支化聚合物的ε平均值>1,而且其值随分子量的增加不断减小。因此,可以由三检测体积排除色谱进行分析确证聚合物的支化结构类型。
(T-BBiB) as initiator, CuBr / dipyridyl as catalyst system, and divinylbenzene (DVB) as branching monomer were synthesized by atom transfer radical polymerization (ATRP ) The branched polymers with different branching structures were synthesized by one step feeding method and the posterior nucleus posterior nucleus method, respectively. Meanwhile, the star polymers determined by ATRP synthesis arms were used as a reference for the tetrafunctional initiator. The Zimm relative branching factors g ’and g and the exponential factor ε (g’ = gε) characterizing the type of polymer branched structure were obtained by three-detection volume exclusion chromatography (TD-SEC). The results show that the branched index exponent ε shows different molecular weight dependence depending on the type of branched structure. The average value of ε of the star-branched polymers is less than 1, and remains relatively constant with the change of molecular weight. The mean value of ε of the random-branching polymers is more than 1, and its value decreases with the increase of molecular weight. Therefore, it can be analyzed by three-detection volume exclusion chromatography to confirm the type of branched structure of the polymer.