2-Bromo-2-methyl-propionic acid 4-benzothiazole-2-ylazo-phenyl ester (BPBE), 2-bromo-2-methyl-propionic acid 4-(6-methoxy-benzothiazole-2-ylazo)phenyl ester (BPMBE) and 2-bromo-2-methyl-propionic acid 4-(6-nitro-benzothiazole-2-ylazo)phenyl ester (BPNBE) were synthesized and acted as initiators for the heterogeneous atom transfer radical polymerization of methyl methacrylate under copper(I) bromide/2,2-bipyridine catalytic system, respectively. The azobenzothiazole-based end group of polymethyl methacrylate was characterized via UV-visible spectroscopy. All rates of polymerizations exhibited first-order kinetic with respect to the monomer and a linear increase in the number-average molecular weight with increasing monomer conversion was observed for all these initiation systems. The polydispersity indices of the polymethyl methacrylates were relatively low (1.08-1.37) up to high conversions at 60 ºC. Moreover, the initiation systems exhibit a high activity that polymerizations could even be performed at ambient temperature (30 ºC).
2-Bromo-2-methyl-propionic acid 4-benzothiazole-2-ylazo-phenyl ester (BPBE)、合成了
2-溴-2-甲基丙酸 4-(6-甲
氧基-
苯并噻唑-2-基偶
氮)
苯基
酯(B
PMBE)和
2-溴-2-甲基丙酸 4-(6-硝基-
苯并噻唑-2-基偶
氮)
苯基
酯(BP
NBE),并在
溴化铜(I)/
2,2-联
吡啶催化体系下分别用作
甲基丙烯酸甲酯异相原子转移自由基聚合的
引发剂。
聚甲基丙烯酸甲酯的偶
氮苯并噻唑基端基通过紫外可见光谱进行了表征。在所有这些引发体系中,所有聚合速率都表现出与单体有关的一阶动力学,并且随着单体转化率的增加,平均分子量呈线性增加。
聚甲基丙烯酸甲酯的多分散指数相对较低(1.08-1.37),直到 60 ºC 时的高转化率。此外,这些引发体系表现出很高的活性,甚至可以在环境温度(30 ºC)下进行聚合。