【摘要】 用氯化苄为引发剂 ,氯化亚铜为催化剂 ,2 ,2′-联吡啶为配体 ,采用开放体系 ,外加搅拌 ,氮气保护下 ,初步研究了苯乙烯在 95℃ ,水为分散相的原子转移悬浮聚合 .结果表明转化率随反应时间变化平稳 ,分子量随转化率基本呈线性增加 ,分子量分布随转化率变窄 ,且分布比一般的自由基聚合窄 (分布指数可达 1 .63 ) .动力学研究表明聚合反应对单体浓度为一级动力学关系 ,经计算 ,聚合体系的活性自由基浓度为 1 .1 8× 1 0 - 8mol/L.为了进一步验证原子转移悬浮聚合的可控性 ,还进行了相同温度下的苯乙烯悬浮热聚合 ,结果与相同时间的原子转移悬浮聚合相比 ,转化率高 (分别为 3 8.5 %和 2 8.1 % ) ,分子量大 (分别为 7764 2和 45 670 ) ,分子量分布宽 (分别为3 .0 2和 1 .67) ,进一步说明了在原子转移催化剂存在下的苯乙烯悬浮聚合具有一定程度的可控性 .更多还原

【Abstract】 The suspension atom transfer radical polymerization(ATRP) of styrene was carried out using benzyl chloride as initiator, cuprous chloride as catalyst, 2,2′ bipyridine as ligand. The dispersion phase is comprised of water, PVA and NaCl. The polymerization was accomplished at 95℃ with an agitator under N 2 atmosphere. The results show that the conversion increased with time smoothly. The plot of ln 0/ versus time was linear, indicating that the polymerization was one order to monomer concentration. The reactive radical concentration was calculated as 1 18×10 -8 mol/L. The molecular weight(Mn) increased with conversion linearly in the main, But they were higher than the calculated values theoretically. The molecular weight distribution (Mw/Mn) was narrower than normal radical polymerization and decreased with the conversion. Mw/Mn reached a minimum value of 1.63. On comparison, the pure thermal suspension polymerization of styrene was also demonstrated at 95℃ for 9 h. The conversion is 38.5%,much higher than that of suspension ATRP (28.1%). The molecular weight is higher (77642) and the Mw/Mn is larger (3.0) than those of suspension ATRP(45670 and 1.67 respectively). This indicates that the suspension polymerization of styrene in the presence of atom transfer catalyst could be well controlled.更多还原