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作 者:李洪峰[1] 胡晓萍[1] 严小丽[1] 孙俊全[1]
机构地区:[1]浙江大学材料与化学工程学院化工系,浙江杭州310027
出 处:《化学反应工程与工艺》2007年第4期365-369,共5页Chemical Reaction Engineering and Technology
基 金:国家自然科学基金(20374043;20396009)
摘 要:合成了一种新的同双核钛茂金属催化剂[(CH3C5H4)TiCl2]2[C5H4CH2CH2OCH2CH2C5H4](A),用元素分析和1^H-NMR进行了表征。在助催化剂的作用下,该催化剂体系可有效催化甲基丙烯酸甲酯(MMA)本体和溶液聚合。考察了助催化剂、反应温度和时间对聚合的影响。结果表明,Al(i-Bu)3催化性能优于Al(Et)3和甲基铝氧烷(MAO)。以Al(i-Bu)3为助催化剂,本体聚合在MMA和A的摩尔比为1500,Al(i-Bu)3和A的摩尔比为20,60℃,反应时间20h条件下,单体转化率达98.6%,PMMA的粘均分子量为7.87×10^5;溶液聚合在MMA和A的摩尔比为1500,Al(i-Bu)3和A的摩尔比为20,80℃,反应时间15h条件下,单体转化率77.3%,PMMA的粘均分子量3.24×10^5。聚合所得PMMA分子量分布为5.0~7.0。A new dinuclear titanocene complex [(CH3C5H4)TiCl2-]2[C5H4CH2CH2OCH2CH2C5H4] (A) was synthesized and characterized by elementary analysis and 1^H-NMR spectrometry. In combination with the cocatalyst of Al(Et)3, methylaluminoxane (MAO) and Al(i-Bu)3, A was active to initiate methyl methacrylate (MMA) bulk and solution polymerization. The influences of cocatalyst, reaction time and temperature on polymerization were studied in detail. The result showed that Al(i-Bu)3 was the best cocatalyst. In combination with cocatalyst of Al(i-Bu)3, under the polymerization conditions of molar ratio of MMA to A 1 500, molar ratio of Al(i-Bu)3 to A 20, 60 ℃, reaction time 20 h, the conversion of MMA and the viscosity average molecular weight of PMMA of bulk polymerization were 98.6% and 7.87 × 10^5 repectively; under the polymerization conditions of molar ratio of MMA to A 1500, molar ratio of Al(i-Bu)3 to A 20, 80 ℃, reaction time 15 h, the conversion of MMA and the viscosity average molecular weight of PMMA of solution polymerization were 77.3 % and 3.24× 10^5 respectively. The molecular weight distribution (MWD) of PMMA was 5.0 -7.0.
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