Nd(P_(204))_3-Al(i-Bu)_3-CCl_4催化体系聚合甲基丙烯酸酯

THE POLYMERIZATION OF METHYL METHACRYLATE WITH Nd(P204)3-AI(i-Bu)3-CCI4 CATALYST SYSTEM

对Nd(P_(204))_3-Al(i-Bu)_3-CCl_4催化体系在60℃加氢汽油中聚合甲基丙烯酸甲酯进行了详细研究。结果表明,催化剂的制备方法对其催化活性影响很大。与Nd(P_(204))_3-Al(i-Bu)_3二元催化体系相比,催化剂的聚合活性大为加强。Al/Nd=7,CCl_4/Nd=4时,催化体系的活性最大。聚合所得的PMMA间同结构含量在75％左右,烷基铝与钕化物摩尔比、CCl_4/Nd摩尔比对聚合物的立构规整性无明显影响。聚合速度对单体浓度呈零级关系,对催化剂浓度呈一级关系,聚合反应活化能为45·69kJ/mol,聚合机理是配位自由基型聚合机理。

It was studied in detail that the polymerization of methyl methacrylate in hydrogenized benzoline at 60℃, with Nd (P204)3-A1 (i-Bu)3-CCl4 catalyst system. The catalyst activity was affected by making method of catalyst. When Al (i-Bu)3/Nd (P204)3 mole ratio is7 , CCl4/Nd (P204)3 mole ratio is 4 the catalyst activity is the best. The content of syndio tacticity in PMMA is about 75%, it is not affected significancely by the mole ratio of Al(i-Bu)3/Nd (P204)3 and CCl4/Nd (P204)3 Rp=Kp[C] .The activation energy of polymerization is 45.69 kJ/Mole, the mechanism of polymerization may be coordinated radical.