聚合工艺对水杨醛亚胺中性镍配合物催化乙烯溶液聚合的影响

Effect of Process on Ethylene Polymerization Catalyzed by Salicylaldiminato Neutral Nickel(Ⅱ) Complex in Toluene

合成了水杨醛亚胺中性镍配合物和双(1,5-环辛二烯)合镍[Ni(COD)2]催化体系。研究了聚合工艺对催化体系在甲苯中催化乙烯聚合的影响。研究表明:随乙烯压力和搅拌速率的增加,聚合活性和聚乙烯的黏均分子量均增加,使得聚乙烯片的拉伸强度提高;室温下催化剂催化活性最高,黏均分子量也最大,聚乙烯晶体结构也较完善。用DSC、WAXD、GPC、动态流变仪以及力学性能测试仪对室温下聚合所得聚乙烯进行了分析,表明聚乙烯是支化的线性高分子量聚乙烯,熔体呈假塑性流体特征。乙烯压力和搅拌速率对聚乙烯的晶体结构无影响。

Salicylaldiminato neutral nickel（Ⅱ） complex and [Ni（COD）_2] were prepared as catalyst system.The effects of polymerization processes on ethylene polymerization catalyzed by the neutral nickel（Ⅱ） complexes in toluene were studied in this work.The results show that the catalytic activity and molecular weight of polyethylene and tensile strength of polyethylene sheet enhance with increase of ethylene pressure and the agitation rate of polymerization.The polymerization activity and molecular weight of polyethylene reach maximum,and the more perfect crystal structure of polyethylene is achieved when the polymerization occurs at ambient temperature.The polyethylene obtained at ambient temperature has characterized by DSC,WAXD,GPC,dynamic rheology and mechanical tests.The results indicate that the polyethylene is linear and high molecular weight,and a little branched.The melting polyethylene behaves pseudoplasticity.The influence of ethylene pressure and stirring speed of polymerization on the crystal structure of the polyethylene obtained are small.