【摘要】 采用负载型二亚胺镍与TiCl4组成的复合催化剂催化乙烯聚合制得具有不同支化度的支化聚乙烯。通过DSC研究了支化聚乙烯在连续自成核/退火过程中的分布结晶,得到产物链结构的支化非均匀性的信息。研究发现支化聚乙烯在经过热分级处理后其熔融曲线呈多峰状,表明产物具有一定的非均匀性;复合催化剂作用下的乙烯共聚物的均匀性比均聚物好;用同时负载方法制备的复合催化剂更容易制备分子链均匀性较好的聚合物。更多还原

【Abstract】 Branched polyethylenes with different branched degrees were synthesized by polymerization of ethylene with （α-diimine）nickel complexes/TiCl₄ combined catalysts. Thermal segregations of branched polyethylene were treated with Successive Self-Nucleation/Annealing （SSA） on DSC, information of molecular heterogeneity of branched polyethylene was obtained. After SSA treated, the multiple endothermic peaks were observed in the DSC thermograms during heating experiments. The heterogeneity of the copolymers is lower than that of the homopolymers. Polymers obtained by combined catalysts which were prepared by simultaneously immobilized of nickel and titanium complexes are of the lowest heterogeneity.更多还原