DSC研究镍-钛复合催化剂制备的聚乙烯支化非均匀性  

INVESTIGATION ON MOLECULAR HETEROGENEITY OF POLYETHYLENE OBTAINED BY Ni-Ti COMBINED CATALYST WITH DSC

作　　者：林少全[1] 吴志勇[1] 张启兴[1] 王海华[1] 

机构地区：[1]中山大学高分子研究所,广东广州510275

出　　处：《高分子材料科学与工程》2004年第1期171-173,178,共4页Polymer Materials Science & Engineering

基　　金：国家自然科学基金及燕山石油化工研究院联合资助(29874039);广东省自然科学基金会资助项目(001280)

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。Branched polyethylenes with different branched degrees were synthesized by polymerization of ethylene with (α-diimine)nickel complexes/TiCl_4 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.

关 键 词：聚乙烯 支化非均匀性 DSC 自成核/退火法 镍-钛复合催化剂 

分 类 号：TQ325.12[化学工程—合成树脂塑料工业]