复配茂金属催化剂对聚乙烯相对分子质量分布的影响

合成了甲基丁基环戊二烯双取代的APE-2茂金属催化剂加合物(MeCp(n-Bu))2-ZrCl2@Et2O@LiCl,并进行了负载化,对APE-2催化剂与为(n-BuCp)2ZrCl2@Et2O@LiCl加合物的APE-1催化剂的复配物催化乙烯的聚合、聚乙烯相对分子质量分布的影响进行了研究.研究结果表明,APE-2催化剂催化乙烯聚合的催化活性较APE-1低.采用不同比例的APE-1与APE-2复配物催化乙烯聚合,可以改善聚乙烯的相对分子质量分布,得到相对分子质量分布在1.66～3.22之间的茂金属聚乙烯.聚合动力学试验表明,该复配催化剂的引发较快、寿命较长.高压聚合试验中负载型APE-1和APE-2催化剂按照摩尔比11复配,可以得到相对分子质量分布大于4的茂金属聚乙烯.

EFFECT OF COMBINED METALLOCENE CATALYSTS ON MOLECULAR WEIGHT DISTRIBUTION OF POLYETHYLENE

The metallocene catalyst adduct APE-2 , ( MeCp (n-Bu))2ZrCl2Et2OLiCl, double substituted by methyl-cyclopentadiene was synthesized, which polymerization activity was lower than that of the metallocene catalyst with APE-1, the adduct, (w-BuCp)2ZrCl2Et2OLiCl. The effect of the combined catalyst of APE-1 and APE-2 on the catalytic polymerization of ethylene and the relative molecular weight distribution of polyethylene was studied. The metallocene polyethylene whose relative molecular weight distribution could be adjusted in the range of 1. 66 - 3. 22 with different ratios of APE-1/APE-2. The polymerization kinetics of the combined catalyst showed that its initial polymerization rate was fast and the life was longer. The metallocene polyethylene with a relative molecular weight distribution higher than 4 could be obtained by using the combined catalyst having 1 : 1 molar ratio of APE-1/APE-2.