Molecular weight and molecular weight distribution of polyethene obtained with rac-Me2Si(Ind)2ZrCl2/methylaluminoxane
Molecular weight and molecular weight distribution of polyethene obtained with rac-Me2Si(Ind)2ZrCl2/methylaluminoxane
复制标题
DOI：
10.1002/(sici)1521-3935(19980101)199:1
复制
发表时间：
1998
影响因子：
2.5
通讯作者：
N. Naga;K. Mizunuma
中科院分区：
文献类型：
--
作者：
N. Naga;K. Mizunuma
以甲基铝氧烷（MAO）为催化剂，在甲苯中进行了乙烯和丙烯聚合.聚丙烯的分子量分布指数（MMD = Mw/Mn）接近2.0，而聚乙烯的MMD呈双峰分布。聚乙烯的MMD与[Al]/[Zr]比和[Zr]浓度无关。然而，当聚合在低温下或通过使用干燥的MAO进行时，高分子量部分消失。在聚合初期，AlMe 3的加入使聚合物中低分子量组分的含量增加。在甲苯和二氯甲烷的混合溶剂中进行聚合时，低分子量组分也有所增加。从这些结果，在催化剂体系中形成的活性物种进行了讨论。
Ethene and propene polymerizations were carried out with the rac-Me 2 Si(Ind) 2 ZrCl 2 (Me = CH 3 , Ind = indenyl)/methylaluminoxane (MAO) catalyst in toluene. The molecular mass distribution index (MMD = M w /M n ) of polypropenes was almost 2,0, while a bimodal MMD was observed for polyethene. The MMD of polyethene was independent of the [Al]/[Zr] ratio and the [Zr] concentration. However, the high molecular weight fraction disappeared when the polymerization was performed either at a low temperature or by using dry MAO. Addition of AlMe 3 to the MAO caused an increase of the low molecular weight fraction at the initial stage of polymerization. The low molecular weight fraction was also increased when the polymerization was conducted in a mixture of toluene and CH 2 Cl 2 as the solvent. From these results, the active species formed in the catalyst system are discussed.