Premium
Molecular weight distribution of polyethylene catalyzed by Ziegler–Natta catalyst supported on MgCl 2 doped with AlCl 3
Author(s) -
Chen YongPing,
Fan ZhiQiang,
Liao JianHe,
Liao ShuangQuan
Publication year - 2006
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.24443
Subject(s) - catalysis , polyethylene , ziegler–natta catalyst , natta , crystallite , molar mass distribution , doping , polymerization , ethylene , polymer chemistry , chemistry , polymer , adduct , dopant , materials science , nuclear chemistry , organic chemistry , crystallography , optoelectronics
Ti‐based Ziegler–Natta catalysts supported on MgCl 2 doped with AlCl 3 were prepared by the reaction of MgCl 2 /AlCl 3 –ethanol adduct with TiCl 4 . No AlCl 3 crystallites were found in the AlCl 3 ‐doped catalysts by WAXD analysis, suggesting that AlCl 3 /MgCl 2 solid solution was formed. The effect of doping on the catalyst performance in ethylene polymerization was investigated. The results showed that the catalysts based on AlCl 3 ‐doped MgCl 2 support exhibited a slightly higher activity than did the MgCl 2 ‐supported catalyst and the molecular weight distribution (MWD) of polyethylene (PE) markedly increased (from 10.8 to 47.9) with the increase of AlCl 3 content in catalysts. The changes in catalyst's active center distribution were studied based on nonlinear fitting of the polymer GPC curves by multiple Flory functions. It was found that increase of types of active centers by introducing AlCl 3 into the support should be responsible for the broadening of MWD of PE. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1768–1772, 2006