摘要
用合成得到的五甲基环戊二烯基三苄氧基钛［ＣｐＴｉ（ＯＢｚ）３］与甲基铝氧烷（ＭＡＯ）组成新型催化体系进行丙烯的均聚合，研究了影响聚合活性及产物分子量的各种因素．结果表明，用甲基取代钛化合物茂环上的氢可使聚合产物分子量增大一个数量级，所制得的聚丙烯为无规聚丙烯，具有高分子量（Ｍｗ＝２０～１００×１０４）．
Propylene polymerizations in the presence of various monocyclopentadienyltitanium compounds and methylaluminoxanes(MAO) have been investigated. It was found that by substituting methyl group for hydrogen in the cyclopentadienyl ring, the titanocene catalyst affords a polypropylene with increasing molecular weight by one order of magnitude. Residual AlMe 3 content in MAO has an determinative effect on catalytic activity for the propylene polymerization. An excess of AlMe 3 in the catalyst system, such as 25% AlMe 3 in MAO, hinders the polymerization by reducing the Ti species to inactive lower valent states. The effects of molar ratio of MAO to Ti complex, polymerization temperature and monomer pressure on catalytic activity and molecular weight of the products are studied in detail. Thus, atactic polypropylene with the molecular weight range of 20～100×10 4, much higher than that prepared by unsubstiuted cyclopentadienyltitanium complex has been synthsized by η 5 pentamethylcyclopentadienyltitanium tribenzyloxide/MAO catalyst. The atatic polypropylenes exhibit excellent elasticity.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
1999年第1期15-19,共5页
Acta Polymerica Sinica
基金
国家自然科学基金
广东省自然科学基金
关键词
催化剂
无规聚丙烯
弹性聚丙烯
聚丙烯
茂钛
Propylene polymerization, Metallocene catalyst, Atactic polypropylene, Elastomeric polypropylene
