CpTi(dbm)Cl_2/MgCl_2-SiO_2/MAO催化乙烯聚合及与其它α-烯烃共聚的研究

研究开发了一种新型非茂负载聚烯烃催化剂——CpTi(dbm)Cl2/MgCl2-SiO2/MAO,并考察了该催化剂的乙烯均聚、乙烯和1-己烯共聚及乙烯和苯乙烯共聚性能。结果表明,该催化剂具有较好的热稳定性,80℃时活性可达4.68×106g/(mol·h)。不同助催化剂对活性的影响规律为MAO>MMAO>TiBA>TEA。乙烯和1-己烯共聚时,催化活性提高,聚合温度70℃,1-己烯体积分数为8％时,活性可达3.61×106 g/(mol·h),共聚物的熔点、结晶度、相对分子质量、密度和堆密度随1-己烯含量增加而下降。乙烯和苯乙烯共聚时,随着苯乙烯含量的增加,共聚活性下降,共聚物的熔点、结晶度和相对分子质量都有较大幅度的下降。

MgCl2-SiO2 Supported Monocyclopentadienyl Titanium Complex Containing β-Diketone Ligand for Ethylene Homo - Polymerization and Ethylene and Other α -Olefins Copolymerization

A novel non - metallocene supported catalyst, CpTi(dbm)Cl2/MgCl2 - SiO2/MAO,was prepared, and the catalysis involved in ethylene homo - polymerization, ethylene - 1 - hexylene and ethylene - styrene copolymerization was investigated. In case of homo - polymerization, the catalytic activity could reach to a value of 4.68 × 106 g/(mol· h) under 80 ℃ and 0.7 MPa. Effects of different co - catalysts on activity were as follows: methylaluminoxane > modified methylaluminoxane > triisobutylaluminum > triethylaluminum. In case of ethylene - 1 - hexylene copolymerization with increasing 1 - hexylene content in feed the catalytic activity increased while melting point, crystallinity, relative molecular mass, density and bulk density of co - polymer decreased. In case of ethylene - styrene co - polymerization, melting point, crystallinity and relative molecular mass of co - polymer rapidly decreased with increasing styrene content in feed increasing, catalytic activity decreased as well.