Development of rare earth polymerization catalysts

点击翻译按钮获取中文摘要

By using the cationic half-sandwich aminobenzyl scandium complexes, we have achieved for the first time the copolymerization of 1, 5-hexadiene with styrene and terpolymerization of 1, 5-hexadiene with styrene and ethylene to give a new family of polymer materials which possess syndiotactic styrene units, cyclopentyl units and vinyl branch units. By using two different scandium metal catalytic systems, which show syndiospecific selectivity for styrene polymerization and cis-1, 4-selectvity for isoprene and butadiene polymerization, respectively, in the presence of a chain-shuttling agent(triisobutylaluminum), we have achieved for the first time the regio-, and stereospecific chain-shuttling copolymerization of styrene, isoprene and butadiene to give unprecedented multi-block copolymers such as sPS-cis-1, 4-PI-cis-1, 4-PBD with high regio-and stereoselectivity.