writer：Liu, DT; Cui, DM; Gao, W
keywords：neodymium; cis-1,4 selectivity; NCN-pincer complex; polyisoprene
source：期刊
specific source：http://apps.webofknowledge.com/full_record.do?product=UA&search_mode=GeneralSearch&qid=10&SID=V2hxdX
Issue time：2011年

The aryldiimine NCN-pincer stabilized neodymium dichloride combined with aluminum alkyls established a new type of homogeneous binary neutral Ziegler-Natta catalyst system. This system exhibited high activity and high cis-1,4 selectivity for the polymerization of isoprene (T(p) = 20 degrees C, 98.2%; T(p) = -20 degrees C, > 99%). Such catalytic performances remained under a broad range of polymerization temperatures and monomer-to-neodymium ratios (from 500 to 8000), reaching high number-average molecular weight (M(n) = 1582 kg/mol) and relatively narrow molecular weight distribution (PDI = 1.68), which was, however, influenced by the amount and bulkiness of aluminum alkyls. Dynamic investigation of thepolymerization was performed, which showed the number-average molecular weight of the resultant polyisoprene had an almost linear correlation withthe conversion, suggesting, in some degree, the polymerization with this catalytic system was controllable.