Highly stereospecific polymerization of isoprene with homogeneous binary Ziegler-Natta catalysts based on NCN-pincer neodymium precursor
作者：Liu, DT; Cui, DM; Gao, W
關(guān)鍵字：neodymium; cis-1,4 selectivity; NCN-pincer complex; polyisoprene
論文來源：期刊
具體來源：http://apps.webofknowledge.com/full_record.do?product=UA&search_mode=GeneralSearch&qid=10&SID=V2hxdX
發(fā)表時間：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.