Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5191924 | Polymer | 2005 | 11 Pages |
Abstract
A new siloxy-substituted α-diimine compound and its corresponding Ni(II) complex, {bis[N,Nâ²-(4-tert-butyl-diphenylsiloxy-2,6-dimethylphenyl)imino]acenaphthene}dibromonickel (6), were successfully synthesized and the molecular structure of 6 characterized by X-ray crystallography. The precatalyst 6 activated by methylaluminoxane (MAO) or diethylaluminum chloride (DEAC) was tested in the polymerization of ethylene, showed to be highly active (e.g. 2.2Ã107 and 1.8Ã107 g polymer (mol Ni.h.bar)â1, respectively) and led to a branched polyethylene (ca. 35-55 branches/1000 C). The catalyst system 6/methylaluminoxane (MAO) catalyzes, at â11 °C, living polymerization of propylene, to a polypropylene showing a syndiotactic-rich microstructure (Pr=0.74). 1-Hexene was also successfully polymerized via a living process, both at â11 and +16 °C. The 13C NMR spectra of the poly(1-hexene)s obtained at room temperature show a microstructure almost exclusively composed by n-butyl and methyl branches, the latter being present in a much higher number. Diblock polypropylene-block-poly(1-hexene) and triblock poly(1-hexene)-block-poly(propylene-ran-1-hexene)-block-poly(1-hexene) copolymers have also been synthesized and characterized by GPC/SEC, DSC and NMR.
Related Topics
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Authors
Jian-Chao Yuan, Leonel C. Silva, Pedro T. Gomes, Pedro Valerga, João M. Campos, M. Rosário Ribeiro, James C.W. Chien, Maria M. Marques,