The Role Of Allylanisole In Metallocene-Catalyzed Propylene Polymerization And Synthesis Of End-Capped Oligomers

(2008) The Role Of Allylanisole In Metallocene-Catalyzed Propylene Polymerization And Synthesis Of End-Capped Oligomers. WILEY-V C H VERLAG GMBH, MACROMOLECULAR REACTION ENGINEERING, 2.

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Abstract

Propylene was copolymerized with allylanisole (AA) using Me2Si(Ind)(2)ZrCl2 and Et(Ind)(2)ZrCl2, and the methylaluminoxane MAO cocatalyst at 70 degrees C and a cocatalyst to catalyst (Al:Zr) molar ratio of 1000. It was fed at 8.5 bar(g). The weight-average molecular weight, (M) over bar (w), for both metallocenes decreased as the AA feed concentration increased. Therefore, allylanisole acted as an in situ chain transfer agent. The chain transfer constants, k(tr)/k(P), of AA for Et(Ind)(2)ZrCI2 and Me2Si(Ind)(2)ZrCl2 turned out to be 0.33 and 0.40, respectively. The characterization of the resulting products by (HNMR)-H-1 demonstrated that AA end-capped the isotactic poly(propylene) chains which showed to be low molecular weight oligomers; 4.96 x 10(3) <= (M) over bar (w) <= 9.80 x 10(3). An appropriate chain transfer mechanism for AA has been proposed.

Item Type: Article
Subjects: General
Divisions: General
Depositing User: Users 4454 not found.
Date Deposited: 23 Aug 2008 12:03
Last Modified: 01 Nov 2019 17:09
URI: http://eprints.kfupm.edu.sa/id/eprint/17667