title: Strong influences of polymerization temperature on ethylene/1-hexene copolymerization catalyzed by (2-PhInd)(2)ZrCl(2)/methyl aluminoxane.
abstract: Ethylene/1-hexene was copolymerized by an unbridged zirconocene, (2-PhInd)(2)ZrCl(2)/MAO (methyl aluminoxane) at 0 degrees C and 50 degrees C respectively. High copolymerization activity and 1-hexene incorporation were observed at 0 degrees C, with the copolymer formed having random sequence distribution and narrow molecular weight distribution. Ethylene polymerization at 50 degrees C showed high activity, but copolymerization at 50 degrees C showed much lower activity, which decreased sharply with increasing 1-hexene concentration in the monomer feed. Copolymer formed at 50 degrees C showed blocky sequence distribution and broad molecular weight distribution. A mechanism model based on ligand rotation hindered by the propagation chain has been proposed to qualitatively explain the observed phenomena.
authors.affiliation: Institute of Polymer Science, Zhejiang University, Hangzhou 310027, China. stonestone5678@yahoo.com.cn
authors.forename: Jian-Ding
authors.initials: JD
authors.lastname: Ye
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Fan
authors.forename: Wei
authors.initials: W
authors.lastname: Wang