FUNCTIONALIZATION OF POLYETHYLENES VIA METALLOCENE METHYLALUMINOXANE CATALYST/

Ethylene was copolymerized with 1,1-dimethyl-2-propen-1-ol, 5-hexen-1- ol, 10-undecen-1-ol, methyl-9-decenoate and 10-undecenoic acid in the presence of the catalyst system (n-BuCp)(2)ZrCl2/MAO. The addition of a polar comonomer resulted in a rapid deactivation of the catalyst, wh ich was mainly due to the interactions between polar comonomer and Lew is acid catalyst components. A comparison between 5-hexen-1-ol and 10- undecen-1-ol revealed that the increase in the number of carbon atoms between the functional group and double bond did not influence the pol ymerization rate decreasing effect of the polar comonomer, but increas ed its incorporation to the copolymer. Steric hindrance in the vicinit y of the hydroxyl group hindered the 1,1-dimethyl-2-propen-1-ol from r eacting with the catalyst components but, on the other hand, the steri c protection made the comonomer unable to copolymerize. Compared with 10-undecen-1-ol, methyl-9-decenoate and 10-undecenoic acid showed lowe r reactivities in the polymerizations. The GPC profiles of the samples showed a reduction in the molar masses and a marked broadening in the molar mass distributions of the polymers with the addition of the pol ar comonomer indicating the presence of multiple active sites in the c atalyst. (C) 1997 Elsevier Science Ltd.