Poly(vinyl alcohol) obtained by hydrolysis of poly(vinyl silyl ethers) and poly(vinyl ethers) synthesized with indenyltitanium trichloride

Abstract

Vinyl ether and vinyl silyl ether (VSiE) monomers were polymerized in methylene chloride with an indenyltitanium trichloride catalyst using methyl aluminoxane as co-catalyst. The polymerization reactions were carried out at different temperatures and using an [MAO]/[IndTiCl3] = 10 molar ratio. The stereoregularity of the polymers was determined by NMR analysis. The molecular weights (Mn's) observed in the polymers obtained from vinyl silyl ethers were lower than the respective poly vinyl ethers. The polymer hydrolysis reactions produced PVA's with the same stereoregularity, the tacticities of new the PVA's were different compared with the PVA produced by the traditional reaction of poly(vinyl acetate) hydrolysis. The most important syndiotacticity (rr) observed in the products obtained from the VSiE polymerization reaction was in the range of 28-39%, while the heterotactic fractions (mr) observed in the PVA's produced from the specific poly(vinyl dimethylphenylsilyl ether) and poly(tert-butyl vinyl ether) hydrolysis reactions were 52 and 57%, respectively. © 2005 Elsevier Ltd. All rights reserved.