Development and application of latent hydrosilylation catalysts. 3. Control of activity of platinum catalysts by poly(vinyl ether) having propargyl moieties

A flexible polymer having propargyl moieties (2) was prepared by the cation ic polymerization of vinyl monomer (1) derived from 4-hydroxybutyl vinyl et her and propargyl bromide. In the presence of the polymer, the catalytic ac tivity of H2PtCl6 towards the hydrosilylation of triethylsilane and trimeth ylvinylsilane was found to be retarded effectively at ambient temperature b ut not on heating. Compared to the monomeric propargyl derivatives, the pol ymeric system was quite effective in controlling the catalytic activity. Un der the same concentration of acetylene moieties and H2PtCl6, the initiatin g temperature of the present system was ca. 50 degrees C higher than for th e catalyst composed of the monomeric propargyl derivatives, but was ca. 20 degrees C lower than for that consisting of the propargylated polystyrene d erivative that the authors have reported recently. Effective control of the crosslinking reaction of silicone resin was also achieved using the presen t latent system. (C) 2000 Elsevier Science B.V. All rights reserved.