Living cationic polymerization of vinyl ethers with a functional group. VII. Polymerization of vinyl ethers with a silyloxyl group and synthesis of polyalcohols and related functional polymers

Abstract

AbstractLiving cationic polymerizations of two silicon‐containing vinyl ethers, 2‐(t‐butyldimethyl‐silyloxyl)ethyl vinyl ether (tBuSiVE) and 2‐(trimethylsilyloxyl)ethyl vinyl ether (MeSiVE), have been achieved with use of the hydrogen iodide/iodine (HI/I2) initiating system in toluene at −15 or −40°C, despite the existence of the acid‐sensitive silyloxyl pendants. The living nature of the polymerizations was demonstrated by linear increases in the number‐average molecular weights (M̄n) of the polymers in direct proportion to monomer conversion and by their further rise upon addition of a second monomer feed to a completely polymerized reaction mixture. The polymers obtained in these experiments all exhibited very narrow molecular weight distributions (MWD) with M̄w/M̄n around or below 1.1. Desilylation of the polymers under mild conditions (with H+ for MeSiVE and F− for tBuSiVE) gave poly(2‐hydroxyethyl vinyl ether), a water‐soluble polyalcohol with a narrow MWD. The living processes also permitted clean syntheses of amphiphilic AB block copolymers and water‐soluble methacrylate‐type macromonomers, all of which bear narrowly distributed segments of the polyalcohol derived from the silicon‐containing vinyl ethers.