Ring-opening polymerization of epichlorohydrin and its copolymerization with other alkylene oxides by quaternary catalyst system

An effective quaternary catalyst consisting of trialkyl aluminum, phosphori c acid, electron donor, and water for ring-opening polymerization of epichl orohydrin (ECH), as well as its copolymerization with ethylene oxide (EO), propylene oxide (PO), and allyl glycidyl ether (AGE) to obtain elastomers, were studied. We investigated the optimum composition for the quaternary ca talyst; the character of the catalyst; the reactivity of the four alkylene oxides during homopolymerization and copolymerization; the behavior of ECH, EO, and PO during terpolymerization; and glass transition temperatures of the copolymer and terpolymers. The results showed that the nitrogen-contain ing electron donors are suitable as the third component, whereas oxygen-con taining electron donors are not. Water as the fourth component can increase the molecular weight of the homopolymer and copolymers of ECH. According t o the polymerizability of tetrahydrofuran with the quaternary catalyst and the reactivity ratios of the four alkylene oxides, the quaternary catalyst was assumed to be of a coordinated anionic type. The reactivity ratios for these four alkylene oxides were determined to be EO > PO > AGE > ECH. They were verified by terpolymerization of ECH, EO, and PO. The glass transition temperature of the terpolymer exhibits a minimum value at nearly 3:1 molar ratio of PO to EO, when the molar ratio of ECH used is constant at the beg inning of terpolymerization. (C) 2001 John Wiley & Sons, Inc.