Anionic polymerization of epichlorhydrin

Abstract The anionic polymerization of epichlorhydrin with potassium hydroxide was studied at 110–120°C. in bulk and in solution. Large molar equivalent ratios of catalyst were needed for polymerization and even when using 150 mole‐% catalyst, the conversion was only about 50%. The polymers obtained were crosslinked and had a low chlorine content. Crosslinking may be due to attack of a propagating chain end on the partially positive carbon attached to the chlorine atom in a polymer, or on a terminal epoxide formed by an intramolecular elimination of chlorine. The water of hydration in the catalyst influenced the polymerization in that it was released on consumption of catalyst causing termination of the polymerization, relatively low conversion, and low chlorine content of the polymers. The polymers had infrared absorptions for both carbonyl and carbon double bonds and gave dinitrophenyl hydrazones that indicate the presence of aldehydes or ketones. Preliminary experiments showed that the crosslinked polyepichlorhydrins obtained can be converted to exchange resins by utilizing either the hydroxyl or the chlorine functions of the polymer. Thus sulfonation and phosphorylation of the polyhydroxy polymer obtained by alkaline hydrolysis of residual chlorine in the polyepichlorhydrin gave inorganic esters that had free acid groups and served as reversible cation‐exchange resins. Amination of the polymers with sodamide gave an anion‐exchange resin, while replacement of the chlorine with cysteine gave a resin that can be used as a chelating agent for heavy metals.