Cyclic polymerization and copolymerization of divinyl acetals

Cyclic polymerization constitutes an intramolecular closure of isolated dienes into five‐ or six‐membered rings with concurrent intermolecular growth of the chain. We have synthesized for the first time divinyl acetals and have investigated their capacity for cyclic polymerization. A method had been developed for the synthesis of divinyl‐acetals through interaction of aldehydes with ethylene chlorodihydrin and the subsequent dehydrochlorination of β,β′‐dichlorodiethylacetals. The structure of the divinyl‐acetal monomers was proved, in particular, by hydrolysis and hydrogenation. It has been shown that, in the presence of initiators of radical polymerization, divinylacetals polymerize only by means of the cyclic mechanism, with the formation of acetal derivative of polyvinyl alcohol, i.e., polyvinylacetals. The name “polyvinylacetal” based on the name of the monomer should be changed to “polydivinylacetal” magnified image Where R = H, CH3, C3H7, iso‐C3H7, iso‐C4H9 and C6H5. Polyvinylacetals have been obtained with an extent of acetylation of 100%. Until recently the possibility of cyclic copolymerization was not known. We have investigated this reaction on the examples of the copolymerization of divinylacetals with vinyl and diene monomers: magnified image where R = H, CH3, and C3H7 and X = OCOCH3, CN, and C6H5.The possibility of cyclic cyclopolymerization has been demonstrated by copolymerization of divinylformal and divinylethanal. All polymers obtained by us are white powders or rubberlike thermoplasts, easily soluble in most organic solvents and possessing high adhesive properties. They do not add hydrogen or bromine, indicating the absence of double bonds. The structure of the polyvinylacetals obtained on cyclopolymerization of divinylacetals was demonstrated by means of hydrolysis. As was to be expectd, polyvinyl alcohol was formed, of which in turn the glycol structure was proved by its oxidation to oxalic acid. Hence two vinyl groups of the divinylacetals during intrainter molecular polymerization react by the “head to tail” mechanism to form polyvinylacetals with six‐membered cyclic structures.