Study of the hardening mechanism and molecular structure of polyphenoxy phenylene methylenes

Abstract

Some problems of the hardening mechanism of polyphenoxy phenylene methylenes have been studied. The oligomers used were products of the reaction between diphenyl ester and formaldehyde containing methylene ester, acetal, methylol and ethoxymethyl functional groups. It was shown that in the presence of acid catalysts (stannic chloride) the process takes place in two stages, the first being involved in reactions of methylol, methylene ester and acetal groups taking place at 130–150°; the second stage takes place at 180–200° and involves the interaction of ethoxymethyl groups with hydrogen of the benzene ring. A study was made of polymer network density of polyphenoxy phenylene methylenes at different stages of hardening. It was established that the polyphenoxy phenylene methylenes consist of di-, tri- and tetrasubstituted diphenyl ester molecules combined with methylene groups. With an increase of the contents of methylene ester and acetal groups, the crosslink density of polyphenoxy phenylene methylenes increases.