The role of tertiary amines as internal catalysts for disulfide exchange in covalent adaptable networks

Abstract

Here we explore the true effects of internal tertiary amines on the bond exchange properties of cross-linked networks with a disulfide exchange mechanism. The creep and stress relaxation data are first compared for the cross-linked samples with and without internal tertiary amines, where the segmental mobility and cross-linking density are adjusted to be the same for a fair comparison. Much greater creep and faster stress relaxation are observed for the sample with internal tertiary amines. The role of tertiary amines in disulfide exchange is then discussed based on the result of electron spin resonance (ESR) spectroscopy focusing on the sulfide radicals during the bond exchange.