Design and basic properties of polyester vitrimers combined with an ionomer concept

Vitrimers are a novel class of cross-linked materials containing associative bond exchange properties. Here we demonstrate the preparation of vitrimers with ionic components to investigate the effects of ion-rich domain formation on vitrimer properties. An amorphous polyester that bears COOH side groups was synthesized, and some fraction of COOH was neutralized with Zn2+. The residual non-neutralized COOH was reacted with diepoxy cross-linkers, resulting in a network with ester bonds, OH groups, and COOH groups neutralized with Zn2+. The sample was further thermally annealed to induce aggregation of Zn2+ ionic groups. The aggregated Zn2+ groups in the network remained active for trans-esterification-based bond exchange, wherein the degree of ion aggregation can be a factor in tuning the bond-exchange properties. The present study provides some important knowledge on the design of new molecular systems of vitrimers with tunable bond exchange properties.