Oxidative Decrosslinking of Network Polymer that Exhibits High Stability and High Degradability

Abstract

Diacylhydrazine is a thermally and chemically stable functional group, although it is oxidatively degraded rapidly into a carboxylic acid by an artificial oxidizing agent such as sodium hypochlorite. Therefore, a network polymer bearing a diacylhydrazine moiety as a cross-linking site exhibits high thermal stability, chemical resistance, and weather resistance during use without being decomposed by natural stimuli such as heat, acid, water, and sun-light. However, it can be decrosslinked immediately after use when it is treated with sodium hypochlorite solution. The epoxy resin cured with a curing agent bearing a diacylhydrazine moiety could be used as an oxidatively degradable adhesive that can be oxidatively dismantled after use. The polymer bearing an ester moiety at the side-chain could be cross-linked by the formation of a diacylhydrazine moiety, and decrosslinked by its oxidative degradation to reproduce the original polymer. A transparent monolith crosslinked with a diacylhydrazine moiety was obtained by the reaction injection molding, and it could be solubilized with sodium hypochlorite solution. The superabsorbent polymer crosslinked with a diacylhydrazine moiety was immediately decomposed into sodium polyacrylate by sodium hypochlorite solution.