Synthesis of Phenolic Resin-Based Epoxy Resins Containing Acetal Linkages and Degradability of Their Cured Epoxy Resins

Abstract

The phenolic resins with rigid substituents were reacted with vinyl ether with a glycidyl group to produce new epoxy resins containing degradable acetal linkages (1 and 2). Glass-transition temperatures (T_g) of cured acetal linkage-containing epoxy resins 1 and 2 were 61°C and 45°C, respectively. Cured boards of acetal linkage-containing epoxy resins and conventional phenolic novolak epoxy resin 4 were prepared. Acetal linkage-containing epoxy resin 1 and 2 had higher charpy impact strength than the conventional phenolic novolak epoxy resin 4. Acetal linkage-containing epoxy resin 1 and 2 underwent smooth hydrolysis with the treatment with aqueous acid in THF at room temperature to give the corresponding phenolic resins in high yield.