Thermally assisted self-healing behavior of anhydride modified polybenzoxazines based on transesterification.

A self-healing polybenzoxazine is synthesized solely based on dynamic ester bonds. For this purpose, an anhydride (succinic anhydride) was added into bisphenol F derived benzoxazine monomer before thermocuring. Owing to the transesterification of newly formed ester bonds, the thermoset network behaves as a thermoplastic at 140 °C in the presence of Zn (Ac), and shows self-healing properties even after multiple damage-healing cycles. Furthermore, kinetics study indicates that the transesterification is a first-order reaction and the activation energy is about 135.4 kJ/mol. This study proposes a facile and economical way to prepare self-healing polybenzoxazine. It has promising applications in coating, adhesive, and other smart materials that rely on structurally dynamic polymers.