Photochemical Crack Healing in Cinnamate-Based Polymers

Abstract

Four kinds of cinnamate-type monomers were synthesized as healing agents. Photoirradiation of the monomers gave cyclobutane-containing crosslinked polymers via [2+2] cycloaddition. Cyclobutane cleavage upon cracking of the crosslinked polymers and re-cycloaddition of the cracked polymers were investigated by FT-IR spectroscopy. Photochemical crack healing was demonstrated by measurement of flexural strength of crosslinked, cracked, and healed polymers. It was observed that microcracks with width of 200 nm to 2 microm were healed by photoirradiation.