Synthesis of photodegradable polyesters from bio-based 3,4-dimethoxycinnamic acid and investigation of their degradation behaviors

Abstract

To address the issue of petroleum resource depletion, it is desirable to develop recyclable materials from bio-based compounds. In addition, low-energy recycling methods such as light irradiation and hydrolysis should be considered. In this paper, bio-based materials, cinnamic acid (CA) derivatives, are introduced as repeating units in polyester main-chain, because CA derivatives undergo reversible [2 + 2] cycloaddition reactions to form dimers under light exposure. Photopolymerization of the monomer with CA moieties at both ends failed, probably because it was difficult to bring the two CA moieties closer together intermolecularly. Polycondensation between the CA dimer with two carboxylic acid moieties and diol compounds successfully provided the polyesters containing CA dimers as repeating units. Furthermore, orthogonal degradation methods, such as light exposure and hydrolysis, of the obtained polyester were investigated.