Coumaric acid, one of the most abundant cinnamic acid derivatives, was employed to prepare an aromatic dicarboxylic acid via photocycloaddition and subsequently synthesized with another biobased aromatic diamine to produce bioderived polyamides containing aromatic and cyclobutane rings. The resulting polyamides exhibited excellent thermal stability and high transparency. In particular, hydroxyl functional groups on the side-chains enabled further chemical modification with units such as acetic anhydride, pivaloyl chloride, hexanoyl chloride, and cinnamoyl chloride. The acetylated bioderived polyamide demonstrated enhanced chemical resistance compared to the unmodified polyamide, reaching levels comparable to those of engineering plastics. Furthermore, the bioderived polyamide with cinnamoylation exhibited photoresponsiveness to ultraviolet irradiation, demonstrated significantly improved chemical resistance to highly polar solvents, and showed that functionalization through chemical modification is possible.
Zhou et al. (Thu,) studied this question.