Synthesis of bio-sourced liquid resins and their photopolymerization with poly(ethylene glycol) diacrylate in the roadmap to more sustainable digital light processing technologies

Abstract

Non-fossil feedstocks for the production of photocurable resins have attracted growing interest from the scientific community and industry in order to achieve more sustainable 3D-printing technologies. Herein, we report the successful photopolymerization process of three diallyl ester monomers, derived from succinic acid, D,L-malic acid and L-(+)-tartaric acid (natural acids), with poly(ethylene glycol) diacrylate, a petroleum-based co-monomer well-known for its fast UV light reaction response. The existence of hydroxyl groups beside the ester units in the malic and tartaric compounds did not influence either the kinetics or the thermal stability of the thermoset polymers. Therefore, the most prominent composition was formed by 50 wt% of the bio-derived diallyl succinate, and 50 wt% of the synthetic, having excellent thermal stability and very good dimensional resolution and transparency in DLP printed samples after light curing, and most importantly, such samples promptly undergo hydrolytic degradation thanks to the presence of the ester linkages that are incorporated by the natural monomer.