Improved thermal properties of polydimethylsiloxane by copolymerization and thiol–ene crosslinking of 2-pyrone-4,6-dicarboxylic acid moiety

Recent environmental issues, such as global warming and climate change, have prompted a shift from petroleum-derived polymers to biomass polymers. We have developed new lignin-derived biomass polymers based on 2-pyrone-4,6-dicarboxylic acid (PDC), a metabolic intermediate of lignin. In previous studies, various polymers have been synthesized using PDC. Many of them showed strong adhesion to metal surfaces and biodegradability. On the other hand, despite the quasi-aromatic ring structure of PDC, its heat resistance remained unresolved. In this study, a diallyl PDC derivative was synthesized and copolymerized with polydimethylsiloxane (PDMS) by Pt-catalyzed hydrosilylation. The resulting polymers were further cross-linked using the PDC ring as the cross-linking point by using thiol–ene click chemistry. It was found that the heat resistance of PDMS was significantly improved by polymerization and cross-linking. By using biomass-based PDC, silicone rubber with low environmental impact, excellent heat resistance, and mechanical strength was successfully developed.