Speaker
Description
Chemical recycling of epoxy–anhydride thermosets remains challenging due to the need to combine efficient network cleavage with mild conditions, process simplicity and recovery of the reaction media. Existing approaches often rely on harsh conditions, high-boiling solvents or catalysts that complicate downstream separation and recycling [1,2]. Recent studies have highlighted solvolysis as a promising strategy for anhydride-cured epoxy networks, while emphasizing the influence of network architecture, bond accessibility and catalyst/solvent selection on depolymerization efficiency [3,4]. Here, we report a sustainable methanolysis strategy catalyzed by triethylamine (TEA) for the depolymerization and upcycling of epoxy–anhydride networks. The process operates at 70 °C and atmospheric pressure, enabling recovery and reuse of both methanol and catalyst. A fully bio-based epoxy, 2,5-bis[(oxiran-2-ylmethoxy)methyl]furan (BOMF), was cured with glutaric anhydride (GA) or hexahydrophthalic anhydride (HHPA), while DGEBA-based networks were used as reference systems. Complete depolymerization of the flexible BOMF/GA network was achieved within 48 h using 20% v/v TEA in methanol. More rigid networks exhibited slower degradation, highlighting the role of network flexibility and ester-bond accessibility. Approximately 90% of TEA and methanol were recovered by mild distillation and successfully reused without significant loss of catalytic activity. The depolymerization products were isolated, characterized and subsequently upcycled into a polyester. Overall, this approach combines mild chemical recycling, process-chemical recovery and polymer upcycling for the valorization of epoxy thermoset waste.
Key words: Epoxy–anhydride thermosets, Chemical recycling, Methanolysis, Triethylamine catalysis, Polymer upcycling
References
1. Kuang, X.; Shi, Q.; Zhou, Y.; Zhao, Z.; Wang, T.; Qi, H. J. Dissolution of Epoxy Thermosets via Mild Alcoholysis: The Mechanism and Kinetics Study. RSC Advances 2018, 8, 1493–1502.
2. Yang, Z.; Zhang, S.; Liang, H.; He, E.; Wang, Y.; Lei, T.; Wu, Z.; Chen, Q.; Zhou, F.; Wei, Y.; Ji, Y. An Efficient and Economical Degradation Strategy for Epoxy Thermosets Based on a Low-Cost Transesterification Catalyst. Polymer Chemistry 2024, 15, 4784–4789.
3. Liu, H.; Zou, Y.; Xu, J.; Zhou, S.; Wu, X.; Liu, Y. Efficient Recycling of Anhydride-Cured Epoxy Resins for Electrical Insulation: Green Economy and Tunable Performance. Polymer Testing 2025, 150, 108934.
4. Sun, X.; Zhang, Y.; Wang, Y.; Niu, M.; Liu, Z.; Liu, J.; et al. Solvolysis for Chemical Recycling of Traditional Epoxy/Anhydride Thermosets: A Review. European Polymer Journal 2026, 250, 114713.
| Conference Topics | Polymer-based materials – Sustainability and Circularity |
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