Epoxy resin thermosets are vital matrix materials in many applications such as coatings, adhesives and electronics owing to their excellent mechanical properties and chemical and thermal resistance. However, their poor recyclability and environmental impact are longstanding concerns. Strong covalent linkages within their structure not only hinder their recycling but also contribute to soil and water pollution. Additionally, the prevalent use of bisphenol A (BPA) as a raw material in epoxy resin production raises health and sustainability concerns. Despite the emergence of BPA alternatives, their widespread adoption remains limited.
Now, Barta and co-workers have developed epoxy-amine thermosets from biomass-derived raw materials, offering a closed-loop solution to thermoset recyclability. Utilizing lignocellulosic-derived precursors such as 2,5-furandicarboxylic acid and glycidol, along with a curing agent such as 4,4′-methylenebis(cyclohexylamine), the as-prepared thermoset maintains key thermomechanical properties such as the glass transition temperature and storage modulus, outperforming its reference BPA-containing counterparts. Importantly, the monomers of these thermosets can be efficiently recovered, establishing a closed-loop system that involves a methanolysis step at low temperatures (approximately 70 °C), without the need for catalysts or additives, yielding highly pure 2,5-furandicarboxylic acid. Subsequent acetolysis treatment allows for the recovery of 4,4′-methylenebis(cyclohexylamine) and glycidol, enabling regeneration of all the raw materials.
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