Recycling Epoxy by Vitrimerization: Influence of an Initial Thermoset Chemical Structure
Liang Yue, Mehrad Amirkhosravi, Xuehui Gong, Thomas Gray, Ica Manas‐Zloczower
Abstract
Epoxy/anhydride-cured thermosets are widely used in aerospace and wind energy structures. Recycling the enormous amounts of epoxy thermoset waste remains a global challenge. Vitrimerization, a practical, low-cost, eco-friendly, and scalable method, was developed for closed-loop recycling of the cross-linked epoxy by converting the permanent network into a vitrimer-type dynamic network. Here, we study the effect of virgin epoxy network properties on network reforming efficiency and the activation energy of the dynamic network by varying the epoxy/anhydride ratio. The results point out that the permanent network cross-link density and glass transition temperature have a more pronounced effect on vitrimerization efficiency in comparison with the concentration of free hydroxyl groups in the system. The result can be potentially used to better control vitrimerization efficiency in recycling epoxy thermoset polymers and tailor the vitrimerized product properties.