Effect of accelerator on properties of epoxy resin re-prepared from alcoholysis recycling

Alcoholysis has emerged as a crucial method for the degradation of anhydride-cured epoxy resin, and the degraded epoxy resin (DER) can be reused to prepare a new resin. Accelerator is commonly employed in the preparation of epoxy resin to expedite the curing process. However, the effect of accelerator content on the re-prepared resin's performance has remained unexplored. Hence, DER is used to replace part bisphenol A diglycidyl ether to prepare new resins with varying accelerator contents, and the comprehensive properties of new resins are investigated. The results demonstrate that the accelerator-free re-prepared resin exhibits a performance that is comparable to that of the original resin. After accelerator is added during the preparation of new resins, the curing temperature of the reconstituted resin shows a decrease, and two peaks appear during the curing exothermic process. Besides, as the accelerator content increases, the insulation performance initially improves and then deteriorates, while the mechanical and thermal properties continue to decline. Through characterisation and chemical simulation analysis, it is believed that excessive accelerators are detrimental to the cross-linking reaction of DER. Therefore, the accelerator content in the new epoxy resin should not be high.