(193ar) Thermal Response Epoxy Under High Rate Impact Loading Via Incorporation of Diels-Alder Substructures

A method of toughening amine-cured epoxy systems under high temperature environment or high rate impact loading was proposed and the resulting epoxy systems were characterized. Accordingly, a thermal reversible Diels-Alder Partially Reacted Substructures (DAPRS) resin was formed by firstly reacting a furan based diaepoxy and bismaleimides to form the Diels-Alder linkages, then partially curing the thermal reversible epoxy linkages with a long chain Jeffamine diamine. The control DAPRS (0% conversion) and modified DAPRS resins were added to a mixture of tetraglycidyl of diaminodiphenylmethane (TGDDM) at different concentration (0% to 20%) and the mixtures were cured. Based on the results of the quasi-static compression test at different temperature and high strain rate compression test, the mechanical properties are tunable by control the conversion and concentration of DAPRS. Besides, the mechanical behavior was also affected by the testing temperature, at high temperature (>70°C) the DAPRS modified systems revealed a longer failure strain, but less Yong’s modulus and Yielding stress, compared to the no DAPRS modified system. The improved toughness at high temperature was found to be due to an enhanced plastic microvoid growth as a result of the presence of the DAPRS in the crosslinked structure of the DAPRS-modified epoxy systems.