Experimental studies of the deformation mechanisms of core-shell rubber-modified diglycidyl ether of bisphenol-A epoxy at cryogenic temperatures

Epoxy polymers, although often used in fiber-reinforced polymeric composites, have an inherent low toughness that further decreases with decreasing temperatures. Second-phase additives have been effective in increasing the toughness of epoxies at room temperature; however, the mechanisms at low temperatures are still not understood. In this study, the deformation mechanisms of a diglycidyl ether of bisphenol-A epoxy modified with MX960 core-shell rubber particles were investigated under quasi-static tensile and impact loads at room temperature and liquid nitrogen temperature. Overall, the core-shell rubber had little effect on the tensile properties at room temperature and liquid nitrogen temperature. The impact strength decreased from neat to 1 wt% and 3 wt% but increased from neat to 5 wt% at room temperature and liquid nitrogen temperature, with a higher impact strength at room temperature at all core-shell rubber loadings. While a large toughening effect was not seen in this study, the mechanisms analyzed herein will likely be of use for further material investigations at cryogenic temperatures.