Ultratough Epoxy Resin Based on an Ionic Complex from Phytic Acid

In this study, phytic acid (PA) and 1,10-diaminodecane (DAD) were neutralized in a single step to develop the biobased ionic complex PA-DAD, which was then utilized as a toughener to increase the toughness of epoxy resin (EP). As a result of the sacrificial ionic bonds between DAD and PA, the fracture toughness of composites containing PA-DAD was substantially enhanced. Compared to neat EP, the tensile and flexural toughness of composited EP increased by 697 and 1028%, respectively, when PA-DAD was added at 6 wt %. Additionally, impact, tensile, and flexural strengths were enhanced by 201, 42, and 45%, respectively. Moreover, the modified EP had favorable flame retardancy due to the high phosphorus concentration of PA-DAD. The EP/6% PA-DAD showed a 27.7, 24.2, and 29.6% decrease in total smoke production, total heat release, and peak heat release rate, respectively, as compared to neat EP. The results of this investigation suggested a simple approach to toughening EP systems, which would expand the use of biobased tougheners.