Evaluation of Interfacial Properties and Microfailure Mechanisms in Single Fiber-Reinforced Epoxy Composites at Low Temperature

Abstract

In this preliminary study, micromechanical techniques were used to compare the interfacial properties of both carbon and glass fiber composites with two structurally different epoxy matrices (YD-114 and YDF-175) at ambient and relatively low temperatures (25 degrees C and -10 degrees C). Tensile modulus of elasticity for both epoxies was higher at lower temperature. Although both fibers exhibited more bimodality at lower temperature than at ambient temperature, glass fiber composites exhibited a statistically greater improvement in tensile strength. This may be attributed to differences in inherent flaws and rigidity. A decrement in stress was observed for YDF-175 epoxy composites under cyclic loadings at both temperatures, which was attributed to lower interfacial shear strength (IFSS). In contrast to the IFSS of conventional YD-114 epoxy composites, the IFSS of both the carbon and glass fibers/YDF-175 epoxy composites studied was higher at the lower temperature. The microfailure pattern observed in microdroplet pullout tests was consistent with the other IFSS results. POLYM. COMPOS., 33:147-157, 2012. (C) 2011 Society of Plastics Engineers