Assessment of F-III and F-12 aramid fiber/epoxy interfacial adhesions based on fiber bundle specimens

In this work, the normal bonding and longitudinal shear adhesion properties of F-III and F-12 aramid fiber/epoxy interfaces were estimated by transverse fiber bundle tension (TFBT) test and 45° fiber bundle tension (45FBT) test, respectively. After the tensile tests, the micro failure mechanisms were investigated by observing the fracture surfaces of the fiber bundle samples using scanning electron microscope (SEM). The interfacial debonding was found coupled with fibrillation at the fiber surface. The different macro failure modes of TFBT and 45FBT samples were subsequently explained via finite element (FE) calculation. The applicability of the fiber bundle tests for the characterization of aramid fiber/matrix interfacial adhesion was eventually discussed.