Evaluation of Interfacial Fracture Toughness and Interfacial Shear Strength of Typha Spp. Fiber/Polymer Composite by Double Shear Test Method

The aim of this paper is to evaluate the Mode II interfacial fracture toughness and interfacial shear strength of fiber/PLLA and fiber/epoxy composite by using a double shear stress method with 3 fibers model composite. The surface condition of the fiber and crack propagation at the interface between the fiber and the matrix are observed by scanning electron microscope (SEM). Alkali treatment on fiber can make the fiber surface coarser, thus increasing the value of interfacial fracture toughness and interfacial shear strength. fiber/epoxy has a higher interfacial fracture value than that of fiber/PLLA. Interfacial fracture toughness on fiber/PLLA and fiber/epoxy composite model specimens were influenced by the matrix length, fiber spacing, fiber diameter and bonding area. Furthermore, the interfacial fracture toughness and the interfacial fracture shear stress of the composite model increased with the increasing duration of the surface treatment.