Mechanical Properties of a High-Modulus Poiyamide-Hydrazide Fiber in Composites and of the Poiyamide-Hydrazide Fiber and Fabric Composites

Abstract

Unidirectional, bidirectional, and fabric laminates were made of one type of X-500 fiber and fabric using, mainly, an epoxy-based matrix and other thermosetting and thermoplastic resins. This particular X-500 fiber (PABH-T), a polyamide-hydrazide, was found to be compatible with most of the resins tried, both with respect to inertness to the fiber and with respect to adhesion. Unidirectional composite properties, including longitudinal tensile modulus and strength, transverse modulus and strength, and shear modulus and strength, were measured. From the measured transverse and shear unidirectional laminate moduli, the transverse modulus and shear modulus of the PABH-T X-500 fibers were measured. To reduce the amount of sample preparation and testing, and to make comparisons of PABH-T X-500 composite stiffness properties to glass fiber and other composites, computational procedures for estimating the stiffness properties of various laminates were worked out so that the comparisons could be made on an equal volume fraction basis with any matrix whose modulus and Poisson's ratio is known. At the 60% volume fraction level-, the PABH-T X-500 composite's specific longitudinal tensile Young's modulus was typically 170 × 10⁶ in. while the transverse specific Young modulus was 10 × 10⁶ in., which would produce a quasi-isotropic laminate with a specific tensile Young's modulus of 72 × 10⁶in. and a specific in-plane shear modulus of 24 × 10⁶ in. Properties measured on bidirectional and fabric laminates are also given.