EFFECTS OF POLAR GROUPS OF POLYMER MATRIX ON REINFORCEMENT-MATRIX INTERACTION IN KEVLAR FIBER-REINFORCED COMPOSITES

In order to investigate the interaction between the polar groups of reinforcement and matrix in polymer composite, mechanical properties were studied for Kevlar fiber-reinforced composites (Kevlar is a registered trademark of E. I. duPont de Nemours Co. Inc. ), in which the kind and fraction of polar components in matrix were varied using blended polymers. For the composites comprised of polymethyl methacrylate and poly(hydroxypropyl ether of bisphenol A) as the matrix, a subtransition, which can be ascribed to the interphase formed on the reinforcement surface by a strong interaction between reinforcement and matrix, appears at a temperature above the primary transition on the E double prime versus temperature curves. For the composite comprised of blending the two polar components as the matrix, each component can contribute to the interaction with the reinforcement. The results obtained from the Fourier transform infrared spectroscopy on the matrix polymer-coated Kevlar cloth do not contradict those obtained by studying the mechanical properties.