Effects of polar groups of polymer matrix on reinforcement‐matrix interaction in kevlar fiber‐reinforced composites

Abstract

AbstractIn order to investigate the interaction between the polar groups of reinforcement and matrix in polymer composite, mechanical properties were studied for the 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″ versus temperature curves. Such a subtransition is obscured or diminished accompanying the decrease in fraction of the polar components in the matrix. The fiber efficiency factors for strength are also decreased with a decrease in the fraction of the polar components. These results imply that the reinforcement‐matrix interaction is affected depending on the fraction of the polar components in matrix.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.