Energy absorption of the Kevlar®/PP hybrid composite: fabric to composite optimization

One method of producing thermoplastic composites is using the co-air-textured yarn technique. Such composite materials are subjected to various loading conditions during their life cycle. For the efficient use of these materials in high-performance applications, their behavior under impact loading should be well understood. This is because polymer composites are sensitive to impact loading. Accordingly, one of the main objectives of the present research was to optimize the parameters to achieve the best energy absorption of Kevlar® /polypropylene weft-knitted hybrid composites under high-velocity impact. The kinetic energy absorption was evaluated using the experimental testing data of the composites. In this study, production parameters such as blend ratio, stitch length, knitting structure, melting time, molding pressure, molding temperature and blending quality were optimized via the response surface method (RSM) to obtain the best specific energy absorption of the composites. The results showed that the desired energy absorption occurred when the absorbed energy on the areal density of the composite had the maximum value. The results also showed that the blend ratio of Kevlar/PP (1:2), a higher blending quality, a higher stitch length, the use of the full-milano knitting structure, a longer molding time (20 min), a higher molding pressure (300 kg/cm2) and a lower molding temperature (160 °C) delivered the best performance in terms of specific energy absorption.