Novel high performance auxetic fibrous structures for composite reinforcement

This paper reports the development of novel auxetic fibrous structures from high performance yarns using knitting technology for application as reinforcement in composites. Two types of high performance yarns, namely, para-aramid (p-AR) and polyamide 6.6 (PA), were used to produce three distinct auxetic structures: purl, re-entrant lozenge and re-entrant star structures. It was observed that all structures produced could achieve maximum negative Poisson's ratios (NPR) of -0.60, -0.54 and -0.47 in the course direction of purl and lozenge and in wale direction of star structures, respectively. The auxetic textile structures also presented better tensile strength and energy absorption (except re-entrant lozenge structure) than plain knitted textiles produced by using the same type of fibres and parameters. (paper)