Improvement of interleaving Aramid pulp micro-fibers on compressive strengths of carbon fiber reinforced polymers with and without impact

Compressive strengths and elastic moduli of Carbon Fiber Reinforced Polymer (CFRP) composites can be noticeably improved by multiple ultra-thin interlays with non-woven Aramid Pulp (AP) micro/nano-fibers. 10-ply CFRP specimens with 0, 2, 4, 6, 8 g/m2 AP were tested under uniaxial compression. Those flexible AP fibers, filling the resin-rich regions and further constructing the fiber bridging at the ply interfaces, can effectively suppress delamination growth and lead to very good improvements both in the compressive strength and the elastic modulus. The CFRP specimen with an optimum interlay thickness has a distinct shear failure mode instead of the typical delamination cracking along the direction of continuous carbon fibers. Compressive Strengths After Impacts (CAI) of 12.35 J were also measured, up to 90% improvement in CAI has been observed. It is concluded those ultra-thin interlays of non-woven AP micro/nano-fibers are beneficial to design and manufacture "high strength" CFRP composites.