Characterization and performance evaluation of nylon-66 composite at various composition of carbon fibers and GNP reinforcement

Recycled reinforcements are being utilized more and more to make sustainable composites for load-bearing structural applications, which now dominate the key transportation industries, because they have lower environmental impact than virgin fiber manufacturing and are also less expensive. In order to improve the mechanical properties of composites, a combination of recycled carbon fibers (rCF) and waste tire-derived graphene nanoplatelets (GNP) with oxygen surface functional groups was used as reinforcement for the nylon-66 matrix. The alignment of the rCF and GNP during the injection molding process was monitored using numerical methods in conjunction with the rheological behavior of the compounds. The effective dispersion of the rCF and GNP was obtained using high shear mixing. In contrast, the flexural modulus and strength of the 20% rCF-0.3% GNP reinforced nylon-66 composites increased by 86% and 35%, respectively, while the tensile strength and modulus improved by 43% and 95%. Further, the addition of 0.3% GNP to the composition resulted in a 7.7% increase in Charpy notched impact energy compared to the 20% rCF composite. Moreover, the flow model developed to study the injection molding process of rCF/GNP reinforced composite using the fiber aspect ratio and distribution in the compounds described fiber alignment and provided insight into mechanical strengthening mechanisms.