Mechanical performance of modified Polypropylene/Polyamide matrix reinforced with treated recycled carbon fibers for lightweight applications

This research paper reports light-weighting future mobility system by modification of recycled carbon fiber composites (RCF). Virgin carbon fiber (VCF) from defense and aerospace sectors needs significant innovation for their high value reutilizations. RCF for composites is at its infancy and fundamental research gap remains to enhance fiber adhesion by its surface science as well as a cost-effective process engineering. A 25% in weight of non-treated versus 400 °C thermally treated VCF and RCF were added in a bi-phase polymer blend of polypropylene (PP) / polyamide 12 (PA12). Results demonstrated 17.7% improved mechanical strength with surface thermodynamics designed with functional maleic anhydride polypropylene (MAPP) and poly[methylene(polyphenyl)isocyanate] (PMPPIC). Characterization methods used included, mechanical properties, XPS, FTIR and SEM. The final recycled carbon fiber reinforced polymer (RCFRP) 20%/80% PP/PA12— PMPPIC has a better impact energy of 16.8% compared to the MAPP RCFRP chemistry without affecting hybrid matrix mechanical strength. Surface design with maleic anhydride functionality enhanced mechanical strength over impact energy for both VCF and RCF composites. Viscosity of the RCFRP composites supports the relationship between viscosity and hybrid matrix polymer adhesion behavior between both surface modifiers used. Finally, the surface energy of the modified composites elucidated the governing mechanism of fiber-matrix adhesion. The fabricated composites are recyclable and meet the stringent light-weighting requirements of many components in mobility vehicles.