Transformation of waste carbon fiber prepreg into sustainable composites: application in the automotive industry components

Abstract

Carbon fiber (CF) prepregs are employed in the manufacture of many different aeronautical structural and non-structural components. Following the cure of the prepregs in molds, trimming is generally used to give the final shape to the components. Considering the aircraft's vast surface area and the use of multiple prepreg layers in each component, an extensive amount of carbon fiber prepreg is discarded. The unique characteristics of carbon fibers render this CF waste highly valuable and requires its efficient recycling. Cured waste CF prepregs were milled and processed in this research to produce chopped carbon fibers for use in the novel composite development. The matrix material used in the composites was selected as recycled polypropylene sourced from old surgical masks, which highlighted the sustainability of the developed composites. To enhance the quality of the fiber-matrix interface and improve the impact resistance of the composites an anhydride-grafted polyethylene (Fusabond) was employed in small quantities. From mechanical characterizations, synergistic effects of the fillers were observed. Besides, compositions containing CF and Fusabond are found more impact resistant than neat matrix. In addition, the use of carbon fibers increased fracture toughness of the matrix through various mechanisms including fiber bridging, fiber pullout, and matrix plastic deformation identified by scanning electron microscopy fractography. Thermomechanical characterizations using dynamic mechanical analysis revealed that carbon fiber raises the neat matrix's glass transition temperature. The developed materials are intended to be employed in the automotive industry to produce inner fender liners, with an optimal composition determined by an optimization research.

Highlights Carbon fiber (CF) derived from aerospace fresh scraps significantly improved the mechanical properties of the polymer matrix. Anhydride-grafted polyethylene incorporation remarkably enhanced the impact resistance of the polymer. CF demonstrated a bridge effect and improved the fracture toughness of the composites. The use of recycled CF presents encouraging prospects in the automotive industry for the production of inner fender liners.