Unconventional recycling of aeronautical ground carbon fiber composite wastes

Carbon fiber–reinforced polymer (CFRP) composites are extensively used in aerospace applications; however, their end-of-life management remains a critical challenge. This study investigates an unconventional recycling route based on the direct hot compression molding of CFRP waste powders, aiming to valorize industrial composite scraps without the addition of virgin polymers or binding agents. The material investigated corresponds to the finest fraction (~300 μm) obtained from a sieving process applied to industrial CFRP scrap powders derived from trimming residues and partially cured aeronautical prepregs. The use of this fine powder fraction promotes effective particle aggregation and consolidation during molding, preventing powder loss during demolding and enabling the fabrication of relatively thick panels despite the absence of additional bonding agents. Compression molding was carried out at 250 °C and 1.5 bar for 20 min. Two material configurations were analyzed: uncoated compression-molded panels and panels coated with a thin polyester layer. The recycled materials were characterized through morphological, thermomechanical, and mechanical analyses. The results indicate that the polyester-coated panels exhibit improved mechanical performance compared to the uncoated configuration. In comparison with previous studies focused on coarser powder fractions (≤1 mm), the present work highlights the potential of the finest powder fraction for effective consolidation, demonstrating the strong influence of particle size on the processability and properties of compression-molded recycled CFRP. These findings confirm the viability of direct compression molding as a sustainable and scalable recycling strategy for tailoring CFRP waste reuse as a function of powder size.