Towards recycling of carpet textile waste made of hybrid natural and synthetic fibers for thermoplastic composites

This study investigates the recycling of carpet textile waste generated from post-industrial manufacturing processes, which constitute a significant portion of solid waste in Egypt. Hybrid carpet waste (≈70 wt% jute + 30 wt% polypropylene) was recycled into thermoplastic composites using recycled polypropylene as the matrix and maleic-anhydride-grafted polypropylene (MAPP) as a compatibilizer, with alkali treated fibers employed to improve fiber matrix interaction. Compounding was performed using a twin screw extruder, and standard specimens were produced by injection molding. The incorporation of 50 wt% carpet waste was successfully achieved without evidence of thermal or mechanical degradation during processing. Alkali-treated carpet fibers containing 2.5 wt% MAPP showed a decrease in tensile, bending, and impact strengths by 5.78%, 10.15%, and 11.40%, respectively, compared with the uncompatibilized condition, due to partial fiber damage. Conversely, untreated carpet fibers containing 10 wt% MAPP enhanced interfacial adhesion, increasing tensile, bending, and impact strengths by 9.68%, 2.43%, and 2.10%, respectively, compared with the uncompatibilized condition, and by 16.41%, 14.02%, and 15.19%, respectively, compared with the alkali-treated condition. Morphological analysis confirmed improved fiber dispersion and matrix coverage in compatibilized composites. Thermal analysis showed that carpet fibers acted as nucleating agents, improving the crystallization behavior of recycled polypropylene, while the char residue from carpet waste enhanced thermal stability. Water absorption and void volume fraction decreased with an increase in the MAPP content due to the hydrophobic nature. Finally, this research demonstrates a sustainable and cost-effective pathway to convert carpet textile waste into value-added thermoplastic composites suitable for different applications.