Waste valorization in sustainable engineering materials: Reactive processing of recycled carpets waste with polyamide 6

Waste resources utilization is of utmost importance today to promote sustainable development and minimize pollution. However, it remains a great challenge to reuse, recycle and turn post-consumer wastes into value-added products. Here, we demonstrate a strategy to reprocess post-consumer recycled carpet waste (PCRC) (containing polyamide, polypropylene and other additives and reinforcing agents) with polyamide 6 (PA 6) at different weight ratios through reactive extrusion. The phase adhesion of the PCRC and PA 6 was improved significantly with the aid of poly(ethylene-octene)-grafted-maleic anhydride copolymer (POE-g-MA) and epoxidized styrene-acrylic copolymer (ESAC). Superior notched impact strength and elongation at break were observed when the blends were modified with POE-g-MA and a small amount of chain extender ESAC (0.5–2 phr). Morphological characterization showed a decrease in PCRC droplets size and enhanced its dispersion in the PA 6. FTIR analysis showed an enhancement of interfacial compatibilization between PA 6 and PCRC by the interaction between maleic anhydride of POE-g-MA and epoxy group of ESAC with polyamide functional group through melt mixing. The effective compatibilization of the blends was also evident from thermal and rheological analysis. The results revealed the possible reuse and utilization of recycled carpet for different polymer blends and composites fabrication with high recycled content for various applications.