From recycled PVC and its blends to eco-friendly materials for the footwear industry in Brazil: Insight into the process and evaluation of the mechanical properties

Abstract

Recycling and upcycling waste polyvinyl chloride (PVC) poses a major challenge to the footwear industry due to its short lifecycle and the environmental impact of destructive trends. This study aimed to recycle thermoplastic polyvinyl chloride (rPVC) from used sports shoes of the most varied kind, obtained from a recycling company. The rPVC and thermoplastic polyurethane (TPU) were melt-blended, prepared by industrial injection molding with different compositions, and the polymer blends were characterized by morphological, thermal, and mechanical means. The overall properties of the recycled polymer blends were improved compared to their parent commercial materials. When TPU and rPVC were blended, the resulting material displayed a remarkable hardness. The abrasion resistance of the TPU/rPVC polymer blends (67/33 and 50/50 wt.%) was enhanced twice compared to PVC, and the rPVC rupture strength (14.73 MPa) was 1.6 times greater than virgin PVC (9.11 MPa). Likewise, The TPU/rPVC blend (50/50% wt.%) also offered significantly greater deformation resistance, indicating that rPVC has a more entangled structure with greater resistance and, thus, greater tensile strength. Polymer blending is accelerating research and development in the footwear industry, and the outcomes have qualified the TPU/rPVC (67/33 and 50/50 wt.%) polymer blends to meet the growing consumer demand for environmentally friendly footwear.