Recycling of binary polymer (PET/SBR) carpet into microfibrillar composites: A life cycle perspective with microplastics quantification

Plastics are generally nonrecyclable materials relative to their circular production. Recycling may reduce greenhouse gases and promote decarbonization goal of plastics, while restricted due to strong incompatibility for binary or ternary polymers waste. Sustainability of sole type is frequently idealized with life cycle assessment (LCA) studies and often neglect the release of wear particulate matter or microplastics (MPs) and fail to provide alternate end-of-life (EoL) recycling solutions. Thus, this study offers recycling of binary polymer product, polyethylene terephthalate/styrene-butadiene rubber (PET/SBR) carpet and sustainability assessment through LCA with quantification of MPs accumulation. A functional unit for PET/SBR carpet in 3.5 kg weight with use phase cleaning (vacuum and detergent cleaning) for 10 years' service life was considered to simulate realistic deposition of MPs. Recycling of binary polymer carpet is utilized in high-performance rubber composites using maleic anhydride (MA) or ionic liquid (IL) compatibilizer, as a potential EoL alternative. The LCA results indicate that the use phase is the highest contributor to the environmental impacts, considering the carpet being detergent washed. Given that, smaller MPs accumulated more in the carpet when vacuum cleaned, attracting other MPs presumably particles being statically charged. Addition of IL in recycling of binary plastic carpet not only improves the curing kinetics of rubber composites but also the enhances dielectric and rheological viscoelastic behaviors compared to the conventional MA compatibilizer.