Valorisation of Post-Consumer Textile Waste for High-Performance PLA Biocomposites through polyvinyl alcohol (PVA) Modification

Each year, 80 million tonnes of textile waste are landfilled, causing significant environmental challenges. Transforming this waste into value-added composite materials supports pollution reduction, raw material conservation, and promotes circularity and sustainability in material innovation. Already, several research have been conducted on this subject, and this waste material is gaining increasing attention from the researchers with time. However, existing studies rarely address the integration of biopolymer, functionality and circularity within such systems, leaving a critical need for holistic, bio-based solutions. In this study, post-consumer textile waste (used cotton bed sheet) was employed as reinforcement in polylactic acid (PLA) matrices, with fibre surfaces modified via alkali (NaOH), polyvinyl alcohol (PVA), and NaOH-PVA combined treatments. Composites were fabricated using a stacking procedure followed by compression moulding, and systematically characterized through FTIR, density, void content, mechanical testing, SEM, DMA, TGA, and water contact angle analysis. FTIR confirmed successful chemical modification, while all composites exhibited acceptable void content (<2%) and density ( 1.31 g/cm3). Mechanical performance improved significantly after textile waste valorisation, with PVA modification yielding 16% increases both in tensile and flexural strength, compared to untreated composites. DMA results revealed higher storage modulus values for modified composites, indicating enhanced fibre–matrix interfacial bonding. TGA demonstrated improved thermal stability with modification, and water contact angle measurements confirmed superior hydrophobicity even after 90 seconds. These findings highlight the potential of chemically modified textile waste-reinforced PLA composites for non-structural and semi-structural applications in automotive, construction, and furniture sectors, contributing to circular economy strategies in composite engineering.