BENGALURU – Multi-layered plastics (MLPs) and synthetic textiles have long been deemed “untouchables” in recycling due to their complex, chemically diverse structures that make them nearly impossible to process. These materials typically end up in landfills or incinerators, contributing significantly to environmental pollution.
Researchers at the Indian Institute of Science (IISc), led by Prof. Suryasarathi Bose from the Department of Materials Engineering, have developed a patented technology called SaLSO (Solvent-Assisted Layer Selective Opening), which promises a scalable solution for these waste streams. The process, which builds on the team’s earlier work on recycling polyurethane and epoxy, can separate the components of MLPs and synthetic textiles, enabling recovery and reuse in high-value applications.
MLPs, used widely in packaging such as potato chip packets, form a market worth over $168 billion, while synthetic textile waste from polyester- and nylon-based products contributes to over 92 million tonnes of waste annually. Recycling efforts have struggled to keep pace due to technical barriers. According to Bose, SaLSO can handle category-7 plastics and mixed polyester textiles, transforming them into usable, upcycled materials.
The process is notable for its simplicity and sustainability — it uses only seawater and bio-acids (naturally occurring, even edible chemicals) to separate polymers like polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). It achieves over 99% recovery yield without toxic solvents, high temperatures, or energy-intensive steps.
In lab trials, the team successfully processed diverse real-world waste, including aluminum-lined snack packets and flour bags, using a reactor with a 500-gram MLP capacity per batch. Designed for easy scale-up, the extracted polymers can strengthen lower-quality plastics without virgin polymers or fillers, thus creating more durable materials.
With industrial trials planned and discussions ongoing with potential partners, IISc aims to commercialize SaLSO soon. If widely adopted, the technology could significantly expand recycling possibilities, integrating circular economy practices into industries that have long lacked sustainable recycling options.