Delamination Recycling of Multilayer Plastic Films

Only a small fraction of plastics produced are being recycled, with the great majority landfilled or released into the environment. Mechanical recycling, currently used to recycle plastic, cannot handle films, which constitute about 40% of all plastic packaging. Polyolefin-rich films are suitable feedstock for pyrolysis; however, pyrolysis breaks down the polymer chains to produce hydrocarbons that are typically used as fuel, which is not true recycling.

Research in our group advances solvent-based molecular recycling, whereby polymers are selectively dissolved and precipitated to achieve separation and recovery. Because the polymer chains do not break and retain all their embodied energy, this is a promising, low-energy, low-greenhouse gas (GHG) plastic recycling methodology.

This project addresses the recycling of multilayer films, which comprise multiple layers of polymer combined into a single film to meet consumer specifications such as preserving food and medicine, acting as an oxygen or moisture barrier, and keeping products sterile. This presentation highlights the solvent-assisted delamination process that we have developed, which recovers the major component, polyethylene, in its solid form, from multilayer films, hence greatly reducing solvent amounts and the corresponding energy needs and GHG emissions compared to dissolution–precipitation recycling. Delamination recycling presents an energy-efficient and environmentally friendly approach to recover value from the approximately 17 million metric tons of multilayer plastic films that are produced every year globally.