Addressing plastic waste through novel upcycling enabled by cold-sintering

Plastic products are ubiquitous and indispensable in our lives. Although plastics are easily available and have beneficial uses, their disposal has created a critical problem associated with the every growing plastic waste generation. Traditional recycling fails to address a majority of the plastic waste and nascent technologies to enable full circularity are not fully developed and economic feasibility questions remain. Here, we demonstrate a new approach that could incorporate plastic waste into long lifetime durable composites through cold-sintering, which is capable of sintering inorganic materials near 100 degrees Celsius. One potential avenue for these composites is structural materials. We show that polypropylene (PP) can be cold-sintered with gypsum to create composites from plastic waste and construction waste at compositions that are between 10% to 50% polymer. The mechanical properties of PP/gypsum cold-sintered composites can exhibit improved properties over their individual components. This approach could address problems associated with waste accumulation through the co-sintering and re-processing of polymers with inorganic materials.