Polyurethane is one of the most commonly used plastics, found in everyday items such as phone cases, car parts and shoes. Polyurethane is a type of polymer whose use grew exponentially during World War II as a replacement for rubber due to its durability. Initially used as adhesives or coatings, the chemistry behind polyurethane evolved until it could be shaped into rigid forms, which now constitute many plastic products. Unfortunately, there is currently no recycling stream for polyurethanes, so most end up in landfills, where they will remain for hundreds of years. Researchers have recently announced a new type of plastic that can self-destruct after use, thanks to the integration of plastic-eating bacteria. Could this be the solution we need to address our plastic waste challenges? Recently, a team at University of California San Diego have created self-digesting plastic by adding spores of bacillus subtilis, a plastic-degrading bacteria, into polyurethanes. The team then genetically engineered the bacteria to withstand the extreme heat required in plastic production. When the plastic is disposed of in a simulated compost environment, nutrients in the compost trigger the plastic to quickly biodegrade. The research showed that adding the bacterial spores to the plastic led to 90% of the plastic disintegrating within 5 months. Don't worry, the plastic won't start biodegrading until it comes into contact with compost, since the spores remain dormant during the useful lifetime of the plastic. Another added benefit of the self-destructing plastic is increased toughness. Researchers found that incorporating spores increased the toughness of polyurethane plastics by 37%. What might this mean for the future? A stronger plastic that degrades quickly after use could significantly reduce waste. More durable plastics would crack or break less often, reducing the need for replacements. For example, a phone case that lasts 3 years instead of 1 would mean less plastic is purchased and disposed of. It also means that by composting our plastics, we can almost fully degrade them within a year. This discovery could be monumental, changing the way we make, use and dispose of plastic.
