Scientists from Rice University in Texas are transforming discarded plastics into non-toxic, naturally occurring materials. They’re doing this by using a newly developed technique called “flash Joule heating,” to rapidly heat plastic materials to very high temperatures. Currently, there are a few plastic recycling techniques that are widely used, with differing results. For example, plastic bags are a huge contributor to the plastic waste stream – Waste Management, a trash collection company, estimates that over one billion plastic bags are used each year in the U.S. alone. Even more shockingly, each plastic bag is used for, on average, less than one hour. Currently, the most common way to recycle plastic bags is by compressing them into composite lumber or small pellets, which can be used for building materials . While this is an excellent way to reuse single-use plastic, this plastic still is not biodegradable.
In contrast, the “flash Joule heating” method turns plastic into graphene, which is highly recyclable and very stable. Graphene itself is incredibly strong and stretchy – 200 times stronger than steel. Graphene is a single layer form of graphite, a naturally occurring carbon-based mineral that is commonly found as pencil lead. Typically, graphite is mined and then mechanically processed in order to separate its layers, forming graphene. However, obtaining graphite can be expensive. By directly generating graphene from plastic waste, it is possible to reduce its production cost. Importantly, a reduced production cost can lead to broad implementation of graphene use outside of academic research – with lower production costs, graphene can be added to concrete, rubber, or asphalt to improve strength and performance. Innovations like this will likely make graphene much more widely available for commercial use.