Everyone knows how much damage plastics are doing to the environment, from the plastics comprising the Great Pacific garbage patch to the microplastics infesting the ocean, to landfill sites that are overflowing with plastic waste. Some types of plastics can be recycled, but the resulting products are often low-quality and not that useful. This means that only a small percentage of all the plastic we create and use ends up being recycled.
Now, chemists from the University of California Santa Barbara and other universities have come up with a new way to recycle plastic into something more valuable, which could help reduce the plastic waste with which we currently pollute the environment.
The method involves approaching plastics on the molecular level. Plastics are made up of chains of carbons which can be combined in all sorts of ways to create different types of plastic. Instead of melting down plastics, which results in lower-quality products at the end, the chemists have found a way to chop up the carbon chains without using a massive amount of heat or giving off nasty emissions.
Lead author Susannah Scott wrote about the research for the academic news website The Conversation, describing how the process for breaking down plastics works: “The process we have developed does not require high temperatures, but instead depends on tiny amounts of a catalyst containing a metal that removes a little hydrogen from the polymer chain,” she wrote. “The catalyst then uses this hydrogen to cut the bonds that hold the carbon chain together, making smaller pieces.”
This process essentially turns waste plastics into a liquid by cutting the carbon chains that the plastic is composed of. The resulting liquid is valuable as it contains molecules called alkylbenzenes, which are solvents and are used in detergent products.
The method has been tested on polyethylene, one of the most common types of plastics which is found in things like food packaging, construction materials, and waterproof coatings. The researchers were able to use a “one-pot process” with a small amount of heat to break down the polyethylene into a useful product.
The process has only been demonstrated on a small scale so far, but the researchers are hopeful it could be adapted to process large amounts of plastic within the next few years. The research is published in the journal Science.
digitaltrends.com, 10 October 2020