Scientists discovered a chemical process that provides biodegradable, valuable chemicals from discarded plastics to be used as surfactants and detergents in a range of applications. The process has the potential to create more sustainable and economically favorable lifecycles for plastics.
The researchers targeted their work on the deconstruction of polyolefins, which represent more than half of all discarded plastics and includes nearly every kind of product — toys, food packaging, pipe systems, water bottles, fabrics, shoes, cars, and furniture.
The chemical construction of polyolefin plastics — long, strong chains of carbon-carbon bonds — makes them tough and durable and also makes them hard to break down. Polyolefins also generally lack the chemical groups that could be targeted in deconstruction processes. Many existing processes to recycle plastic result in less valuable, less usable components, making the economic feasibility of recycling far less appealing.
The new process uses what is already known about key steps of polymerization — the assembling of long polymer strands — but in reverse, by breaking some of the carbon-carbon bonds in the chains. Once a few carbon-carbon bonds are broken, the shortened polymer chains transfer to an aluminum end group to form reactive species. The catalysts and reactions for the process are related to those used in alkene polymerization, leveraging well understood chemistry.
The intermediates of the transformation are easily converted into fatty alcohols or fatty acids or are used in other synthetic chemistry to create chemicals or materials that are valuable as detergents, emulsifiers, pharmaceuticals, and cosmetics. Because the process is catalytically controlled, desirable product chain lengths can be targeted for synthesis. The end products are biodegradable, unlike polyethylene and polypropylene starting materials.