The method could be effective in recycling plastics from milk cartons, food containers and plastic bags, say researchers at the Virginia Tech College of Science. 

The chemical structure of polyethylene – one of the most commonly used plastics in the world today – is strikingly similar to that of fatty acids, which are used as a chemical precursor to soap.

Both materials are made of long carbon chains, but fatty acids have an extra group of atoms at the end of the chain. Due to this chemical similarities, the research team set out to develop a process to convert polyethylene into fatty acids, which could then be used to produce soap. 

Guoliang ‘Greg’ Liu, associate professor of chemistry, came up with the idea while looking at a fireplace. He then began to wonder what would happen if polyethylene could be burned in a safe laboratory setting. 

“Firewood is mostly made of polymers such as cellulose,” Liu said. "The combustion of firewood breaks these polymers...