US researchers are working on infinitely recyclable plastic.

Only 5 per cent of plastic is actually recycled, and when it is, it often goes into low-value materials which still end up in landfill.

But a team at Colorado State University has now developed a new plastic polymer which can be easily recycled into its base components to make new products, over and over again.

While scientists have made plastics which are recyclable in this way before, this is the first time the resulting plastic is strong enough to actually be useful.

Some polymers, such as polyethylene terephthalate in soft drink bottles, can be ‘depolymerised’ back to their starting monomers.

This means that true virgin material can be repolymerised for repeated use.

The new polymer is based on a five-membered ring cyclic monomer derived from γ-butyrolactone that could be produced at ambient temperature and mild conditions.

The high-molecular-weight polymer exhibits high crystallinity and thermal stability, but at hot enough conditions, or at lower temperatures in the presence of a zinc chloride catalyst, the polymer can be returned to its starting monomers and thus recycled into new material.

The researchers hope their polymer can form the basis of a ‘closed-loop’ plastic supply chain.

The latest paper is accessible here, and the research team has also produced a perspective article outlining a future where waste plastic is a valued and sought-after commodity.