Research: New method to break down plastic

Researchers in the UK have developed a novel method to break down plastics using just ultraviolet (UV) light.

The researchers at the University of Bath discovered that adding sugar units to polymers increases their degradability when exposed to UV radiation.

UV radiation has a wavelength of 10 nanometres (nm) to 400 nm, shorter than that of visible light, but longer than X-rays. Many plastics that bear the biodegradable label can only be composted in industrial settings.

The researchers noted that public concern about plastic waste has led to the widespread usage of PLA (Poly lactic acid), which is a renewable, sustainable alternative to polymers made from crude oil. PLA is used in everything from throwaway cups and teabags to three-dimensional (3D) printing and packaging.

Although PLA is sometimes advertised as biodegradable, it only dissolves under industrial composting conditions of high temperatures and humidity, which are not possible in residential compost heaps.

It is also not easily degradable in natural environments, such as soil or the ocean. "Lots of plastics are labelled as biodegradable, but unfortunately this is only true if you dispose of it in an industrial waste composter - if put into domestic compost heaps, it can last for years," said Antoine Buchard from the University of Bath.