Will plastics soon be easier to degrade?

 (Image: Pixabay CC0)
(Image: Pixabay CC0)

A research team has developed a new type of polymer, the main component of plastics, which is more easily degradable than conventional materials. Mechanical treatment such as grinding, combined with the use of an alkaline solution, is all that’s needed to facilitate chemical recycling and reduce environmental impact.

According to UN figures, humanity produces around 430 million tonnes of plastic every year, which, if improperly disposed of, harms both the environment, creating problems for plants, wildlife and human health. Developing a plastic with less impact is obviously as crucial as it is urgent. This is the goal set by an international research group, including four researchers from the Institut Adolphe Merkle at the University of Fribourg.

Plastic has the defects of its qualities

Plastics are made up of long chains of molecules called polymers. Very strong and stable, these chains resist natural decomposition processes, which explains why plastics accumulate in nature. To remedy this, researchers at the Institut Adolphe Merkle, in collaboration with colleagues at the University of Darmstadt and Strathclyde, have developed new chemical structures that make it easier to break the bonds between molecules.

Easier disposal

To achieve this, the scientists turned to cyclobutene, a hydrocarbon molecule that can be easily incorporated into many types of plastic. When incorporated into polymers, this chemical compound enables them to disintegrate into smaller molecules under the action of mechanical forces and an alkaline solution", explains Peng Liu, polymer chemistry specialist at the Institut Adolphe Merkle. It is this property that facilitates the chemical degradation of plastics, helping to reduce environmental pollution.

Degradation on demand

The main challenge when it comes to designing degradable polymers is that they must not degrade prematurely, i.e. during use. We have solved this problem with cyclobutene," explains Christoph Weder, Professor at the Institut Adolphe Merkle, "because it acts as a degradation switch. This is activated under specific environmental conditions combining mechanical forces and alkaline conditions, such as those found in the oceans. It is in this way that we believe plastics incorporating our chemical compound can be more easily broken down and disposed of.’

Mechanically triggered on-demand degradation of polymers synthesized by radical polymerizations , Nature Chemistry