Predictive rule reveals which sulfur-based building blocks create sustainable, degradable plastics

Plastics pose a significant waste problem: many conventional plastics do not degrade or do it only with many difficulties. This makes research on new essential plastics – materials that retain useful properties but can also be deliberately decomposed or recycled. Such innovations could lead to more sustainable materials, allowing the use of plastics in a way that retains long -term resources.

According to a study published in the journal International edition of Angewandte ChemieIncorporating sulfur atoms into polymers chains makes them more degradable.

Sulfur atoms improve the sustainability of polymers because the links between carbon and sulfur atoms are easier to break than connections between carbon and other carbon or oxygen atoms. This allows plastics containing sulfur to degrade under relatively soft conditions. However, the synthetic strategies of these plastics are always underdeveloped, which hinders large-scale production.

A first step towards mass production has now been carried out: an international research team, including members of the University of Martin Luther Halle-Wittenberg, Texas A&M University and the University of Bayreuth, developed a method to test and compare various construction blocks containing sulfur for their ability in plastic production.

“With our study, we were able to establish a predictive rule which indicates which sulfur -based construction blocks give perfectly structured and clean polymers – and who do not,” explains Professor Alex J. Plajer, junior professor of macromolecular chemistry at the University of Bayreuth.

Until now, the construction blocks and the reaction conditions used to produce these plastics containing sulfur must be specifically adapted and optimized for each combination of components.

“There was no plan to produce lasting plastics with sulfur under standardized conditions,” explains Plajer.

Using their new method, the researchers have identified carbonyl sulfide as a sulfur -based construction element particularly suitable for plastic production. The carbonyl sulfide reacts very reliablely, forming long uniformly structured polymers chains – and it does so with a minimum use of a catalyst to facilitate the chemical reaction. In addition, the reaction produces very few unwanted by-products.

“Our results set the foundations for the development of new sustainable materials which can be decomposed in a controlled manner,” concludes Plajer.