New Degradable Adhesive Utilizes Thionolactone Additive For Recycling Applications

In an effort to address recycling of products using adhesives and adhesive labels, a University of Surrey team has developed an experimental new degradable adhesive which is described as being "very similar to that used on commercial packaging tape." Its key ingredient is a chemical additive known as thionolactone, which makes up just 0.25% of its composition. 

The goal is to help recycling processes and help decrease adhesive residues in recycling facilities' water systems. This will help increase efficiency and the effectiveness of removing adhesives from end products. Degradable adhesives do already exist but, according to the researchers, they tend to lack the sticking strength of their conventional counterparts.

"Adhesives are made from a network of chain-like polymer molecules that are linked together, which leads to the residue build-up we see left behind when recycling materials such as glass and cardboard," said the researchers. "Our additive creates what we call degradable thioester connections in the polymer network, and provides an innovative solution to making recycling processes residue-free."

The Surrey researchers report that typical connections are completely degraded via the simple processes of either aminolysis (a chemical reaction with ammonia) or thiolysis (a reaction with a molecule called coenzyme A). In lab tests incorporating substrate materials such as glass, steel, plastic and paper and that labels utilizing the new adhesive could be detached up to 10 times faster than those using a traditional adhesive.

The researchers are now investigating the commercial viability of the adhesive, along with its environmental sustainability. A paper on their research was recently published in the journal Angewandte Chemie.

Source: New Atlas