Making tougher biodegradable plastics from plants
Replacing petro-chemical-based plastics with plant-based alternatives is a growing area of research. One popular form of plant-derived plastic is Poly(lactic) acid, or PLA, a type of biodegradable plastic that is currently used to make bottles, bags and is woven into fibers to make clothes in place of polyester. Although PLA has similar mechanical properties to PETE polymer, it has significantly lower heat-resistance, which limits its uses. Researchers are now developing a new chemical catalyst to improve the properties of PLA, making it stronger and more heat-resistant so it can be used for a wider range of applications.
PLA is made from renewable plant sources such as corn starch, wheat or sugarcane, and although its been known of for more than a century, it has only gained commercial interest recently due to its biodegradability. In an effort to extends the range of uses for PLA to include applications such as engineering plastics for the automotive industry, microwavable trays and hot drink cups, scientists from the University of Bath and Tel Aviv University are developing a new chemical catalyst to improve the process of making these plastics
As Professor Matthew Davidson, Whorrod Professor of Sustainable Chemical Technologies at the University of Bath and Director of the University’s Centre for Sustainable Chemical Technologies, explains: “PLA can be made up of two types of building blocks that are mirror-images of each other. Using the current technology, when the plastic is made with both types present they are jumbled together within the structure of the plastic.”
The joint British-Israeli project new project is looking to improve the properties of PLA by developing a selective catalyst that will build up a polymer of ‘left-handed’ and ‘right-handed’ building blocks in a structured order, making the resultant plastic stronger and more heat-resistant. The team says such catalysts are the key to providing renewable and biodegradable plastics that will help reduce society’s reliance on oil.