Compostable plastic in development

A plastic which is made from a sugar-based polymer that may be composted at home is being developed by scientists at the Imperial College London. Currently, 99% of plastics contain fossil fuels which has lead to research into a more sustainable source of plastic, particularly in the food packaging industry. Other degradable plastics have been developed using materials such as corn starch and sugar beet, but these are food crops and research is now focusing on finding non-food crop polymers from which to make plastics.

The degradable polymer is made from sugars produced from the breakdown of lignocellulosic biomass, which comes from non-food crops such as fast-growing trees and grasses, or renewable biomass from agricultural or food waste. “Our key breakthrough was in finding a way of using a non-food crop to form a polymer, as there are ethical issues around using food sources in this way,” said Dr Charlotte Williams who leads the team of Engineering and Physical Sciences Research Council scientists.

“For the plastic to be useful it had to be manufactured in large volumes, which was technically challenging. It took three-and-a-half years for us to hit a yield of around 80% in a low energy, low water use process,” explains Dr Williams. This is significant as the leading biorenewable plastic, polylactide, is formed in a high energy process requiring large volumes of water. In addition, when it reaches the end of its life polylactide must be degraded in a high-temperature industrial facility. In contrast, the oxygen-rich sugars in the new polymer allow it to absorb water and degrade to harmless products – meaning it can be tossed on the home compost heap and used to feed the garden. Read more..