Despite accounting for just a small portion of plastic use, polylactic acid (PLA) is gaining favor as brand owners seek environmental credentials.
PLA is often touted as biodegradable since it is made from lactic acid produced by sugar fermentation.
Many biodegradable polymers are only compostable under industrial circumstances, but scientists at the University of Bath have discovered a technique to break down plastics using just UV light.
Plastics degrading using UV light?
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Scientists at the University of Bath's Centre for Sustainable and Circular Technologies (CSCT) have improved the degradability of PLA by inserting varying quantities of sugar molecules into the polymer.
They discovered that adding as little as 3% sugar polymer units to PLA resulted in a 40% breakdown of the biopolymer within six hours of exposure to UV radiation.
As public awareness about plastic waste grows, PLA made from sugar fermentation is increasingly extensively utilized as a renewable, viable approach to plastics produced from crude oil products used everywhere from throwaway cups and teabags to 3D printing and packaging.
It is frequently labeled as biodegradable; however, its degradability in natural settings, such as soil or ocean, is restricted, and it only dissolves under commercial composting conditions of high temperatures and humidity, which are not feasible in residential compost heaps.
The technique is most promising since it is compatible with existing plastic production methods, which means it may be evaluated and deployed swiftly by the plastics sector.
The researchers, who published their findings in Chemical Communications, expect that their discoveries will be utilized in the future by the plastics industry to help make plastic trash more degradable at the end of the product's life.
The research was headed by Dr. Antoine Buchard, Royal Society University Research Fellow and Reader in Polymer Chemistry at the CSCT, and was funded by the Royal Society.
He stated that many plastics are labeled as biodegradable, but this is only true if they are disposed of in an industrial waste composter.
If they are disposed of in residential compost heaps, they can persist for years, as per ScienceDaily.
According to Buchard, most PLA plastics are composed of lengthy polymer chains that are tough for water and enzymes to break down.
The study incorporated carbohydrates into polymer chains, which are held together by bonds that can be destroyed with UV radiation.
This weakens the plastic, causing it to break down into smaller polymer chains that are more susceptible to hydrolysis.
According to Buchard, this might make the plastic considerably more biodegradable in the natural environment, such as the ocean or a garden compost heap.
Scientists have previously experimented with hydrolysis to improve PLA degradability, but this is the first time light has been used as an agent, according to the researchers.
It's early days, and it'll be interesting to watch if this research holds up outside of the lab.
However, Buchard is optimistic that "technology might be employed in the future to develop polymers that are tough while used, but can break down readily when reuse and recycling are no longer available," as per Plastics Today.
