In November 2014, researchers at the North Dakota State University Centre for Sustainable Materials Science released a paper outlining the development of a new bio-plastic which can be broken down when exposed to ultraviolet light for just three hours. This is the fastest recorded time to biodegrade plastic.
The scientists focused on using oilseed from agricultural crops, lignin, cellulose and sucrose to generate building blocks of molecules, mixed with light-absorbing molecules called photo-triggers. The bonds of these molecules are broken down when exposed to light.
By heating this mixture, the scientists were able to create long repeating chains of small molecules that formed a solid polymer (plastic) when cooled. When they then exposed the solid plastic to ultraviolet light at a wavelength of 350 nanometres, which is within the range of wavelengths that the sun emits, the light-absorbing molecules (photo-triggers) broke off from the long chains of molecules. This triggered the plastic to degrade.
The process was so efficient that it took just three hours of exposure to ultraviolet light for the plastic to break down into a clear solution. According to the team’s recently published paper, these molecules can then be recovered and re-used to make new plastic.
Photo credit: John Dalkin / Flickr
Applications could include cars and electronics, where plastics are notoriously difficult to recycle. Could this see the end of scrap yards and e-waste mountains?