The detriment of ever increasing use of plastics is widely known; it includes the consumption of fossil fuels and the rising amounts of trash. In response, many are turning to biomass as a resource for bioplastics, but these present their own challenges when it comes to recycling. In order to be recycled properly, plastics must be consistently stable while in use, with no possibility of early degradation.
Making high-grade plastics from biomass that can be made to break down into reusable components could be a new strategy for reducing these drawbacks. Researchers in the journal Angewandte Chemie demonstrated that a “destruct command” could be sent using light of a particular wavelength. Recycling should ideally be upcycling rather than downcycling.
An interdisciplinary team of researchers from the United states—Jayaraman Sivaguru at the Center for Photochemical Sciences, Bowling Green State University in Bowling Green, Ohio, and Mukund P. Sibi and Dean C. Webster at North Dakota State University in Fargo—have chosen bio-based plastics for which degradation can be triggered by irradiation with light, and aimed to be polymerized again to make similarly high-performance polymers.
The researchers were able to develop crosslinked polymers that contain building blocks in their backbone based on vanillin. Vanillin can be produced from materials such as lignin, a byproduct of cellulose production.
According to the report in SciTech Daily, “The vanillin derivative developed by the team absorbs light at 300 nm and enters into an excited state. This leads to a chemical reaction that triggers the degradation of the polymer. Because this wavelength is not contained in the spectrum of sunlight that reaches the earth, unplanned degradation is avoided. The researchers were able to recover 60% of the monomers, which could be polymerized again with no loss of quality”.
The capability to produce photodegradable, recyclable, and renewable crosslinked polymers made of biomass resources seems as a highly promising approach for making more sustainable plastics that can pose minimal to no environmental risk.