Reducing plastic pollution by adding RNA-inspired 'breaking points'

Once plastic products are used and discarded, they can linger in oceans, collecting in large "garbage patches" and harming sea life. One potential solution, a biodegradable polymer called polylactide (PLA), has so far not fully lived up to its promise, showing little sign of breakdown once in seawater. In a new study in the Journal of the American Chemical Society, researchers set out to address this issue by incorporating RNA-inspired breaking points to the polymer. 

By some estimates, conventional plastic can take hundreds of years to decompose in the ocean, but no one really knows how long it will continue to clutter the seas. One replacement material, PLA, can be manufactured from natural sources, such as corn and potato starch. It can rapidly degrade under specific conditions, such as when composted, and is often used in compostable tableware and cutlery.

In experiments, they immersed films of the new PLAs in artificial seawater and measured the change in weight of the films, as well as the release of lactic acid, a degradation product of PLA. The polymer with the highest concentration of breaking points, 15 percent, broke down completely to lactic acid after two weeks. Polymers with lower concentrations took longer, and some could require as much as several years, they calculated. These results showed that the degradation rate can be tailored, depending on the amount of breaking points in the material. The potential applications aren't limited to PLA, according to the researchers. Adding breaking points may speed the decomposition of other plastic polymers and become a key strategy for preventing further marine pollution, they write.