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.