Ultrafast bulk degradation of polylactic acid by artificially cultured diatom frustules

In the field of governing our Plastic Planet, polylactic acid (PLA) has been considered to be a promising and ecologically friendlier alternative to traditional petroleum-based plastics. However, PLA-based products degrade slowly in the natural environment, likely resulting in a large accumulation of PLA waste worldwide in the near future. Herein, we have incorporated artificially cultured diatom frustules (DFs) into PLA, and found an improvement of more than eightfold on the degradation rate, from more than 24 months to 3 months or even less, as compared with the pure PLA. Mechanistic investigations illustrate that DFs change the degradation behavior of PLA from surface erosion to bulk erosion by the induced microfibril crystals. Simulation analysis verifies that the unstable crack propagation inside the PLA matrix greatly accelerates the degradation. The method developed in this work provides an efficient way to achieve rapid and adjustable degradation of biodegradable polymers for the urgent and widespread usage of green plastic productions.

Automated summary

In this study, diatom frustules were incorporated into PLA, resulting in a significant improvement in degradation rate. This method provides an efficient way for the rapid development of biodegradable plastics.