Marine Biodegradable Polylactide-Based Materials

Polylactide (PLA) is a widely used biopolymer. However, it has low biodegradability in natural environments, including soil, marine, and freshwater systems. Given the severity of plastic pollution in the ocean, this study was aimed at enhancing the marine biodegradability of PLA. This was accomplished by blending with a poly(ethylene succinate) (PES)-based copolymer, referred to as PESSeb15, which was synthesized from succinic acid, ethylene glycol, and sebacic acid through melt-mixing. The addition of 30 wt % PESSeb15 significantly enhanced the marine biodegradability of PLA, as determined by biochemical oxygen demand (BOD) tests in seawater. The residues and microbial communities in the BOD test solutions were studied to elucidate the biodegradation mechanisms. The results revealed that PESSeb15 was biodegraded in the initial stages, followed by PLA. The marine biodegradability of a powder mixture of PLA and PESSeb15 was also studied. No biodegradation of PLA occurred, highlighting the significance of proximity between the PLA and PESSeb15 components in enhancing biodegradability. This research is expected to broaden the range of applications for PLA.