Biodegradation behavior of polyesters with various internal chemical structures and external environmental factors in real seawater

Releasing non-degradable plastics into the oceans contributes to ghost fishing and microplastic generation, thus increasing the interest in biodegradable alternatives. However, biodegradable plastics decompose slowly in marine environments, and understanding how their chemical structure influences their degradation behavior in the oceans is a growing focus. Herein, we investigated the effects of intrinsic factors such as crystallinity of polyester, the difference in Tg determined by the chemical structure, presence of natural nanofillers and additives on seawater decomposition. Moreover, the biodegradation behavior of polyesters was analyzed based on environmental conditions, such as water temperature and microbial communities. The biodegradation degrees were as follows: poly(butylene succinate-co-carbonate) > poly(butylene adipate-co-furanoate) ≫ poly‌(butylene succinate) > poly(butylene adipate-co-terephthalate) ≫ poly(ʟ-lactic acid). No clear trend in molecular weight change of existing samples was observed because cleaved polymer chains were washed out through surface hydrolysis mechanism. Microbial species richness increased significantly during summer, with no dependency on the type of polyester. This study provides insights into the biodegradation behavior of various polyesters in seawater.