The fundamental degradation mechanism of PLA relies on the hydrolysis of ester bonds in its molecular structure. PLA polymer chains contain a large number of ester groups (-COO-). When exposed to humid, high-temperature or natural microbial environments, water molecules penetrate the material interior and break the long polymer chains through hydrolysis reaction. The long-chain macromolecules are gradually decomposed into short-chain oligomers, lactic acid monomers, and finally completely mineralized into carbon dioxide and water, leaving no microplastics or harmful residues.