Polylactic acid (PLA) is a fatty acid-based biodegradable plastic derived from renewable plant resources such as corn starch and sugar cane. It can be regarded as a “hard and transparent plastic originating from the fields” - it is synthesized through the ring-opening polymerization of lactide cyclic dimer or direct condensation, thus possessing the characteristics of renewable raw materials, complete biodegradability (breaking down into water and carbon dioxide within a few months under industrial composting conditions), as well as excellent transparency and glossiness. PLA not only has rigidity and tensile strength similar to polystyrene (PS), but also has good food contact safety and processing formability (suitable for injection molding, blow molding, spinning, etc.), and is widely used in disposable tableware, food packaging boxes, biodegradable garbage bags, 3D printing materials, biomedical sutures, drug controlled-release carriers, and other occasions that require short-term use or biocompatibility.