Synthesis, Modification and Application of Polylactic Acid

The massive use of petroleum-based plastics has caused tremendous damage to the world's environment, so it has become increasingly urgent to develop biodegradable materials represented like polylactic acid (PLA). PLA is a non-polluting, completely degradable and renewable polymer material with high strength, high modulus and good biocompatibility. However, the disadvantages of conventional PLA, such as poor heat resistance and limited flexibility, limit its application. Therefore, its modification is needed. This article summarizes the structure and properties of PLA and describes the synthesis methods based on direct polymerization, ring-opening polymerization and enzyme-catalyzed polymerization. The article also reviews the methods of PLA modification, including physical modification by adding fibrous materials, nucleating agents, and compound modification, and chemical methods such as copolymerization and cross-graft modification. Moreover, the article presents the applications of PLA in packaging and medical materials. At the end of this article, future research and development directions of PLA are discussed.