Introduction to Polylactic Acid (PLA) Biodegradable Plastics

Introduction to Polylactic Acid (PLA) Biodegradable Plastics

PLA is a new type of biodegradable material. It is made from starch raw materials extracted from renewable plant resources such as corn and sugarcane. There are two main methods for synthesizing PLA, namely direct polycondensation of lactic acid and ring-opening polymerization of lactide. Method (also called two-step method), of which the two-step polymerization route is the most commonly used. Firstly, lactic acid is distilled under reduced pressure to obtain lactide, and then lactide is used as the monomer to react under the conditions of initiator, high temperature and high vacuum. PLA is generated for a certain period of time.

PLA has both bio-based sources and biodegradable properties, non-toxic, non-irritating, easy to process and high strength, but its brittleness, poor toughness, and slow crystallization rate are limited in the application of engineering plastics. In view of the defects of poor toughness and large brittleness, modification methods are often used to improve its comprehensive performance and ensure its biodegradability.

PLA has mechanical properties similar to polypropylene. At the same time, its gloss, clarity and processability are similar to those of polystyrene. It can be processed into a variety of food and beverage products through general plastic processing methods such as extrusion, injection molding, and blow molding. Packaging materials, medical sutures, tissue engineering stents and other medical materials also have PLA.