Polylaktidacid

Polylaktidacid, commonly abbreviated PLA, is a biodegradable thermoplastic polymer derived from lactic acid monomers. It exists in stereoisomeric forms, including poly-L-lactic acid, poly-D-lactic acid, and the racemic poly-D,L-lactic acid, which influence crystallinity, mechanical properties, and thermal behavior. PLA is typically produced from renewable resources such as corn starch or sugarcane and is valued for its biodegradability and biocompatibility.

Commercial production of PLA generally involves first fermenting sugars to lactic acid, converting it to lactide, and then polymerizing the lactide by ring-opening polymerization. Alternative routes include direct polycondensation of lactic acid. Catalysts such as tin octoate or metal-based systems enable high molecular weights. PLA exhibits a glass transition around 60–65°C and a melting temperature near 150–160°C, with crystallinity and properties tunable by stereoregularity and processing conditions. It can be made into films, fibers, foams, and 3D printing filaments, and is often blended with other polymers to improve toughness or thermal resistance.

PLA is widely used in packaging, disposable tableware, textiles, and biomedical devices such as sutures, drug-delivery systems, and resorbable implants. Its biodegradability means it can decompose under industrial composting conditions, converting to water, carbon dioxide, and biomass, though degradation rates vary with temperature, moisture, and microbial activity. Chemical recycling to lactic acid is also explored. Limitations include relatively low heat resistance, brittleness, and slow crystallization, which can restrict certain high-temperature or structural applications.