Polylactide (PLA) is a biodegradable, thermoplastic, aliphatic polyester derived from lactic acid. It can be easily produced in a high molecular weight form through ring-opening polymerization using a stannous octoate catalyst.
Due to the chiral nature of lactic acid several distinct forms of polylactide exist: poly-L-lactide (PLLA) is the product resulting from polymerization of lactid acid in the L form. PLLA has a crystallinity around 37%, a glass transition temperature between 50-80° C and a melting temperature between 173-178° C. The polymerization of a mixture of both L and D forms of lactic acid leads to the synthesis of poly-DL-lactide (PDLLA) which is not crystalline rather than amorphous.
Polylactide can be processed like most thermoplastics into fiber and film. It has also been used in a number of biomedical applications, such as sutures, dialysis media, and drug delivery devices. PLA is attractive as a sustainable alternative to petrochemical-derived products since it can be produced from a more economic resource such as corn starch.