Polylactic acid, also known as poly(lactic acid) or polylactide (PLA), is a plastic material. As a thermoplastic polyester it has the backbone formula (C3H4O2)n or [–C(CH3)HC(=O)O–]n. PLA is formally obtained by condensation of lactic acid C(CH3)(OH)HCOOH with loss of water. It can also be prepared by ring-opening polymerization of lactide [–C(CH3)HC(=O)O–]2, the cyclic dimer of the basic repeating unit. Often PLA is blended with other polymers. PLA can be biodegradable or long-lasting, depending on the manufacturing process, additives and copolymers.