Poly (lactic acid) (PLA)

Poly (lactic acid) (PLA) degrade biologically into acid, a product of the carbohydrate metaolism, and a importance as a substitute for the non-degradable thermoplastics has attracted a lot of attention in recent years.

PLA are of considerable interest as biodegradable polymers in medical applications and also potentially for use as environmentally friendly packaging materials. PLA is a thermoplastic, high strength, high modulus polymer which can be made from annually renewable resources to yield articles for use in either the industrial packaging field or the biocompatible/ bioabsorbable medical device market (Migliaresi et al., 1988).

PLA exists in L and D- form, which are optical isomers. PLA with large amount of L- form isomer is highly crystalline. In general, the crystallinity and biodegradability depend on the content of D0 form isomer (Zhang et al., 1993).