High molecular weight polylactic acid is generally produced by the polymerization of lactide. Lactide is prepared by the depolymerization of low molecular weight polylactic acid. There are difficulties in the preparation of high molecular weight polylactic acid and high purity lactide isomers due to...http://www.google.es/patents/US5357034?utm_source=gb-gplus-sharePatente US5357034 - Lactide polymerization
