Research progress in synthesis of poly (lactic acid) by direct polycondensation

Poly (lactic acid) as a completely biodegradable plastics has considerable properties, but the high prices prevent it from being used as normal materials. A low cost poly(lactic acid) may be synthesized by the direct polycondensation. The poly (lactic acid) synthesized by the solution polycondensation,direct melt polycondensation,melt polycondensation/chain extending and melt polycondensation/solid polymerization is reviewed.The development trends in this field are also predicted.