Synthesis of Poly(Lactic Acid-co-Glycolic Acid) by Direct Melt Polycondensation Without Catalysts

Poly(lactic acid-co-glycolic acid)(PLGA) was synthesized with lactic acid and glycolic acid by direct melt polycondensation without catalysts.The products were characterized by GPC,FTIR,1H-NMR.In this work,the effects of reaction time,polymerization temperature(Tp) and LA/GA feed ratio on molecular weight were investigated.Results indicated that in the range of Tp we discussed,molecular weight gradually increased and then decreased as the reaction time increased;the maximal molecular weight of PLGA decreased while Tp increased;the optimal ranges of Tp and reaction time were 160~170 ℃ and 57~69 h respectively;under the same reaction conditions,the molecular weight of PLGA increased while the LA/GA feed ratio decreased.The objective of this study is to develop an economical,safe and effective method for the synthesis of PLGA.