Synthesis technology of poly-lactic acid by ring-opening polymerization

The synthesis technology of poly-lactic acid (PLA) by ring-opening polymerization was developed, the effect of PLA synthesis conditions, such as catalyst type and content, reaction time and temperature, lactide purity, etc. were discussed. In the preparation of lactide, the catalyst of ZnO/La_2O_3 were charged in twice, and higher output, up to 52%, was reached. PLA was prepared through the lactide ring-opening polymerization with the catalyst of Sn(Oct)_2 in toluene, under the condition of reaction temperature 130—180℃, reaction time 8 h and system vacuum controlled at 0.098 MPa, the molecular mass of prepared PLA reached 2.4×104 g/mol. The results are better than the references.