Direct synthesis of poly(l-lactic acid) by melt polycondensation under continuous microwave irradiation

作者：Zhang Ying Min^*; Li Kai Ming; Wang Peng; Jiao Chun Yan; Han Ning

来源：Polymer Materials Science and Engineering, 2009, 25(10): 27-30.

• Average molecular weight
• Binary catalyst systems
• Cocatalyst
• Constant temperature
• Continuous microwave irradiation
• Direct synthesis
• L-Lactic acid
• Melt polycondensation
• PLLA
• Poly L lactic acid
• Polymerization conditions
• Polymerization process
• Polymerization time
• Prepolymerization
• Vacuum level

Poly (L-lactic acid) (PLLA) was directly prepared through melt polycondensation started from industrial L-lactic acid under continuous microwave irradiation. In this paper the effects of dehydration vacuum level, pre-polymerization temperature, polymerization time at constant temperature, the catalyst species on polymerization process were studied. Finally, it is concluded that the optimum polymerization conditions are: the use of a binary catalyst system consisting of SnCl2 and TSA as co-catalyst(SnCl2/TSA=1:1, SnCl2: 0.45%) increased the molecular weight of PLLA efficiently, firstly, under 0.080 MPa dehydration lasts for 15 min; then, under 0.090 MPa pre-polymerization runs for 30 min; finally, reactant system remains constant temperature for 20 min after being increased to 230 °C, where PLLA with viscosity-average molecular weight as high as 6.02×104 g/mol is synthesized.

• 出版日期2009