Microwave-Assisted Synthesis of Poly(L-lactic acid) via Direct Melt Polycondensation Using Solid Super-Acids

摘要

A microwave-assisted method of synthesizing high-molecular-weight PLA using SSA as greencatalyst was developed. Yellowish PLA with M_v above 2.0 x 10~4g mol~(-1)was obtained whenthe reaction was run at 260 ~°C within 60 min under microwave irradiation with 0.4 wt.-% SSA.This method used only 10% of the energy consumption necessary for conventional heating,and the catalyst could be used five times withoutlosing catalytic activity. The improvement in M_vand the decrease in the energy consumptionunder microwave irradiation suggested thatselective heating and hot spots effects played acrucial role. The method was shown to be a time-saving, green and a promising way to lower thecost and spread the application of PLA.