Microwave Assisted Synthesis of Poly(lactic acid) and its Characterization using Size Exclusion Chromatography

Poly(lactic acid) (PLA) has been synthesized catalytically under vacuum by microwave (MW) irradiation using stannous octoate (SnOct2) as catalyst. The polymerization is carried out at 180○C up to 30 min. PLA with a molar mass of 104 g.mol−1 and a yield over 97% was produced in 20 min by the ring-opening polymerization of L-lactide using (SnOct2) as catalyst under microwave irradiation with a power level of 180 W. The structural investigations are done by NMR and FTIR. The average molar mass of PLA is determined by means of size exclusion chromatography, (SEC). The characterization is done using three different columns. The polymerization rate is much faster with microwave heating than conventional heating. Microwave irradiation gives rapid energy transfer and high-energy efficiency, hence, a faster reaction rate.