The influence of various heating methods without catalysis to prepare polyesters from citric acid : glycerol blends were studied. In the presence of short-term microwave treatments, i.e., 60 s at 1200 W, blends of glycerol and citric acid invariably formed solid amorphous polyesters. Fourier transform infrared spectroscopy showed that citric acid and glycerol blends can form highly stable polymers composed of ester bonds. The glycerol citrate polyester polymers exhibited the least degradation in water, more in acid solutions (0.11.0M HCl), and the most deterioration in strong alkaline solutions (0.11.0M NaOH) after 72 h soakings. Polyesters of glycerol and citric acid were studied with differential scanning calorimetry and thermal gravimetric analysis. The polyesters were found to be thermally stable (up to 313 degrees C). (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012