Neat PGS by Microwave-Assisted Processing. As a time- and energy-efficient alternative, prepolymerization was performed by using a microwave oven (Panasonic NN-ST642W) in a chemical hood. The microwave oven was set to provide an output of 600 W to the mixture of glycerol and SA. Although the prepolymerization process summed up to 30 min, the microwave oven was vented by opening the door, and the temperature of the mixture was measured by thermometer every 1 min to prevent overheating of samples and buildup of produced gas. After completing the microwave step, prepolymers were allowed to cool and dissolved in THF at room temperature