2.3. Thermogravimetric Analysis (TGA)

TGA was performed to evaluate the thermal stability of samples to make sure that they do not decompose during heating. TGA was carried out on the powders using a Mettler Toledo TG50 measuring module coupled to a Mettler Toledo MT5 balance [21]. Approximately 8−10 mg samples were analyzed (n = 3) in open aluminum pans, using nitrogen as the purge gas with a flow rate of 40 mL/min. Samples were heated from 25 to 250 °C at a rate of 10 °C/min. Mettler Toledo STAR^e software (version 6.10) was used to determine the mass loss based on the slope of TGA trace. Samples were considered as stable at temperatures at which the mass loss was smaller than 5% of the initial sample weight.