*3.5. Thermal Gravimetric Analysis (TGA)*

The thermal stability of pure PPy and PPy/GA composites was investigated by thermal gravimetric analysis (TGA). The TGA curves of pure PPy and PPy/GA composites are shown in Figure 5b. The thermograms were recorded in the nitrogen atmosphere by heating the samples at a temperature ranging from 25 to 800 ◦C. The TGA of PPy shows weight loss at three stages. The first stage of weight loss (10%) from 35 to 150 ◦C is attributed to the volatilization of water molecules from the polymer. The second stage of weight loss, from 150 to 400 ◦C, is attributed to the decomposition of the dopant molecule DBSA. The PPy backbone is completely decomposed in the third stage of weight loss from 440 to 800 ◦C [41].

All the composites show the same thermogram and also show weight loss at three stages. Water molecules are removed during the first stage of weight loss, which occurs at low temperatures ranging from 35 to 150 ◦C. At temperatures ranging from 300 to 480 ◦C, the degradation of GA components causes the second readily apparent weight loss. The third and final weight loss occurred at a high temperature of 500 ◦C, which is attributed to the decomposition of the PPy backbone. During the polysaccharide degradation process, there is no significant difference, and at high temperatures, approximately the same amount of residue is obtained [42]. The degradation of the PPy chain has been pushed to 500 ◦C in the composite form. This indicates that the GA has been integrated into the PPy matrix, and it also improves the composites' thermal stability at 500 ◦C. The degradation of the pure PPy chain begins at 450 ◦C, whereas the degradation of the main polymer chain in composites begins at around 500 ◦C. This implies that the PPy/GA composite has good thermal stability. At 800 ◦C, the overall stability of PPy is greater than that of PPy/GA composites. Pure PPy causes less overall weight loss than the PPy/GA composite.
