*2.6. Swelling Study*

Various parameters such as initiator concentration (KPS) solvent volume, time, cross-linker concentration (NMBA), microwave power, monomer concentration (DMA) and amount of RGO were optimized to obtain the maximum swelling percentage. The swelling percentages of gum tragacanth-cl-*N,N*-dimethylacrylamide and reduced graphene oxide incorporated gum tragacanth-cl-*N,N*-dimethylacrylamide hydrogels in deionized water were examined for a fixed period of 16 h. The pre-weighed dry piece of the sample was added in 50 mL of distilled water for 16 h. Then, swelled hydrogel was weighed. The swelling percentage was calculated using Equation (1) [28]:

$$\text{Swelling } \%= \frac{\text{W}\_{\text{s}} - \text{W}\_{\text{d}}}{\text{W}\_{\text{d}}} \times 100\tag{1}$$

where, Ws = weight of swelled gum tragacanth-cl-*N,N*-dimethylacrylamide hydrogel, Wd = weight of dry gum tragacanth-cl-*N,N*-dimethylacrylamide hydrogel.
