*3.1. Mechanism for Synthesis of Gum Tragacanth-cl-N,N-dimethylacrylamide Hydrogel*

In this work, gum tragacanth-cl-*N,N*-dimethylacrylamide hydrogel and reduced graphene oxide incorporated gum tragacanth-cl-*N,N*-dimethylacrylamide hydrogel composite were prepared by radical copolymerization of DMA and GT in the presence radical initiator (KPS) and the cross-linking action of NMBA. Under microwave radiations, KPS was decomposed and radical ions were generated [25]. These primary free radicals led to the generation of DMA monomer radical (through addition reaction with KPS) and GT alkoxy radical (through abstraction of hydrogen by KPS). The grafting of DMA radical and GT alkoxy radical was carried through radical copolymerization reaction (Scheme 1). The crosslinker NMBA led to the cross-linkages between different chains to facilitate the

construction of three-dimensional gum tragacanth-cl-*N,N*-dimethylacrylamide hydrogel polymeric network. Finally, the dispersion of RGO led to the generation of reduced graphene oxide incorporated gum tragacanth-cl-*N,N*-dimethylacrylamide hydrogel composite.
