ABSTRACT This study proposes the synthesis of a poly(amidoxime) functionalized graphene oxide by using polyacrylonitrile (PAN)‐grafted graphene oxide (GO) precursor with different grafting percentages. A significant novelty in this study is that the emulsion graft polymerization of acrylonitrile on a gamma‐irradiated and silanized GO substrate has been thoroughly investigated for amidoxime conversion. The study investigates not only the reaction conditions (i.e., the amount of monomer, initiator, and surfactant), but also the influence of substrate treatment such as the amount of silane coupling agent and surfactant type on grafting percentage. Notably, we demonstrate that using sodium dodecyl sulfate instead of commonly used Tween 80 significantly improved GO dispersion and polymer grafting percentage. Furthermore, the influence of the PAN grafting percentage on the efficient amidoxime conversion was investigated, which is crucial to achieve desired functional properties. The developed hybrids were characterized by different spectroscopic techniques, including Fourier transform infrared spectroscopy, X‐ray diffraction, Raman spectroscopy, thermogravimetric analysis, and scanning electron microscopy.