I think bonding between is not possible GO and RGO because rgo is prepare from GO. after reduce of GO all oxy group is remove during the formation of RGO.

Hello Trung Ho Ba , why you want to use a GO/rGO mixture for obtaining your fibers, the hydrophilic/hydrophobic character of each one could affect your processing method at first. Then based on the literature, a rational relation between GO sheet size and polydispersity, concentration, liquid crystallinity, and spinnability are principal factors for leading to fiber spinnability so you need to characterize your GO and commercial rGO in order to establish the best methodology for your purpose, if your commercial rGO is very reduced and sp2 domain reconstructed it very hard to achieve a physical bonding between GO and rGO. The formulation of GO solutions in a range of processable concentrations enables the spinning of continuous conducting, strong, and robust fibers at concentrations as low as 0.075 wt%, eliminating the need for relatively concentrated spinning dope dispersions. The dilute GO dispersion is suitable for fiber spinning using a number of coagulation strategies as non‐solvent precipitation, dispersion destabilization, ionic cross‐linking, and polyelectrolyte complexation. The One-step continuous spinning of graphene fibers by in situ spinning of GO in basic coagulation baths (i.e. NaOH, KOH), and can eliminate the need for post‐treatment processes. I think that you can find a lot of literature that can be very helpful for you.

Regards.