Graphene oxide/polybenzimidazole composites fabricated by a solvent-exchange method

Homogenous organic dispersion of graphene oxide (GO) sheets was prepared by a solvent-exchange method. This method enabled the simultaneous achievement of full exfoliation and high concentration of GO in several organic solvents such as dimethyl sulfoxide, which would facilitate the fabrication of individual graphene reinforced polymer composites through a solution-based process. To this end, poly 2,2′-(p-oxydiphenylene)-5,5′-bibenzimidazole] (OPBI)/GO composites were fabricated. X-ray diffraction characterization showed that the GO sheets were individually incorporated into the OPBI matrix. Scanning electron microscope images that taken of the fracture surface of the composites revealed that the GO sheets were spontaneous aligned parallel to the surface of the composite films as the content of GO exceeded 0.3 wt.%. The incorporation of GO also showed profound effects on the macroscopic properties of OPBI. Compared to pure OPBI, the composites showed a 17% increase in Young’s modulus, 33% increase in tensile strength and 88% improvement in toughness by the addition of only 0.3 wt.% of GO. Moreover, although the thermal stability of GO is far inferior to OPBI, it is found the thermal stability of OPBI is still improved by the addition of GO.