Preparation and properties of aligned graphene composites

The applications of epoxy resins have been limited in the field of multifunctional materials, owing to their brittleness and single functionalization. Modifying the resin matrix with graphene is considered as one of the effective ways to toughen and expand the functionalization of epoxy resin. In this paper, graphene-based composites were prepared under superstrong magnetic field environments, generated by a superconducting magnet. The composites had anisotropic photopermeability. The results of photopermeability measurements of the graphene oxide composites showed that the graphene oxide was aligned by the superstrong magnetic field. The orientation time of graphene oxide with a mass fraction from 0.05 to 0.5 wt% was about 3 min and the orientation rate was inversely proportional to the additive amount of graphene oxide and viscosity of the resin matrix. The photopermeability and thermal expansion of the anisotropic composites with different types of graphene materials were compared. The photopermeability parallel to the direction of the magnetic field lines was better than that perpendicular to the magnetic field lines. The photopermeability parallel to the magnetic field lines of the composites with graphene oxide was larger than those of nanographene sheets or reduced graphene oxide. The coefficient of linear expansion parallel to the direction of the magnetic field lines was smaller than that perpendicular to the magnetic field lines. The coefficient of linear expansion perpendicular to the magnetic field lines of the composites with nanographene sheets was larger than those of reduced graphene oxide or graphene oxide.