Graphene based room temperature flexible nanocomposites were prepared using epoxy thermosets for the first time. Flexible behavior was induced into the epoxy thermosets by introducing charge transfer complexes between functional groups within cross linked epoxy and room temperature ionic liquid ions. The graphene nanoplatelets were found to be highly dispersed in the epoxy matrix due to ionic liquid cation–π interactions. It was observed that incorporation of small amounts of graphene into the epoxy matrix significantly enhanced the mechanical properties of the epoxy. In particular, a 0.6 wt% addition increased the tensile strength and Young’s modulus by 125% and 21% respectively. The electrical resistance of nanocomposites was found to be increased with graphene loading indicating the level of self-organization between the ILs and the graphene sheets in the matrix of the composite. The graphene nanocomposites were flexible and behave like ductile thermoplastics at room temperature. This study demonstrates the use of ionic liquid as a compatible agent to induce flexibility in inherently brittle thermoset materials and improve the dispersion of graphene to create high performance nanocomposite materials.

No abstract

This study investigates the influence of reduced graphene oxide (rGO) coated glass fabrics on the strain sensing and the mechanical characteristics of fiber‐reinforced composites. Graphene oxide was applied in two thicknesses (threefold and fivefold coatings) onto a fabric using a padder mangle machine followed by thermal reduction and infused with an epoxy to manufacture rGO‐enhanced composite. The tensile modulus and flexural strength of the rGO‐enhanced composites with threefold coating were improved by 27% and 6.2%, respectively, compared with the equivalent composite manufactured without rGO. The normalized resistance (ΔR/R0) of composites increased by 0.89% and 3.48% under a cyclic tensile force of 1000 and 4000 N. The magnitude of ΔR/R0 was stable within 30 cycles suggesting a consistent strain sensing performance with a gauge factor of 15.55. The electrical response of the rGO‐enhanced composite was evaluated using a new industrial standard for sensors, by assessing calibration curves. The composite showed low hysteresis and low electrical viscosity which make these materials suitable for industrial piezoresistive strain sensors.

No abstract