Fabrication Of Graphene/Epoxy Electrical Nanocoatings And Investigation Of Its Strain Sensitivity

Because of graphene's excellent mechanical properties,high electron mobility in room temperature and significant thermal properties,it has been extensively used in electronic devices,energy storage,sensors,solar cells and so on.In addition,graphene is also usually used as a filler to put into the resin matrix to enhance its performance.Epoxy resin,as the best thermosetting resin material of comprehensive performance,is also used to prepare composites,adhesives and coatings.The combination of graphene and epoxy resin can synthesize the properties to prepare composites with excellent performance.The composites can be applied to structural health monitoring research.In this paper,the graphene / epoxy resin(GnP / EP)conductive nanocoating is prepared by dispersing the graphene into the epoxy resin,and its sensitivity to the stress is explored.In this paper,the raw materials of preparing conductive coatings and the preparation method are firstly optimized.The raw materials are epoxy resin(E-51),graphene nanoplates(GnP-M2),polyvinylpyrrolidone(which is dispersant,PVP),triethylenetetramine(which is curing agent,TETA)and ethanol.The preparation method is pre-dispersion method.The conductivity of GnP/EP conductive nanocoating was tested by Four-probe tester,and also the electrical conductivity is the most important basic parameter of conductive nanocoating;the microscopic appearance of conductive nanocoating was observed by scanning electron microscopy(SEM)for explaining electrical conductivity performance;the preparation effect of GnP/EP nanocoating can be determined by X-ray diffraction(XRD);and the strain sensitivity of the GnP/EP conductive nanocoating based on wooden blocks and cement mortar was tested by Universal tester and Four-probe tester.The types and range of GnP / EP conductive nanocoating's basic parameters were determined by single factor tests and orthogonal test.The parameters of the nanocoating: GnP-M2(content: 0.5wt% of epoxy resin),PVP(content: 2wt% of GnP-M2),TETA(content: 22.43 wt% of epoxy resin).According to the analysis from the orthogonal test,the effect of dispersant PVP is significant for dispersing.And about the technological parameters,that is,considering the quality of the coating,operability,energy conservation and other aspects to determine the final parameters.The time of ultrasonic dispersion is 1h,curing condition is curing for two days at room temperature,spread the composite when it has climbing phenomenon.At last,the strain sensitivity of GnP/EP conductivity nanocoating was tested.The tensile properties(Tensile-strength is 40.68 MPa,elongation at break is 4.74% and elastic modulus is 1102.40MPa)were measured firstly.And then the conductive nanocoating was spread on the pre-test position of the wood and cement mortar block to test its adaptability to the gradual increase of the strain.It was found that the electrical conductivity of the GnP-M2/EP conductive nanocoating on wood and the conductivity of the GnP-M2/EP conductive nanocoating on cement mortar block both are fluctuate at certain value,showing some stability.