Research On Conductivity And Strain Resistance Effects Of CNT/rGO-SCF Multi-scale Modified Epoxy Resin

Epoxy resin has received more and more attention due to its excellent mechanical properties and chemical properties.However,due to the insulating properties of epoxy resin,its application fields are limited.In order to realize the conductive modification of epoxy resin,the method of adding conductive filler is adopted to form a conductive network inside,thereby possessing conductive properties.On this basis,a strain resistance experiment was carried out on the conductive modified epoxy resin composite to study the response relationship of the strain resistance,which provides a basis for its application in strain sensors.First,by adding short carbon fiber(Short Carbon Fiber,SCF)to prepare SCF single-phase modified epoxy resin composites with different mass fractions.Through the measurement of resistivity,it is found that the resistance of the sample decreases gradually with the increase of the SCF mass fraction,and when the dispersion threshold is 1.5 wt%,it is modified from an insulating material to a conductive material.The strain resistance experiment shows that the resistance of the composite material increases with the increase of strain,with a linear first and then an exponential change trend with the tensile strain,and a good linear change trend with the bending strain,and with the increase of the SCF mass fraction,the strain resistance The stability is enhanced,but the strain sensitivity coefficient is reduced.In the cyclic resistance experiment,the composite material gradually changed from irregularity to regularity with the increase of SCF mass fraction,and reached the limit value of constant resistance change rate after a certain number of cycles.This value increased with the increase of SCF mass fraction Decrease.Second,carbon nanotubes(CNT)and reduced graphene oxide(reduced graphene oxide,r GO)are used to modify the epoxy resin in a coordinated manner with SCF respectively.The resistance measurement shows that the addition of CNT and r GO further reduces the resistivity of the composite material,indicating that both CNT and r GO have a synergistic effect with SCF.The strain resistance experiment shows that the stability of the strain resistance change trend of the composite material is further improved,and the linearity is stronger,indicating that the internal conductive network is more complete and the destruction regularity,but the more complete conductive network leads to the appearance of the composite material strain sensitivity coefficient Decline slightly.By comparing CNT/SCF and r GO/SCF synergistically modified composite materials,it is concluded that r GO has a stronger optimizing effect on the conductive properties of composite materials,and its strain resistance effect has better linearity and stability,and has better synergy with SCF.Third,the microscopic morphology of the sample was characterized by a scanning electron microscope,and it was found that SCF,CNT and r GO can be uniformly dispersed in the epoxy resin.According to the analysis of the microscopic characterization results,the mechanism of synergistic conductivity modification between CNT and r GO and SCF was obtained.