Effect Of Polyvinylpyrrolidone On Properties Of Carbon Crystal And Carbon Crystal Epoxy Electrothermal Films

As a material made from carbon fiber,carbon crystal has the advantages of light weight,heat conduction and conductivity.However,because carbon crystal has large specific surface area and strong hydrophobicity,there is not only the problem of poor interface performance with the collective material in the matrix material,but also the adsorption effect of large particles on small particles,This seriously limits the dispersion of carbon crystal in the matrix material,which leads to the serious limitation of its application in thermal and electrical.Polyvinylpyrrolidone(PVP)is an amphiphilic polymer,which can pass through the surface of many carbon materials ?-? The dispersion of carbon materials in various matrix materials was improved by physicochemical grafting in the form of bond or hydrogen bond.The hydrophilicity of carbon materials modified by PVP was improved,because when PVP was introduced to the surface of carbon materials,the strong hydrophilic caprolactone structure was introduced to the surface of carbon materials,At the same time,the active functional groups on the surface of the carbon materials are also increased,which makes the chemical interaction between the modified carbon materials and the matrix materials enhanced,so as to improve the dispersion and dispersion stability of the carbon materials.In this paper,surface modified carbon crystal and carbon crystal electrothermal film(1)were prepared by two different ways.By coating method,polyvinylpyrrolidone(PVP)with different molecular weight was selected as sizing agent of coating method to modify the surface of carbon crystal after impurity removal.The mechanism of surface modification of carbon fiber by polyvinylpyrrolidone was studied by FTIR.The dispersity and interface properties of the modified carbon crystal were tested by contact angle and UV VIS spectrophotometer.In addition,the modified carbon crystal was mixed with waterborne epoxy resin and curing agent was added to prepare carbon crystal electrothermal film,The electrical properties of carbon crystal electrothermal films modified by different molecular weight polyvinylpyrrolidone were tested(2)Polyvinylpyrrolidone(PVP)K30 was prepared into solutions with different concentrations.The effects of different concentrations of PVP as dispersant on carbon crystal dispersion and interfacial properties were investigated.The electrical properties of PVP / carbon crystal / waterborne epoxy resin films prepared with different concentrations of PVP dispersant were tested by four probe tester,The two ends of the film were pasted with conductive copper foil and electrified to test the electrothermal properties of PVP / carbon crystal / waterborne epoxy resin film.The results show that PVP can form hydrogen bond with the surface of carbon crystal,so that PVP molecules can be coated on the surface of carbon crystal,and strong hydrophilic groups can be introduced into the surface of carbon crystal,which improves the hydrophilicity and interface properties of carbon crystal,improves the wettability of carbon crystal by waterborne epoxy resin,and makes the carbon crystal disperse more evenly in the matrix of waterborne epoxy resin.At the same time,the electrical and electrothermal properties of the carbon crystal / waterborne epoxy resin film were improved.The conductivity of pvpk30 modified carbon / waterborne epoxy resin film is 31 times higher than that of unmodified carbon / waterborne epoxy resin film,and the resistivity is reduced by 95%.Through the comparison of carbon crystal modified by pvpk30 and carbon crystal with pvpk30 as dispersant,it is found that the two different treatment methods have almost the same effect on the properties of carbon crystal and carbon crystal / waterborne epoxy resin film.The latter simplifies the preparation of carbon crystal/waterborne epoxy resin film.