| Epoxy resin(EP)has excellent corrosion resistance,chemical and thermal stability,high adhesion and other advantages,so it is widely used in coatings,adhesives,composite materials and other fields,and it is one of the most widely used resins in coatings.However,a single epoxy resin has some shortcomings,such as brittleness,curing defects,low UV strength,so the comprehensive performance of the resin should be improved by modifying epoxy materials,especially the anti-corrosion,and the discovery of nanoparticles provides a new way to modify epoxy.In this paper,nanoscale fillers were used to modify the two epoxy resins respectively,and the effects of filler type and doping amount on the properties of epoxy coatings were explored.The waterborne epoxy resin with water as the solvent is environmentally friendly,non-toxic and harmless,but the anti-corrosion is less ideal,and the composite anticorrosion coating(water-based EP/Al2O3)is prepared by using nano-alumina(Al2O3)to modify the epoxy resin by solution blending to improve the original resin system and improve the comprehensive performance of the coating.Through apparent comparison and microscopic characterization of the existence state and internal morphology of the composite coating,the adhesion of the coating to the base metal is uniformly analyzed from the perspective of theoretical inference and simulation verification,and the polarization curve and AC impedance diagram of the coating are obtained by electrochemical workstation test,the corrosion resistance of the composite coating is studied,and the anti-corrosion mechanism is explained.The results show that the nanoparticles in the composite coating doped with filler are uniformly dispersed,the energy between the coating and the substrate metal is increased by 3 times,and the coating adhesion is improved.At the same time,the corrosion current density of the composite coating is reduced by 1-2 orders of magnitude compared with a single resin,and it has a lower low-frequency impedance modulus,showing excellent corrosion resistance,and 5wt%Al2O3/EP has the best corrosion resistance.Using nano-Ti3C2Tx(a new two-dimensional nanomaterial MXene)as filler and oily epoxy resin as the main film-forming substance to prepare a composite coating(oily EP/MXene).the addition of MXene makes the defects of epoxy resin filled,the overall interface tends to a more stable state,and the adhesion to the base metal is enhanced.In the polarization curve,the 0.5wt%MXene/EP composite coating has the lowest corrosion current density and the most positive corrosion potential,and the current value is reduced by 4 or 5 orders of magnitude compared with bare steel and pure EP,which not only shows good corrosion resistance to metals,but also proves that the addition of MXene also modifies epoxy resin and improves the corrosion resistance of the composite coating.However,the mass fraction of Ti3C2Tx is not positively correlated with the improvement of corrosion resistance,and the 1.5wt%MXene/EP composite coating does not show better corrosion resistance than pure resin.In summary,this paper studies the comprehensive properties of waterborne EP/Al2O3 and oilborne EP/MXene composite coatings,because the addition of nano-filler makes up for the original defects of the resin,and it improves the stability of the resin.In addition to,it enhances the barrier ability of the coating to the corrosive medium,and it greatly improves the corrosion resistance of the composite coating,so epoxy resins modified by nano-fillers have broad application prospects. |
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