Preparation And Performance Of Epoxy Resin Self-healing Anti-corrosion Coating

Traditional coatings form a barrier between the metal and the environment to prevent the corrosion medium from invading the metal matrix,but bubbles and microcracks are inevitably generated during the curing or use of the coating,which greatly reduces the protective ability of the coating.In the face of these problems,the current commonly used treatment methods are manual repair or direct replacement of coatings,these methods are complex processes,high costs,easy to cause waste of resources,not conducive to the friendly development of the environment.For this reason,self-healing coatings have emerged,which can achieve the healing of coating defects under certain conditions,and the healed coating can achieve the level of protection of a complete coating.Self-healing anti-corrosion coating can be divided into two types according to the repair mechanism,among which the intrinsic self-healing anti-corrosion coating can be based on the complete coating,using the introduction of reversible chemical bonds to achieve the healing of the coating,this self-healing method will not cause new damage to the coating,greatly retain the original structural framework of the coating,and then effectively realize the recovery of the protective performance of the coating.In this paper,flexible molecular chains containing hydrogen bonding units and modified graphene oxide were prepared by synthesizing hydrogen bonding units,using the reaction of hydrogen bonding units,polyetheramines and graphene oxide.The structure of the prepared materials was characterized by infrared spectroscopy(FT-IR),nuclear magnetic resonance instrument(NMR),X-ray diffractometer(XRD),scanning electron microscopy(SEM)and transmission electron microscopy(TEM)to prove that the preparation was successful.Subsequently,the flexible molecular chain was grafted in the epoxy resin chain segment by the reaction of amino group and epoxy group,and the modified graphene oxide was introduced into the polymer through the cross-linking reaction between hydrogen bond and hydrogen bond,based on the crosslinking reaction between hydrogen bond and the interface effect between graphene oxide and epoxy resin,the self-healing performance and anti-corrosion performance of composite coatings were improved,FT-IR was used to characterize the molecular structure of the material,and Raman spectrometer(Raman),universal tensile testing machine,salt spray accelerated corrosion test chamber,Electrochemical workstations and pull-off adhesion testers test and analyze the self-healing properties,corrosion resistance and adhesion of coatings.The results show that the self-healing performance and corrosion resistance of epoxy resin are significantly improved by flexible molecular chains,the tensile strength healing efficiency of the coating with an optimal addition amount of 20 wt.%after recovery at 30°C for 48 h reaches 47.8%,and the impedance value at the scratches of the coating is maintained at 8.41×10~7Ω·cm~2 after soaking in 3.5 wt.%NaCl solution for 240 hours,the break point frequency is 12.58 Hz,and the adhesion of the coating is 1.86 MPa after 100 h immersion.The loss rate was 27.34%.With the addition of modified graphene oxide,the tensile strength of the coating and the healing efficiency were improved,when the addition amount was 1.0wt.%,the healing efficiency increased to 62.1%,and the impedance value at the scratches of the coating after soaking in 3.5 wt.%NaCl solution for 240 h could reach 1.58×10~9Ω·cm~2,and the breakpoint frequency was 1.00 Hz.After 100 h immersion,the adhesion of the coating is 1.96 MPa,and the loss rate is only 25.19%,and the coating shows excellent protection ability.