Preparation And Properties Of Functional Anticorrosive Coatings

Metal material is a widely used engineering material,which plays an irreplaceable role in machinery manufacturing,aerospace,construction,agricultural production,etc.However,the global metal corrosion problem is becoming more and more serious,which not only brings huge losses to the economy and society,but also causes serious pollution problems and even various catastrophic accidents.Therefore,it is of great significance to social development to take appropriate measures to protect the corrosion of metal materials.Among many protective measures,organic coating has become the most widely used protective method due to its advantages of simple operation,low cost and stable effect.However,the traditional anti-corrosion coating is easy to fail in the actual use environment,causing metal corrosion,and all replacements require a large workload and high cost.Therefore,it has a broad application prospect to prolong its anti-corrosion aging through composite functional design of the coating,and the predecessors have also carried out in-depth research on this work.Among them,loading functional particles in the coating to realize its self-healing,corrosion inhibition or superhydrophobic function is a way with profound application prospects.The existing self-healing methods mainly include intrinsic self-healing and micro-nanocapsule loading self-healing agents.The intrinsic self-healing method is not applicable in the real corrosive environment due to its harsh use environment,and the self-healing anti-corrosion microcapsule coating loaded with self-healing agent has the problem that the repair effect and the repair speed are difficult to synergize.For composite coatings loaded with corrosion inhibitor,direct loading will greatly affect the coating strength.However,when nano-containers are used to load corrosion inhibitors,due to the loading capacity and compatibility of nano-containers,their anti-corrosion performance needs to be improved,and synergistic enhancement can be formed by super-hydrophobic treatment on them.In this paper,different organic coatings were prepared on the treated tinplate surface.Two different loading systems were introduced in it to realize the self-healing and corrosion inhibition functions of the coating,which further improved the anti-corrosion performance of the coating.It provides a new idea for the development of functional anti-corrosion coatings.The specific research contents of this paper are as follows:(1)Microcapsules with rapid self-healing effect are loaded in the water-based polyurethane coating,which improves the intelligent anti-corrosion performance of the coating.In this paper,a simple self-assembly method was used to prepare graphene oxide microcapsules,with graphene oxide(GO)as the shell,a mixture of linseed oil and cobalt octoate as a healing agent,and a Pickering emulsion method.Under the action,due to the hydrophilic properties of the outer edge of graphene oxide and the hydrophobicity of the inner edge,it self-assembles in the outer layer of the healing agent to form a microcapsule structure,which is dispersed in the water-based polyurethane coating to prepare a self-healing effect.Graphene oxide microcapsule self-healing anti-corrosion coating.The self-healing and anti-corrosion effect and speed were characterized by scanning electron microscope,optical microscope,3D profilometer and electrochemical impedance spectroscopy,and the mechanical properties such as hardness and adhesion were also characterized,which proved that it has ultra-fast self-healing The rapid and stable anti-corrosion coating was successfully prepared.At the same time,the curing speed was further explored by using a rheometer,which once again proved its rapid self-healing effect.The coating will produce anti-corrosion effect about 5 minutes after mechanical damage.After 12 hours,the coating can be basically repaired and the micro-cracks can be smoothed out,while the conventional self-healing coating usually takes several days or even ten days to complete this process.(2)The corrosion inhibitor 2-mertobenzothiazole(MBT)was loaded in HNTs by negative pressure method,and modified with 3-aminopropyl triethoxysilane(KH550),and then dispersed in epoxy resin coating.At the same time,superhydrophobic modified Si O₂particles were sprayed on the coating surface.The release process of MBT was confirmed by UV-vis spectra.The nanovessel loaded with corrosion inhibitor could maintain slow release within 72 hours,ensuring the durability of the sustained release effect.The anti-corrosion and self-healing effects of the coating were characterized by electrochemical workstation.Compared with the pure epoxy resin coating,the superhydrophobic coating still had a good anti-corrosion effect after soaking in 3.5%Na Cl solution for 72 hours.Using contact Angle measurement instrument on the super hydrophobic properties of the coating were characterized,water droplets on the coating surface contact Angle of pure epoxy resin coating after CA is about 65-70°,and the contact Angle of super hydrophobic composite coating can be as high as 159°,is still as high as 154°after soaking in 72 h,at the same time using small new month diamond algal fouling resistance of coating were tested,The coating without superhydrophobicity treatment was immersed in algae growth solution for 168h before serious algae growth on the surface,while the superhydrophobicity coating was not seriously algae growth after immersing for one month,further demonstrating its stability and antifouling performance.The preparation of superhydrophobic self-healing anticorrosive composite coatings provides some new ideas for the development of anticorrosive functional coatings in the future.(3)MS 2017 software was used to conduct molecular dynamics simulation of the composite coating,and the influence of adding GO nanosheets on the adhesion of polyurethane coating on the iron base,as well as the influence of OTS modification on the adhesion of Si O₂particles on the surface of E51 epoxy resin and its superhydrophobic properties were investigated.The simulation results show that adding GO nanosheets into polyurethane coating has no significant effect on the adhesion of coating,which is consistent with the experimental results in Chapter 2.The adhesion of Si O₂nanoparticles on epoxy resin coating was further improved by OTS modification,and its hydrophobic performance was significantly improved,which was consistent with the experimental results in Chapter 3.