Design And Preparation Of Porous Organic Skeleton Materials And Their Application In Anticorrosion And Antifouling Coatings

The 21st century is the“century of the sea”.The development of marine resources and marine economy are closely related to the prosperity of the country.However,the marine environment is complex and changeable,which arouses many problems such as corrosion and biofouling to the metals.The existing anticorrosion and antibiofouling technologies for metals have some defects to some extent.For example,in anticorrosion coating field:the existing pretreatment technologies of the coating protection system are difficult to prepare the pretreatment layer with micron-level thickness and roughness,and the pretreatment reagents are not environmentally friendly with high volatile organic compound（VOC）emission.Few nanocontainers have both“active protection”and“passive protection”performance,or have good compatibility with the resin.The hydrophobicity of the nanocontainer itself is limited.After the release of the corrosion inhibitors is exhausted,the hydrophilic nanocontainer will accelerate the corrosion.In antifouling coating field:There are few existing antibiofouling technologies that have both physical type and chemical type.The“heterogeneous”existence of nanoparticles in superhydrophobic coating is one of the main sources of weak wear resistance of them.Superhydrophobic coatings are not capable of room-temperature curable,fluorine-free,wear-resistant,acid-alkali resistant,and antibacterial at the same time.To solving these problems,this paper takes advantage of the advantages of porous organic skeleton materials,such as strong designability and controllable of the structure morphology,and then combines the characteristics of the marine environment and the metals used for marine equipment.With porous organic skeleton materials as the main line,the paper focuses on solving many problems existing in the existing technologies of anticorrosion and antibiofouling.Novel anticorrosion and antibiofouling technologies have been successfully designed.The research work of this paper mainly includes the following three parts:Part 1 Novel polymer organic skeleton pretreatment layer in coating protection systemIn view of the deficiencies of the coating protective pretreatment layer technology in the field of marine metal corrosion protection,the“polymer organic skeleton pretreatment layer”coating system was designed.The solvent used in the pretreatment reagent is 100%water,and the pretreatment layer with a thickness of 3-5μm and micron level roughness can be prepared on the mild steel substrate.The micro-nano porous structure is prepared by the PA-PVA pretreatment layer,which is conducive to loading the slow-release agent and forming a physical"interlock structure"with the subsequent epoxy coating,greatly improving the protective performance of the entire coating system.It is expected to replace the traditional phosphating,silane and other pretreatment layer technologies.Part 2“dual-function”nanocontainers based on metal organic frameworks（MOFs）in protective coating systemTwo modification strategies were designed,considering the MOFs nanocontainers only have the“active protection”function.The“dual function”nanocontainers with both“active protection”and“passive protection”were successfully prepared.（1）The“graphene oxide/metal-organic-framework nanocontainer”was designed.The composite nanocontainer was a“two-dimensional”（barrier properties of graphene oxide nanosheets）and“three-dimensional”（porosity of MOFs）composite structure,which had both“active protection”and“passive protection”performances.Two typical MOFs,ZIF-8 and Ui O-66,were selected as examples to achieve excellent anticorrosion performance on T2 copper and archaize bronze.（2）A general strategy of“superhydrophobic nanocontainer”was proposed.According to this strategy,a“superhydrophobic MOF nanocontainer”was designed,and the synthesis conditions were adjusted.The results show that the protective performance of the inhibitor loaded superhydrophobic nanocontainer is better,and the compatibility between superhydrophobic nanocontainer is improved.Those are theoretically verified by molecular dynamics simulation.Part 3 Novel antifouling coating based on MOFs components（1）MOFs thin films were prepared on the surface of titanium alloy by simple electrodeposition technology,in which pyromellitic acid with excellent antibacterial effect was used as the ligand of MOFs;On the basis of this film,it is treated with superhydrophobic and super-lubricating treatment.Aminated silicone oil（NH₂-oil）was used to replace traditional lubricating oil,and then loaded with isocyanate curing agent for curing silicone oil to realize the fixation of lubricating oil.Above all,the“double immobilized”coating with antibacterial and antifouling performance was prepared.The coating has both“physical antifouling”（lubricity）and“chemical antifouling”（antibacterial）.The film prepared by this technology can effectively reduce the adsorption of protein on the surface of titanium alloy and has a broad-spectrum antibacterial performance.（2）A robust,room-temperature curable and molecular-level superhydrophobiccoating with excellent antibacterial and antifouling properties based on MOF was designed and prepared.The commonly used epoxy resin is used as the coating skeleton,the molecular-level aminated NH₂-Ui O-66（a kind of MOFs material）nanoparticles are used as the roughening component,（NH₂-oil）is used as the low surface energy material,triclosan is used as the"bacteria repellent"component,and isocyanate is used as the curing component.The above components were cured at room temperature through the grafting reaction between isocyanate and-OH,-NH₂ to improve the mechanical stability and wear resistance of the coating.Meanwhile,the biocide triclosan realizes“immobilization”in the form of chemical grafting,solving the problem of leakage and pollution of the bactericide of the antibacterial coating fundamentally.The protein adsorption is reduced after application to titanium alloy,the bacteriostasis rate is more than 99.98%,and the adhesion of chlorella is significantly reduced.It has a promising future for industrial application.