| As a new high-performance coating,the excellent corrosion resistance of fluorocarbon coating has become an important material to solve the problem of material corrosion and resources wasting in daily life.Therefore,the research subject of the high-performance anti-corrosion fluorocarbon coating prepared by fluorocarbon resin as film-forming material is not only the premise of product performance optimization,but also provides theoretical and practical value for the in-depth development and application of fluorocarbon coating,which is of great significance.In this paper,polyvinylidene fluoride PVDF resin and fluoroolefin-vinyl ether copolymer FEVE resin were combined with enhancement resin to improve the adhesion of the coating film.The factors affecting the formula and the corrosion resistance of three kinds of fluorocarbon coatings prepared from two kinds of fluorocarbon resins were analyzed..The main research work and conclusions are as follows:In this paper,PVDF anticorrosive coatings were prepared by using PVDF resin as the main film-forming material,enhanced system adhesion by thermoplastic acrylic resin.The influence of acrylic resin content on the strength and anticorrosive property of the coating film was investigated through structural composition and mechanical property test.The results show that the addition of acrylic resin changed the crystal phase of PVDF resin and improved the adhesion and hardness of PVDF coating.At the same time,when the content of acrylic resin is 10~30 wt%,the mass loss of the coating film saturated in acid is small,and the tensile strength is less affected by aging;the mass loss is 12 % when the content of acrylic resin is 40 wt%,and the strength decreases by 25 % after aging for 350 h.Secondly,the general-purpose FEVE coatings used at room temperature were studied.The formulation of the FEVE coatings,including the ratio of film-forming resin,curing agent,solvent,filler and auxiliary agent,was optimized.The corrosion resistance of PVDF and FEVE coatings under the optimal formula was analyzed by electrochemical impedance spectroscopy.The results show that the anti-corrosion performance of FEVE coating is slightly higher than that of PVDF coating.At the same time,the protection mechanism of fluorocarbon coating of two different molding processes is roughly the same: At the initial stage of soaking,the coating has good protection against moisture and ion permeation;at the middle of immersion,the ions penetrate into the interface to produce corrosion micro-cells,and the corrosion products accumulate and fill pores at the interface.The filling of filler particles extends the ion permeation path and slows down the corrosion rate.The microporous structure on the surface of the coating rapidly expands into a reticular corrosion region after the immersion,and the electrochemical reaction between the electrolyte solution and the substrate causes the coating expansion and stripping and lose the protective effect.Finally,according to the insufficient adhesion of FEVE coating,the epoxy resin was used to improve the adhesion of the coating,and the comprehensive performance of the epoxy composite fluorocarbon coating was analyzed from the uniformity of blend phase.The results show that the 5 wt%,10 wt% epoxy/FEVE system has good compatibility and the acid resistance and corrosion resistance of the FEVE coating were improved.The low-frequency impedance of the 5 wt% epoxy/FEVE coating is improved by three orders of magnitude compared with that of pure FEVE coating,and the anti-corrosion performance was still excellent after soaking for 42 d.When the specific gravity of epoxy resin is increased to 20 wt%,the uniformity of blending system decreases,which aggravates the micro-crack damage during the coating immersion and reduces the anti-corrosion performance. |
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