| Metal corrosion brings huge economic losses and building damage to human beings every year.Reasonably and effectively inhibiting metal corrosion has become a hot spot of attention.Through the efforts of researchers,it was found that the addition of organic fillers,preservatives,inorganic fillers and other substances in the resin could not only acts as a physical barrier,but also play an auxiliary preservative role.At present,most anticorrosive coatings are made of resin.The resin itself has good barrier properties.With the development of the era,water-based epoxy resins have attracted attention because of their environmental protection and high efficiency.The conductive compound polyaniline is added to the resin as an organic filler to improve the corrosion resistance of the composite coating.However,its shortcomings,such as poor water dispersibility and poor compatibility,have made it highly criticized.This article focuses on the development of polyaniline coatings and epoxy resin coatings,and the research status of water-based composite coatings.The results show that how to improve the water dispersibility and resin compatibility of polyaniline has become the research focus of polyaniline coatings.Therefore,in this paper,a series of cationic gemini surfactants were prepared to modify the sulfonated polyaniline to improve the water dispersibility of the polyaniline.Afterwards,the modification ability of surfactant to polymer was discussed and the polymer with the best overall performance was determined.Finally,it was compounded with water-based epoxy resin to evaluate the performance of the coating.The specific results are as follows:(1)Five amine cationic gemini surfactants,GS10,GS12,GS14,GS16,and GS18,were successfully prepared.Five types of surfactants were comprehensively evaluated by means of infrared spectrum,X-ray diffraction,nuclear magnetic resonance(1H-NMR)and dynamic light scattering instrument(DLS).Then,SPANI-GS polymers with different carbon chain lengths were prepared,and the synthesis of these seven compounds was successfully characterized by means of infrared spectrum,ultraviolet spectrum,and X-ray diffraction.The SEM,TEM,particle size distribution histogram,solution dispersive optical figure and other means were used to comprehensively observe and characterize the dispersibility of the polymer.It was found that the dispersion of SPANI-GS has been greatly improved after the introduction of gemini surfactants.Through the analysis of GS10,GS12,GS14,GS16,and GS18 surfactants,it was found that a surfactant with a reasonable chain length could better improve the dispersibility of the polymer and SPANI-GS 12 polymer had the best dispersion properties.(2)On the basis of the previous section,the effect of GS12 content on the dispersion properties of polymers was further discussed.Four polymers with different contents of SPANI-GS 12 were prepared.The synthesis of these polymers was successfully characterized by means of infrared spectrum,ultraviolet spectrum and XRD.The dispersibility of these polymers was characterized by SEM,particle size distribution histogram and solution dispersibility.When the concentration of GS12 was 0.2%,the polymer had the smallest particle size,better dispersibility and the best dispersion stability in solution.SPANI-GS 12-0.2%polymer had the best overall performance.(3)SPANI-GS/WEB composite anticorrosive emulsions,adhesive films and paint films with different carbon chain lengths were prepared and tested.Based on this,the modification of SPANI with different contents of GS12 was investigated.Composite anticorrosive emulsions,adhesive films and paint films with different contents of SPANI-GS 12 were prepared and comprehensively evaluated.Electrochemical impedance spectroscopy(EIS)analysis of SPANI-GS/WEB with different carbon chain lengths shows that the addition of GS with different chain lengths has improved the corrosion resistance.Compared with PANI/WEB coating,SPANI-GS 12/WEB composite coating has improved coating resistance by 4-5 orders of magnitude.Based on this,the electrochemical performance of composite anticorrosive coatings with different contents of SPANI-GS 12 was tested.It showed that when the mass fraction of GS12 was 0.2%,the Rcoat value of SPANI-GS 12-0.2%/WEB was higher than that of other samples.It also displayed that the mechanical properties of the SPANI-GS/WEB composite anticorrosive coatings with different carbon chain lengths were further improved.The mechanical properties of the SPANI-GS12 composite anticorrosive coatings at different concentrations were analyzed.The results showed that the mechanical properties of SPANI-GS12-0.2%/WEB were better than other samples.SPANI-GS12/WEB coating also has good antibacterial performance. |
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