| With the increasing awareness of environmental protection,water-based coatings have gradually replaced solvent-based coatings and are widely used in various fields.However,waterborne coatings generally have poor hydrophobic properties.In order to expand the range of applications of waterborne coatings,it is necessary to modify them hydrophobically.According to the principle of superhydrophobic surface,it is necessary to improve the roughness of the surface of the aqueous coating,and to reduce its surface energy is a common method for hydrophobic modification.However,the rough structure prepared by this method is easily destroyed,so it is necessary to study a preparation method of a highly stable hydrophobic coating.In this paper,fluorocarbon silane is first used to prepare hydrophobic SiO2,and then blended with aqueous styrene-acrylic emulsion to improve hydrophobicity,then blended with aqueous styrene-acrylic emulsion to improve hydrophobicity.Synthesis of fluorine-containing monosiloxane by tridecafluorooctylmethacrylate and y-aminopropyl-triethoxysilane,fluorine-containing monosiloxane and γ-(2,3-epoxypropoxy)-propyltrimethoxysilane fluorine-containing disiloxane is prepared from trimethoxysilane as a raw material.The two fluorocarbon silane structures were characterized by infrared spectroscopy(FT-IR)and nuclear magnetic resonance spectroscopy(1H NMR).The modified nano-SiO2 was used to obtain F1-SiO2,F2-SiO2,and the structure was characterized by FT-IR.SEM showed that the fluorine-containing monosiloxane can improve the dispersion of SiO2 and improve the agglomeration phenomenon,the fluorine-containing disiloxane can be on the surface of SiO2.A rough structure is formed.The effects of the amount of F1-SiO2,F2-SiO2,the amount of styrene-acrylic emulsion on the coating contact angle,pencil hardness and adhesion were studied.The results showed that the amount of F1-SiO2 was 5.3wt%,the water contact angle was 140.2° when the styrene-acrylic emulsion was 8wt%,the amount of F2-SiO2 was 5.3wt%,and the water contact angle was 148.4° when the styrene-acrylic emulsion was 8wt%.The contact angle is improved and other comprehensive performance is better.SEM and AFM showed that the F2-SiO2/styrene-acrylic emulsion formed a micro-nano structure on the surface of the coating,which was higher than the F1-SiO2 styrene-acrylic coating,and Ra increased from 225 nm to 267 nm.The two coatings had good acid resistance.The contact angles were 138° and 140.4° after soaking for 10h in acidic solution.The alkali resistance was poor.The contact angles were 68.4° and 72.3° after soaking for 2h in alkaline solution.The salt-tolerance of F2-SiO2/styrene-acrylic coating was better than that of F1-SiO2/styrene-acrylic coating.After soaking in salt solution for 1 0h,the contact angle was 138.9°.Fl-SiO2/styrene-acrylic coating under the load of 50g,the coating water contact angle is 118.3° after 40 cycles of 400 mesh sandpaper;the F2-SiO2/styrene-acrylic coating is 142.7° after 80 cycles of friction,mechanical Increased stability.Perfluoropolyether trisiloxane was prepared by using K-type trihydroxy perfluoropolyether,allyl chloride and trimethylhydrosilane as main raw materials,and its structure was characterized by FT-IR.F3-SiO2 was obtained by modifying nano-SiO2,and its structure was characterized by FT-IR.SEM showed that perfluoropolyether trisiloxane could form a rough structure on the surface of SiO2.The effect of the amount of F3-SiO2 on the coating was investigated.The results showed that the amount of F3-SiO2 was 3.6wt%and when the styrene-acrylic emulsion was 8wt%,the hydrophobicity and other comprehensive properties of the emulsion were better,and the contact angle was 152.0°.SEM and AFM surface F3-SiO2 formed a micro-nano structure on the surface of the coating which improved the coating roughness and Ra was 368 nm.The coating was significantly improved in abrasion resistance. |
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