Preparation And Performance Study Of Waterborne Acrylic Anticorrosive Coating

Waterborne polyacrylic anticorrosive coating was one of the earliest and most widely used waterborne coating products.This paper started from the polyacrylic emulsion of waterborne polyacrylic anticorrosive coating,and it was modified by adding water and hydrophobicity to waterborne polyacrylic coating.The modified polyacrylic emulsion was prepared from the monomer,and the anticorrosive coating was prepared based on the modified emulsion.The performance and mechanism analysis of the prepared emulsion and coating were carried out.Firstly,a fluorine-modified polyacrylic was prepared by using methyl methacrylate(MMA),butyl acrylate(BA),acrylic acid(AA)as a polymerization monomer,and dodecafluoroheptyl methacrylate(DFMA)as a modified monomer.A series of emulsions were prepared by core-shell emulsion polymerization.The best preparation process was emulsifier with sodium dodecyl benzene sulfonate(SDS)and OP-10 complex emulsifier,and SDS:OP-10=2:1.The optimum addition amount of the initiator was 2.5%of the total amount of the monomers,the ratio of the soft and hard monomers was 6:5,and the optimum addition amount of the DFMA was 6%.The emulsion was characterized and tested,a core-shell structure with a thermal decomposition temperature of 282? and a water static contact angle of 80.8°.Compared with the unmodified polyacrylic coating,the corrosion resistance of the modified was greatly improved.When the sample was immersed for a long time,the effective protection time of the coating was 100 h.The diffusion behavior was manifested in three phases of unity.After 100 h of immersing time,the protective effect of the coating was weakened,and the coating completely failed after the immersion time exceeded 200 h.Fluorine-silicon modified polyacrylic emulsion was prepared on the basis of fluorine-modified with vinyl triethoxysilane(VTEO)and tetraethyl orthosilicate(TEOS)as modifiers.The thermal decomposition temperature reached 298? and the hydrophobic angle increased to 99°.Electrochemical indicated that the corrosion resistance of the coating increased first and then decreased with VTEO-TEOS content,and the effect of VTEO-TEOS was preferably 3.0%.The long-term immersion observation of the sample indicated that the effective protection time of the coating was 168 h,the corrosion process and the diffusion behavior of water showed a unified three stages.After the immersion time of 168 h,the protective effect of the coating was weakened,and completely failed after 300 h immersion time.The two modified emulsions were prepared by adding modified nano-TiO2 and other pigment filler additives.The coating had excellent physical properties,to analysis the corrosion resistance of it.The fluorine-modified coating was analyzed,the open circuit potential remains stable for 1 5 d?and the corrosion trend was small.The impedance showed three trends with time,the high-efficicncy protection phase of 0?19 d,the impedance reduction phase of 19?27 d and the failure phase after 27 d.The analysis of the fluorine-silicon modified coating showed that the protection performance appeared severely corroded after 11 d.The protective mechanism of the prepared coating was mainly the physical shielding effect.The modified TiO2 with small particle size was mixed with other pigments with large particle size to make the coating denser,the corrosion path of ions was more complicated.