Synthesis And Characterization Of Styrene-acrylic Emulsion For Aqueous Metallic Protection Coating

A series of alcohol maleic diester with surfactant action were synthesized.Firstly,monomaleate were synthesized with maleic anhydride and dodecanol.After acylation reaction,the monomaleate was made to react with polyethylene glycol?PEG?for the synthesis of dimaleate.The structures of these products were characterized by infrared absorption spectra?FT-IR?,hydrogen nuclear magnetic resonance?1H-NMR?.FT-IR and1H NMR,results indicate that a series of dimaleate with different length of hydrophilic chain were successfully synthesized,namely dimaleate?PEG200?,dimaleate?PEG400?,and dimaleate?PEG600?.A series of styrene-acrylic emulsion were synthesized with traditional phosphate emulsifier.And the performance of the styrene-acrylic emulsion was tested.The results show that polymerization stability was good when the styrene-acrylic emulsion was synthesized with mixed emulsifying agents composed with ionic emulsifier and non ionic emulsifier with gel fraction less than 2%.The calcium ion stability,storage stability,freeze-thaw stability of all the styrene-acrylic emulsion were poor and emulsion breaking occurred when the styrene-acrylic was being tested.The water absorption of coating films which were produced with all the styrene-acrylic emulsion was above 60%.The salt spray resistance was poor.And serious rusting occurred after 3d under the salt spray environment.A series of styrene-acrylic emulsion were synthesized with mixed emulsifying agents composed with reactive dimaleate surfactant and potassium monoalkyl ether phosphate?PE939?.And the performance of the styrene-acrylic emulsion was tested and compared with the one of the styrene-acrylic emulsion which was synthesized with traditional phosphate emulsifier.The results show that polymerization stability was good when the styrene-acrylic emulsion was synthesized with dimaleate surfactant with gel fraction less than 1.3%.The stability of all the styrene-acrylic emulsion was better than that of the styrene-acrylic emulsion which was synthesized with traditional phosphate emulsifier.A small amount of gel was formed in the condition of high-concentration CaCl₂.The water absorption of the coating films were less than 26%.The salt spray resistance of the styrene-acrylic emulsion synthesized with dimaleate?PEG400?was best.Only a small amount of speck of rust occurred after 3d under the salt spray environment.In summary,dimaleate surfactants were synthesized successfully,the styrene-acrylic emulsion were prepared using dimaleate surfactants.This article provide a new technology for the preparation of styrene-acrylic emulsion for aqueous metallic protection coating.