Preparation And Characterization Of Cross-linkable Styrene-Acrylate Emulsion And Paint Film

With the continuous development of coating technology,it plays an increasingly important role in industrial production and people's daily life.And it can protect the substrate and make appearance much more beautiful.However,the traditional solvent-based coatings contain a mass of volatile organic compound(VOC)which is usually above 40%.These volatiles will volatilize into the atmosphere during the painting and construction process,which will pollute the environment seriously and cause great harm to the human body.Therefore,water-based coating has become an important research direction of green environmental protection,which is in accordance with the concept of sustainable development.Water-based coatings are mainly composed of film-forming substances(emulsions),additives,water and pigments.The emulsion plays a decisive role in the performance of the coating,and the additives and pigments can improve the performance and application performance of the coating effectively.In this paper,the anticorrosive properties of the synthesized coatings are improved through three aspects: emulsion synthesis,selection of additivting and selection of pigments and fillers.Cuting from emulsion synthesis,in this paper the styrene-acrylic emulsion uses styrene(St),methyl methacrylate(MMA)and butyl acrylate(BA)as the main monomers via semi-continuous seed emulsion polymerization.The effect of the addition amount of ammonium persulfate(APS)as an initiator,OS-15/K-12 as compound emulsifier and solid content on the emulsion performance are investigated.The results show that the cohesion rate of the emulsion is lowest and the conversion rate of the monomers is highest when the amount of the initiator and OS-15/K-12 with the mass ratio of 5:3 is 0.5% and 1.5% of the monomer mass,respectively.The emulsion is the most stable when the solid content is44%.Furthermore,through the introduction of functional monomers and cross-linking systems,the denseness and corrosion resistance of the coating film are improved successfully.Through the introduction of functional monomer acrylic acid(AA)and crosslinkable monomers hydroxyethyl acrylate(HEA),N-methylol acrylamide(NMA)and ketohydrazine cross-linking system(DAAM / ADH).The different properties of the emulsion are characterized by FT-IR,TGA,laser particle size analyzer and polarization curves.The results shows when the amounts of AA,HEA,NMA,PP70,and DAAM /ADH are 3% to 4%,1.3%,3%,1.5%,and 2: 1,the overall performance and anticorrosive performance of the polymer emulsion film are better.Finally,a water-based styrene-acrylate coating is prepared based on a cross-linkable styrene-acrylate emulsion.The influence of the mass ratio of hard and soft monomers,phosphate monomers,amount of emulsifier and additives,and pigment volume concentration(PVC),the type of thickener and corrosion inhibitor on the corrosion resistance of the coating are investigated.The electrochemical impedance spectroscopy(EIS)and Tafel curve of the coating are carried out by electrochemical workstation.The results indicate that the phosphate monomer and iron-titanium compound powder as antirust pigment could improve the anticorrosive property of coating.