Modified Waterborne Polyurethane Based On Fluorinated Acrylate And Its Application In Mental Corrosion

In this paper,a waterborne polyurethane-acrylate composite emulsion was synthesized in three steps.First the polyurethane prepolymer is synthesized.Then the polyurethane prepolymer is capped with hydroxyethyl acrylate.Then the remaining acrylic monomers are added to the polyurethane instead of part of the solvent.Then the polyurethane is emulsified after neutralization.Finally emulsion undergoes free radical reaction at 75?.The synthetic emulsion is prepared into a metal anti-corrosion coating,and through a series of tests,the performance of the coating is explored.The first chapter introduces the corrosion mechanism of metals and the principle of anticorrosion of paints.With the improvement of living standards,humans are paying more and more attention to the environment.Therefore,many countries have restricted the production and discharge of harmful substances to the human body and the environment.Waterborne coatings will gradually exceed the market position of solvent-based coatings.This chapter also introduces four common water-based anticorrosive coatings,which are water-based acrylates,water-based polyurethanes,water-based epoxy resins,and water-based inorganic zinc-rich anticorrosive coatings.The synthetic raw materials,mechanism and development status of these four coatings are described in detail,and the synthesis method,classification and development status of water-based polyurethane are mainly introduced.The second chapter uses the acetone method,waterborne polyurethane with hydroxyethyl acrylate(HEA)ends was synthesized by using isophorone diisocyanate(IPDI),polyadipate-1,4-butanediol diol(PBA2000,Mn=2000)as the main raw material and trimethylolpropane(TMP)as crosslinking agent.The hard monomer methyl methacrylate(MMA),the soft monomer butyl acrylate(BA)and the crosslinking agent trimethylolpropane triacrylate(TMPTA)monomer are neutralized and emulsified together with the aqueous polyurethane prepolymer.Finally acrylate modified waterborne polyurethane composite emulsion were prepared by free radical polymerization.the influence of the proportion of acrylate on the performance of composite materials was explored by adjusting the mass ratio of waterborne polyurethane to acrylate.Stability and particle size analysis showed that the composite emulsion was stable and the stability was more than 6 months;the addition of acrylic esters reduced the tensile strength and pencil hardness of the WPUA composite film,but the adhesion of the composite material is improved,that is Level 1 is increased to level 0;thermogravimetric analysis shows that the heat resistance of the composite material has been greatly improved.With the increase in acrylate content,a thermal decomposition temperature of 5% from 248?to 290? and a thermal decomposition temperature of 50% occur 370? to 403?;with the increase in the amount of acrylate added,the water absorption rate decreased from 35.7% to 13.1%,the contact angle also increased from 60.8 ° to 75.3°,water resistance has been greatly improved.The third chapter is based on the second chapter,that is,on the basis of acrylate modified water-based polyurethane,the organic fluoroacrylate monomer 2,2,2-trifluoroethyl methacrylate(SF-000258)is adopted.The amount of SF-000258 was adjusted to explore the effect of SF-000258 on the performance of the composite material.To this end,the infrared spectrum test,emulsion stability test,mechanical property test,pencil hardness test,adhesion test,and thermogravimetric test were performed on the composite material.Characterization methods such as water resistance test and contact angle test.Infrared spectrum indicates that SF-000258 participated in the reaction and has been introduced into the composite material.As the amount of SF-000258 added increases,the mechanical properties of the composite first increase and then decrease,and the maximum increase to 37 MPa,Pencil hardness also increases first and then decreases,the maximum is 3H,the water absorption rate also decreased from 14.5% without fluorinated monomer to 7.5% after fluorinated monomer modification,and the contact angle increased from 74.1° to 94.7°.The heat resistance of the soft section of the composite material is also improved.Chapter 4 is based on Chapter 3.The synthetic organic fluorine(The mass fraction of 2,2,2-trifluoroethyl methacrylate in the total resin is 9%)acrylate modified waterborne polyurethane composite emulsion is are formulated into the coating by adding to the pigment,filler titanium dioxide,anticorrosive pigments iron phosphate,zinc phosphate,iron titanium powder and various additives.And then the coating adhesion,pencil hardness,acid and alkali resistance,water resistance and salt spray resistance are tested.The test shows that: The coating film adhesion is 0,and the impact resistance is excellent,which can be comparable to the commercially available coatings.In addition,the WPUFAT1 and WPUFAT2 coating films are equivalent to WPUT0 in water resistance,acid and alkali resistance,and rust prevention effect,but the WPUFAT3 coating film has rust resistance.The effect is poor,which also shows that the use of iron phosphate and zinc phosphate as antirust pigments has a better rust prevention effect,and the use of iron titanium powder as an anticorrosive pigment has a poor effect.