Properties And Surface Phase Structure Of Side-chain Two-component Modified Polyurethane Coatings

Water resources are one of the renewable energy resources which are mainly developed and used in China.The exploitation and utilization of water resources cannot be separated from metal materials such as hydraulic machinery.Hydraulic machinery parts operating in a complex water environment are faced with erosion and corrosion of the substrate.Therefore,the coating is required to have excellent anticorrosive property,abrasion resistance and erosion resistance in the protection of hydraulic metal structure.Surface protection technology is used to strengthen the substrate to solve the damage that usually begins on the surface of the overcurrent component.Special segment groups were introduced into the polyurethane side chain by means of chemical modification to prepare coatings to solve the damage of metal parts.The surface properties and mechanism of synthetic coatings were discussed in this article.Fluorocarbon chain group was introduced into the hard segment of polyurethane side chain by chemical modification,and the amount of fluorine-containing group?-CF₂CF₃?was controlled by changing the molar ratio of TEOH-10/MDI.The hydrophobic group?-COOCH₃?was introduced in the form of chain extender to construct the micro-phase separation structure of hydrophilic and hydrophobic microzone at the micro and nano level,and FPU synthesis was completed.Comprehensive consideration of coating surface strength,hardness,thickness and other performance indicators.The FPU coating was prepared by parameter design and material composition ratio selection.Analysis of coating tissue composition by means of characterization.FTIR-ATR was used to determine the structure of FPU and analyze its components,and NMR characterized the chemical displacement of each group.The surface morphology of coating was observed and analyzed by SEM and EDS.The results show that fluorocarbon chain and hydrophobic group exist in the hard segment structure of polyurethane side chain.With the introduction of modified groups,the side chain becomes more flexible.After the introduction of fluorocarbon chain,the molecular structure migrated from the chain to the surface of the material to form a agglomerate state,which affected the coating morphology.The performance of the coating was evaluated and analyzed theoretically by means of testing.The test of water contact Angle showed that the FPU coating remained strong hydrophobicity before and after the aging test.The results show that the organic fluorine film and hydrophobic groups on the coating surface prevent the infiltration of water molecules by coating water absorption,dry and wet state adhesion test.By comparing the effects of temperature melting rate cooling rate solvent volatilization rate on the aging resistance of physical crosslinked structures,the aging degree with time was obtained.Conduct friction coefficient test,erosion resistance test on the coating,combined with DSC detection,the mechanism was analyzed from the aspects of microphase separation,thermodynamic driving force and crosslinking reaction.It is concluded that the increase of crosslinking density,the enhancement of aggregation behavior of fluorocarbon chain segment and the formation of micro-phase separation structure of internal hydrogen bond reduce the coating surface energy.It is proved that the prepared coating meets the test expectation.