In order to enhance the water and heavy corrosion resistance of waterborne polyurethane(WPU),Mannich base corrosion inhibitor was synthesized by Mannich reaction in this paper.M/EUSiWPU composite coatings with hydrogen-bond interactions were prepared by introducing hydrophobic structures such as Si—O—Si into the WPU molecular chains using 4,4′-(1,1,3,3-tetramethyldisiloxo-1,3-dipropyl)bis-2-methoxyphenol(EUSi)as the chain extender.Nuclear magnetic resonance hydrogen spectroscopy,infrared spectroscopy analysis,emulsion stability analysis were used to characterize EUSiWPU,Mannich base and composite emulsion.Water absorption test and electrochemical test were used to analyze the performances of composite film and coating.The preliminary results of the experiments show that the Mannich base and EUSiWPU have been synthesized.The M/EUSiWPU-3 containing Mannich base with a mass fraction of 3%has a uniform particle size distribution and its emulsion stability is strong.The water absorption of the composite coating decreases with the increasing of corrosion inhibitor content.The minimum water absorption is 19.60%,and the low-frequency impedance of the composite coating is also enhanced,which is nearly four orders of magnitude higher than that of EUSiWPU coating.The addition of Mannich base shifts the coating self-corrosion potential positively,and the self-corrosion current firstly increases and then decreases.The M/EUSiWPU-3 has the lowest corrosion rate of 5.25×10-6 A/cm2,the smallest self-corrosion current density of 2.30×10-7μA/cm2 and the protection efficiency of 97.56%.
Heavy Corrosion ResistanceMannich BaseCorrosion InhibitorHydrogen BondComposite Coating
NETL
NSTL
万方数据
