PUF/PANI-CO double-walled microcapsules were prepared by in-situ polymerization and physical deposition using castor oil(CO)as core material,urea-formaldehyde resin(PUF)and polyaniline(PANI)as wall materials,characterized by FTIR,XRD and SEM,and then added to waterborne epoxy coating(WEC)for the synthesis of PUF/PANI-CO/WEC composite coating.The corrosion behavior of PUF/PANI-CO/WEC composite coating was analyzed by electrochemical impedance spectroscopy(EIS)and salt spray test.The results showed that PUF/PANI-CO were a double-walled microcapsule with a dense outer wall formed by cross-deposition of PANI on the inner wall of PUF with CO as core material,with a particle size of 3～4 μm.After soaking PUF/PANI-CO/WEC in 3.5％(mass fraction)NaCl solution for 30 d,the low-frequency impedance of the coating was 7.600×108 Ω·cm2,while the adhesion between PUF/PANI-CO/WEC and metal matrix was 15.64 MPa.The corrosion resistance of PUF/PANI-CO/WEC was attributed to three aspects:PANI/PUF-CO had good dispersion and stability,which could effectively improve the barrier property of water-borne epoxy coating;The core material released when the wall material breaks could fill the defects in the coating,thus blocking the transmission path of the corrosive medium.PANI could improve the stability of microcapsules and promote the formation of passivation film on the surface of metal matrix,delay the infiltration of corrosive media,and thus play a good role in protecting the matrix.
关键词
金属腐蚀/水性环氧树脂/聚苯胺/微胶囊/电化学阻抗谱/功能材料
Key words
metal corrosion/waterborne epoxy resin/polyaniline/microcapsules/electrochemical impedance spectroscopy/functional materials
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