The Preparation And Investigation Of Anti-corrosion Properties For Graphene Oxide/Polyvinylidene Fluoride Composite Coatings

Graphene oxide(GO)has a rigid structure,high specific surface area and rich active surface functional groups,which is widely used in the fields of energy,electronic information,biological medicine and catalysis.Polyvinyl fluoride(PVDF)has high mechanical properties and anti-corrosion properties,which is widely used as metal coating.Preparation of polymer nanofibers by electrospun has become a new technology for the preparation of metal anti-corrosion coatings.In this paper,The modified Hummers method was used to synthesizeand GO,which was characterized by AFM,XRD and FTIR.GO/PVDF composite coating and fiber coating were prepared by conventional spinning method and electrospun method,in order to use GO to improve the mechanical properties and anti-corrosion properties of the composite coating.GO/PVDF composite coatings was fabricated by spinning method and the GO dispersion situation,crystallization behavior,thermal properties,mechanical properties and anti-corrosion properties of different GO content was tested by SEM,XRD,FTIR,DSC,tensile testing machine and the electrochemical workstation.The results showed that the proper content of GO can evenly dispersed in the PVDF matrix,and promote the crystallization of PVDF,enhance the mechanical properties and anti-corrosion properties of PVDF substrate.As GO content reached 0.5%,the tensile strength and elongation of the composite coating was 83.63 MPa and 38.9%,increased by 25% and31% when compared with the pure PVDF coating.Meanwhile its impedance modulus values was about 108 Ω·cm2 and increased by 1.4 magnitude when compared with the pure PVDF coating,so the anti-corrosion property of the GO/PVDF composite spining coating was good;Pure PVDF fibers was fabricated by electrospun method at different spinning solution concentration,different applied voltage and different receiving distance.Used SEM to observe the fiber morphology and analyse fiber diameter distribution in order todetermine the optimum electrospun conditions.GO/PVDF composite fiber coatings was fabricated by electrospun method under the optimum electrospun conditions and the fiber morphology,crystallization behavior,thermal properties,mechanical properties and anti-corrosion properties of different GO content was tested by SEM,XRD,FTIR,DSC,and the electrochemical workstation.The results showed that when the concentration of PVDF was 12%,the electrospun voltage was 15 k V and the receiving distance was 15 cm,the fiber obtained the most uniform morphology.For GO/PVDF composite fiber coatings,the proper amount of GO would not affect the fiber morphology,but can promote the crystallization of PVDF,enhance the anti-corrosion properties of PVDF substrate.As GO content reached 0.5%,the impedance modulus value was higher than 109 Ω·cm2 and increased by 1 order of magnitude when compared with the pure PVDF fiber coating,so the anti-corrosion property of the GO/PVDF composite fiber coatings was excellent.Finally,compared the two different coatings which fabricated by spinning method and electrospun method with 0.5% GO content.Fitted the equivalent circuit and analysed the corrosion protection mechanism.The results show that the impedance modulus of the eletrospun fiber coating was higher by nearly 2 orders of magnitude than the spinnig coating,which was attributed to the special nano-fiber structure and the barrier effect of GO.