Preparation Of Modified Polyaniline/Epoxy Composite Coatings And Study On Their Anti-corrosion Performance

Epoxy coating has important applications in the field of corrosion prevention, butthe anticorrosive durability is far from expected. polyaniline as a new kind ofpolymer material，it has widely application prospect in field of metal anti-corrosion.But the insoluble properties，hard dispersion and poor adhesion to metal substratelimit its application. The glass flake and chopped glass fiber can greatly improve themechanical property and penetration resistance for the coatings when they are addedinto paints. In this paper，the different mass ratio of polyaniline was coated on thesurface of glass flake and glass fiber. These composites were added into epoxy toprepare the epoxy coatings and applied on the metal substrate. The influence ofdifferent composites anti-corrosion performance for the coating were studied and thebest mass ratio proportion was selected out. In this paper，the main researchcontents and results are as follows：（1）Polyaniline (PANI)，different mass ratio of polyaniline/glass flake（PANI-GF）and polyaniline/glass fiber（PANI-GB） composites were prepared byin situ oxidative polymerization. The characterization of structure of PANI-GF andPANI-GB composites by X-ray diffraction（XRD）and infrared spectroscopy（FTIR）.It can be seen that the structure of PANI was not affected by addition of GF and GB.But thermal stability of composites was greatly improved by addition of inorganicparticle. glass flake and glass fiber But the a lot of polyaniline accumulated on thesurface of GF and GB with the content of PANI increased.（2）The morphology of the composites was characterized by SEM. It can beseen that a lot of polyaniline accumulated on the surface of GF and GB with thecontent of PANI increased. when the mass ratio of polyaniline and glass flake is2:1，the polyaniline can coated on the surface of glass flake uniformly，for the PANI-GBcomposites，it is1:1. （3）The composites were added into epoxy resin by ball-milling method andthe epoxy coating was successfully prepared. From the observation of cross sectionof coatings，it can be seen that the addition of filler can improve the penetrationresistance for coatings. The cross section of coatings is very compact and uniformwhen the PGF2(2：1) and PGB1(1:1) were added into epoxy coatings.（4） The anti-corrosion performance of coatings was characterized byelectrochemical impedance spectroscopy （EIS） and salt spray test. Theanti-corrosion properties was improved by addition of GF, PANI and PANI-GFcomposites，but when the mass ratio of PANI and GF was2:1（PGF2），the coatinghas a better protection ability of other coatings，it attributed to the passivation effectof polyaniline and penetration resistance of glass flake and the dispersion uniformlyof composites in the coating；For the PANI-GB coating，when the ratio of PANI andGB in the composites is1:1（PGB1），The coating anti-corrosion performance is betterthan other coatings. The salt spray test results is consistent to the EIS results.