Study on the synthesis of PANI/CNT nanocomposite and its anticorrosion mechanism in waterborne coatings

Abstract

In this paper, PANI encapsulated CNT (PANI/CNT) composite with nanofibers morphology has been successfully prepared through the oxidative polymerization of aniline in stable CNT suspension. The thickness of the PANI shell and the interface interaction can be adjusted by the mass ratio of aniline to CNT based on the formation of the weak electron donor-acceptor interactions between CNTs and aniline salts in the in-situ oxidative polymerization system. The synthesized PANI/CNT nanocomposite has the reversible redox activity not only in acidic but also in neutral medium. The PANI/CNT organic composite coating can be prepared by filling PANI/CNT nanocomposite into the water-based acrylic/amino baking paint. The results of polarization curve, electrochemical impedance and salt spray resistance indicate that the composition and morphology of PANI/CNT nanocomposite have a significant effect on the intelligent metal protection function when deliberate damage occurs and the long-term corrosion resistance of the composite coating. The PANI/CNT (8:1) nanocoating exhibits the most excellent intelligent protection activity, while the PANI/CNT (2:1) nanocoating demonstrates the excellent long-term anticorrosion performance. The nanofibrous PANI/CNT nanocomposite benefits to form a conductive network in the organic coating, which determines the cathodic inhibition and the anodic passivation protection of PANI/CNT metal anticorrosion mechanism. This research provides a new idea for the preparation of environmentally friendly active anticorrosive materials.