A waterborne uniform graphene-poly(urethane-acrylate) complex with enhanced anticorrosive properties enabled by ionic interaction

Homogeneous dispersion of graphene (GR) in waterborne polymer matrix still remains a challenge. In this work, a novel strategy to prepare waterborne graphene/polymer nanocomposite of high uniformity and stability is developed via in situ incorporation of cationic graphene (CGR) in anionic poly(urethane-acrylate) (WPUA) prepolymer. Compared to WPUA and GR-WPUA, the water resistance, tensile strength and anticorrosive properties of CGR-WPUA are significantly increased. With respect to WPUA and GR-WPUA coatings with 0.5% GR addition, the impedance modulus at lower frequency decreased by one order of magnitude and the coating resistance decreased by two orders of magnitude after 25 days of immersion. While the impedance modulus and coating resistance of 0.5% CGR-WPUA are of the same order before and after immersion. The as-prepared CGR-WPUA coating was endowed with superior long-term anticorrosive properties. It is also found that the corrosion protection efficiency of CGR-WPUA increased by 78.2% in comparison to WPUA and increased by 32.0% compared with GR-WPUA. This work demonstrates the critical role of graphene-polymer interaction for anticorrosion applications of waterborne graphene/polymer nanocomposite.