Polydopamine enwrapped titanium dioxide-assisted dispersion of graphene to strength fire resistance of intumescent waterborne epoxy coating

Abstract

Herein, polydopamine (PDA) with excellent hydrophilicity and strong adhesion was used to decorate the TiO2 nanoparticles. Then, the obtained PDA modified TiO2 was directly combined with graphene (Gr) through the π-π non covalent interaction to improve the water dispersion stability of hydrophobic Gr. After that, the above hybrids (TPG) was added to the intumescent waterborne epoxy coating to explore its fire protection ability. The fire resistance of the intumescent composite coating was tested by big panel method test, furnace test and thermogravimetric analysis (TGA). And the structure and morphology of the inorganic residual char were analyzed by FT-IR, XPS, SEM and XRD technology. The results showed that the introduction of PDA effectively improved the oxidation resistance of the composite coating, while TiO2 nanoparticles enhanced the stability of the char layer. More importantly, the incorporation of Gr further enhanced the barrier effect of char layer on thermal and mass. The 1.5 % TPG based sample exhibited the maximum expansion rate (8.61), the highest carbon residue (29.7 %) and the best heat insulation property due to the synergistic fire prevention effect of PDA, TiO2 and Gr nanosheets.