Vinyl intumescent coatings modified with platelet-type nanofillers

Abstract A solvent-borne poly(vinyl acetate)-based intumescent paint was modified with two types of platelet-type nanofillers, i.e. a natural sodium montmorillonite (MMT) and a 3-layer graphene (Gn). MMT was incorporated into the coating formulation after its pre-swelling in cyclohexanol while Gn was applied in a powder form. Thermal insulation features of dry coatings were investigated by means of a gas flame-heated programmable furnace (according to a cellulosic fire curve). Additionally, thermogravimetrical, structural (FTIR, XRD) and mechanical properties of the coatings and obtained chars were analyzed. It was revealed that Gn positively affected the thermal insulation and intumescence effectiveness as well as compressive strength of charred coatings. The highest values of that parameters (+13%, +74% and +92%, respectively) were noted for samples containing the lowest dose of Gn (1 wt. part/100 wt. parts of the paint solids). MMT-based system exhibited a far higher mechanical resistance, however, its thermal protection was limited in relation to the other samples. Moreover, the addition of MMT (or Gn) affected chemical composition as well as size and distribution of cells in a foamed char.