Influence of talc particle size on the optical transparency, flame retardancy, and smoke release suppression of waterborne transparent fireproof coatings applied on wood surface

Abstract

Talc with particle sizes of 1250 mesh (Talc‐1250), 3000 mesh (Talc‐3000), and 5000 mesh (Talc‐5000), used as synergist, was added into transparent fireproof coatings applied in wood substrates, and the influence of talc particle size on the comprehensive properties of the coatings was analyzed carefully. The results show that adding talc exerts super synergistic effect on enhancing the flame retardancy and smoke release suppression properties in the resulting coatings, and the synergistic efficiency of talc is varied with the talc particle size. Fire resistance analysis shows that the MTPPE2 coating containing Talc‐3000 exhibits better synergistic effects, accompanying a minimum back temperature of 106.3°C at 900°C and a maximum intumescent factor of 116.3. SEM‐EDS and FTIR analyses show that adding Talc‐3000 in the MTPPE2 coating contributes to the formation of a more intumescent and compact char against fire concomitant with the highest P/C mass ratio of 0.36 in char. Transparency analysis shows that the transparency of the coatings gradually decreases with the decrease of talc particle size, and the Talc‐1250 with exfoliated morphology imparts less loss of transparency to the coating while the Talc‐3000 and Talc‐5000 with intercalated morphologies induce more obvious light scattering in the coatings.Highlights Talc was used to enhance the comprehensive properties of transparent fireproof coatings. Synergistic efficiency of talc on the fire safety of coatings varies with its particle size. Talc with a particle size of 3000 mesh exerts an optimum synergism in the coatings. Transparency of the coatings gradually decreases as talc particle size decreases.