Preparation of amino wood coatings with superior flame retardancy, smoke suppression, and transparency using fully bio-based flame retardants

The development of efficient, eco-friendly and cost-effective transparent fire-retardant coatings is crucial for maximizing the value of wood resources. In this study, an all-biobased flame retardant (PA-CS) was synthesized from corn starch (CS) and phytic acid (PA). A modified melamine resin (MFGT) with intrinsic flame-retardant properties was prepared by incorporating melamine, formaldehyde, allyl glycidyl ether, and tannic acid. The resulting MFGT@xPA-CS system demonstrated excellent thermal stability and low curing activation energy. Additionally, the system was used on the surface of wood and demonstrated good transparency, outstanding flame retardancy, smoke suppression, and char-forming ability. Cone calorimeter tests revealed that the peak heat release rate (PHRR) of [email protected] decreased by 31.12%, and total smoke production was reduced by 48.03%. Additionally, the residual char increased from 34.93% (c-MFGT) to 43.25% ( [email protected] ), and the I D /I G ratio of the residual char decreased by 40.58% from 3.08 (c-MFGT) to 1.83 ( [email protected] ). Gas-phase and condensed-phase pyrolysis products revealed synergistic effects between the phosphorus in PA-CS and the nitrogen in MFGT. Based on these results, a potential flame-retardant mechanism was proposed. This study presents a novel strategy for developing transparent intumescent flame-retardant coatings and broadens the application of biomass-based flame retardants.