Improving fire safety and corrosion resistance of wood using dual-layer tung oil-based coatings

A novel approach utilizing tung oil (TO)-based coatings to improve the fire safety and corrosion resistance of wood was presented. This study focuses on the development of methyl 11,13,15-tris((diethoxyphosphoryl)oxy)-10,12,14-trihydroxyoctadecanoate (MTTO), a tung oil-derived structural flame retardant polyol using innovative methods. Synthesizing MTTO from epoxidized TO methyl ester (eTOME) and diethyl aminophosphate achieved a high yield of 91%. Molecular characterization of MTTO was performed using various spectroscopic techniques. The application of 50% MTTO solution coated with 1% tung oil (MTTO-b-TO) treated wood demonstrated excellent flame retardant properties, belonging to UL-94V-0 class of materials. The incorporation of MTTO increased the LOI of the material from 21.4% to 37.9% and 36.1%, respectively. Furthermore, the treated wood with MTTO-b-TO exhibited significantly lower mass loss rates compared to pure wood after undergoing anti-white or brown-rot fungus experiments. These findings provide valuable insights for the rational design of tung oil-based coatings, offering enhanced wood protection, sustainable resource utilization, and reduced health and environmental risks.