ObjectiveWooden materials are easy to get ignited when furniture and buildings go up in flames. It can cause the fast fire spread and produce much toxic gases leading to the human death. In order to reduce the fire hazard of furniture and buildings, wood must be treated for fire retardancy. In this study, an intumescent flame retardant (IFR) system of phytic acid and melamine was prepared and used as a flame retardant of wood, the flame retardancy of the treated wood was then investigated. The purpose of this paper is to provide a new thought and enrich the IFR system.

MethodTwo-step impregnation method was conducted to assemble the phytic acid-melamine flame retardant in the interior of Populus cathayana. The weight percent gain, bulking, pyrolysis and combustion behavior of the modified wood was assessed. The morphology of the residue of treated wood after combustion was analyzed in order to discuss the mechanism of phytic acid-melamine IFR system.

ResultThe first peak of heat release rate and the total heat release of 15% phytic acid and 5% melamine treatment group (PM2) were reduced by 91.24% and 79.05% compared with that of control, respectively. The PM2 group showed stronger smoke suppression performance, and reduced the total smoke emission by 52.94% compared with the control group. The mean carbon monoxide yield of PM2 group was reduced by 51.29% compared with the P15% group. The amount of carbon residue of PM2 group was significantly increased, which was 69.58% higher than that of P15% group and 278.4% higher than that of the control group. The PM2 group had the optimum effect on promoting the residue and reducing the heat release.

ConclusionThe phytic acid and melamine flame retardant system can be penetrated into the wood. The combined treatment of phytic acid and melamine can reduce the heat release rate, total heat release, total smoke release and CO yield of flame retardant treated wood. Phytic acid takes part in catalyzing the dehydration and carbonization of wood which leads to the lower temperature of degradation reaction and promotion of the formation of carbon residue of wood. The synergistic effect between phytic acid and melamine can enhance the formation of carbon residue of wood.