Abstract: Waterborne wood flame-retardant coating were investigated with KOH/Na₂SiO₃ modified silica fume as binder through sol-gels method. Melamine faced MDF test pieces were made and the oxygen index of the test piece was measured. Analysis of crystal phase change and apparent morphology of samples and raw materials were carried out to research the effects of brookite/anatase TiO₂ on flame retardant properties and microstructure. The results showed that the amount of TiO₂ could improve the flame retardant performances, it displayed the optimum flame retardant performance for the specimen with 2% mass fraction of TiO₂, the LOI of fiberboard reached 31.4%, the burning volume (Small chamber method) was only 8.2 cm³, it decreased by 56% in comparison with the specimen without TiO₂. The brookite/anatase TiO₂ holds a stable structure during the combustion process, which is benefit for silica fume-based waterborne wood coatings to develop complete, uniform, denser layer structures, leading to an increase in the weight loss temperature and a decrease in heat flow, therefore it improves the flame retardant performance.

Key words: flame retardant, silica fume, waterborne coatings, TiO₂