Progress in Fire-Retardant Research on Wood and Wood-Based Composites: a China Perspective
Wang Qingwen, Wang Fengqiang, Hu Yunchu, Li Jian
The fire retardant research on wood and wood-based composites, which was carried out in China in the past two decades, was reviewed with 55 references. While many kinds of fire retardants for wood and wood-based composites have been studied, the mainstream is still the compound or the mixture containing phosphorus, nitrogen and boron elements, which can be used in the form of water solution in the impregnation of solid wood. The fire-retardant treatment methods for wood panels are either pretreatment of veneers, fibres, particles and strands before hot pressing, or the impregnation of waterproof panels by fire-retardant solution. Though attempts have been done in lab to mix fire retardants with the glue, it has proved to be very difficult to spray glue with effective amount of fire retardants smoothly in the real manufacturing of fire-retardant panels. Fire retarding mechanism of phosphorus-nitrogen-boron fire retardants have been investigated systematically. The results indicated that for a proper fire-retardant formulation phosphorus-nitrogen compounds and boron compound are highly synergistic, that the catalytic charring effect of a fire retardant on wood is a key factor to its fire-retardant efficiency, and that a chemical fire-retardant mechanism for boric acid was proposed. The fire-retardant research on wood plastic composites has attracted more attention in recent years, however, most results are basically preliminary because of the difficulty for choosing or setting up a suitable fire retardant system that is effective to both of wood and plastics. Research on smoke suppression of wood was also discussed which was even more preliminary and innovative efforts are needed.
Keywords: fire retardant, smoke suppression, wood, wood panel, wood-plastic composite