木材阻燃剂FRW的阻燃机理

在综合分析热分析法、锥形量热仪法和FTIR法获得的FRW阻燃机理研究结果并吸收木材阻燃机理研究现有成果的基础上,推导进而提出了木材阻燃剂FRW的阻燃机理。其主要内容是:1)FRW阻燃木材受热时,阻燃剂FRW分解产生不燃性气体和不挥发的酸性熔融物质,具有降低体系温度和氧气浓度及屏蔽热辐射的作用,降低了木材的热解速度;2)FRW的组分硼酸和GUP的酸性分解产物催化木材脱水、降解,以及木材热解产物的缩合、聚合、芳构化等反应,能改变木材的热解途径并使其向着有利于炭化的方向变化,FRW显著的催化成炭作用,使阻燃木材的燃烧放热量大大降低,这是FRW阻燃机理的主要方面;3)硼酸与GUP起阻燃作用的温度和方式不同,并且有相互补充的作用,因而表现出阻燃协同效应。

The Fire-Retardant Mechanism of Fire-Retardant FRW for Wood

On the basis of comprehensive study of the result of the thermal analysis, the cone calorimetry and the FTIR for wood treated with fire-retardant FRW, by combining the current theory for fire-retardant wood, the fire-retardant mechanism of FRW was proposed. Its main points were as follows: When wood treated with FRW was heated to sufficient high temperature, FRW in the treated wood decomposes to produce noncombustible gas and nonvolatile acidic molten substance, the later have the effects of decreasing the temperature and shielding heat and diluting oxygen in the air, and this diminishes the pyrolysis rate of wood. The acidic products, formed by the decomposition of boric acid and GUP (components of FRW), catalyze the reactions of wood such as dehydration and degradation, the reactions of the pyrolytic products of wood such as condensation, polymerization and reactions to form aromatic structure. This changes the process of wood pyrolysis and promotes charing. The remarkable catalytic charing effect of FRW, which consumedly decreased the heat release of fire-retardant wood, is the key point of its fire-retardant mechanism. Boric acid and GUP take effects at different temperature by different fire-retardant mechanisms, and the two make up for each other, so they are synergistic.