用XRD法研究ULDM纤维素结晶区的热稳定性

Study on the thermal stability of cellulose crystalline region of ULDM by X-ray diffraction

纤维素结晶区的热稳定性对超轻质木纤维发泡材料(ULDM)的阻燃性能有关键影响作用。提高纤维素结晶区的有序程度和结晶度,材料的阻燃性能相应获得提高。在氮气保护下,对未阻燃处理、无机复合阻燃剂各组分分别单独阻燃处理和复合阻燃剂阻燃处理的ULDM试样分别热处理到指定温度,通过X-射线衍射(XRD)法分析纤维素结晶区随温度变化的趋势和阻燃剂各组分对结晶区的影响。结果表明:复合阻燃剂的酸脱水成炭作用和硅化合物与碳链形成的化学键结合提高了纤维素结晶区的有序性和结晶度,纤维素结晶区的完全热解破坏温度由400℃提高到500℃以上。经阻燃处理后纤维素结晶区热解过程是逐步降解,防止了由于结晶区的瞬间热解崩溃而发生爆燃的现象。

The thermal stability of cellulose crystalline region had critical effect on flame retardant properties of ultra-low density wood-based foaming material （ULDM）. Enhancing order degree and crystallization degree of the cellulose crystalline, the flame retardant performance increased correspondingly. Under the protection of nitrogen, no fire retardant treated, inorganic composite fire retardant components treated respectively and fire retardant composite treated samples of ULDM were heated to the specified temperature. By X-ray diffraction （ XRD）, crystalline region of cellulose changes with the temperature and effects of each flame retardant component on the crystallization zone were analyzed. The results showed the action of acid dehydration into carbon and silicon compounds form chemical bond with carbon chain by composite flame retardant improved the order and erystallinity of crystalline region. Furthermore, failure temperature of complete pyrolysis about cellulose crystalline region increased from 400 ℃ to 500 ℃ when ULDM had been treated by composite flame retardant. Treated by flame retardant cellulose crystalline region pyrolysis process was gradually degraded, preventing the flash pyrolysis collapse in crystalline regions and deflagration phenomenon.