脱木质素和硅酸钠浸渍的协同处理对巴沙木木材阻燃性能的影响

Flame Retardant Properties of Sodium Silicate Modified Delignified Wood of Ochroma pyramidale

以巴沙木(Ochroma pyramidale)木材为研究对象,制备尺寸为(纵向×径向×弦向)100 mm×100 mm×2 mm的试件(天然木材试件);采用“质量分数2%的亚氯酸钠溶液+加冰醋酸”,在85℃蒸煮3 h,脱除木材中大部分木质素,冲洗、蒸煮除去残留的化学物质,真空冷冻干燥后制备脱木质素木材试件;采用质量分数为30%的硅酸钠溶液,浸渍天然木材试件、脱木质素木材试件,85℃水浴高温浸渍1.5 h,浸渍材气干7 d、55℃干燥12 h后,制备阻燃木材试件、阻燃脱木质素木材试件;参照相关标准,测定试件的氧指数、点燃时间、热释放速率、总热释放量、总烟释放量、一氧化碳产量、二氧化碳产量、残余物质量、热稳定性;分析天然木材、脱木质素木材、阻燃木材、阻燃脱木质素木材的燃烧性能。结果表明:与天然木材相比,阻燃木材、阻燃脱木质素木材的氧指数显著提高。脱木质素处理和硅酸钠浸渍,对降低木材的热释放速率、总热释放量、总烟释放量、一氧化碳产量、二氧化碳产量均具有促进作用。热质量分析表明,脱木质素处理对木材残炭量影响较小,阻燃木材、阻燃脱木质素木材的热分解速率明显下降;“脱木质素+硅酸钠浸渍”协同处理,有利于木材成炭,热稳定性提高。

Using Ochroma pyramidale wood as the research object,specimens with dimensions of(longitudinal×radial×Tangential)100 mm×100 mm×2 mm were prepared(natural wood specimen).The 2%sodium chlorite solution and glacial acetic acid was used for cooking at 85℃for 3 h to remove most of the lignin in the wood,the residual chemical substances were removed by washing and cooking,and the delignification wood samples were prepared after vacuum freeze drying.Using 30%sodium silicate solution,natural wood samples and delignified wood samples were impregnated with 85℃water bath at high temperature for 1.5 h,and the impregnated wood was air-dried for 7 d and dried at 55℃for 12 h to prepare flame retardant wood samples and flame retardant delignification wood samples.The oxygen index,ignition time,heat release rate,total heat release,total smoke release,carbon monoxide production,carbon dioxide production,residual mass and thermal stability of the specimen were measured according to relevant standards.And the combustion properties of natural wood,delignification wood,flame retardant wood and flame retarded delignification wood were analyzed.The results showed that compared with natural wood,the oxygen index of flame-retardant wood and flame-retardant delignified wood was significantly increased.Delignification treatment and sodium silicate impregnation have a promoting effect on reducing the heat release rate,total heat release,total smoke release,carbon monoxide production,and carbon dioxide production of wood.The thermal mass analysis showed that delignification treatment had little effect on the carbon residue of wood,and the thermal decomposition rate of flame retardant wood and flame retardant delignified wood decreased obviously.The collaborative treatment of delignification and sodium silicate impregnation is conducive to wood char formation and thermal stability improvement.