SiO2溶胶对八硼酸钠处理木材抗流失性能的影响(英文)

Effects of SiO_2 Sol on Leachability of Wood Impregnated with Disodium Octaborate Tetrahydrate

八硼酸钠因具有阻燃、防腐和价廉等诸多优点,被认为是应用最广泛的木材保护改性剂之一。但是,其极易流失的缺陷限制了处理材在户外的使用范围。通过测定处理材抗浸提值和比较处理材在流失试验前后阻燃性能的变化,研究了SiO_2溶胶对八硼酸钠处理木材抗流失性能的影响。利用二:次加压浸注处理工艺,对杉木试件先进行八硼酸钠浸注处理,然后进行SiO_2溶胶浸注处理。按相应的试验方法测定处理材的抗流失性能,采用锥形量热仪法测定处理材的阻燃性能。结果表明:经八硼酸钠+SiO_2溶胶处理的木材试件抗浸提值在不同浓度下分别达到了60.64%,71.06%,72.24%,81.14%和188.58%,而只经单一八硼酸钠处理的木材试件抗浸提值均小于4.5%(甚至为负数)。通过比较两类处理材在流失试验前后的热释放速率峰值和成炭率的差异,证明SiO_2溶胶改善了八硼酸钠处理木材的抗流失性能。说明经八硼酸钠+SiO_2溶胶处理的术材具有良好的阻燃性能并且能持久保持。

Disodium octaborate tetrahydrate(DOT) was recognized as one of the most widely used modification agent for timber protection due to various advantages such as being fiame-retardant,non-corrosive and inexpensive.However,its high susceptibility to leaching limited its significance for outdoor applications.The aim of the paper was to investigate the effects of SiO_2 sol on teachability of wood impregnated with disodium octaborate tetrahydrate by calculating the leach resistant value(LRV) and comparing the fire retardant performance before and after leaching.Specimens of Chinese fir were pre-impregnated with aqueous solutions of disodium octaborate tetrahydrate at various concentrations and then SiO_2 sol by vacuum-press impregnation process.Leaching test was conducted according to a laboratory procedure,while fire retardant test was carried out on a cone calorimeter.Results showed that the leach resistant value(LRV) of the specimens treated with DOT in presence of SiO_2 sol arrived at 60.64%,71.06%,72.24%,81.14%and 88.58%,while that of the only DOT-treated specimens were below 4.5%(even below zero).By comparing the pkHRR and RCP of specimens before and after leaching,the improving effect of SiO_2 sol on leach resistance was proved.Wood specimens treated with DOT+SiO_2 possess durable and favorable fire retardant property.