Development and Topochemistry of Wood-Inorganic Composites

提出了一种保留木材多孔结构特征的木无机复合材料的制备方法，该方法涉及醇基硅烷的溶胶-凝胶过程，利用结合水在木材细胞壁内形成硅胶。这种硅胶被发现是选择性地在细胞壁内形成的，并且凝胶的形成量被发现对于具有较高的结合水含水量的样品更高。对不同硅胶用量制备的复合材料的评价表明，硅胶用量越大，复合材料的尺寸稳定性和阻燃效果越好。将超声波辐射应用于上述方法，促进烷氧基硅烷的水解，发现其处理有效地增加了木材细胞壁内硅胶的吸收率，从而提高了尺寸稳定性和阻燃效果。为了比较，还制备了在细胞腔内填充硅胶的木-无机复合材料，并研究了无机材料的拓扑化学效应对尺寸稳定性和阻燃效果的增强。结果清楚地表明，与在细胞腔内形成的硅胶相比，在细胞壁内形成的硅胶不仅具有尺寸稳定性，而且具有阻燃效果。

A method was developed for preparing wood-inorganic composites with retaining a porous structure characteristic of wood, and it involves the sol-gel process of alcoxysilanes to form silica gel within wood cell walls by the use of bound water. This silica gel was found to be selectively formed within the cell walls and the amount of the gel formed was found to be higher for the specimens with the higher moisture content of bound water. Evaluation of the prepared composites with different amounts of silica gel formed indicated that the composites with the higher amount of the gel retained revealed the better dimensional stability and fire-retarding effect.The ultrasonic radiation was applied to the above method to promote the hydrolysis of the alkoxysilane and its treatment was found to be effective to increase the uptake of the silica gel within the wood cell walls, which has resulted in the improvement of the dimensional stability as well as fire-retarding effect.Just for comparison, wood-inorganic composites filled with silica gel within the cell lumens were also prepared, and topochemical effects of the inorganic materials was studied on property enhancement in dimensional stability and fire-retarding effect. The result clearly indicated that silica gel formed within the cell walls was more effective not only for dimensional stability but also for fire-retarding effect, compared with silica gel formed within the cell lumens.