Topochemistry on the Property Enhancement of Wood with Inorganic Materials

通过溶胶-凝胶法制备木材-无机复合材料的研究，发现正硅酸乙酯（TEOS）制备的SiO_2木材-无机复合材料在尺寸稳定性、阻燃性等方面都有明显的提高，为进一步提高其性能，本文研究了在正硅酸乙酯/乙醇/乙酸反应体系中，以亚磷酸三甲酯（TMP）和硼酸三甲酯（TMB）。所制备的SiO_2-P_2O_5-B_2O_3复合材料具有良好的上级阻燃性能。但是，P_2O_5和B_2O_3凝胶的耐候性较差; TMP由于其气味难闻，在环境安全方面不能接受。对于（1）的问题，将HFOETMOS（2-七氟辛基乙基三甲氧基硅烷）以少量（相对于TEOS的摩尔比为1/2，000）加入到反应体系中。同时，还增加了复合材料的憎水性，以防止P_2O_5和B_2O_3凝胶的流失。此外。for（2） ...更多信息 用硅醇盐低聚物代替TMP和TMB水解缩合得到的TEOS制备SiO_2-P_2O_5-B_2O_3复合材料。这样，生产环境得到了改善。此外，由于Si、P、B组分之间存在共价键，改性后的SiO_2-P_2O_5-B_2O_3凝胶具有很好的稳定性，不易流失，对木材的阻燃效果显著。在上述反应体系中加入含磷阻燃剂和少量HFOETMOS，制备的SiO_2木材-无机复合材料也显示出木材的抗烧蚀性和高阻燃性。其中，TiO_2凝胶仅分布在细胞壁内的TiO_2复合材料的尺寸稳定性和耐火性都得到了提高，表明局部化学效应对木材的性能增强作用。少

From our study on wood-inorganic composites by the sol-gel process, SiO_2 wood-inorganic composites from tetraethoxysilane (TEOS) were found to be enhanced in dimensional stability, fire-resistance and so on. To improve their properties further, multicomponent SiO_2-P_2O_5-B_2O_3) wood-inorganic composites were studied in a reaction system of TEOS/EtOH/acetic acid to which trimethylphosphite (TMP) and trimethylborate (TMB) were added. Obtained SiO_2-P_2O_5-B_2O_3 composites were superior in fire-resistance. However, (1) P_2O_5 and B_2O_3 gels are not stable against weathering and (2) TMP is not acceptable in terms of safety in environment for its production due to its offensive oder. For the problem of (1) , HFOETMOS (2-heptafluorooctylethyltrimethoxysilane) was added in a small quantity to the reaction system (1/2,000 in the molar ratio to TEOS). Concomitantly, water-repellent property was added to prevent the composites from a leaching of P_2O_5 and B_2O_3 gels. Furthermore. for (2) … More , silicon alkoxide oligomers instead of TEOS to which TMP and TMB were hydrolized and condensed, were used for preparing SiO_2-P_2O_5-B_2O_3 composites. By doing so, the production environment was improved. Additionally, this modified oligomers are so stable due to covalent bonds among Si, P,and B components that obtained SiO_2-P_2O_5-B_2O_3 gels were resistant against their leaching, and very effective for fire-resistance of wood. SiO_2 wood-inorganic composites prepared from the above reaction system to which phosphorus-containing fire-resistant agents and a small amount of HFOETMOS were added, also revealed antileachability and high fire-resistance of wood.On TiO_2 wood-inorganic composites, composites with various types of TiO_2 distribution were prepared from titanium alkoxides and titanium chelates. Among tem, TiO_2 composites in which TiO_2 gels are distributed only within the cell walls were found to be enhanced in dimensional stability and fire-resistance, indicating that the topochemical effects exist on the property-enhancement of wood. Less