混晶TiO2制备硅灰基水性木结构涂料研究

Prepare of diatomite-based waterborne wood coating by mixed crystal TiO2

以NaOH/Na2SiO3改性硅藻土为基料,板钛矿/锐钛矿混晶TiO2为功能性填料,采用溶胶-凝胶法制备水性木结构阻燃涂料,研究了混晶TiO2对其阻燃性能及微观结构的影响。阻燃性能结果表明,当TiO2掺量为2%时,刷涂该涂料纤维板的阻燃性能最佳,其LOI值达到29.1%,炭化体积(小室法)仅为8.7cm^3,较不掺TiO2的样品减小了54%。掺入的混晶TiO2在NaOH/Na2SiO3改性硅藻土体系中性能稳定,有助于该涂料在燃烧过程中形成结构较为致密、具有相互交联孔网结构的海绵状物质,导致硅质阻燃层的热导率降低,阻燃性能提高。提出了混晶TiO2在NaOH/Na2SiO3改性硅藻土水性木结构涂料中的作用机理,包括遮光剂、增强体和光催化效应。

A diatomite-based waterborne wood coating was prepared through sol-gels method using NaOH/Na2 SiO3 modified diatomite as basic material, Brookite/Anatase mixed crystal TiO2 as the functional filler.Effects of Brookite/Anatase mixed crystal TiO2 on its flame-retardant properties and microstructures were investigated. The results of flame-retardant properties showed that the specimen which mass fraction of TiO2 was 2% displayed the optimum flame retardant performance, the value of LOI reached 29.1%,the burning volume of fibreboard covered this coating(Small chamber method) was only 8.7 cm3, it decreased by 54% in comparison with the specimen without TiO2. The hybrid TiO2 hold stable properties in the system of NaOH/Na2 SiO3 modified diatomite, they favor the coating to form denser, spongy and mutual cross-linking network structures during the process of firing, leading to the decrease in the thermal conductivity of siliceous flame retardant layer and an improvement of flame-retardant performance. The mechanisms of TiO2 in the flame retardant coating were proposed including opacifier, enhancer and photocatalys.