木材表面纳米TiO_2疏水薄膜的构建及抗光变色性能

Construction of hydrophobic nano-TiO_2 on wood surface and analysis of its anti-photodiscoloration performance

为了改善木材的耐候性,采用溶胶-凝胶法常温条件下在木材表面构筑纳米TiO2薄膜,并修饰低表面能物质硬脂酸,使木材表面由亲水性变为疏水性,同时利用TiO2对紫外线优良的散射能力,提高木材的耐光老化性能。利用场发射扫描电子显微镜(FE-SEM)、X射线能谱仪(EDX)以及傅里叶变换红外光谱仪(FTIR)对处理材进行形貌、结构及化学组成表征,并测试其疏水及抗光变色性能。结果表明:木材表面负载纳米TiO2颗粒,并将硬脂酸的疏水长链烷基引入木材表面,木材的表面水接触角可提高到130°左右,呈现强疏水性。纳米TiO2薄膜同时赋予木材良好的抗光变色性能,其中质量分数5%TiO2溶胶处理的木材在经过120h加速光老化后,其总色差值(ΔE*)仅为对照试样的45%。

Wood surface was modified by nonaTiO2 coating via solgel process at room temperature, followed by low surface energy treatment with stearic acid in order to transform the wood surface from hydrophilic to hydrophobic. In the meanwhile, the photostability of wood was also improved due to excellent UVshielding property of nanoTiO2 . The surface morphology, structure and chemistry of the treated wood were studied by field emission scanning electron microscopy （ FESEM） , energy dispersive Xray analysis （ EDX） , and fourier transform infrared spectroscopy （ FTIR） . The hydrophobicity and antiphotodiscoloration performance of treated wood were tested. The results showed that the TiO2 nanoparticles were successfully introduced onto the wood surface, and the longchain alkyl groups of stearic acid were grafted to provide hydrophobicity. The water contact angles of the treated wood were improved remarkably to approximately 130° displaying high hydrophobicity. The nanoTiO2 films also improved the antiphotodiscoloration performance of wood remarkably. The overall color change （ΔE） of the wood samples treated with 5% TiO2 sol, was only 45% of the corresponding value of the control samples after 120 h artificial accelerated weathering.