TiO2/PDMS增强表面热改性木材耐老化性的协同效应

目的表面热改性木材是一种常见的室外用木材，但易受光照和水分的作用发生老化现象，这在一定程度上限制了它的应用。因此，探究一种有效可行的改性方法提高表面热改性木材的耐老化性能十分必要。方法本研究采用二氧化钛(TiO₂)和聚二甲基硅氧烷(PDMS)单独或复合处理作为表面热改性的预处理手段，采用场发射扫描电子显微镜(FE-SEM)和傅里叶红外光谱(FTIR)测试其微观结构和表面物质的变化，探讨了不同处理手段对于提高表面热改性木材耐老化性能的改性效果及其作用机理。结果TiO₂或PDMS单独改性处理不能有效提高表面热改性材的耐老化性能。TiO₂/PDMS复合改性处理有效提升了表面热改性材在老化过程中的颜色稳定性、疏水性能和耐磨性能，这是TiO₂的紫外屏蔽效应和PDMS的防水效应共同作用的结果。木材表面形成的纳米TiO₂能够散射、反射和吸收紫外光，防止木材内部组分因吸收紫外光发生剧烈降解，PDMS可减少TiO₂颗粒因水分和摩擦影响而产生的流失。结论TiO₂/PDMS复合改性处理对改善表面热改性材耐老化性能具有协同作用。 

Synergistic effect of TiO2 and PDMS on improving anti-weathering properties of surface thermally-modified wood

ObjectiveSurface thermally-modified wood is commonly used in outdoor conditions, and prone to aging under the effects of light and moisture, which limits its application to some extent. Therefore, it is necessary to explore an effective and feasible modification method to improve the anti-weathering properties of surface thermally-modified wood.MethodIn this study, titanium dioxide (TiO₂) and polydimethylsiloxane (PDMS) were used separately or corporately as a pretreatment method for surface thermal modification. Changes of microstructure and substance composition on wood surface were measured by means of field emission scanning electron microscope (FE-SEM) and Fourier transform infrared spectroscopy (FTIR), and the efficiency and mechanism of each treatment methods for improving the aging resistance of surface thermally-modified wood were discussed.ResultTreatment with TiO₂ or PDMS alone can not improve anti-weathering property of surface thermally-modified wood effectively, while TiO₂/PDMS composite modification treatment effectively improved the color stability, hydrophobicity and abrasion resistance of surface thermally-modified wood due to UV-shielding property of TiO₂ and waterproof effect of PDMS. The nano-TiO₂ which formed on wood surface can scatter, reflect and absorb UV light to prevent wood components from being destroyed by absorbing UV light, and PDMS can reduce the loss of TiO₂ particles due to the influence of moisture and friction.ConclusionTiO₂ and PDMS have a synergistic effect on improving the anti-weathering property of surface thermally-modified wood.