增强-染色复合改性杨木的强度和耐光色牢度

【目的】通过木材增强-染色联合改性,提高人工林杨木的物理力学和装饰性能,为人工林速生软质木材的高效增值利用提供技术支持。【方法】将水溶性低分子质量三聚氰胺脲醛树脂(MUF)与酸性大红G复配得到复合染色剂,通过真空加压浸渍处理,对杨木进行增强-染色一体化改性,测试改性材颜色、强度、氙光老化等性能,并利用SEM分析其微观性状。【结果】增强-染色复合改性材的Δa~*、Δb~*、ΔC~*、ΔL~*与ΔE~*等色差指标与水染材基本一致;复合染色材表面与内部颜色差异小于水染材。与未处理材相比,增强-染色复合改性材的密度、抗弯弹性模量(MOE)、抗弯强度(MOR)和抗压强度分别提高了38.2%、6.28%、20.67%和48.87%,与树脂增强改性材相当。SEM分析结果表明,MUF改性材和复合改性材细胞腔和细胞间隙被改性剂填充;与水染材相比,复合改性材中的染料颗粒分布更均匀。耐光色率度测试结果表明水染材颜色在10 h内变化最快,50 h开始趋于平缓;增强-染色复合改性材在光照50~75 h颜色变化加快,75 h后趋于稳定,其耐光色牢度比水染材提高了28.3%。【结论】染料的添加对树脂MUF的增强改性作用无明显影响,染料的加入也不影响水溶性低分子质量MUF树脂的高渗透性,树脂填充细胞腔和细胞间隙使得两种改性材的密度和力学强度均大大提高,树脂对染料的包覆和固结使得复合染色材的耐水色牢度明显提高,增强-染色复合改性材比水染材具有更好的耐光色牢度。将木材功能性改良与染色相结合的杨木增强-染色一体化改性技术,能显著改善速生杨木材料的物理力学和装饰性能。

Strengths and light fastness of the strengthening?dyeing modified poplar wood

Objective]This study is to improve the physical, mechanical and decorative properties of Chinese fir wood simultaneously, and provide technical support for the efficient value?added utilization of fast?growing soft wood.Method]The strengthening?dyeing modifier was prepared by mixing the acid red G with the self?made melamine?urea?formaldehyde resin ( MUF) which was of low?molecular?weight and water?soluble, and the planted poplar wood was mod?ified with the compound modifier by impregnation treatment, then its color, strength, light fastness and microstructure morphology were studied. Result] The Δa?,Δb?,ΔC?,ΔL? and ΔE?of strengthening?dyeing modified wood were consistent with water dyed wood, and its surface and internal color difference was less than water dyed wood. Compared with untreated wood, the density, bending modulus, bending strength and compressive strength of strengthening?dyeing modified wood were increased by 38.2%, 6.28%, 20.67% and 48.87%, respectively, which were similar to those of the resin strengthened wood. Cell lumens and intercellular space of the wood treated by MUF and compound modifier were filled. Compared with water dyed wood, the dye particles was more uniform in compound modified wood. Color degrada?tion rate of the water dyed wood was the fastest within 10 h at Xenon light, and begin leveling off at 50 h. While color degradation rate of the strengthening?dyeing modified wood begin accelerating within 50-75 h, then begin leveling off at 75 h.The color fastness to light of the strengthening?dyeing modified wood was increased by 28.3% than water dyed wood.Conclusion] Compared with the dye water solution the compound modifier had better and more uniform dyeing effect. The additional dye had no significant effect on the wood modification of the resin. The SEM analysis showed that the dye did not affect the MUF' s good permeability. The density and mechanical strength of treated wood have been greatly im?proved by the filling of cell lumens and intercellular space by modifiers;compound modified wood had better color fast?ness to water as. The strengthening?dyeing modified wood had better color fastness to light than water dyed wood. This technology integrated the functional modification and dyeing of fast?growing poplar wood, its process was simple, and the treated wood exhibited high strength and good color, which could be directly used to make high value?added solid wood products.