氮气介质环境中热处理樟子松木材主要性能的变化

Effect of N_(2) Heat Treatment on Main Properties of Pinus sylvestris var.mongolica Wood

以氮气为介质,采用160℃、180℃、200℃3种不同温度,2、4、6 h 3种不同时间分别对樟子松木材进行热处理改性,分析热处理前后樟子松材色、尺寸稳定性及力学性能的变化规律,并采用FTIR及XRD手段分析了其变化机理。结果表明,樟子松木材色差随热处理温度和时间增大而增大,而明度随热处理温度和时间增大逐渐降低,处理材红绿色品指数a*值和黄蓝色品指数b*值均大于未处理材。樟子松木材平衡含水率随热处理温度和时间的增大逐渐减小,ASE和吸湿滞后现象随温度的增大逐渐增大。樟子松木材的顺纹抗压强度、抗弯弹性模量及抗弯强度随热处理强度的增加呈现先增大后降低的趋势,但在200℃下对这3个力学性能指标影响均不显著。热处理温度对樟子松材色及尺寸稳定性影响均极显著,热处理时间对樟子松木材明度、黄蓝色品指数b*、色差、平衡含水率和体积湿胀率影响均极显著。研究结果为高品质樟子松热处理木材的生产提供科学依据。

To analyse the change pattern of colour, dimensional stability and mechanical properties before and after heat treated wood under N_(2),Pinus sylvestris var.mongolica wood was heat treated at the temperature of 160℃,180℃ and 200℃,for 2 h, 4 h and 6 h.FTIR and XRD also were used to analyse the mechanism of these changes.The results showed that with the increase of heat treatment temperature and time, the ΔE* increased while the L*,equilibrium moisture content(EMC) decreased.The a* and b* of heat treated Pinus sylvestris var.mongolica wood were bigger than that of untreated one.The hygroscopic hysteresis and anti-swelling efficiency(ASE) increased with the increase of temperature.The compression strength parallel to grain, modulus of elasticity in static bending and bending strength of heat treated Pinus sylvestris var.mongolica wood increase first then decrease with the increase of thermal proces intensity, but the influence of thermal proces intensity on mechanical properties of thermal Pinus sylvestris var.mongolica wood is not significant.Treatment temperature has extreme significant on the color, dimensional stability of Pinus sylvestris var.mongolica wood after heat treated with N2.Treatment time has extreme significant on the brightness b*,ΔE* and equilibrium moisture content and volume swelling rate of Pinus sylvestris var.mongolica wood after heat treated with.The results of this study could provide scientific basis for production of thermal P.sylvestris wood with high quality.