高温热处理对中山杉木材物理力学性能的影响OA北大核心CSTPCD
Effect of high-temperature heat treatment on the physical and mechanical properties of Taxodium hybrid'Zhongshanshan'wood
中山杉(Taxodium hybrid'Zhongshanshan')是落羽杉属杂交选育出的优良无性系品种,但其木材存在尺寸稳定性差、力学强度低等缺点,限制了其开发应用范围.以中山杉木材为研究对象,使用过热蒸汽对其进行改性,研究了处理温度(175,195,215 ℃)和处理时间(1,2,4 h)对中山杉物理性质、化学成分和力学性能的影响.结果表明:处理温度的升高和处理时间的延长使木材表面材色逐渐向深褐色转变,其中处理温度对色度的影响更显著.热处理材的质量损失率随着处理温度升高和处理时间延长而增大,处理温度对质量损失率影响更显著.热处理材半纤维素的质量分数随温度的升高显著降低,温度达到215 ℃时,半纤维素的质量分数与未处理材相比下降近65％,而纤维素质量分数相对稳定,下降了 11.47％.由于纤维素和半纤维素中具有吸水性的游离羟基数量减少,热处理材的饱水湿胀率和全干干缩率随温度升高而下降,抗胀(缩)率随处理温度升高逐渐增大,尺寸稳定性明显提升.但高温处理对木材的抗弯强度和抗弯弹性模量具有消极影响,尤其是处理温度影响显著.当处理温度达到215℃且处理时间为4 h时,热处理材抗弯强度和抗弯弹性模量分别下降了 27.74％和31.45％.
Taxodium hybrid'Zhongshanshan'is an excellent asexual variety of the genus Taxodium that was selected by crossbreeding.However,this wood species has many drawbacks such as poor dimensional stability and low me-chanical strength,which limits the scope of its application.The superheated steam treatment method was used for the treatment of the Taxodium hybrid'Zhongshanshan',and the specific studies were conducted on the effects of treat-ment temperature(175,195,or 215 ℃)and treatment time(1,2,or 4 h)on the physical properties,chemical composition and mechanical properties of Taxodium hybrid'Zhongshanshan'.The experimental results indicated that,in terms of physical properties,the increase of treatment temperature and the prolongation of treatment time gradually changed the surface color of wood from light yellow to dark brown,in which the treatment temperature had a more significant effect on the color compared to the time.The mass loss rate of heat-treated wood increased with the in-crease of treatment temperature and the extension of treatment time,and the effect of treatment temperature on mass loss rate was more obvious than that of the time.In addition,the saturated swelling rate and over-dry shrinkage rate of the heat-treated wood decreased with the increase of temperature,and the ASE(anti swelling efficiency)gradually in-creased with the increase of treatment temperature,and the dimensional stability was obviously improved.In terms of chemical properties,the mass ratio of hemicellulose of the heat-treated wood decreased significantly with the increase of temperature,when the temperature reached 215 ℃,the mass ratio of hemicellulose decreased by approximately 65％compared with the untreated wood,and the cellulose mass fraction decreased by 11.47％compared with the un-treated wood.In terms of mechanical properties,high-temperature treatment had a negative effect on the modulus and rupture(MOR)and modulus of elasticity(MOE)of wood,especially the treatment temperature had a significant effect.When the treatment temperature reached 215 ℃ and the treatment time was 4 h,the MOR of the heat-treated wood decreased by 27.74％and the MOE decreased by 31.45％.The mechanical properties of Taxodium hybrid'Zhongshanshan'itself are poor,and the heat treatment would further reduced the mechanical strength of Taxodium hybrid'Zhongshanshan'wood.However,after the heat treatment,the wood achieved beautiful color and good di-mensional stability,which suggested that using the heat-treated wood for decorative wall panels and other cir-cumstances that do not require high mechanical properties.
任安捷;赵洋;王新洲;徐朝阳;於朝广;潘彪
南京林业大学材料科学与工程学院,南京 210037江苏省中国科学院植物研究所,南京 210014
林学
高温热处理中山杉尺寸稳定性物理力学性能
high-temperature heat treatmentTaxodium hybrid'Zhongshanshan'dimensional stabilityphysical and mechanical property
《林业工程学报》 2024 (004)
25-33 / 9
国家自然科学基金(31971585);江苏落羽杉属树木育种及培育省级长期科研基地项目(LYKJ(2021)05).
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