摘要
【目的】以速生人工林杨木为试验材料,利用定向重组技术制备高硬度重组木,揭示压缩率对杨木重组木表面硬度的影响规律,为杨木表面改性及其重组木制备工艺优化提供可靠的方法和科学依据。【方法】利用定向重组技术制备压缩率50%、55%和59%共3种杨木重组木,选取杨木、红榉和俄罗斯柞木为对照样,采用万能力学试验机测定3种木材和3种不同压缩率杨木重组木样品表面的金氏硬度;应用超景深三维显微镜(UDTM)、场发射扫描电镜(SEM)观察样品表面的宏观和微观形貌以及样品金氏硬度测试过程中破坏面的宏观和微观形貌;运用压汞法(MIP)测试样品孔隙率;使用激光共聚焦显微镜(LSCM)和透射电子显微镜(TEM)表征酚醛树脂在重组木中的分布情况。【结果】杨木重组木的金氏硬度随压缩率增大而增大,与杨木相比,压缩率59%杨木重组木的金氏硬度增加12.63倍,其硬度高于俄罗斯柞木和红榉。金氏硬度测试过程中的应力-应变曲线显示,压缩率越大,重组木的比例极限应力越大。场发射扫描电镜(SEM)和超景深三维显微镜(UDTM)观察可知,杨木原木的破坏面呈韧性断裂,制备的重组木随压缩率增大其破坏模式逐渐变为脆性断裂。压汞法(MIP)测试样品孔隙率可知,定向重组可显著降低杨木的孔隙率,压缩率越大,重组木的孔隙率越低。激光共聚焦显微镜(LSCM)和透射电子显微镜(TEM)观察可知,随压缩率增大,酚醛树脂沿胶层带分布的宽度和深度逐渐增加,且渗透到导管、木射线和纤维细胞的细胞腔中。通过纳米压痕测试重组木细胞壁力学性能,当重组木压缩率为55%、施胶量为15%时,其细胞壁硬度和弹性模量相较原木分别提高54.65%和20.14%。重组木表面硬度增大主要是因为杨木经定向重组后,其导管和木纤维细胞被压缩密实,孔隙率降低,单位体积内的细胞实质密度增加,细胞之间的结合�
【Objective】In order to provide reliable methods and scientific basis for the modification of poplar wood surface and the optimization manufacturing process of wood scrimber,the directional recombination technology was applied to manufacture the wood scrimber of poplar with high-hardness,and then the effect of compression ratios(CR)on the surface hardness of wood scrimber was studied.【Method】The wood scrimber with compression ratios of 50%,55%and 59%were prepared by the directional recombination technology,and the poplar,beech and Russian oak were taken as the control samples.The values of Janka hardness was measured by the universal mechanical testing machine.And the macroscopic and microscopic morphology of samples,as well as the damaged surface for samples during the testing process of Janka hardness were observed by ultra-depth-offield three-dimensional microscope(UDTM)and field emission scanning electron microscope(SEM).Additionally,the porosity of the samples was tested by mercury injection porosimetry(MIP)and distribution of phenol-formaldehyde resin(PF)within the wood scrimber was characterized by laser scanning confocal microscopy(LSCM)and transmission electron microscopy(TEM).【Result】The Janka hardness values of wood scrimber increased with increasing compression ratios.The Janka hardness value of wood scrimber with compression ratio of 59%increased by 12.63 times compared with that of poplar wood.Furthermore,the Janka hardness value of wood scrimber was much higher than those of Russian oak and beech.In practical applications,the appropriate compression ratio of the wood scrimber can be determined according to the needs in different area.The analysis of stress-strain curve of Janka hardness showed that the proportional ultimate stress of wood scrimber increased with increasing compression ratio.The observation of SEM and UDTM revealed that the failure surface of poplar wood was ductile fracture,but changed to brittle fracture for the wood scrimber.The porosity of the samples tested by MIP sh
作者
贺颖奇
王鲁飞
张亚梅
余养伦
于文吉
He Yingqi;Wang Lufei;Zhang Yamei;Yu Yanglun;Yu Wenji(Research Institute of Wood Industry,Chinese Academy of Forestry,Beijing 100091;Shandong Shengchang New Material Co.,Ltd.,Linyi 276000)
出处
《林业科学》
EI
CAS
CSCD
北大核心
2024年第9期141-149,共9页
Scientia Silvae Sinicae
基金
山东省重点研发计划“多场景绿色宜居技术集成应用和示范应用”(2021SFGC0201)。
关键词
速生杨木
定向重组
压缩率
硬度
重组木
fast-growing poplar wood
directional reorganization
compression ratio
hardness
wood scrimber
