基于时域核磁共振技术的木材吸湿过程研究
收稿日期: 2015-06-01
修回日期: 2016-04-11
网络出版日期: 2016-06-05
基金资助
国家自然科学基金资助项目(30800866,31160141).
Moisture Sorption in Wood Studied by Time Domain Nuclear Magnetic Resonance
Received date: 2015-06-01
Revised date: 2016-04-11
Online published: 2016-06-05
木材吸湿会对其力学性能和尺寸稳定性产生影响,深入了解木材吸湿过程中水分状态的变化有重要意义.利用时域核磁共振(TD-NMR)技术,以美国黄杨木和红橡木作为研究对象,对木材吸湿过程中水分状态和弛豫特性进行研究.结果显示:吸湿过程的前4h,两种木材试件结合水峰面积迅速增大,自由水峰面积无明显增长,说明在吸湿初期,增加的水分主要以结合水为主;在达到吸湿平衡后,红橡木试件内自由水峰面积约为黄杨木试件内自由水峰面积的2倍,这是由于与黄杨木相比,红橡木管孔孔径较大,因此在吸湿过程中,红橡木的自由水吸湿速度较快,吸湿量大于黄杨木.
关键词： 时域核磁共振(TD-NMR); 木材吸湿; 自由感应衰减(FID); 自旋-自旋弛豫时间(T2); 黄杨木; 红橡木
高玉磊 , 张明辉 . 基于时域核磁共振技术的木材吸湿过程研究[J]. 波谱学杂志, 2016 , 33(2) : 295 -304 . DOI: 10.11938/cjmr20160212
The mechanical properties and dimensional stability of wood are influenced by moisture sorption. Understanding changes of the state of water during wood sorption has great significance. In this study, the state and relaxation property of water in American yellow poplar and red oak during the sorption process were investigated by time-domain nuclear magnetic resonance (TD-NMR). It was found that, in both species, the peak area of bound water increased rapidly during the first 4 hours of the sorption process, while the peak area of free water showed no obvious change. These results suggested that water amount increases in the early sorption stage could mainly be attributed to bound water. Under the equilibrium condition of moisture sorption, the peak area of free water in red oak doubled that in American yellow poplar, likely due to the pore aperture of former is bigger than the later, providing more space for absorbed free water. It was also observed that the amount and rate of free water sorption were higher in red oak than in American yellow poplar.
[1] Lu Heng(卢衡). The Fifth Academic Conference of the China Heritage Protection Technology Association(中国文物保护技术协会第五次学术年会论文集)[C]. Beijing(北京), 2008.
[2] Li Chao(李超). Study on the Relaxation Characteristics of Water in Wood by TD-NMR(木材中水分弛豫特性的核磁共振研究)[D]. Hohhot(呼和浩特):Inner Mongolia Agricultural University(内蒙古农业大学), 2012.
[3] Liu Yi-xing(刘一星), Zhao Guang-jie(赵广杰). Wood Resources Materials Science(木质资源材料学)[M]. Beijing(北京):China Forestry Press(中国林业出版社), 2004.
[4] Wei Xiang(魏象), Liu Xue(刘学), Wang Hong-qiang(王红强), et al. The Fifth Academic Conference of the China Heritage Protection Technology Association(中国文物保护技术协会第五次学术年会论文集)[C]. Beijing(北京), 2008.
[5] Ma Da-yan(马大燕), Wang Xi-ming(王喜明), Zhang Ming-hui(张明辉). Mechanism of water sorption during adsorption process of wood studied by NMR(核磁共振研究木材吸着过程中水分吸附机理)[J]. Chinese J Magn Reson(波谱学杂志), 2011, 28(1):135-141.
[6] Cao Jin-zhen(曹金珍). Interaction Between Water and Wood During Adsorption and Desorption Processes(吸着·解吸过程中水分与木材之间的相互作用)[D]. Beijing(北京):Beijing Forestry University(北京林业大学), 2001.
[7] Xu Xiang-jiang(徐相江), Yin Ji-bo(尹继波), Yang Liang-qing(杨亮庆), et al. Analyse on effecting of steaming treatment on the wood economic value(气蒸处理与木材经济价值的影响)[J]. Forestry Science & Technology(林业科技), 2013, 38(1):44-47.
[8] Hartley I D, Avramidis S, MacKay A L. 1H NMR studies of water interactions in sitka spruce and western hemlock:moisture content determination and second moments[J]. Wood Sci Technol, 1996, 30(2):141-148.
[9] Li Jian(李坚). Wood Protection Science(木材保护学)[M]. Beijing(北京):Science Press(科学出版社), 2006.
[10] Feng De-jun(冯德君), Zhao Jing-feng(赵泾峰). Heat treatment of wood hygroscopicity and dimensional stability(热处理木材吸湿性及尺寸稳定性研究)[J]. Journal of Northwest Forestry University(西北林学院学报), 2011, 26(2):200-202.
[11] Huang Yan-kuai(黄彦快), Wang Xi-ming(王喜明). Wood hygroscopic mechanism and its application(木材吸湿机理及其应用)[J]. World Forestry Research(世界林业研究), 2014, 27(3):35-40.
[12] Gong Ren-mei(龚仁梅), Zhang Xiao-hui(张晓慧). Effect of steam time on wood hygroscopicity(汽蒸时间对木材吸湿性能的影响)[J]. Forestry Science and Technology(林业科技), 1995, 4:46-47.
[13] Cai Jia-bin(蔡家斌), Li Tao(李涛). Influence of two high-humidity thermal treatments on moisture absorption behavior of spruce wood planks(不同湿热处理工艺对云杉板材吸湿性能的影响)[J]. China Forestry Science and Technology(林业科技开发), 2011, 25(6):80-82.
[14] Xu Bo(徐博). Moisture content and temperature changes of wood during adsorption processes(吸湿过程中木材的含水率及温度变化)[J]. Chinese Agricultural Science Bulletin(中国农学通报), 2013, 29(13):51-55.
[15] Shao Zhu-wei(邵朱伟), Zhang Ming-hui(张明辉), Li Xin-yu(李新宇). Curing process of urea-formaldehyde resin studied by time-domain nuclear magnetic resonance(利用时域核磁共振研究脲醛树脂的固化过程)[J]. Chinese J Magn Reson(波谱学杂志), 2014, 31(3):372-380.
[16] Du Tian-peng(杜天鹏), Zhang Zi-wei(张子微), Zeng Dan-yun(曾丹云), et al. Structure and function of influenza virus fusion peptide studied by nuclear magnetic resonance spectroscopy(流感病毒融合肽磁共振研究进展)[J]. Chinese J Magn Reson(波谱学杂志), 2014, 31(4):596-607.
[17] Huang Gui-kun(黄桂坤), Qiu Li(邱莉), Jiao Yang(焦杨), et al. NMR assignments of two minor ginsenosides extratced from panax notoginseng (Burk.) F. H. Chen(三七中2个微量人参皂苷的NMR信号全归属)[J]. Chinese J Magn Reson(波谱学杂志), 2014, 31(3):415-425.
[18] Xu Y, Araujo C D, Mackay A L, et al. Proton spin-lattice relaxation in wood:T1 related to local specific gravity using a fastexchange model[J]. J Magn Reson, 1996, 110(1):55-64.
[19] Nanassy A J. Use of wide line NMR for measurement of moisture content in wood[J]. Wood Sci, 1973, 5(3):187-193.
[20] Provencher S W. A general purpose constrained regularization program for inverting noisy linear algebraic and integral equations[J]. Comput Phys Commu, 1982, 27(3):229-242.
[21] Araujo C D, MacKay A L, Hailey J R T, et al. Proton magnetic resonance techniques for characterization of water in wood:Application to white spruce[J]. Wood Sci Technol, 1992, 26(2):101-113.
[22] Merela M, Oven P, Sersa I, et al. A single point NMR method for an instantaneous determination of the moisture content of wood[J]. Holzforschung, 2009, 63(3):348-351.
[23] Sharp A R, Riggin M T, Kaiser R, et al. Determination of moisture content of wood by pulsed nuclear magnetic resonance[J]. Wood Fiber, 1978, 10(2):74-81.
/
| 〈 |
|
〉 |