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生物质化学工程 ›› 2018, Vol. 52 ›› Issue (3): 16-22.doi: 10.3969/j.issn.1673-5854.2018.03.003

• 研究报告 • 上一篇    下一篇

NaOH/尿素冷冻活化木材纤维的工艺研究

马盼盼, 陈冰玉, 邸明伟   

  1. 东北林业大学 材料科学与工程学院, 黑龙江 哈尔滨 150040
  • 收稿日期:2017-03-31 出版日期:2018-05-30 发布日期:2018-05-31
  • 通讯作者: 邸明伟(1972-),男,教授,博士生导师,从事生物质材料加工利用及胶黏剂与胶接研究工作;E-mail:dimingwei@126.com。 E-mail:dimingwei@126.com
  • 作者简介:马盼盼(1990-),女,山东单县人,硕士生,从事生物质材料加工利用研究工作
  • 基金资助:
    国家林业公益性行业科研专项(201504501);国家自然科学基金资助项目(31670567)

Activation Processes of Wood Fiber Under Freezing by NaOH/urea Aqueous Solution

MA Panpan, CHEN Bingyu, DI Mingwei   

  1. College of Materials Science and Engineering, Northeast Forestry University, Harbin 150040, China
  • Received:2017-03-31 Online:2018-05-30 Published:2018-05-31

摘要: 利用NaOH/尿素混合水溶液在冷冻条件下对木材纤维进行活化处理,通过无胶胶合压制纤维板的力学性能测试、傅里叶变换红外光谱以及X射线衍射分析表征了木材纤维的冷冻活化效果。结果表明:冷冻条件下NaOH/尿素的混合水溶液对木材纤维具有一定的活化效果,优选的活化工艺为NaOH和尿素的总质量(NaOH与尿素质量比为7:12)与木材纤维质量比为1:12,冷冻温度-15℃,冷冻时间1.0 h,木材纤维含水率20%。木材纤维经NaOH/尿素混合水溶液冷冻活化后,所得无胶胶合板材的静曲强度和内结合强度分别由未处理的32.16和0.29 MPa提高至45.53和1.21 MPa,吸水率和厚度膨胀率由未处理的53.95%和22.57%降低至43.62%和10.34%。傅里叶变换红外光谱和X射线衍射表征发现,NaOH/尿素混合水溶液的冷冻活化破坏了木材纤维中纤维素的氢键结构,促使了纤维素I型晶格扩张,产生了新的结晶变体,使分子缔合程度变小,木材纤维表面的羟基活性增强。

关键词: 木材纤维, 无胶胶合, 冷冻活化, 氢氧化钠, 尿素

Abstract: The wood fiber was activated by sodium hydroxide/urea mixed aqueous solution under freezing treatment. The freezing activation effect of wood fiber was characterized by measuring the mechanical properties of the self-bonding fiberboard hot-pressed with activated wood fiber and implementing the analysis of Fourier tansform infrared spectroscopy and X-ray diffraction. The experimental results showed that the sodium hydroxide/urea mixed aqueous solution had a certain activation effect on the wood fiber under freezing treatment. The optimized activated process was described as the mass ratio of total sodium hydroxide and urea (the mass ratio of sodium hydroxide to urea 7:12) to wood fiber 1:12, freezing temperature -15℃, freezing time 1.0 h, and wood fiber moisture content 20%. The static bending strength and internal bonding strength of fibreboard prepared with wood fiber freezing-activated by sodium hydroxide/urea mixed aqueous solution increased from 32.16 and 0.29 MPa to 45.53 and 1.21 MPa, and the water absorption rate and the thickness swelling rate decreased from 53.95% and 22.57% to 43.62% and 10.34% respectively compared to those of the unactivated wood fiber. Microscopic characterization by Fourier tansform infrared spectroscopy and X-ray diffraction showed that the hydrogen bonding structure of cellulose in the wood fiber was destroyed under the freezing activation treatment with sodium hydroxide/urea mixed solution, the expansion of cellulose I lattice was promoted and a new crystalline modification was produced, which reduced the degree of molecular association and consequently enhanced the hydroxyl activity of the wood fiber surface.

Key words: wood fiber, self-bonding, freezing activation, sodium hydroxide, urea

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