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    刘丹丹, 关惠元, 黄琼涛. 热处理对表面密实材变形固定及性能影响[J]. 北京林业大学学报, 2018, 40(7): 121-128. DOI: 10.13332/j.1000-1522.20180175
    引用本文: 刘丹丹, 关惠元, 黄琼涛. 热处理对表面密实材变形固定及性能影响[J]. 北京林业大学学报, 2018, 40(7): 121-128. DOI: 10.13332/j.1000-1522.20180175
    Liu Dandan, Guan Huiyuan, Huang Qiongtao. Effects of thermal treatment on deformation fixation and properties of surface densified wood[J]. Journal of Beijing Forestry University, 2018, 40(7): 121-128. DOI: 10.13332/j.1000-1522.20180175
    Citation: Liu Dandan, Guan Huiyuan, Huang Qiongtao. Effects of thermal treatment on deformation fixation and properties of surface densified wood[J]. Journal of Beijing Forestry University, 2018, 40(7): 121-128. DOI: 10.13332/j.1000-1522.20180175

    热处理对表面密实材变形固定及性能影响

    Effects of thermal treatment on deformation fixation and properties of surface densified wood

    • 摘要:
      目的高温热处理是一种广泛使用的木材压缩变形固定方法,以往研究中大多对木材进行整体热处理,但整体热处理方式耗时长能耗大,且表面密实材仅仅是表面几毫米的密实层需要固定,因此有必要探究一种适合表面密实材的变形固定方法。
      方法本研究采用热压机对表面密实材进行表面热处理,并对不同条件处理后的试件进行回弹率、表面硬度、耐磨性、材色的测定和红外光谱分析,探讨热处理对表面密实材变形固定和性能的影响。
      结果热处理对固定木材表面的压缩变形效果显著,且吸湿、吸水和水煮回弹率均随着处理温度的升高或处理时间的延长而降低。当温度高于200 ℃,延长处理时间会造成木材表面硬度和耐磨性的降低。随着热处理温度的升高或处理时间的延长,表面密实材的明度差、红绿轴色品指数差和黄蓝轴色品指数差的绝对值增大,色差增大,材色变深。热处理后各吸收峰的吸光度均呈现降低的趋势,且随热处理温度的升高和处理时间的延长降低越明显,在高温作用下木材3大组成成分纤维素、半纤维素和木素由于热解反应导致其含量降低,另外影响木材尺寸稳定性的羟基和羰基的数量也相应减少。
      结论热处理可以对表面密实材进行有效地变形固定,但提高处理温度或延长处理时间会导致木材表面硬度和耐磨性的降低以及材色的变化。

       

      Abstract:
      ObjectiveThermal treatment at high temperature is a widely used method for deformation fixation of compressed wood. Wood is always treated as a whole in previous studies, but wood treated as a whole takes a long time and wastes a lot of energy, and only a few millimeters of surface densified layer need to be fixed. Therefore, it is necessary to explore a method for deformation fixation of surface densified wood.
      MethodIn this study, hot press was used for surface thermal treatment of surface densified wood, then spring-back, surface hardness, abrasion resistance, wood color and chemical composition of the specimens treated by different conditions were measured, effects of thermal treatment on deformation fixation and properties of surface densified wood were discussed.
      ResultThe results showed that: effects of thermal treatment on deformation fixation of surface densified wood were significant, spring-back of moisture absorption, water absorption and water boiling absorption all decreased with the increase of processing temperature and the extension of processing time. Surface hardness and abrasion resistance would be reduced when processing temperature was above 200℃ and processing time was extended. With the increase of processing temperature and the extension of processing time, the absolute value of brightness, red green ratio index and yellow blue ratio index increased, chromatic aberration also increased, wood color got darker. Absorbance of each absorption peak decreased after thermal treatment, and the decrease was more obvious with the increase of processing temperature and the extension of processing time. Cellulose, hemicellulose and lignin of wood were reduced because of pyrolysis reaction, and the number of hydroxyl groups and carbonyl groups affecting the dimensional stability of wood also correspondingly decreased under high temperature.
      ConclusionThermal treatment could effectively fix the deformation of surface densified wood, however, increasing processing temperature and extending processing time would lead to the decrease of hardness and abrasion resistance of wood surface, and the change of wood color.

       

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