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杉木密化材固定过程中不同热处理路径的化学应力松弛

批准号30070606 学科分类环境地球化学 ( D0707 )
项目负责人徐海 负责人职称 依托单位北京林业大学
资助金额0.00
万元
项目类别面上项目 研究期限2001 年 01 月 01 日 至
2003 年 12 月 01 日
中文主题词杉木;热处理;固定;化学应力松弛
英文主题词Chinese Fir;heat treatment;set;Chemical relaxation

摘要

中文摘要 通过对杉木压缩密化材热处理永久固定过程中不同热处理路径的化学应力松驰(chemical stress relaxation)的研究,从根本上弄清楚关于压缩密化材永久固定机构的“架桥结合反应”和“分子链切断反应”两种截然不同的观点观点。选择杉木压缩密化材热处理永久固定过程中的最佳热处理路径,为开发杉木压缩密化加工新技术、新工艺奠定理论基础和提供技术参数。
英文摘要 (1) The T-T plane (heating temperautre and heating time) was established by the two parameters of the recovery of compression set (RS) and the heat treat mass loss WS to divide the Physical and chemical process. In the plane we can find the different heating pathways which can vertify the equivalent of the two parameters..(2)the simple pathway of heating at 200 oC had least influence on wood properties, whereas the simple pathway of heating at 180 C caused much damage. From the flexural vibration experimental results, specific dynamic Young's modulus from knocking on the tangential section of specimens deceased significantly after fixation, and loss tangent significantly increased. The area below the surface of tangential section, which directly involved in compression, seems to be damaged much. In the complex pathways, rising temperature from 180 oC to 200 oC caused less damage than that of reducing temperature from 200 oC to 180 oC. So it can be concluded the temperature of 180oC must be critical for cleavage and linkage of bonds in heat-treatment..(3) Relative crystalline increased at early stage of heating fixation, and then decreased more and more later on. Hemicelluloses and lignin decomposition was induced by the fixation process, esp. At 180 C, lignin was degraded actively and sorbed water lost after heating, but cellulose didn't change obviously. Although different fixation pathways can result in same recovery level, the major chemical reactions underlying them are various, which consisted in the difference of fixation mechanisms.
结题摘要 (1)以回复率RS,热处理重量损失率WS为参数建立了T-T平面(热处理温度和热处理时间),区划物理过程和化学过程平面。在该平面上能够找到检证了两参数的等效性的不同热处理路径。(2)200℃的单一路径,热处理引起的损伤程度最小,180℃路径损伤相当大。从振动法研究结果,弦切面比动态杨氏模量热处理后明显减少,损失正切值增加。直接参与压密化处理的弦切面表面附近的损伤比较大。在复合热处理路径中,从180℃到200℃的升温过程中,压密化材的损伤相对小,从200℃到180℃的降温复合路径中的损伤却相对比较大。可以推断180℃,即是热处理过程中,切断和架桥反应两者占主导地位。(3)压缩密化材的结晶度在初期呈增大趋势,随着热处理时间的延长逐渐减少。木材主成分半纤维素和木素发生热分解,引起了纤维素的结晶构造发生了某种程度变化。在180oC热处理过程中,木素的热分解非常活跃。还伴随着吸着水的移动。纤维素没有发生明显的化学反应。在10%回复率的不同热处理路径中,发生了半纤维素,木素的热分解反应以及吸着水的"物理性脱水"现象,主化学成分反应类型不同,即不同处理路径的固定机理不同。

成果

序号 标题 类型 作者
1 Application of Clausius-Clapeyron on Non-Equilibrium Wood- Water System 会议 Cao Jinzhen|Zhao Gunagjie|
2 Creep of Heat treated Compressed wood of Chinese Fir 会议 Zhao Guangjie|Wang Jieying|
3 Creep Behavior of Dematrix wood of Chinese Fir 会议 Xie Manhua|Zhao Guangjie|
4 The T-T plane of Heat or Steam Treatment of Wood and the Equivalents of Different treatment Paths 会议 Zhao Guangjie|tang Xiaoshu|Lu Wenhua|
5 Creep Behavior of Dematrix wood of Chinese Fir by Different Reagents 会议 Zhao Guangjie|Xie Manhua|Lu Wenhua|

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