摘要
竹材是一种重要的森林资源,以其环保、可再生、强度好等优势广泛应用于家具、建筑等领域,但由于竹材干缩各向异性,竹材在加工使用过程中容易劈裂,限制了其应用。热处理是一种有效提高竹材尺寸稳定性的方法,针对竹材易劈裂的性质,以毛竹为研究对象,采用不同温度(80℃、100℃、120℃、140℃、160℃、180℃、200℃)、压力0.08MPa、时间2h对其进行真空热处理,通过处理后毛竹的开裂情况、干缩率、截开后间隙和抗劈力变化分析真空热处理对毛竹开裂行为的影响。结果表明:除100℃外,80℃、120℃、140℃、160℃处理的竹环未出现明显裂隙;随温度升高,竹环周长、直径、壁厚干缩率基本呈上升趋势,同一温度下壁厚干缩率>直径干缩率>周长干缩率;除80℃和100℃,其他温度处理后的竹环间隙均较未经处理时有不同程度减小,160℃时最小,较未处理材降低了82.6%;真空热处理后毛竹抗劈力较未处理时下降,但在160℃时有所增加,比未处理材增加了4.3%。真空热处理可显著改善竹环开裂现象,但处理过程伴随竹材干缩及抗劈力下降,处理工艺有待进一步优化。
Bamb bamboo is an important forest resource.It is widely used in furniture,construction and other fields with its advantages of environmental protection,regeneration and good strength.However,due to the anisotropy of bamboo drying shrinkage,bamboo is easy to split in the process of processing and use,which limits its application.Heat treatment is an effective method to improve the dimensional stability of bamboo.According to the splitting nature of bamboo,moso bamboo is taken as the research object.It is vacuum heat treated at different temperatures (80℃,100℃,120℃,140℃,160℃,180℃,200℃),pressure of 0.08mpa and time of 2H,the effect of vacuum heat treatment on the cracking behavior of Moso bamboo was analyzed by the cracking,dry shrinkage,clearance after cutting and change of splitting resistance of moso bamboo after treatment.The results showed that there were no obvious cracks in the bamboo rings at 80℃,120℃,140℃ and 160℃ except 100℃;with the increase of temperature,the drying shrinkage rate of perimeter,diameter and wall thickness of bamboo ring basically showed an upward trend.At the same temperature,the drying shrinkage rate of wall thickness > diameter > perimeter;Except at the temperature of 80℃ and 100℃,the gap between bamboo rings treated at other temperatures decreased to varying degrees compared with untreated bamboo,and the smallest at 160℃,which decreased by 82.6% compared with untreated bamboo,;After vacuum heat treatment,the splitting resistance of Moso Bamboo decreased compared with that of untreated bamboo,but the temperatures at 160℃,which was 4.3% higher than that of untreated wood.Vacuum heat treatment can significantly improve the cracking of bamboo ring,but the treatment process is accompanied by the decrease of bamboo drying shrinkage and splitting resistance,and the treatment process needs to be further optimized.
作者
马静文
孙玮
王雪花
MA Jing-wen;SUN Wei;WANG Xue-hua(Nanjing Forestry University,College of Furnishings and Industrial Design,Nanjing,210037)
出处
《林业和草原机械》
2021年第5期44-49,共6页
Forestry and Grassland Machinery
基金
国家自然科学基金项目(31800471)。
关键词
毛竹
内应力
干缩
开裂
抗劈力
moso bamboo
internal stress
dry shrinkage
crack
splitting resistance
