摘要
以杉木为试材,采用9组热处理工艺对杉木进行了高温热处理试验。通过对热处理前后杉木力学性能和尺寸稳定性的比较,探讨了热处理温度和处理时间对其性能的影响。结果表明:随热处理温度的升高和时间的延长,试材的抗弯强度(MOR)和抗弯弹性模量(MOE)均呈下降趋势,但热处理温度影响更为显著;热处理对MOR的影响比MOE的要大;顺纹抗压强度随时间的变化规律并不明显,但随温度的升高逐渐降低。杉木热处理后,试材由绝干到气干和绝干到吸水尺寸稳定时2个阶段的径向线湿胀率、弦向线湿胀率、体积湿胀率均低于未处理材的,弦向线湿胀率大于径向线湿胀率;就整体而言,3个指标均随处理温度的升高和时间的延长而减小。抗胀率均为负值,其绝对值随处理温度的升高和时间的延长而增大,尺寸稳定性增强幅度逐渐增大,且受温度的影响较为显著,在210℃下降得最明显。
In this study,we selected Chinese fir （Cunninghamia lanceolata） as the test material to investigate the effect of nine high-temperature heat treatment technologies.The mechanical properties and dimensional stability of the Chinese fir before and after heat treatment were determined to evaluate the effects of temperature and processing time on wood properties.The results show that the bending modulus of rupture （MOR） and the bending modulus of elasticity （ MOE） of heat-treated Chinese fir decrease with increases in temperature and time,but the effect of temperature is more important.The MOR of heat treated Chinese fir increased much greater than the MOE.The compressive strength parallel to the grain showed no significant change over time,but decreased with temperature.The radial,tangential and volume swelling rates of the specimens were lower than those of untreated wood from oven-dry to air-dry （relative humidity 65% ,temperature 20℃ ） and from oven-dry to the stage of dimensional stability in water absorption.The tangential swelling rate was greater than the radial swelling rate.On the whole,the three indices decreased with increases in temperature and time.Anti-shrink efficiency （ASE） of treated wood was negative and its absolute values increased with increases in temperature and time.The enhanced range of dimensional stability increased gradually,which was more affected by temperature and declined significantly at 210℃ .
出处
《北京林业大学学报》
CAS
CSCD
北大核心
2010年第4期232-236,共5页
Journal of Beijing Forestry University
基金
浙江省科学技术项目(2008C32023
2006C12047)
浙江省新世纪151第一层次人才资助项目
关键词
高温热处理
杉木
力学性能
尺寸稳定性
high-temperature heat treatment
Chinese fir
mechanical properties
dimensional stability
