高温快速热压处理对毛竹材物理力学性能的影响  

Physical and mechanical properties of Phyllostachys edulis with fast hotpressing and high temperature

作　　者：莫珏 马中青[1] 聂玉静[1] 马灵飞[1] MO Jue;MA Zhongqing;NIE Yujing;MA Lingfei(Zhejiang Provincial Collaborative Innovation Center for Bamboo Resources and High-Efficiency Utilization,School of Engineering,Zhejiang A&F University,Hangzhou 311300,Zhejiang,China)

机构地区：[1]浙江农林大学工程学院浙江省竹资源与高效利用协同创新中心

出　　处：《浙江农林大学学报》2019年第5期974-980,共7页Journal of Zhejiang A&F University

基　　金：国家自然科学基金资助项目（31270592）;“十三五”国家重点研发计划项目（2017YFD0601105）;浙江省竹资源与高效利用协同创新中心开放基金（2017ZZY2-14）;中国科协青年人才托举工程项目（2018QNRC001）;国家林业公益性行业科研专项（201204702)

摘　　要：选取4~6年生的毛竹Phyllostachys edulis材为原料,采用热压机对毛竹材进行高温快速热压处理,研究不同热处理温度(225,250,275,300,325,350和375℃)下竹材物理力学性能的变化。结果表明:随着热处理温度的升高,竹材平衡含水率和气干密度明显下降(P<0.05),与未处理材相比分别降低了34.39%~53.95%和7.89%~13.04%。相同热处理温度下,弦向干缩率的变化率>体积干缩率的变化率>径向干缩率的变化率;当温度达到375℃时,弦向全干干缩率下降了86.81%,径向全干干缩率下降了83.60%,体积全干干缩率下降了83.95%,达各向的最大值。热处理温度升高,竹材顺纹抗压强度、抗弯强度和抗弯弹性模量均先增加后减少,其中,顺纹抗压强度在375℃时达最小值(63.78 MPa);抗弯强度在250℃时达最大值(151.00 MPa),在375℃条件下达最小值(61.85 MPa);抗弯弹性模量在300℃时达最大值(10 487.44 MPa),在375℃时达最小值(7 071.14 MPa)。认为竹材接触式快速热处理工艺提升了竹材尺寸稳定性和力学性能。To improve dimensional stability and weather resistance of a material,heat treatment,with fast hotpressing and high temperature,was used.Pieces of 4-6 year-old Phyllostachys edulis were selected.Samples were treated with different temperatures(225,250,275,300,325,350,and 375℃).Physical and mechanical properties were tested before and after treatments.Results showed that with an increase of temperature,there was an obvious decrease in equilibrium moisture content(34.39%-53.95%)and bamboo density(7.89%-13.04%)both P<0.05.With the same conditions,the following occurred:rate of change for tangential shrinkage rate>rate of change for volume shrinkage rate>rate of change for radial shrinkage rate.When the temperature reached 375℃,tangential oven-dry shrinkage rate decreased 86.81%;whereas,radial oven-dry shrinkage rate dropped 83.60%,and volume oven-dry shrinkage rate decreased 83.95%,reaching a maximum in all directions.Compression strength parallel to the grain,modulus of rupture(MOR),and modulus of elasticity(MOE)of the bamboo increased with temperature first and then decreased.Compression strength reached a minimum of 63.78 MPa at 375℃.MOR reached a peak at 250℃with 151.00 MPa,and decreased to 61.85 MPa at 375℃.MOE performed best at 300℃with 10 487.44 MPa,and worst at 375℃with 7 071.14 MPa.Thus,this experiment proved that fast hot-pressing with high temperature can improve the dimensional stability of the bamboo,the mechanical properties also generally improved after treatments.

关 键 词：木材学 毛竹材 高温热压 快速热处理 尺寸稳定性 力学性能 

分 类 号：S781.2[农业科学—木材科学与技术]