【摘要】 对锯切木材薄板只用常温水浸泡至饱水状态后进行横纹压缩强化,利用动态热分析仪分析压缩前后的木材动态力学性能,讨论薄板在横纹压缩强化处理后的木材与素材表现出的力学特性差异;从动态变化的微观层面探讨常温水浸泡至饱水状态后,不经热软化预处理,直接进行薄板横纹压缩强化方法的可行性和有待改进、完善之处。试验结果表明:大青杨(P.ussuriensis)薄板压缩强化材的储存模量均出现明显次级松弛和主转变,次级松弛阶段压缩材储存模量值均高于素材,且随热处理时间增加储存模量缓慢下降,主转变阶段随热处理时间增加,储存模量下降速率加大;热处理时间为10、13、16 h的3种薄板压缩材均出现玻璃化转变温度大幅降低,损耗角正切值大幅下降;热处理时间10、13 h试件,主转变损耗模量峰值大幅度增加;玻璃化区域内热处理10、13 h的2种薄板压缩材试件储存模量值最高,动态力学性能最好。更多还原

【Abstract】 Saw cutting sheets from poplar(Populus ussuriensis) wood were soaked in water at room temperature to water-saturated state and then were compressed perpendicular to grain.The dynamic thermo-mechanical analyzer was used to examine the mechanical properties between the compressed and the untreated,aiming to probe the feasibility of wood sheets by compression-strengthened under water-saturated state and without softening pretreatment,and find out the possible future improvements.Results showed that significant changes occurred in the secondary relaxation and primary transform of storage modulus of compression-strengthened poplar wood,and storage modulus of compressed sheets in the secondary relaxation phase was higher than that of the untreated sheets.With the increase of heat treatment time,the storage modulus in the secondary relaxation phase decreased slightly,and the storage modulus in the primary transform phase decreased at an increasing rate.For the compressed sheets with heat treatment for 10,13 and 16 hours,their glass-transition temperature showed significant reduction,and tangential loss angles also markedly decreased.For the compressed sheets with heat treatment for 10 and 13 hours,their peaks of loss modulus in the primary transform phase observably increased.The compressed sheets with heat treatment for 10 and 13 hours showed the highest values in glass-transition region,and the corresponding dynamic mechanical properties were the best.更多还原