负压轻炭化木材物理力学性能

对比了奥克榄Aucoumea klaineana，椴木Tilia europaea，单瓣豆Monopetalanthus sp.等3种木材在同一炭化条件下物理力学性能的变化，探究负压轻炭化处理木材的可行性与实际效果。将3种木材分别置于真空炭化箱内以160℃，0 MPa的条件处理3.0 h，然后将木材按照国标规定的木材物理力学试材锯解及试样截取方法加工，之后分别测量木材的密度、色差、冲击韧性、抗弯强度、抗弯弹性模量、硬度、干缩率和湿胀率。结果表明:在该炭化工艺下单瓣豆的体积干缩系数降低了16.00%，尺寸稳定性有较大改善；抗弯强度增加了18.00%，径面、弦面和端面硬度分别增加了19.00%，33.00%和50.00%，冲击韧性损失24.00%。负压轻炭化能够在一定程度上改善木材的尺寸稳定性，并且使其物理力学性能不受太大损失。

Physical and mechanical properties of low thermo-vacuum treated wood

Heat treated wood is widely used in indoor and outdoor construction, decoration, and furniture because of its favorable dimensional stability, excellent corrosion resistance, and approximate padauk color. However, with many deficiencies in the existing heat treatment process of wood, such as excessive loss of mechanical strength and timber color being too heavy, this study was conducted to provide a reference during actual production for the feasibility and practical effect of low thermo-vacuum treatments with lower temperatures. Changes in physical and mechanical properties of three kinds of wood-okoume, basswood, and andoung, using the same thermo-vacuum treatment conditions were tested. The three woods were placed in a vacuum carbonization tank at 160℃ and 0 MPa conditions for 3 h. Then the timber was sawn according to experimental requirements with wood density, color deviation, toughness, bending strength, modulus of elasticity in static bending, static hardness, shrinkage, and swelling rate being measured. Results showed that dimensional stability of heat-treated andoung was greatly improved with its volume shrinkage coefficient decreasing 16.00%. Moreover, andoung had an increase in flexural strength and hardness, with increased bending strength (18.00%), hardness of its radial section (19.00%), tangential section (33.00%), and end surface (50.00%). Also, its impact toughness loss was less (24.00%). Overall, low thermo-vacuum treatment could improve dimensional stability of wood as it avoided loss of physical and mechanical properties of the timber.