汽蒸改性杨木胶合板的尺寸稳定性和力学强度

Research on Dimensional Stability and Strength Properties of Poplar Plywood by Steam Treatment

杨木是国内外种植和使用最广泛的速生人工林树种之一,为林产工业提供了大量的原料。但杨木容易翘曲变形,尺寸稳定性差,且强度不高,影响其使用价值。本研究将杨木单板经高温汽蒸处理后,再压制成胶合板,测量计算其厚度收缩率、抗胀缩率ASE、抗弯强度和弹性模量,结果表明其尺寸稳定性有所提高,而强度变化不大。汽蒸处理时的含水率、蒸汽压力和时间这3个因素对抗弯强度和弹性模量均无显著影响,但压力是影响尺寸稳定性的主要因素。实验确定了汽蒸处理杨木胶合板的最佳工艺参数为:含水率14%,压力0.5 MPa,时间15 min。

Poplar is widely planted and used in the world and it provides plenty of raw materials for forestry, industry, but it has low dimensional stability and bad strength properties. We researched the poplar plywood pressed with poplar veneers which were treated by high temperature steam, measured and calculated its ASE, MOR and MOE. The results show its dimensional stability is higher than untreated plywood, and its strength properties don＇t change a lot. This paper researched three influence factors （ moisture content, steam pressure and time） on physical properties and mechanical properties of treated poplar plywood. The results show moisture content, steam pressure and time have no great effect on MOR and MOE, but the steam pressure is the important factor which affects the dimensional stability. This paper shows the optimal parameter of poplar plywood treated by steam is： MC 14%, steam pressure 0.5 MPa, time 15 min.