Bytner Olga, Laskowska Agnieszka, Drożdżek Michał, Kozakiewicz Paweł, Zawadzki Janusz
The Institute of Wood Sciences and Furniture, 159 Nowoursynowska St., 02-776 Warsaw, Poland.
Materials (Basel). 2021 Mar 18;14(6):1491. doi: 10.3390/ma14061491.
Black poplar ( L.) was thermally modified in nitrogen atmosphere. The effects of the modification process on poplar wood were evaluated for temperatures: 160 °C, 190 °C, and 220 °C applied for 2 h; and 160 °C and 190 °C for 6 h. The percentual impact of temperature and time of modification on the properties of modified wood was analysed. The study permitted the identification correlations between the chemical composition and selected physical properties of thermally modified poplar wood. The dimensional stability of poplar wood was improved after thermal modification in nitrogen. The higher the temperature of modification, the lower the equilibrium moisture content (EMC) of black poplar. At the temperature of 220 °C, EMC was two times lower than the EMC of non-modified black poplar. It is also possible to reduce the dimensional changes of wood two-fold (at the modification temperature of 220 °C), both in radial and tangential directions, independently of the acclimatization conditions (from 34% to 98% relative humidity, RH). Similar correlations have been found for wood that has been soaked in water. Higher modification temperatures and longer processing times contributed to a lower swelling anisotropy (SA).
黑杨（L.）在氮气气氛中进行了热改性。针对以下温度条件评估了改性过程对杨木的影响：160℃、190℃和220℃，处理2小时；以及160℃和190℃，处理6小时。分析了改性温度和时间对改性木材性能的百分比影响。该研究确定了热改性杨木的化学成分与选定物理性能之间的相关性。在氮气中进行热改性后，杨木的尺寸稳定性得到改善。改性温度越高，黑杨的平衡含水率（EMC）越低。在220℃时，EMC比未改性黑杨的EMC低两倍。在220℃的改性温度下，无论环境条件（相对湿度从34%到98%，RH）如何，木材在径向和切向方向的尺寸变化都有可能降低两倍。对于浸泡在水中的木材也发现了类似的相关性。较高的改性温度和较长的处理时间导致较低的肿胀各向异性（SA）。
