After thermal modification at 210 °C using the Thermowood method, changes in Pinus radiata D. Don wood cell wall components and hygroscopicity were studied for subsequent comparison with recently felled wood of the same species in samples from the same region of provenance (Basque Country, Spain). To this end, samples were characterised by sorption isotherms at 15, 35 and 50 °C fitted to the Guggenheim–Anderson–de Boer (GAB) model, the chemical composition was obtained by high performance liquid chromatography (HPLC) and infrared spectroscopy (FTIR), and crystallinity and structural organisation of cellulose (crystal orientation) were determined using powder and 2D X-ray diffraction (XRD). Heat treatment caused the following changes in the wood: a decrease in the equilibrium moisture content (EMC); a smaller hysteresis area and therefore more hygroscopically stable wood; a decrease in the hemicellulose content; an increase in the relative percentage of cellulose, lignin and extractives; and a higher degree of crystallinity and crystal orientation of the cellulose. The reorganisation of cellulose could be explained by epitaxial growth of cellulose starting from the highly oriented crystalline regions during the recrystallisation process. All these chemical and structural changes induced by heating could explain the reduction in hygroscopic properties of wood, as well as its stability.

使用Thermowood方法在210°C进行热改性后，辐射松D发生变化。研究了唐木细胞壁成分和吸湿性，以便与来自同一产地（西班牙巴斯克地区）的样品中最近采伐的同一物种的木材进行比较。为此，样品的特征在于适合于古根海姆-安德森-德波尔（GAB）模型的15、35和50°C的吸附等温线，化学成分通过高效液相色谱（HPLC）和红外光谱（FTIR）获得），并使用粉末和2D X射线衍射（XRD）测定纤维素的结晶度和结构组织（晶体取向）。热处理引起木材的以下变化：平衡水分含量（EMC）的降低；较小的滞后面积，因此吸湿性更稳定的木材；半纤维素含量降低；纤维素，木质素和提取物的相对百分比增加；以及纤维素的更高的结晶度和晶体取向度。纤维素的重组可以通过在重结晶过程中纤维素从高取向晶体区域开始外延生长来解释。加热引起的所有这些化学和结构变化可以解释木材的吸湿性下降及其稳定性。