Hot water extraction (HWE) treatment changes the physicochemical properties of the wood, including hygroscopic properties. HWE treatment decreases the hydroxyl accessibility of the wood, but the relevance of other mechanisms that change hygroscopic properties are not fully understood. This study investigates the effect of drying on the hydroxyl accessibility and sorption properties of wood. Pressurized hot water extraction (HWE) treatment was applied at 140 °C for 1–5 h to Scots pine (Pinus sylvestris L.) sapwood samples in order to remove increasingly more hemicellulose from the cell wall matrix. Following HWE treatment, half of the wood samples were oven-dried and then re-soaked, while the other half was kept in a fully saturated state. The samples were investigated by applying a new approach that was based on the deuteration of accessible hydroxyl groups, which was followed by the measurement of mass loss due to re-protonation. Sorption properties of the wood samples were studied by measuring moisture content, sorption isotherms and dimensional changes. The present results showed that accessible hydroxyl group content decreased only due to hemicellulose removal during the HWE treatment and was unaffected by oven-drying. However, oven-drying enhanced the effect of HWE treatments in reducing the water-saturated dimensions and the moisture content of wood. Therefore, the additional reductions in hygroscopicity and water-saturated dimensions were not related to changes in sorption site density.

热水提取 (HWE) 处理会改变木材的物理化学特性，包括吸湿特性。HWE 处理降低了木材的羟基可及性，但尚未完全了解改变吸湿性的其他机制的相关性。本研究调查了干燥对木材羟基可及性和吸附性能的影响。加压热水提取 (HWE) 处理在 140 °C 下对苏格兰松 ( Pinus sylvestrisL.) 边材样品，以便从细胞壁基质中去除越来越多的半纤维素。HWE 处理后，将一半的木材样品烘干，然后重新浸泡，而另一半则保持完全饱和状态。通过应用基于可触及羟基的氘化的新方法对样品进行研究，然后测量由于再质子化导致的质量损失。通过测量水分含量、吸附等温线和尺寸变化来研究木材样品的吸附特性。目前的结果表明，可接近的羟基含量仅由于 HWE 处理期间去除了半纤维素而降低，并且不受烘箱干燥的影响。然而，烘箱干燥增强了 HWE 处理在减少木材的水饱和尺寸和水分含量方面的效果。因此，吸湿性和水饱和尺寸的额外降低与吸附位点密度的变化无关。