ABSTRACT

Thermal-hydro-mechanical (THM) densification treatments were performed on Populus spp. (poplar), Picea abies (spruce), and Fagus sylvatica (beech). Prior to THM treatment, a low-molecular weight resin was impregnated into the wood structure. Densification results, mechanical characteristics (modulus of elasticity, rupture, and hardness), and set-recovery were assessed. All wood species were exposed to the same THM treatment and the specific anatomy, density, and physical behaviors yielded results specific to wood species making comparisons between species difficult. However, the mechanical performance of all samples was largely dictated by the specimens' surface density as seen in the density profiles. Spruce specimens had high levels of set-recovery after the THM treatment, which is believed to be caused by pit aspiration from kiln drying, limiting impregnation of the resin. The THM treatment used in this study was successfully applied to poplar, spruce, and beech. The resin impregnation combined with THM treatment led to densified wood with improved mechanical properties. The improvements were the greatest in poplar, including the largest reduction in set-recovery, which was the objective of this study. When comparing mechanical properties to commercially available structural wood-composites the results from this study indicate that resin impregnated THM treated wood could be used in this application.

摘要

在胡杨属植物上进行了热-水-机械（THM）致密化处理。（白杨），欧洲云杉（云杉），和水青冈（山毛榉）。在THM处理之前，将低分子量树脂浸渍到木结构中。评估了致密化结果，机械特性（弹性模量，断裂和硬度）和恢复定形。所有木材种类都接受相同的THM处理，并且特定的解剖结构，密度和物理行为产生了特定于木材种类的结果，这使得很难在种类之间进行比较。但是，如密度分布图所示，所有样品的机械性能在很大程度上取决于样品的表面密度。在THM处理后，云杉样品的凝固回复率很高，据信这是由于窑干燥产生的凹坑抽吸引起的，从而限制了树脂的浸渍。本研究中使用的THM处理已成功应用于杨树，云杉和山毛榉。树脂浸渍与THM处理相结合，使致密木材具有改善的机械性能。该改进是杨树中最大的，包括最大程度地减少了固定恢复，这是本研究的目的。当将机械性能与市售结构性木材复合材料进行比较时，这项研究的结果表明，树脂浸渍的THM处理过的木材可用于此应用中。