Predicting the pore-filling ratio in lumen-impregnated wood
Predicting the pore-filling ratio in lumen-impregnated wood
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预测内腔浸渍木材的孔隙填充率
DOI：
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发表时间：
2017
影响因子：
3.4
通讯作者：
O. Scherman
中科院分区：
文献类型：
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作者：
Guanglu Wu;D. Shah;Emma;H. Burridge;T. Reynolds;Patrick H. Fleming;P. Linden;M. Ramage;O. Scherman
与大多数其他木材改性方法不同，管腔浸渍通常是通过气孔填充率(PFR)(即填充的管腔孔隙率)而不是重量百分比增量(WPG)来评估的。在管腔浸渍过程中，浸渍剂作用于木材中的空隙，而不是固体块(例如细胞壁)，但在加工过程中无法像WPG那样方便地测量PFR。在这里，它演示了如何可以直接从WPG计算PFR，如果未经处理的木材的体积密度是已知的。用甲基丙烯酸酯单体的液体混合物对锡特卡云杉无结试件进行加压浸渍，通过实验考察了湿润率与容重的关系。在验证模型的基础上，可以进一步研究不同工艺参数，如液压，对管腔浸渍的影响。骨密度是该模型中的另一个关键参数，它直接反映了不可到达的毛孔和闭合的管腔的数量，可以通过氦化学计量独立确定。渗透性可以用PFR和骨密度来定性地评价。例如，由于节周围抽出物含量较大，多节木材的渗透性较差，反映在较低的骨骼密度和低效的管腔浸渍(低PFR)上。尽管该模型在实验室范围内进行了检验，但它为不同参数对管腔浸渍的精确影响提供了指导，从而提高了对木材浸渍改性的基本理解并使其能够更好地控制。
Lumen impregnation, unlike most other wood modification methods, is typically assessed by the pore-filling ratio (PFR) (i.e. the fraction of luminal porosity filled) rather than by weight percentage gain (WPG). During lumen impregnation, the impregnants act on the voids in the wood rather than on the solid mass (e.g. cell walls), but the PFR cannot be measured as conveniently as the WPG during processing. Here, it is demonstrated how the PFR can be calculated directly from the WPG if the bulk density of the untreated wood is known. The relationship between the WPG and bulk density was examined experimentally by applying a pressured impregnation on knot-free specimens from Sitka spruce with a liquid mixture of methacrylate monomers. Based on the validated model, it was possible to further study the effect of different process-related parameters, such as hydraulic pressure, on lumen impregnation. Skeletal density is another key parameter in this model, which directly reflects the amount of inaccessible pores and closed lumens, and can be independently determined by helium pycnometry. The permeability can be qualitatively evaluated by PFR as well as skeletal density. For instance, poor permeability of knotty wood, due to the large extractives content around knots, was reflected by a lower skeletal density and inefficient lumen impregnation (low PFR). Although this model was examined on a laboratory scale, it provides guidance on the precise effect of different parameters on lumen impregnation, thereby improving the fundamental understanding of and enabling better control over the modification of wood by impregnation.