摘要:
该研究中测定了蒸馏水、二碘甲烷、甲酰胺和甘油等4种参照液体在不同水基防腐处理 (包括铬化砷酸铜CCA以及另外两种商品名为NW和NS的处理) 后的木材表面所形成的接触角, 并根据酸碱作用理论计算得到其表面自由能及其两个分量——LifshizvanderWaals (LW) 分量和酸碱作用 (AB) 分量.结果表明, NW和CCA处理使木材表面的疏水性有所增加, 而NS处理由于早材的水分渗透速率加快总体表现为亲水性增加.利用蒸馏水、二碘甲烷、甲酰胺这3种参照液体计算得到的未处理早材、未处理晚材、CCA处理早材、CCA处理晚材、NW处理早材、NW处理晚材、NS处理早材和NS处理晚材的表面自由能分别为43.1、44.5、43.4、45.1、49.4、40.6、46.0和40.9mJm2.由此可见, CCA处理材的表面自由能接近于未处理材, 而经过NW和NS处理后, 早材和晚材的表面能都有一定程度的变化, 但对于木材整体来说表面自由能仍接近于未处理材.
关键词:
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木材
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表面自由能
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防腐剂
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接触角
Abstract:
In this study, the contact angles of four different reference liquids (distilled water, diiodomethane, formadide and glycerol) formed on the surfaces of wood treated with chromated copper arsenate (CCA) and other two new-emerging copper-based water-borne systems (commercial name: NW and NS) were measured with a sessile drop method. Based on the contact angle data, the surface energy was obtained using a acid-base approach. The total surface energy consisted of a Lifshiz-van der Waals (LW) parameter and an acid-base (AB) parameter.Resultsshowed that NW and CCA treatments made the wood surface more hydrophobic while an NS treatment had the reverse effect on the wood surface mainly due to the increased penetration of earlywood. By using three liquids, diiodomethane, formamide and distilled water, the total surface energy obtained for untreated earlywood, untreated latewood, CCA-treated earlywood, CCA-treated latewood, NW-treated earlywood, NW-treated latewood, NS-treated earlywood and NS-treated latewood were 43.1, 44.5, 43.4, 45.1, 49.4, 40.6, 46.0, and 40.9 mJ/m2, respectively. The surface energy of CCA-treated wood was almost the same as that of untreated wood. After NW and NS treatments, the surface energy of both earlywood and latewood both changed little. But for an entire piece of wood, the average surface energy of wood after NW and NS treatments remained the same.
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