In this study, the contact angles of three different reference liquids （including distilled water, diiodomethane, and formamide） and PF resin on the surfaces of Chinese fir （Cunningharnia lanceolata） samples untre...In this study, the contact angles of three different reference liquids （including distilled water, diiodomethane, and formamide） and PF resin on the surfaces of Chinese fir （Cunningharnia lanceolata） samples untreated or treated with different concentrations of ACQ-D （ammoniacal copper quat Type D） solutions were measured. Then, the surface free energy was calculated by two approaches： acid-base approach and geometric mean approach. ACQ-D treatment caused higher contact angles and lower surface free energies at a retention level corresponding to the commodity treated wood products. When wood was treated with much higher concentrations of ACQ-D, the total surface free energy of wood would be higher than the untreated control. Acid-base/polar components related with the hydrogen bonding state in wood were considered to be responsible for the observed changes according to the applied approaches. The hydrophobic properties and also higher contact angles of PF resin drop on wood surfaces after ACQ-D treatment at a reasonable retention level confirms the changes on surface free energy.展开更多
In order to improve the leaching resistance of active ingredient-copper in ammoniacal copper quat-type D （ACQ-D） treated Chinese fir （Cunninghamia lanceolata Hook.）, microwave post-treatments were carried out. The...In order to improve the leaching resistance of active ingredient-copper in ammoniacal copper quat-type D （ACQ-D） treated Chinese fir （Cunninghamia lanceolata Hook.）, microwave post-treatments were carried out. The percentages of leached copper from ACQ-D treated Chinese fir with different microwave post-treatments were obtained after leaching tests by analyzing the copper retention in treated wood. The fixation mechanism of copper in the treated wood was determined with the help of SEM and FTIR spectra, while the valence conversion of copper after microwave post-treatments was studied by UV spectroscopy. Our experimental results show that the percentage of leached copper was reduced significantly after microwave post-treatment over time. This development was reinforced by allowing even more time for the treatment as well as with an increase in the power of microwave post-treatment. The leaching resistance of copper in wrapped samples was better than that in unwrapped samples, which is attributed to the combined effects of temperature and moisture content. Compared with air-dried samples, the valence conversion in the samples with microwave post-treatments changed slightly, which demonstrates that microwave post-treatments cannot impair the natural decay resistance of ACQ-D treated wood. SEM and FTIR spectra showed the presence of crystal particles formed by chemical reactions between copper and wood ingredients in wood cell walls and wood pits. Only a small amount of copper reacted with cellulose, while lignin and hemicellulose were the major bonding sites for copper in wood. Given the experimental results of mechanical properties, microwave post-treatments had a slight effect on the compression strength parallel to the grain and on the erystallinity of ACQ-D treated Chinese fir.展开更多
基金Supported by the Foundation for the Author of National Excellent Doctoral Dissertation of China (Grant No. 200352)
文摘In this study, the contact angles of three different reference liquids （including distilled water, diiodomethane, and formamide） and PF resin on the surfaces of Chinese fir （Cunningharnia lanceolata） samples untreated or treated with different concentrations of ACQ-D （ammoniacal copper quat Type D） solutions were measured. Then, the surface free energy was calculated by two approaches： acid-base approach and geometric mean approach. ACQ-D treatment caused higher contact angles and lower surface free energies at a retention level corresponding to the commodity treated wood products. When wood was treated with much higher concentrations of ACQ-D, the total surface free energy of wood would be higher than the untreated control. Acid-base/polar components related with the hydrogen bonding state in wood were considered to be responsible for the observed changes according to the applied approaches. The hydrophobic properties and also higher contact angles of PF resin drop on wood surfaces after ACQ-D treatment at a reasonable retention level confirms the changes on surface free energy.
基金the FANEDD of China (No. 200352)the Fok Ying Tong Education Foundation (No. 101028) for financial support
文摘In order to improve the leaching resistance of active ingredient-copper in ammoniacal copper quat-type D （ACQ-D） treated Chinese fir （Cunninghamia lanceolata Hook.）, microwave post-treatments were carried out. The percentages of leached copper from ACQ-D treated Chinese fir with different microwave post-treatments were obtained after leaching tests by analyzing the copper retention in treated wood. The fixation mechanism of copper in the treated wood was determined with the help of SEM and FTIR spectra, while the valence conversion of copper after microwave post-treatments was studied by UV spectroscopy. Our experimental results show that the percentage of leached copper was reduced significantly after microwave post-treatment over time. This development was reinforced by allowing even more time for the treatment as well as with an increase in the power of microwave post-treatment. The leaching resistance of copper in wrapped samples was better than that in unwrapped samples, which is attributed to the combined effects of temperature and moisture content. Compared with air-dried samples, the valence conversion in the samples with microwave post-treatments changed slightly, which demonstrates that microwave post-treatments cannot impair the natural decay resistance of ACQ-D treated wood. SEM and FTIR spectra showed the presence of crystal particles formed by chemical reactions between copper and wood ingredients in wood cell walls and wood pits. Only a small amount of copper reacted with cellulose, while lignin and hemicellulose were the major bonding sites for copper in wood. Given the experimental results of mechanical properties, microwave post-treatments had a slight effect on the compression strength parallel to the grain and on the erystallinity of ACQ-D treated Chinese fir.
