The purpose of this study was to explore the differences of the hemicelluloses extracted by hydrothermal pretreatment using water and alkaline solutions(Na OH or KOH). The physicochemical properties and structural cha...The purpose of this study was to explore the differences of the hemicelluloses extracted by hydrothermal pretreatment using water and alkaline solutions(Na OH or KOH). The physicochemical properties and structural characteristics of two water-soluble and four alkali-soluble hemicelluloses extracted from the triploid of Populus tomentosa Carr. through the hydrothermal pretreatment were comparatively studied. It was observed that the alkalis(Na OH and KOH) were more effective than distilled water as extractants. Sugar analysis showed that xylose(66.83%~86.49%) was the major constituent, followed by glucose(6.83%~18.49%). Mannose(1.40%~8.42%), galactose(2.17%~4.05%), and arabinose(0.21%~2.26%) were also detected in the hemicellulosic fractions. The results of gelpermeation chromatography(GPC) indicated that the hemicelluloses extracted using the alkaline solutions had relatively higher molecular weights than those solubilized in distilled water. Further, based on spectroscopic ~1Hnuclear magnetic resonance(~1H-NMR) and two-dimensional heteronuclear singular quantum correlation(2D-HSQC) analyses, it was confirmed that the hemicellulosic fractions had a major structure of(1→4)-b-D-xylan and a minor structure of(1→4)-a-D-glucan with small amounts of substituted sugars and glucuronic acid attached.展开更多
Novel derivatives containing bi-perfluorooctane-sulfonamide group were designed and synthesized. The FNMR, FTIR were used to characterize derivatives structures. The compounds were applied to paper for oil-repellency....Novel derivatives containing bi-perfluorooctane-sulfonamide group were designed and synthesized. The FNMR, FTIR were used to characterize derivatives structures. The compounds were applied to paper for oil-repellency. The results show that treated paper had excellent oil-repellency at very low concentration of bi- perfluorooctane-sulfonamide derivatives. When novel compounds, polyvinyl alcohol （PVA） and oxidized starch were applied together as coat sizing, the oxidized starch and PVA did not affect the oil repellency properties of paper.展开更多
基金financial support from the Fundamental Research Funds for the Central Universities(No.JC2013-3,BLYJ201616)Beijing Higher Education Young Elite Teacher Project(No.YETP0763)
文摘The purpose of this study was to explore the differences of the hemicelluloses extracted by hydrothermal pretreatment using water and alkaline solutions(Na OH or KOH). The physicochemical properties and structural characteristics of two water-soluble and four alkali-soluble hemicelluloses extracted from the triploid of Populus tomentosa Carr. through the hydrothermal pretreatment were comparatively studied. It was observed that the alkalis(Na OH and KOH) were more effective than distilled water as extractants. Sugar analysis showed that xylose(66.83%~86.49%) was the major constituent, followed by glucose(6.83%~18.49%). Mannose(1.40%~8.42%), galactose(2.17%~4.05%), and arabinose(0.21%~2.26%) were also detected in the hemicellulosic fractions. The results of gelpermeation chromatography(GPC) indicated that the hemicelluloses extracted using the alkaline solutions had relatively higher molecular weights than those solubilized in distilled water. Further, based on spectroscopic ~1Hnuclear magnetic resonance(~1H-NMR) and two-dimensional heteronuclear singular quantum correlation(2D-HSQC) analyses, it was confirmed that the hemicellulosic fractions had a major structure of(1→4)-b-D-xylan and a minor structure of(1→4)-a-D-glucan with small amounts of substituted sugars and glucuronic acid attached.
文摘Novel derivatives containing bi-perfluorooctane-sulfonamide group were designed and synthesized. The FNMR, FTIR were used to characterize derivatives structures. The compounds were applied to paper for oil-repellency. The results show that treated paper had excellent oil-repellency at very low concentration of bi- perfluorooctane-sulfonamide derivatives. When novel compounds, polyvinyl alcohol （PVA） and oxidized starch were applied together as coat sizing, the oxidized starch and PVA did not affect the oil repellency properties of paper.
