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- Hasani, Merima, 1978, et al.
(författare)
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Cationization of Cellulose by Using N-Oxiranylmethyl-N-Methylmorpholinium Chloride and 2-Oxiranylpyridine as Etherification Agents
- 2009
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Ingår i: Journal of Applied Polymer Science. - : Wiley. - 1097-4628 .- 0021-8995. ; 114:3, s. 1449-1456
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Tidskriftsartikel (refereegranskat)abstract
- Cationization of cellulose under aqueous alkaline conditions was studied. Two new epoxy reagents, N-oxiranylmethyl-N-methylmorpolinitim chloride and 2-oxiranylpyridine, were used for preparation of cationic cellulose ethers. Using the first agent, cationic ethers were obtained in one step, whereas the latter one yielded a reactive intermediate used as a precursor for two different cationizations. Etherification with the commonly used 2,3-epoxypropyltrimethylammonium chloride was also performed and used as a reference reaction. By changing water content in the reaction mixture two groups cellulose ethers with different degrees of cationization were prepared. As expected, reducing the water content resulted in a higher degree of etherification and hence a more pronounced cationic character of the obtained ethers. Characterization by FTIR, elemental- and gravimetric analysis confirmed the formation of the desired ethers. Their ability to interact with water and adsorb the acid dye, methyl orange, was also studied, confirming further introduction of the cationic substituents and revealing different reactivities of the used epoxy reagents. From characterization, it could be concluded that N-oxiranylmethyl-N-methylmorpholinium chloride exhibits higher reactivity toward cellulose than both the reference compounds and 2-oxiranylpyridine. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 1449-1456, 2009
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| 2. |
- Sjöberg, John, et al.
(författare)
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Cross-sectional analysis of the polysaccharide composition in cellulosic fiber materials by enzymatic peeling/high-performance capillary zone electrophoresis
- 2005
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 6:6, s. 3146-3151
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Tidskriftsartikel (refereegranskat)abstract
- A combined enzymatic, chemical, and analytical approach was used to determine the cross-sectional carbohydrate composition in cellulosic fibers. The outer surface of cellulosic fibers was enzymatically removed layer-by-layer with precise quantitative control, and the monosaccharides in the peelings were subsequently analyzed by high-performance capillary electrophoresis (HPCE) after precolumn derivatization with a UV label. This method was applied to dissolving pulps and regenerated cellulose fibers, with special emphasis on the cross-sectional distribution of hemicelluloses. Commercially available enzyme solutions were used, resulting in a reproducible peeling. Significant differences were found in the hemicellulose distribution across the fiber of different dissolving pulps, dependent on both natural source (beech or spruce) and preparation process (acidic sulfite cook or prehydrolysis kraft cook). Among the dissolving pulps, beech prehydrolysis kraft pulp showed the highest enrichment of surface xylan. Similar, albeit smaller, differences were noticed between various regenerated fibers (viscose, viscose Modal, and Lyocell): a thin hemicellulose-rich outermost layer was found in all the regenerated fibers studied.
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