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Visar resultat 1 - 5 av 10 avhandlingar som matchar ovanstående sökkriterier.

1. 1. The cell wall ultrastructure of wood fibres : effects of the chemical pulp fibre line

   Författare :Jesper Fahlén; Ulf W. Gedde; Drek G. Gray; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Chemical engineering; atomic force microscopy; cellulose; cell wall; drying; fiber; Kemiteknik; Chemical engineering; Kemiteknik;

   Sammanfattning : Knowledge of the ultrastructural arrangement within wood fibres is important for understanding the mechanical properties of the fibres themselves, as well as for understanding and controlling the ultrastructural changes that occur during pulp processing. The object of this work was to explore the use of atomic force microscopy (AFM) in studies of the cell wall ultrastructure and to see how this structure is affected in the kraft pulp fibre line. LÄS MER

3. 2. Investigating cellulose structure using solid-state NMR spectroscopy

   Författare :Alexander Idström; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; CNC; crystallinity index; regenerated cellulose; 2D NMR; native cellulose; pulp; Solid-state NMR; ionic liquids; CP MAS 13C-NMR; hornification;

   Sammanfattning : Cellulose is the most abundant polymer in nature and it is an important constituent in most flowers, trees, and even some animals. Cellulose has an established use in many important products, such as textile fibers, paper and paperboard, and recently new applications have received increased attention. LÄS MER

4. 3. Adsorption of xylans on cellulosic fibres -Influence of xylan composition on adsorption characteristics and kraft pulp properties

   Författare :Tobias Köhnke; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Xylan; Hornification; Lignin-carbohydrate complexes; Cationization; Isolation; Softwood kraft pulp; Extraction; Adsorption;

   Sammanfattning : Xylans are polysaccharides present in large amounts in cell walls of vascular plants. They possess an inherent affinity to cellulose and will thus adsorb irreversibly on cellulose surfaces. LÄS MER

5. 4. Investigating structural changes of cellulose using NMR spectroscopy

   Författare :Alexander Idström; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; crystallinity index; NCC; ionic liquids; CP MAS 13C-NMR; hornification; native cellulose; regenerated cellulose; NMR cryoporometry; pulp; Solid-state NMR;

   Sammanfattning : In this thesis solid-state NMR and NMR cryoporometry were used to gain information of the structure of cellulose. Measurements were conducted on both native and regenerated cellulose, exposed to a range of different treatments. LÄS MER

7. 5. Physico-Chemical Properties of Plant Polysaccharides Investigated with NMR Techniques

   Författare :Åsa Östlund; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NMR diffusometry; Dissolution of cellulose; Chemical shift imaging; Fiber hornification; Xylan; Molecular weight; Pore size distribution; Cryoporometry; Cellulose solution; 19F NMR; Gelation of cellulose; Self-diffusion; Pulsed field gradient NMR; TBAF DMSO; 1H NMR;

   Sammanfattning : In the lead of developing new biomaterials from plant sources it is of importance to be able to control and vary the properties, such as flexibility, strength, and hygroscopicity of the final material. These properties are highly directed by the interactions between constituents on a molecular level. LÄS MER