Sökning: "hemicellulose"

Visar resultat 41 - 45 av 148 avhandlingar innehållade ordet hemicellulose.

1. 41. Interactions between Wood Polymers in Wood Cell Walls and Cellulose/Hemicellulose Biocomposites

   Författare :Jasna Stevanic Srndovic; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; dynamic FTIR spectroscopy; viscoelasticity; orientation; Norway spruce; protein; glucomannan; xyloglucan; polymer interactions; pectin; imaging FTIR microscopy; primary cell wall; nanocomposite films; dynamic 2D FTIR spectroscopy; xylan; wood fibre; cellulose; secondary cell wall; DMA; lignin;

   Sammanfattning : A wood fibre is a complex multi component biocomposite that is hierarchically organised. The arrangement of a wood fibre on the ultrastructural level is highlycontrolled by the interactions between the main structural polymers, i.e. cellulose, various hemicelluloses and lignin, as well as in some parts also pectin and protein. LÄS MER

3. 42. Separation of Biomass Components by Membrane Filtration - Process Development for Hemicellulose Recovery

   Författare :Holger Krawczyk; Avdelningen för kemiteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Biomass; hemicelluloses; pulp mill process water; alkaline extract; membrane filtration;

   Sammanfattning : One of the major challenges facing the world today is the reduction of our dependency on fossil resources as their exploitation has severe negative effects on the environment. One way of realizing this is to utilise the components of lignocellulosic biomass to a greater extent as feedstock for various industrial products. LÄS MER

4. 43. Isolation, characterization and enzymatic hydrolysis of water-soluble wood polysaccharides

   Författare :Jon Lundqvist; Biokemi och Strukturbiologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; size exclusion chromatography; beta-mannosidase; beta-mannanase; endoglucanase; ethyl hydoxyethyl cellulose; metabolism; Biokemi; Biochemistry; Metabolism; microwave irradiation; O-acetyl-galactoglucomannan; isolation;

   Sammanfattning : The need for new renewable products has enhanced the interest in cellulose and hemicellulose as raw material. The wood plant cell wall is a complex mixture of cellulose, hemicellulose, lignin and minor amounts of pectin, proteins and extractives. Several interactions between the compounds make them difficult to separate without modification. LÄS MER

5. 44. Preparation and Characterization of Chemical Pulps from Wood and Reed Canary Grass

   Författare :Helena Håkansson; Karlstads universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; pulping; wood; reed canary grass; acid hydrolysis; microcrystalline cellulose; Chemical Engineering; Kemiteknik;

   Sammanfattning : This thesis presents laboratory results from ethanol pulping of reed canary grass for the production of paper pulp. The focus was on the influence of cooking pa-rameters on the delignification. The strength of the grass pulps was found to be low and the use of such pulps will therefore be limited to a few products. LÄS MER

7. 45. Structural changes during cellulose composite processing

   Författare :Helena Halonen; Monica Ek; Tommy Iversen; Derek D. Gray; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; CP MAS 13C NMR; cellulose; fibril aggregation; biocomposite; compression moulding; supramolecular structure;

   Sammanfattning : Two approaches for creating a new all-cellulose composite material have been studied: the biosynthesis of compartmentalised bacterial cellulose fibril aggregates and the compression moulding of commercial chemical wood pulps processed with only water. The objective was to study the structural changes during processing and the complexity of relating the mechanical properties of the final biocomposites to the nanoscale structure was highlighted. LÄS MER