Sökning: "fiber types and size"
Visar resultat 1 - 5 av 38 avhandlingar innehållade orden fiber types and size.
1. Distributions Of Fiber Characteristics As A Tool To Evaluate Mechanical Pulps
Sammanfattning : Mechanical pulps are used in paper products such as magazine or news grade printing papers or paperboard. Mechanical pulping gives a high yield; nearly everything in the tree except the bark is used in the paper. This means that mechanical pulping consumes much less wood than chemical pulping, especially to produce a unit area of printing surface. LÄS MER
2. Lignin polysaccharide networks in softwood and chemical pulps : characterisation, structure and reactivity
Sammanfattning : The chemical interactions between the main wood components i.e., cellulose, hemicelluloses and lignin are of fundamental importance for understanding the chemical aspects of wood formation and its reactivity during fibre processing e.g during chemical pulping of wood. LÄS MER
3. Preparation and characterization of nanoporous cellulose fibres and their use in new material concepts
Sammanfattning : The overall objective of the work in this thesis is to better utilize the non-collapsed structure of the delignified wood-fibre cell wall in the preparation of new types of materials.In order to utilize the fibres in new materials, it is crucial to have a well-defined starting material and to know how it reacts to certain treatments of the fibres. LÄS MER
4. Macro-, Micro- and Nanospheres from Cellulose : Their Preparation, Characterization and Utilization
Sammanfattning : The structure of a polymeric material has a great influence in many fundamental scientific areas as well as in more applied science, since it affects the diffusion, permeability, mechanical strength, elasticity, and colloidal properties of the materials. The results in this thesis demonstrate that it is possible to fabricate solid and hollow cellulose spheres with a cellulose shell and encapsulated gas, liquid or solid particles and with a sphere size ranging from a few hundreds of nanometres to several millimetres, all with a tailored design and purpose. LÄS MER
5. Physicochemical properties of root fiber suspensions. A comparison between parsnip (Pastinaca sativa) and yacon (Smallanthus sonchifolius)
Sammanfattning : The physicochemical properties of two root suspensions, parsnip (Pastinaca sativa) and yacon (Smallanthus sonchifolius), were studied and compared at different concentrations and after being subjected to processes such as homogenization and heating. The study and the evaluation of the physicochemical properties of these plant materials in the form of pastes might help to increase the interest in these two roots, and possibly encourage their further industrial use. LÄS MER