Search for dissertations about: "self-diffusion coefficients"

Showing result 1 - 5 of 14 swedish dissertations containing the words self-diffusion coefficients.

2. 1. NMR Self-Diffusion Studies and Stability Studies of Emulsions

   Author : Ingrid Lönnqvist; LTH Ingenjörshögskolan vid Campus Helsingborg; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; coalescence; emulsion stability; size distribution; restricted diffusion; self-diffusion coefficient; self-diffusion PGSE NMR; surfactant; emulsifier; continuous phase; microemulsion; phase diagram; emulsion; multiple emulsion; cream; conductivity; Physics; Fysik; Chemistry; Kemi;

   Abstract : The aim of this study is to characterize emulsion systems by self-diffusion PGSE NMR methods. The specifics of the emulsions studied are all taken from the literature and they are of the W/O or O/W type stabilized with different emulsifiers. READ MORE

4. 2. Nuclear magnetic resonance studies of water self-diffusion in porous systems

   Author : Daniel Topgaard; Fysikalisk kemi; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; diffusion diffraction; nonfreezing; anisotropy; tortuosity; cross relaxation; emulsion; starch; cellulose; porous material; water; NMR; self-diffusion; Physical chemistry; Fysikalisk kemi;

   Abstract : Proton nuclear magnetic resonance (NMR) was used to study the self-diffusion of water in porous systems that respond to a change in water content in order to elucidate the porous structure and the properties of the confined water. In the carbohydrate systems cellulose fibers and starch granules, water is free to move throughout the porous objects, albeit with a rate reduced from the value of the bulk liquid, The reduction is related to the tortuosity of the pore space filled by water. READ MORE

5. 3. Water diffusion and free volume in hydrophilic polymers

   Author : Charlotte Trotzig; Centrum för analys och syntes; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Physical chemistry; free volume; self-diffusion; degree of crystallinity; glass transition temperature; tensile storage modulus; surface tension; isotherm; HPMC; PEO; water; triacetin; clay; Macromolecular chemistry; dynamic mechanical analysis; Fysikalisk kemi; differential scanning calorimetry; nuclear magnetic resonance; positron annihilation; Makromolekylär kemi;

   Abstract : During moisture uptake in polymers, the diffusion of the water molecules is believed to occur via unoccupied voids. These voids are called free volume cavities and their sizes are continuously altered when the moisture content in the polymer is enhanced. READ MORE

6. 4. Association Phenomena in Aqueous Solutions of Surfactants and Hydrophobically Modified Polymers

   Author : Susanne Nilsson; Fysikalisk kemi; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; self-diffusion; rheology; cellulose ethers; associating polymers; polymer-surfactant interactions; polymer network; Fysikalisk kemi; Physical chemistry;

   Abstract : Interactions between ionic surfactants (sodium dodecyl sulfate and dodecyltrimethylammonium chloride) and nonionic polymers ((hydroxyethyl)cellulose, ethyl(hydroxyethyl)cellulose and their hydrophobically modified analogous) have been studied by means of rheology, pulsed field gradient nuclear magnetic resonance (PFG NMR), time-resolved fluorescence quenching (TRFQ), dynamic light scattering (DLS) and cryo-transmission electron microscopy (cryo-TEM). In all experiments surfactants have been added in various amounts to polymer solutions at fixed concentrations. READ MORE

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

   Author : Åsa Östlund; Chalmers tekniska högskola; []
   Keywords : 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;

   Abstract : 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. READ MORE