<p>The objectives of this work were (i) to develop a new methodfor the preparation of thin cellulose model films, (ii) to usethese model films for swelling measurements and (iii) to relatethe swelling of fibers and films to the dry strength ofpaper.</p><p>In the new film preparation method, NMMO(N-methylmorpholine-N-oxide) was used to dissolve cellulose andDMSO (dimethyl sulfoxide) was added to control the viscosity ofthe cellulose solution. A dilute solution of the cellulose wasspin-coated onto a silicon oxide wafer and the cellulose filmthus prepared was then precipitated in deionised water. Asaturated layer of glyoxalated-polyacrylamide was used toanchor the film onto the silicon oxide wafer. This proceduregave films with thicknesses in the range of 20-270 nm. Thefilms were cleaned in deionised water and were found by ESCAanalysis and contact angle measurements (θ<20°)to be free from solvents. Solid state NMR measurements onfibers spun from NMMO also indicated that the model filmconsisted of about 50% crystalline material and that thecrystalline structure was of the cellulose II type.Determination of the molecular weight distribution of thecellulose surface material showed that the NMMO treatmentcaused only a minor breakdown of the cellulose chains and thatlow molecular mass oligomers of glucose were not created.</p><p>It was further shown that atomic force microscopy (AFM)measurements could be used to determine the thicknessof thecellulose films, in both the dry and wet states. The thicknesswas determined as the height difference between the top surfaceand the underlying silica wafer measured at a position where anincision had been made in the cellulose film. The cellulosesolutions were also directly spin-coated onto the crystal usedin the Quartz crystal microbalance (QCM-D), pre-treated withthe same type of anchoring polymer. With this application,these model surfaces were shown to be suitable for swellingmeasurements with the QCM-D. The extent of swelling and theswelling kinetics in the presence of electrolytes, such asNaCl, CaCl2 and Na2SO4, and at different pH were measured inthis way. The films were found to be very stable during thesemeasurements and the results were comparable to the swellingresults obtained for the corresponding pulps. The swelling ofboth fibers and films followed the general behavior ofpolyelectrolyte gels in the presence of electrolytes and was inaccordance with the Donnan equilibrium theory. The films havebeen shown to differ from fibers with regard to the absence ofa covalent interior network. This influences the evaluation ofthe deswelling effects measured on the model films. Theswelling effect seen with different electrolytes has also beenconsidered in relation to the tensile strength of paperprepared from a kraftliner-pulp. In this study, it was foundthat there was no direct relationship between the swelling ofthe fibers, measured as WRV, and the strength of the paper inthe presence of different electrolytes at pH 5.</p><p><b>KEYWORDS:</b>absorption, carboxymethyl cellulose,cellulose, cellulose fibers, dissolving pulps, donnanequilibrium, electrolytes, film, ion exchange, ionization,kinetics, liner boards, microscopy, spinning, surfaces,swelling, tensile strength, water, water retention value.</p>

Colon cancer is the second most common type of cancer in the United States. Its incidence is linked epidemiologically to high levels of bile acids in the feces. Bile acids have been implicated as promotors and cocarcinogens in the etiology of colon cancer and as comutagens and mutagens in bacteria. These observations suggest the hypothesis that bile acids may interact directly with DNA. Using agarose gel electrophoresis we showed that bile acids convert covalently closed circular plasmid DNA to the open circular form, indicating strand breakage. We next treated the single stranded circular DNA of phage M13 with bile acids and found that the transfection efficiency of this DNA declined up to a thousand-fold. The concentrations of bile acids used were of the same magnitude as the fecal bile acid concentrations found in colorectal cancer patients. This inactivation was largely prevented when the bile acids were pretreated with cellulose fiber.

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Xyloglucan is a hemicellulose found in the primary cell walls of many plant species. Found adjacent to the cellulose, it is believed to function as a cementing material which contributes crosslinks and rigidity to the cellulose framework. The only noncovalent linkage reported in the primary cell wall cellulose-hemicellulose-pectic polysaccharide matrix of the cultured tissues is that between xyloglucan and cellulose. Therefore, the xyloglucan:cellulose association has been of great interest to researchers. Xyloglucan can be bound to cellulose in vitro to simulate this in vivo relationship. Previously, the sorption of xyloglucan fragments onto cellulose under non-physiological conditions had been studied, but little information was available on xyloglucan polymer sorption onto cellulose under more natural conditions. This thesis examined the sorption of the xyloglucan polymer isolated from Tamarindus indica onto cellulose fibers (cotton linters) in an aqueous environment. The structure of the xyloglucan isolated from Tamarindus indica in this thesis resembled that of other tamarind xyloglucans reported in the literature. Due to the milder isolation procedure employed, the molecular weight of this polymer was much larger than those previously found. No acetyl, pyruvate, methoxyl, or carboxyl groups were found. The molecular weight and certain structural features (e.g., no fucose units) also differed from the xyloglucan found in plant primary cell walls. When sorbed onto well characterized cotton linters, this xyloglucan exhibited equilibrium sorption within 24 hours. The equilibrium adsorption isotherm was defined. Monolayer sorption occurred. A maximum specific sorption value of 3.9 milligrams of xyloglucan sorbed per gram of cotton linters was calculated using Langmuir's adsorption isotherm theory. This value was compared with other values found in the literature for similar polymer adsorption studies. The effect of molecular weight on sorption equilibrium was also examined and found to be insignificant over the molecular weight range of the polymer isolated in this thesis.

Thesis (Ph. D.)--Institute of Paper Chemistry, 1937. / Includes bibliographical references (p. 83-87).

In the past decade, electrostatic layer-by-layer (LBL) assembly has gained attention because it is a facile and robust method to prepare thin polymer films. Due to the industrial importance and natural abundance of cellulose, its incorporation into LBL films is of particular interest. This thesis examines the use of nanocrystalline cellulose, prepared by sulfuric acid hydrolysis of cotton, in polyelectrolyte multilayer films. Conventional solution-dipping and a spin-coating variant of LBL assembly both resulted in chemically defined, reproducible, and smooth films with adjustable properties. Surface morphology was studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM), and film growth was monitored by X-ray photoelectron spectroscopy (XPS) and optical techniques. Orientation of the rod-like cellulose nanocrystals imparted anisotropic film properties, and birefringence was calculated from angle dependent and wavelength dependent optical reflectometry measurements. While spin-coating resulted in radial orientation of the nanocrystals, electrostatic adsorption in a magnetic field led to linear alignment. The internal structure, surface orientation and wettability of these materials were investigated. The attractive and repulsive forces acting close to the surface of the multilayer films in aqueous media were measured by colloid-probe AFM and the interaction forces between the film surfaces and charged colloidal-probes were compared to the predictions of the DLVO theory. The applications and advantages of polyelectrolyte multilayers containing nanocrystalline cellulose and their potential as model cellulose surfaces are discussed.

Thesis (Ph.D.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references.

Thesis (M.S.)--Oregon State University, 2005. / Printout. Includes bibliographical references (leaves 46-48). Also available on the World Wide Web.

Thesis (M.S.) in Civil Engineering--University of Maine, 2009. / Includes vita. Includes bibliographical references (leaves 74-76).