MORPHOLOGY OF CELLULOSE, CELLULOSE ESTERS, AND CELLULOSE ESTER - LEWIS BASE PENDANT VINYL POLYMER BLENDS IN FIBERS, FILMS, AND ULTRATHIN DEPOSITS

This work is presented in three separate sections: (1) the molecular and crystal structure of Celluloses IV(,I) and IV(,II), (2) morphological changes in a Cellulose Triacetate hollow fiber with application of stress and fouling by iron (III) oxide, and (3) polymer-polymer interaction in blends of Cellulose Acetate with Lewis base pendant group vinyl chain polymers.;Methodology in section 1 consists of x-ray diffraction techniques coupled with stereochemical modeling. Model selection is reinforced by heterogeneous conversion of the fibrous materials to fiber products with well characterized crystalline structures. In section 2, crystallinity changes are followed by both x-ray diffraction and differential scanning calorimetry. Techniques in section 3 include characterization of homopolymers by chemical reactivity and NMR spectroscopy, differential scanning calorimetry to determine blend thermodynamics, and Fourier Transform Infra-red spectroscopy to follow interactions as a function of homopolymer substitution. Section 3 also contains an extensive section dealing with synthesis of cellulose acetates with known substitution patterns.;The common thread running through each section is the structure and morphology of cellulose di- and tri-acetate in homogeneous and blend thin films and fibers. In section 1, the conversion of Cellulose IV to the known Cellulose Triacetate crystal structures is used as a final proof of the models proposed for the two Cellulose IV polymorphs. In section 2, the concentration is on the degree of crystallinity, crystallite size, and crystallite orientation in a Cellulose Triacetate hollow fiber caused by simulated use conditions. The results may account for losses in efficiency observed for the hollow fibers over time, during use as reverse osmosis membranes. In section 3, the focus is on the complex morphologies that occur upon forming blends with a semi-crystalline polymer as one of the components. The adverse effect of crystallinity on alloy formation is described, in addition to the major subject, which is the determination of the specific interaction that leads to miscibility of the polymer pair.