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Degree

Doctor of Philosophy, Case Western Reserve University, Chemistry, 1990.

Abstract

Structurally novel fibrous polymers with tubular siloxane backbones and organic surfaces have been prepared from the tube silicate K₂CuSi₄O₁₀. The K₂CuSi₄O₁₀ has been prepared by sintering, devitrification, and gel-glass devitrification procedures. It has been purified with magnetic separation techniques and characterized with X-ray powder diffractometry and energy dispersive spectroscopy. The tube polymers have been prepared by liberation of the tubes from the silicate with acid followed by alkoxylation of the newly liberated tubes with primary alcohols. They have been characterized by infrared spectroscopy, ²⁹Si MAS-NMR spectroscopy, X-ray diffraction, hydrolysis gas-chromatography procedures, and electron microscopy. The results obtained show that the polymers are made up of high aspect ratio fibers with diameters of ∼14-17 A. The results also show that these fibers have a framework that is the same as that of the parent tube anion with ∼65% of the silicon atoms in the tube framework having pendent alkoxy groups. These polymers are compatible with many organic solvents and form non-flowing gels when dispersed by sonication in certain polar organic solvents. In addition, structurally novel alkoxysiloxy sheet polymers with planar siloxane frameworks have been prepared using similar alkoxylation procedures. The preparation of these sheet polymers shows that the alkoxylation procedures used with K₂CuSi₄O₁₀ can be extended to include other polymeric silicates. Also, trimethylsiloxy tube polymers derived from K₂CuSi₄O₁₀ have been prepared. The preparation of these polymers shows that groups other than alkoxy groups can be grafted on the tube in this silicate. Finally, a novel finite element technique for modeling tube structures has been developed. This technique has been used to determine the elastic moduli of a set of hypothetical tube structures having molecular dimensions. The structure-property relationships of this set of tubes has been investigated and the structural relationships of these tubes to known and possible molecular structures have been studied.

Keywords

Tube polymers derived potassium copper silicon oxygen molecular modeling hypothetical structures

Advisor

Malcolm E Kenney

Pages

237p.

Document number: case1054644360
Permalink: http://rave.ohiolink.edu/etdc/view?acc_num=case1054644360

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