Thesis (M.S.)--University of Michigan, Ann Arbor, 1976. / Typescript (photocopy). eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 68-73).

A comparison of the wet-spinning and dry-jet wetspinning of acrylic fibres has been carried out using a commercial acrylic polymer (Courtelle). redissolved in dimethyl formamide. The higher speeds possible in dry-jet wet-spinning have been related to the higher free velocity and the higher draw ratios possible. It is believed that the presence of the air-gap in dry-jet wet-spinning allows the removal of the dies well effects as well as other viscoelastic behaviour before coagulation and that this leads to fibres with superior mechanical properties, especially in improvements in extensibility. Conditions are described which allow the production of high tenacity acrylic fibres with tenacity up to 5.8 g/d tex. In an attempt to produce fibres with better mechanical properties under hot-wet conditions, copolymershave been prepared using bicyclo [2,2,1] hepta-2,5-diene as a comonomer. Fibres from such copolymers have low extensibilities and satisfactory fibres could be made only by incorporating, in addition to the bicyclo [2,2,1] hepta-2,5-diene monomer, itaconic acid and by dry-jet wet-spinning. In one such case a fibre was obtained with a slightly higher hot-wet modulus and a considerably reduced hot-wet extensibility when compared with Courtelle fibre

Thesis (M.S.)--West Virginia University, 2010. / Title from document title page. Document formatted into pages; contains viii, 49 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 41-48).

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Deniers of treated and untreated fibers were determined and the „ results were used in calculations of tenacity and initial modulus. Tensile properties were measured on a constant—rate—of—extension machine. Shrinkage of treated and untreated fibers were measured after they were boiled in water for 15 min. The glass transition temperatures (Tg) were obtained by differential scanning calorimetry. The ratio of the intensities of the CN/CH stretching bands were found by infrared spectroscopy, using the KBr method / Ph. D. / incomplete_metadata

published_or_final_version / Dentistry / Master / Master of Philosophy

published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

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No description available.