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Advanced materials: The fabrication, characterization and study of novel ceramics and composites
As advances in technology prompt demands for materials with specific and wide ranges of properties, traditional materials have often not been able to meet these more challenging needs. There is also an exigency to process these materials with minimal consumption of energy at low cost. To address these needs there has been a considerable impetus to develop new materials, new processing strategies and/or new synthetic strategies. This thesis focuses on the synthesis, characterization, and manipulation of a variety of new and advanced materials. ^ The two main topics of this thesis are, firstly, a composite system where the growth of an inorganic phase takes place within a polymer film. Composite films of CdS in PEO were formed by an in situ reaction of CdCl2/PEO composite films with an octane solution of hexamethyldisilathiane [S(TMS) 2]. Organized crystallization of the product was found only to occur in thin films (<300nm) in the presence of surfactant. Crystals were found to be uniform in size, shape, phase and crystallographic orientation. The principles of this system have been further developed and used to produce novel phases of lead sulfides at room temperature and pressure, and the first known synthesis of single crystals of Lithium Niobate at room temperature and pressure. ^ The second part of this thesis deals with the synthesis and characterization of poly(methyl)silyne (PMSy), a polymer precursor to silicon carbide (SiC). The synthesis of PMSy is both cheap and simple. The polymer is non-pyrophoric which is unique among current SiC preceramic polymers. The pyrolysis of PMSy results in a ceramic of unrivaled purity, it is the only perfectly stoichiometric SiC than has been obtained from any polymeric precursor. Ceramic films have also been produced from PMSy, and are the smoothest, the most continuous, the most perfect and defect free that have ever been reported. ^
Chemistry, Inorganic|Chemistry, Polymer|Engineering, Materials Science
Michael W Pitcher,
"Advanced materials: The fabrication, characterization and study of novel ceramics and composites"
(January 1, 2001).
Electronic Doctoral Dissertations for UMass Amherst.