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Hybrid inorganic-organic resins may provide higher temperature performance in oxidizing environments than their organic counterparts. Phthalonitrile (PN) polymers are excellent candidates for hybridization due to their high thermal stability and glass transition temperatures and their need for improved long-term oxidative stability and toughness. In this work phenyl-substituted organosilicon linkages were incorporated into PN monomers to investigate their effect on the processing, thermo-mechanical properties, and thermal and oxidative stability. Three hybrid silicon-containing phthalonitrile monomers were synthesized incorporating diphenoxydiphenylsilane, tetraphenylsilane, and hexaphenyldisiloxane moieties. Processability of the polymers was highly dependent on catalyst content and an ideal concentration was determined. The impact on glass transition, coefficient of thermal expansion, stability in TGA, and long-term oxidative stability at 250 °C was evaluated. As-synthesized materials performed significantly better than polymers produced from purified monomers. Degradation of the tetraphenylsilane phthalonitrile monomer was examined in detail via IR-TGA and analysis of aged samples. Multiple degradations were identified involving both the organic and hybrid sections of the polymer. Synthesized materials are compared with commercial phthalonitrile reference materials and to other silicon-phthalonitriles in recent literature. Explanations of behavior and suggestions for future improvements are provided. / PHD / High temperature plastics and plastic composites are needed for electronics and aerospace components. Phthalonitriles (PNs) are one chemistry that shows promise for these applications. PN materials show excellent stability and strength at high temperatures. In this work, the inclusion of silicon-containing linkages into PN plastics was investigated with the intention of improving the properties and long-term stability in air at high temperatures. Three silicon-containing PN compounds were produced. The processing of un-cured resins was characterized and optimized. Resins were then cured at high temperatures. Each polymer’s softening point, thermal expansion, and stability in air and under inert conditions were evaluated. The effect of purity was considered, and it was found that as-produced PN plastics behaved better than highly purified PN plastics. The degradation reactions were studied during long-term exposure to high temperatures and short-term exposure to even higher temperatures. These silicon-containing PN materials were also compared with commercial PN plastics and with other PN literature. Explanations of behavior and suggestions for future improvements are provided.

Geothermal energy can make an important contribution to the U.S. energy portfolio. Production areas require seismic monitoring tools to develop and monitor production capability. This paper describes modifications made to a prototypical seismic tool to implement improvements that were identified during previous tool applications. These modifications included changing the motor required for mechanical coupling the tool to a bore-hole wall. Additionally, development of a closed-loop process control utilized feedback from the contact force between the coupling arm and bore-hole wall. Employing a feedback circuit automates the tool deployment/anchoring process and reduces reliance on the operator at the surface. The tool components were tested under high temperatures and an integrated system tool test demonstrated successful tool operations. / Master of Science

A high temperature magnetic bearing system using high temperature permanent magnets from Electron Energy Corporation (EEC) is under development. The system consists of two radial bearings, one thrust bearing, two radial catcher bearings and one motor. The purpose of this research is to develop one of the critical components of the system, namely, the High Temperature Permanent Magnet motor. A novel High Temperature Permanent Magnet (HTPM) Brushless DC(BLDC) motor capable of operating at 1000 degrees F (538 degrees C) is designed. HTPMs developed at Electron Energy Corporation are buried into the rotor. The high temperature motor is designed to produce 5.1kw of power at a top running speed of 20000 rpm. The numerical values of the motor voltage, power and torque output are predicted from calculations of the nonlinear finite element model of the motor. The motor stator is wound, potted, cured and high potential tested at 1000 degrees F. A servo amplifier from Advanced Motion Control is used to drive the high temperature motor. High temperature displacement sensors are set up for sensing the rotor position to form a closed loop motion control. However, the noise problem of the high temperature sensors causes a failure of this approach. An open loop approach is then developed and this approach succeeds in spinning the rotor with the capability of self-starting. The status of the full system assembling is introduced. Some other components of the system are briefly presented.

published_or_final_version / abstract / Electrical and Electronic Engineering / Master / Master of Philosophy

published_or_final_version / abstract / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

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No description available.