Browsing by Subject "zirconium phosphate"
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Item Effects of Y_(2)O_(3) and ?-ZrP Additives on Lubrication of Grease(2014-07-28) Kim, Chung JwaDevelopment of novel additives in lubricants is a promising approach for high performance and energy saving devices. Those include automotive, marine, and wind turbines. In a wind turbine, the unplanned break-down rate of bearings caused by improper lubricants is 40% ~50%. The objective of this research is to 1) develop novel nanomaterials as grease additives, and 2) obtain understanding in tribological performances of the same. The research focuses on zirconium phosphate and yttrium oxide nanoparticles as additives in grease. Experimental approach is used to investigate the effects of those nanomaterials on lubrication of grease. Experiments such as tribological experiments at room and elevated temperatures, galling resistance tests, and characterization of worn surfaces will be conducted. Characterization includes optical microscope, interferometer, and scanning electron microscope (SEM). Results showed that the addition of nanoparticles induced reduction of coefficient of friction. In addition, the wear rate of the test samples was reduced by adding nanoparticles. This research investigates the effects of nanoparticles with unique shape and structure and develops understating in mechanisms. The research results will be beneficial to the application of lubricants for high performance and efficiency. This thesis contains six chapters. Chapter I is the background information about tribology and materials needed to understand this research. Chapter II describes the motivation and objectives. Chapter III discusses the experimental procedures and materials used in this research. Chapter IV and V present and discuss the results obtained from yttrium oxide and zirconium phosphate, respectively. Chapter VI discusses the major conclusions obtained from the results and offers suggestions for future work.Item Structure-property relationship in core-shell rubber toughened epoxy nanocomposites(Texas A&M University, 2004-09-30) Gam, Ki TakThe structure-property relationships of epoxy nanocomposites with inorganic layer-structure nanofillers have been studied to obtain the fundamental understanding of the role of nanofillers and the physics of polymer nanocomposites in this dissertation. Several polymer nanocomposite systems with modified montmorillonite (MMT) or ?-zirconium phosphate (ZrP) nanofillers were prepared with epoxy matrices of different ductility and properties. The successful nanofiller's exfoliations were confirmed with X-ray diffraction and transmision electronic microscopy (TEM). Dynamic mechanical analysis (DMA) on the prepared epoxy nanocomposites revealed the significant increase in rubbery plateau moduli of the epoxy nanocomposite systems above Tg, as high as 4.5 times, and tensile test results showed improved modulus by the nanofiller addition, while the fracture toughenss was not affected or slightly decreased by nanofillers. The brittle epoxy nanocomposite systems were toughened with core shell rubber (CSR) particles and showed remarkable increase in fracture toughness (KIC) value up to 270%. The CSR toughening is more effective at ductile matrices, and TEM observation indicates that major toughening mechanisms induced by the CSR addition involve a large scale CSR cavitation, followed by massive shear deformation of the matrix.Item Surface Modification of Layered Zirconium Phosphates: A Novel Pathway to Multifunctional Nanomaterials(2014-04-08) Mosby, Brian MatthewThe surface functionalization of inorganic nano particles for improved and novel applications is the topic of this dissertation; specifically the surface modification of inorganic layered materials. In this case the goal is to exclusively modify the surface or exterior layers of the material, while leaving the internal layers and structure unchanged. This allows for organic derivatives of layered materials in which the interlayer chemistry is not lost to achieve organic functionalization. The addition of organic character along with the retention of the original interlayer character produces a material with dual functionality and opens the window for many unique compounds and applications. The surface reactivity of ?- zirconium phosphate nano platelets was investigated with a variety of coupling agents. Initially, covalent attachment of molecules to the exterior surface of the nano particles was attempted with silanes and epoxides. Subsequently, the ion exchange character of the surface phosphate groups was used to deposit metal ions on the surface. The metal ion layer was then coordinated with phosphonic acid ligands to produce surface functionalized ZrP. In all cases the exclusive functionalization of the surface and covalent attachment of the reactive groups to the inorganic layer was confirmed using a combination of techniques including X-ray powder diffraction, XPS, electron microprobe, Solid State NMR, FTIR, and TGA. The viability of producing nano particles with both a controlled interior and exterior by combining the intercalation chemistry of ZrP with the newly developed surface chemistry was then investigated. Characterization of the resulting materials indicated that functionalization of intercalated ZrP was successful and an efficient procedure for the design of multifunctional nanoparticles. The control of the interlayer and surface allows for nanoparticles to be designed for particular applications. Polymer nanocomposites and a photo-induced electron transfer system were prepared using the multifunctional nanoparticles as test cases.