A study of the Structure, Properties, and Applications of Polymeric Phosphate Glass Systems
Date
2001
Authors
Tischendorf, Brad Conrad
Major Professor
Advisor
Otaigbe, Joshua
Committee Member
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Abstract
A series of studies was performed in order to increase the knowledge and understanding of the structure and possible applications of phosphate glasses. The short- and intermediate-range order of the polyphosphate glass network of the composition xZn0 + (1-x)P2O5 was investigated, with 0.35 [less than or equal to symbol] x [less than or equal to symbol] 0.80. The short-range order was probed using 31P solid-state magic angle spinning nuclear magnetic resonance (MAS NMR), liquid state NMR and Raman spectroscopy. MD simulations were used to investigate the structural and physical properties of a series of binary zinc phosphate glasses, xZnO·(1-x)P2O5, (40 [less than or equal to symbol] x [less than or equal to symbol] 70) where x is the mole percent modifier. A forcefield model incorporating coulombic, two- and three-body interactions was employed, with the model parameters being empirically derived from known zinc-phosphate crystal structures. This new zinc-phosphate forcefield model was used to perform MD calculations of densities, glass transition temperatures, T[Subscript g], average coordination numbers, CN, radial distribution functions, G(r), and pair distribution function, g(r), allowing comparison to experimentally observed values. A feasibility study was performed aimed at making useful, durable phosphate glass fibers from phosphate glasses.
The focus the work was to demonstrate a practical method for making useful glass fibers from a tin-phosphate glass composition (SnO + P205 + SnF2, T[Subscript g]1150C) as phosphate glass fibers had been thought too difficult to make in the past. The variations in morphology and local structure in a series of tin fluorophosphate glass-polyethylene (TFPPE) hybrids were investigated using solid-state 1H, 13C and 31P MAS NMR. Combination of direct polarization 13C MAS NMR experiments with various delay times and carbon spin-lattice relaxation filtered cross-polarized (CP) MAS NMR experiments allowed quantification of the monoclinic, orthorhombic, amorphous, and intermediate phases in the low-density polyethylene (LDPE) component of the TFPPE hybrids. The results of all of these studies are reported and suggestions for the future work in this field based off these results are given.
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thesis