Date of Award

Fall 12-2018

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

School

Polymer Science and Engineering

Committee Chair

Joshua U. Otaigbe

Committee Chair School

Polymer Science and Engineering

Committee Member 2

Sarah E. Morgan

Committee Member 2 School

Polymer Science and Engineering

Committee Member 3

William L. Jarrett

Committee Member 3 School

Polymer Science and Engineering

Committee Member 4

Derek L. Patton

Committee Member 4 School

Polymer Science and Engineering

Committee Member 5

Joseph D. Lichtenhan

Abstract

Preparation and characterization of tin fluorophosphate glass (Pglass) matrix nanocomposites incorporating polyhedral oligomeric silsesquioxane (POSS) were investigated on the structural, thermal, morphological, mechanical, and rheological properties. Various processes including synthesis, extrusion and sintering processes were applied to prepare the nanocomposite samples. Another application of POSS with hydrophobic functional groups on the well-structured nanoscale silicate cage with three silanol groups was investigated to present the feasibility to use POSS molecule as a coating material on the surface of the hydrophilic inorganic glass. In addition, Poly(ethylene terephthalate) polymer matrix composites incorporating Pglass was studied to present the benefits of the Pglass with ultra-low glass transition temperature.

The synthesized nanocomposites were effectively mixed in the carbon crucible by gases produced during the process, resulting in homogeneous dispersion of POSS in the Pglass matrix, showing transparent optical property and improved rheological, mechanical, and thermal properties. While during the extrusion process mechanical force was used to homogeneously mix the TSP-POSS in the Pglass matrix, determining highly porosity due to the function of a foaming agent of POSS. The studies revealed tunable morphology with respect to the amount of POSS and extrusion conditions. 29Si Solid state NMR showed that after extrusion process silanol groups of TSP-POSS are all consumed by condensation reaction, consistent with the result of NMR analysis using the Pglass matrix nanocomposites prepared by sintering process.

The novel approach using POSS molecule which is grafting hydrophobic function groups on the core, are utilized to lead increased hydrophobicity of the glass surface. To mimick a lotus leaf with a combination of roughness and low surface energy, the micro-sized Pglass particle and hydrophobic POSS were used. Contact angle of the obtained surface-modified hydrophobic Pglass showed significant improvement compared to pure Pglass bulk. In addition, Pglass/PET hybrids were successfully prepared using a mixing process. Various characterizations were performed to understand structure-property correlation in the hybrids with respect to amount of Pglass in the PET and experimental conditions. Unique properties of Pglass/PET hybrids are attributed to the plasticizer and nucleation effects of polydispersed Pglass particles as well as the increased interfacial interaction between two components in the hybrids.

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