Date of Award

2002

Degree Type

Thesis

Degree Name

M.A.Sc.

Department

Electrical and Computer Engineering

First Advisor

Hackam, R.

Keywords

Engineering, Electronics and Electrical.

Rights

CC BY-NC-ND 4.0

Abstract

The aging characteristics of polytetrafluoroethylene (PTFE) are studied. The effects of salinity and temperature on the surface properties of PTFE are reported. To investigate the phenomenon of the loss and recovery of hydrophobicity, the surface of PTFE was subjected to various wetting conditions. The contact angle is a good indication of hydrophobicity and is used to determine the state of the surface of PTFE. It is observed that the hydrophobicity of PTFE decreased with increasing salinity, temperature and the duration of exposure. The surface free energies due to London dispersion (gammaSD) and hydrogen bonding (gammaSH) forces on the surface of PTFE are calculated from the contact angle measurements using both water and its components. A study is performed to measure the coefficient of diffusion of water into PTFE for different salinities and temperatures. The increase in the weight of PTFE with increasing and methyl iodide. A computer program in "C" has been developed to calculate the surface free energy time of immersion is measured. The recovery of hydrophobicity, after aging, up to 5000 h is studied. The average surface roughness and peak surface roughness is also measured during the aging and correlated with the loss of hydrophobicity. The effect of RF discharges on the hydrophobicity is also investigated. The effect of aging on the ac and dc flashover voltage at 10mS/cm saline solution at 0 +/- 1.5, 22 +/- 4, 44 +/- 2, 73 +/- 2° and 99 +/- 2°C shows a decreasing trend with increasing temperature. The decrease in ac and dc flashover voltage is correlated with the loss of hydrophobicity of PTFE and surface roughness. In order to study the changes due to the loss of hydrophobicity on the PTFE surface, a Fourier transform infrared spectroscopy (FTIR) is carried out from which a mechanism responsible for the loss of hydrophobicity is suggested. Source: Masters Abstracts International, Volume: 40-06, page: 1593. Adviser: R. Hackam. Thesis (M.A.Sc.)--University of Windsor (Canada), 2002.

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