Date of Award

1-1-2016

Document Type

Thesis

Degree Name

M.S.

Department

Engineering

First Advisor

Maciej Kumosa

Abstract

Single component room temperature vulcanized (RTV-1) silicone based caulk used in high voltage insulators and other applications is frequently subjected to environmental pollutants. Aging of RTV-1 silicone rubber is the result of various stressors, including environmental aging conditions such as UV, acid, and salt exposure from ocean mist. Loss of hydrophobicity due to damage of the hydrophobic methyl groups, as well as loss of mechanical strength due to depolymerization via hydrolysis as a result of aqueous salt exposure were the two main factors of material aging assessed in this work. Multiple RTV-1 formulations were initially assessed for resistance to aging in aqueous salt, with one particular RTV-1 material subsequently chosen for further study in successive aging experiments. 3% NaCl salt solution experiments were conducted to analyze physical, mechanical, and chemical changes. A subsequent but preliminary hypochlorous acid aging experiment was then conducted, with results indicating accelerated RTV aging as a result of super diffusive hypochlorous acid. Comparatively, a molecular dynamics model was developed to analyze salt ion, water, nitric acid, and hypochlorous acid diffusion through the RTV polymer network, indicating hypochlorous acid as super diffusive, chlorine as diffusive, and water as subdiffusive. Conclusively, the experimental and molecular dynamics results provide a method to better understand the impact of contaminants and pollutants on RTV-1 material aging as a product of molecular diffusion.

Provenance

Recieved from ProQuest

Rights holder

Monika Bleszynski

File size

62 p.

File format

application/pdf

Language

en

Discipline

Materials Science, Mechanical engineering

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