Date on Master's Thesis/Doctoral Dissertation

8-2006

Document Type

Master's Thesis

Degree Name

M.S.

Department

Chemical Engineering

Committee Chair

Starr, Thomas L.

Subject

Elastomers

Abstract

Elastomer degradation when exposed to chloraminated potable water is dependent on a number of poorly understood factors. Temperature and chloramine concentration are both believed to play roles, however, they have not been adequately defined. In order to estimate the material performance and predict the service life of elastomeric parts, knowledge of degradation modes, rate constants of the aging process and their activation energies is useful. EPDM elastomers are used in numerous applications which require resistance to ozone attack and weather due to their stable, saturated polymer backbone structure. Accelerated aging experiments were conducted on both EPDM - S and EPDM - P at three concentration levels and temperatures. Tensile properties are used to study the extent of degradation through a 30-day aging period which are used to estimate the crosslink densities of both the materials. A rate expression is developed based on the rate of change in cross link densities. The rate constants are estimated and they are used to estimate the activation energies and frequency factors using an Arrhenius relationship.

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