Date of Award

1984

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Abstract

A unique film badge design in which a reagent 10,10'-dimethyl-9,9'-biacridylidene (DBA) is dissolved homogeneously in a gas-permeable, silicone-polycarbonate copolymer film, was evaluated. The ambient concentration of ozone can be determined from its reaction with DBA. The disappearance of DBA upon ozonolysis can be monitored at 4300 (ANGSTROM) without extraction or desorption from the polymer membrane. Unlike other reagents for ozone determination, DBA is specific for ozone. Interferences from nitrogen dioxide and sulfur dioxide are less than 1%. Prior to this experimental work, a mathematical diffusion model was developed to predict the response of such a device to a given pollutant dose. This model predicted a response which varies as the square root of pollutant dose. The experimental work confirms the mathematical model. In the framework of the diffusion model, it is possible to calculate the intrinsic permeability of ozone in a polymer. The value of the intercept in a plot of the square root of twice the permeability against membrane thickness, extrapolated to zero thickness, is taken to be the intrinsic permeability of ozone.

Pages

232

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