Predicting temperature effects on chemical protective clothing permeation.

Abstract

Although the polymer literature contains many references to the effects of temperature on diffusion coefficients of gases and vapors, little attention has been paid to the effect of temperature on permeation of liquids in either the polymer or industrial hygiene literature. Nevertheless, it is an important problem in the selection and use of chemical protective clothing (CPC) because most permeation tests are conducted at 20-25 degrees C, but actual polymer/solvent systems are often at higher temperatures in field use. A simple relationship between temperature and permeation rate does not exist; this may be the reason that little effort has been made at factoring temperature into CPC selection and use. In this study, five polymer/solvent systems were tested at 25, 37, and 50 degrees C. An Arrhenius relationship was used to relate temperature and permeation for these and 11 other data sets from the literature. Constants from the Arrhenius equations were calculated with excellent correlation and were used to construct equations for estimating temperature effects. With knowledge of steady-state permeation rate or breakthrough detection time at 25 degrees C and thickness for any polymer/solvent combination, the equations allow one to predict a new permeation rate or breakthrough detection time at any other temperature within a range of approximately 25-65 degrees C.