Student Research: Natasha Johnson
, Industrial Hygiene (IH), 2004
Faculty Advisor: Michael S Morgan
Permeation of Various Glove Materials by a Binary Mixture Under a Temperature Gradient
There are many commercially available gloves, designed to protect the worker from dermal exposure to chemicals. Unfortunately, the all purpose chemical glove does not exist. The ideal glove would be comfortable to wear, tactile, inexpensive and impermeable to all chemicals. A glove may form an effective protective barrier against different solvents as pure compounds, but may not provide adequate protection against a mixture of these solvents.
The goal of this project was to determine steady state permeation rates, and breakthrough times of mixture components as a function of mixture composition through a variety of different glove materials in the presence of a temperature gradient. Preliminary testing was conducted using a single solvent to determine the effect of a temperature gradient on permeation. The temperature gradient was set up to mimic the situation of a worker wearing a glove. The challenge side of the chamber was exposed to room temperature, while the collection chamber was immersed in a waterbath at 34 C (skin temperature). A standard (ASTM F739) test method was followed using a permeation test cell.
The temperature gradient did not have a statistically significant effect on the permeation parameters of breakthrough time and steady state permeation rate, but a consistent pattern of longer breakthrough times and lower steady state permeation rates were observed for cases when the gradient was present compared to when it was absent.
In a binary mixture of toluene and MEK, mixture composition and glove type were the most significant predictors of breakthrough time and steady state permeation rate for both analytes after adjusting for glove thickness. These two variable together with their interaction explained 79.3% to 96.7% of the variability in the above parameters.
As found in other studies, basing glove selection on individual mixture components is not an acceptable practice. Neither nitrile rubber nor butyl rubber were able to provide adequate protection for all mixture compositions. Nitrile gloves should not be used with either toluene of MEK, or any mixture of these solvents when continuous contact may occur for prolonged periods. Butyl rubber is a better choice for use with mixtures of MEK and toluene especially when the mixture is predominately composed of MEK.