Evaluation of a simple weight-loss method for determining the permeation of organic liquids through rubber films.
The standard ASTM method for determining permeation of liquid penetrants through polymeric films (F739-85) was compared with a simple weight-loss method. The weight-loss permeation cell was constructed of off-the-shelf components, a conventional analytical balance was used to measure the weight loss, and a chamber with continuous ventilation was used to hold the cell at constant temperature and evacuate the permeating penetrant. The advantages and limitations of the weight-loss method were illustrated by using data obtained from the permeation of acetonitrile, n-hexane, and methanol through films of four acrylonitrile-butadiene copolymers. The steady-state flux obtained by using the weight-loss method gave results statistically equivalent to the more analytically complex ASTM standard method. The weight-loss method required the experimenter to monitor the weight of the cell and its contents over time to obtain the steady-state flux whereas the ASTM method required the experimenter to chemically analyze for the penetrant concentration in the effluent gas stream as a function of time. The ASTM method required more analytical skill and training and more costly analytical equipment than did the simple weight-loss method. The weight-loss method needs further improvement and validation but shows promise even in its present form. By using the weight-loss method, the potential exists for far more chemical protective clothing users to conduct their own low-cost permeation testing as an initial screening to determine the relative permeation performance of candidate protective clothing materials. The weight-loss method is not meant to replace the standard ASTM method but to supplement it as a screening test.
Mickelsen
R L
RL
National Institute for Occupational Safety and Health, Division of Safety Research, Morgantown, WV 26505.
Hall
R C
RC
Chern
R T
RT
Myers
J R
JR
D005069:Evaluation Studies as Topic; D015386:Hazardous Substances; D006801:Humans; D009787:Occupational Medicine / Q000379:methods*; D011108:Polymers; D011481:Protective Clothing / Q000592:standards*
D015386:Hazardous Substances; D011108:Polymers