Important Experimental Parameters for the Nitrogen Dioxide Permeation Testing of the Propellant Handler's Ensemble Coverall Material

摘要

We reviewed a NASA and an Air Force permeation test procedure and found them to be inadequate for their intended purpose of being standards for inter-laboratory comparison of the permeation resistance of material samples. In order to evalute the importance of the various experimental parameters that were neither defined nor controlled by these earlier test specifications, we developed a new permeation test apparatus and procedure and applied them to the evaluation of the experimental parameters and several coverall materials. In this report we describe a test apparatus and detailed procedure for carrying out reproducible conditioning of material samples by controlled exposure to known volumes of liquid hypergols at a well-defined temperature as well as subsequent quantitative permeation testing of the conditioned samples under conditions of controlled temperature, absolute pressure, differential pressure, and equivalent concentration of dinitrogen tetroxide vapor (N204). We applied this apparatus to the nitrogen dioxide (NO2) permeation testing of three materials: the E.I. du Pont de Nemours chlorobutyl material currently used in the construction of the rocket fuel handler's clothing outfit (RFHCO) the du Pont cholorobutyl material proposed for use in the Propellant Handler's Ensemble (PHE), and the ILC Dover chlorinated polyethylene material currently used in the Chemturion (CHEM) protective ensemble. Both the RFHCO and PHE coverall materials resisted No2 permeation for more than 60 min under all test conditions that were investigated.