PERMSELECTIVITY MEASUREMENTS OF ION BEAM MODIFIED BARRIER MEMBRANES FOR IMPROVED CHEMICAL/BIOLOGICAL PROTECTIVE CLOTHING

摘要

Elastomeric materials have commonly been used over the years to provide barrier properties in chemical/biological (CB) protective clothing. One novel approach to reducing the weight of CB protective clothing is based on the use of selectively permeable membranes. The ideal permselective membrane for CB protective garments would provide a high moisture vapor transport rate while providing extremely low to negligible transport rates of hazardous chemicals and biologicals. The goal of the work reported in this abstract is to improve the permselectivity of membranes through the ion beam modification of their surface layers. Measurement of permselectivity was made through a vapor permeation method. A wide variety of untreated and ion beam modified commercially available membrane materials were tested as functions of activity level for water and a number of organic compounds. The variables initially investigated included ion type and irradiation energy level. Irradiation generally decreased permeation of both water and organic compounds, but measurements suggest that the organic compound permeation was decreased to a higher degree, thus increasing permselectivity. This effect is significantly more pronounced in certain modified membrane chemical structures when compared to others. This paper primarily addresses the ion beam modification process and the vapor permeation method utilized to determine permselectivity.