Polymer systems can absorb and subsequently reemit various toxic chemicals as a vapor. This is a significant challenge for polymers exposed to chemical warfare agents that people may interact with after contamination.  The absorption and vapor emission processes are specific to the chemistry of the chemical and polymer systems.  Chemical warfare agent simulants are often used for environmental testing in place of the highly toxic agents.  Therefore, there is a need to understand the relationships across chemicals for transport into and out of materials.  To prevent negative health effects resulting from exposure to the chemicals emitted by these polymers into the atmosphere, there is also a need to understand the decontamination of these chemicals from polymers.  To reduce exposure, the decontaminant must access the absorbed chemicals and consider the surface and subsurface transport and reactivity. This work sets the foundation for modeling liquid-phase decontamination of absorbing polymeric materials with the focus on determining relationships between agents and simulants.  The correlations of agents to simulants must consider the three way interactions in the chemical-material-decontaminant system where transport and reaction occur in polymer materials.  To this end, diffusion modeling of the subsurface transport of simulants (e.g., chloroethyl phenyl sulfide, methyl salicylate) and live chemical warfare agents (e.g., Bis (2-chloroethyl) sulfide [mustard gas], O-ethyl S-[2-(diisopropyl-amino)ethyl] methylphosphonothioate [VX], and O-Pinacolyl methyl-phosphonofluoridate [soman]) was conducted for various polymer systems (e.g., polyurethane paint coatings, silicone elastomers).  The models utilized 1D and 2D finite difference diffusion and reaction models to simulate absorption and reaction in the polymers, and subsequent vapor flux of the chemicals out of the polymers.  Experimental vapor flux measurements were used to determine model parameters.  Through modeling, an understanding of the surface and subsurface chemistry relationship of simulant to live chemical warfare agent was established.

Modeling the transport of chemical warfare agents and simulants in polymeric substrates to predict vapor exposures

248th National Meeting (2014)

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