Decontamination of Chemical Warfare Simulants Using Electrospun Media

Abstract

Protective clothing and face masks form the primary line of defense against chemical warfare agents (CWA) for soldiers and also the general public in the event of an emergency. Activated charcoal and charcoal impregnated fabrics are being used to protect from the CWA and are considered to offer the best protection ever. While this perception is unequalled, it is also imperative to consider the significant drawbacks of this material. The foremost disadvantage of activated charcoal is that it does not decontaminate nerve and the mustard agents, which are most frequently used in chemical attacks, but merely adsorbs them. This means the protective material upon exposure to nerve and mustard agents itself forms a contamination threat and calls for careful handling and disposal. Another limitation of equivalent significance is the evaporative impedance offered by the material introducing heat stress and discomfort to the wearers. These two concerns form the motivation for this study. The objective of this research is to understand and to evaluate the detoxification abilities of electrospun nanofibers against chemical warfare agents and assess the possibility of using the electrospun nanofibers as protective membranes in face masks and warfare clothing. Electrospinning was chosen as the method of fabricating the nanofibers as it is a simple and versatile technique with scope for mass production. Moreover, precise control of dimensions and morphology is possible at nanoscale which is not achievable by other techniques that currently exist for this purpose. Membranes from electrospun nanofibers are also known to possess high porosities (upto 80%) and hence breathability (moisture ? vapor exchange) will not be an issue. The study compares the performance of 5 types of electrospun materials viz. a) Functionalized polymer nanofibers, b) Ceramic nanofibers c) Functionalized Carbon nanofibers, d) Polymer nanocomposites with carbon nanoparticles (nanodiamonds) and e) Polymer nanocomposites with metal oxide nanoparticles. To compare the effect of decontamination, simulants of nerve and mustard agents were used. It is also shown that among these 5 different categories of materials, the polymer nanocomposites with metal oxide nanoparticles would be most appropriate for development of protective filters and garments based on breathability and non-selective decontamination nature. In the last part of this work, a modeling approach is shown so as to fabricate reactive filters with the least resistance to breathability using electrospun Polymer nanocomposites with metal oxide nanoparticles that could replace the activated carbon which is currently the gold standard for chemical protection suits and filters.