Low permeability and self-decontamination are extremely desired features for protective equipment against chemical warfare agents (CWAs). ∼4 nm TiO 2 nanoparticles were synthesized in the porous matrix of MCM-41 (45 wt%) as a novel reactive adsorbent for the degradation of sarin and VX. TiO 2 /MCM-41 (∼520 m 2 /g) was embedded in a polydimethylsiloxane (PDMS) sheet. PDMS was chosen as a model for an air-impermeable barrier with high permeability to CWAs. The incorporation of the reactive adsorbent decreased the diffusion coefficients, increased the breakthrough time, and dramatically decreased the desorption of sarin and VX vapors. The adsorbed CWAs in the hybrid matrix decompose (≥99%) to the nontoxic corresponding acids after 1 and 3 days for VX and sarin, respectively. This study demonstrates, for the first time, the potential of TiO 2 / MCM-41 as a reactive adsorbent embedded in polymeric matrices to improve the protection level and safety of protective equipment via combined adsorption and self-decontamination.

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In this study, a reactive adsorbent filler was integrated into a polymeric matrix as a novel reactive protective barrier without undermining its mechanical, thermal, and chemical properties. For this purpose, newly synthesized TiO2/MCM/polydimethylsiloxane (PDMS) composites were prepared, and their various properties were thoroughly studied. The filler, TiO2/MCM, is based on a (45 wt%) TiO2 nanoparticle catalyst inside the pores of ordered mesoporous silica, MCM-41, which combines a high adsorption capacity and catalytic capability. This study shows that the incorporation of TiO2/MCM significantly enhances the composite’s Young’s modulus in terms of tensile strength, as an optimal measurement of 1.6 MPa was obtained, compared with that of 0.8 MPa of pristine PDMS. The composites also showed a higher thermal stability, a reduction in the coefficient of thermal expansion (from 290 to 110 ppm/°C), a 25% reduction in the change in the normalized specific heat capacity, and an increase in the thermal degradation temperatures. The chemical stability in organic environments was improved, as toluene swelling decreased by 40% and the contact angle increased by ~15°. The enhanced properties of the novel synthesized TiO2/MCM/PDMS composite can be used in various applications where a high adsorption capacity and catalytic/photocatalytic activity are required, such as in protective equipment, microfluidic applications, and chemical sensor devices.

Simple plastic face shields have many advantages compared to regular medical masks. They are easily cleaned for reuse and comfortable to wear. In light of the spreading COVID-19 pandemic, the potential of face shields as a substitution for medical masks, as a recommendation to the general population, was tested. Testing the efficacy of the protective equipment utilized a cough simulator that was carefully tuned to replicate human cough in terms of droplet size distribution and outlet velocity. The tested protective equipment was worn on a manikin head simulating human breathing. An Aerodynamic Particle Sizer (APS) was used to analyze the concentration and size distribution of small particles that reach the manikin head respiration pathways. Additionally, Water sensitive papers were taped over and under the tested protective equipment, and were subsequently photographed and analyzed. For droplets larger than 3μm by diameter, the efficiency of shields to block cough droplets was found to be comparable to that of regular medical masks, with enhanced protection on face parts the mask does not cover. Additionally, for finer particles, of the order 0.3 to few microns, a shield was found to perform even better, blocking about 10 times more fine particles than the medical mask. This implies that for the general population that is not intendedly exposed to confirmed infected individuals, recommending the use of face shields as an alternative to medical masks should be considered.