Reactive Materials Research for Self-Detoxifying CB Protective Clothing

Transcription

1 Reactive Materials Research for Self-Detoxifying CB Protective Clothing Heidi Schreuder-Gibson U.S. Army Natick Soldier Center Natick, MA

2 Concept Place reactive materials in fabrics that detoxify Contaminants on clothing within hours of exposure. O CH 3 CH 3 N N Cl O HO H 2 COCH 2 O OH CHLORAMINE Bactericide, Agent Decon O n HD Catalyst Modified Cyclodextrins Poly(vinyl)amines CH 2 CH CH 2 CH OH m NH 2 n

3 Approach Chloramides & Quats -Shell Fabric Bio, HD, VX Sporicide and Agent Decon, Water Repellancy POM Catalysts Liner Materials HD Carbon Surfaces Polymer Film Surfaces Nanoparticles Attached to Fabrics, HD, VX Blended into Fibers Particulate Absorbants Reactive Permselective Membranes -Liners G, VX

4 Nanoparticle Reaction Rate Studies Depletion of 2-CEES - In Solution - In Vapor

5 0.35 Solution Depletion of 2-CEES Comparison of Old and New POMs Nanoparticle TiO 2 vs Catalyst 0.3 CEES Remaining (mg) Very reactive catalyst TiO2 New POM Exposure Time (hours)

6 Equilibrium Vapor Adsorption Measurements ADSORBANT % CEES Vapor Uptake Carbon Spheres 56 NanoAl 2 O 3 -PLUS 99 NanoAl 2 O 3 10 NanoTiO 2 17

7 Thermal Desorption GC/MS Sample in Tube

8 Depletion of CEES Formation of Products Mass Spec (Counts) NanoAluminaPLUS Shell Shell+Chloramide Shell+Nano/Chloramide CEES Ethylthio ethanol CEES Oxide Ethyl vinyl Sulfide Diethyl sulfide Oxidation (CEES-OH) (CEES=O) Dehalogenation

9 Some Products from Oxidation Reactions of 2-CEES Chloroethylene Cl-CH=CH Cyclization SO CH 2 -CH 2 CH 2 -CH 2 Thiirane 3.06 S Time-->

10 NMR (HRMAS) Sample preparation SAMPLE Vapor chamber for exposing catalyst to U.S. Army Research, Development & Engineering Command vaporous agent/simulant 4 mm HRMAS rotor for examining small volumes of sample (< 100 µl)

11 4.5 hrs 1 H 1D Spectra Reaction Kinetics CEES Peaks at 2.8 and 2.6 disappear upon vapor exposure to nano-al 2 O hrs 24.6 hrs 27.8 hrs 63.3 hrs 71.4 hrs 94.8 hrs

12 100 Normalized 2-CEES Degradation Kinetics By Solid State NMR % CEES Remainin Alumina Alumina Plus Titania Time (hrs)

13 Rate of CEES Vapor Depletion in HRMAS NMR Studies Rate Activity % CEES/hr mgcees/24hr mgnanoparticle NanoAl 2 O NanoTiO NanoAl 2 O 3 -PLUS * *30 g/m 2 of nanoal 2 O 3 -PLUS needed to meet current protection requirements. 100 g/m 2 of nanotio 2 needed.

14 POM Catalyst Reactions with 2-CEES - POM on Carbon Surface - Effect of Copper Content

15 POM/Carbon Reduces 2-CEES in GC/MS Mass Spec (Counts) New Reaction Products Found CEES Ethylthio ethanol CEES Oxide Ethyl vinyl Sulfide 0 POM POM POM 1Cu POM 2Cu POM 5Cu POM 10Cu Diethyl sulfide

16 Reaction Product from Carbon/POM + 2-CEES Isopropanol+Water Isopropanol

17 Dimer of 2-CEES from Oxidation Reaction OH Dimerization S Cl- S+

18 CEES Vapor Diffusion Studies Thick vs Thin Supported Selectively Permeable Films Reactive PVAM (polyvinyl amine-co-vinyl alcohol) Non-Reactive Nafion, Membrane C, Membrane T

19 Reactive Selectively Permeable Membranes CH 2 CH CH 2 CH Polyvinyl alcohol-co-amine, PVA-Am OH m NH 2 n PVA-Am Film Hydrolyzes DFP, G-agent Simulant PVA-Am Film (Seen by ph indicator). After DFP Vapor Exposure

20 Water Vapor Diffusion Resistance (s/m) Nafion (140 µm) (Thick) Expanded Polytetrafluorethylene (eptfe) (Best) Water Vapor Diffusion Gore-Tex Laminate (Thin, Supported) High Water Vapor Diffusion Resistance Low Polyvinyl Alcohol / Polyvinyl Amine Copolymer (PVA-Am) PVA-Am M12 PVA-Am M6 PVA-Am L6 Mean Relative Humidity PVA-Am L12 (Thick) (Thick) (Thick) (Thick) (Worst)

21 Water Vapor Diffusion Thin, Water Vapor Supported Flux of Membranes Films Water Vapor Flux at 50% RH (g/m2/da Number of Film Layers 2 Nafion M12 MembraneC MembraneT Gore-Tex

22 CEES Vapor Diffusion Thin, Supported Films CEES Vapor Penetration (%). 0 Weatherproof Memb Nafion 1-Layer Nafion 3-Layer Membrane T Membrane C M12 1-Layer 80RH 0RH 50RH 80RH 50RH 0RH 3mg CEES applied M12 2-Layer

23 Conclusions Chloramide-treated fabrics break down 2-CEES in solution and in vapor challenge tests. One of the major by-products was the nontoxic sulfoxide. Other by-products include dimers. Chloramides bound to nanoparticles of alumina were reactive, but not as active as the chloramides alone.

24 Conclusions NanoAl 2 O 3 -PLUS more adsorptive than activated carbon. NMR found that NanoAl 2 O 3 -PLUS depleted 2-CEES at a rate of 0.74 mgcees/mgnanoparticle/day. A fabric weight of 1-33 grams per square meter of NanoAl 2 O 3 -PLUS needed to meet the 1mg/cm2/day protection requirement for clothing systems. 100 gsm of nanotio 2 would be needed for protective fabrics to meet Chemical Protection requirements.

25 Conclusions Carbon-bound POMs faster than free POM in the decomposition of 2-CEES. Carbon-bound POMs can be optimized with Cu to increase depletion of 2-CEES by 7x. Copper-containing POMs completely neutralize 2-CEES in 30 min. Produce CEES-oxide (sulfoxide) product.

26 Conclusions Thin supported PVAM films have high water vapor permeation, similar to commerical permselective membranes C and T. Thin supported Nafion has the highest water vapor permeation. Thin supported Nafion and MembraneC allow CEES penetration above 50RH Thin supported PVAM films and MembraneT block CEES below 80RH.

27 Chloramide Underneath Bio, HD & VX Reactive Fabric System Design Sporicide Water-Repellent SHELL Nanoparticle sandwich Reactive Permselective Liner Quaternary Amine on Top Carbon-Nylon Tricot Knit Scrim

28 Acknowledgements Professor Craig Hill and Dr. Nelya Okun, Emory University for POM Catalysts Gentex Corporation for spherical carbon Reactive Materials Team at Tyndall AFB For Chloramides & Test Data Edgewood NMR Group for MAS Results Erkol, Ltd. for PVAM Polymers Phil Gibson, Joel Carlson, John Walker at Natick