Elastomeric Selectively Permeable MembranesFor Chemical and Biological Protective Clothing

2002 CBC Research Conference Presentation Qtruong Nov 02 espm

Quoc TruongPhysical Scientist

OFFICE SYMBOL: AMSSB-RIP-C(N)COM: (508) 233-5484; DSN: 256-5484 FAX: (508) 233-4994 or 4331 EMAIL: quoc.truong@natick.army.mil

U.S. Army Soldier, and Biological Chemical Command (SBCCOM)Soldier Systems Center (SSC)Natick, MA 01760-5019

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1. REPORT DATE 01 JUL 2003

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4. TITLE AND SUBTITLE Elastomeric Selectively Permeable MembranesFor Chemical andBiological Protective Clothing

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7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) U.S. Army Soldier, and Biological Chemical Command (SBCCOM)Soldier Systems Center (SSC) Natick, MA 01760-5019

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14. ABSTRACT

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Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18

•ADVANCED LIGHTWEIGHT CB PROTECTION PROGRAM (DTO CB-06a-12-D) WAS SUCCESSFULLY COMPLETED IN FY00, WHERE SPM UNIFORMS WERE PREFERRED OVER CURRENT CHEMICAL PROTECTIVE GARMENTS

Accomplishments:Developed and demonstrated SPM garments that are 50% lighter weight than any fielded garment with equivalent or better protection.

Integrated novel closure systems and demonstrated their effectiveness via MIST @ERDEC, @DPG

Conducted field-assessments for field durability and perception of comfort of prototype CB duty uniforms.

•Ft. Lewis, WA with the ManeuverSupport Battle Labs (MSBL)•Pohakuloa and Kaneohe Bases, Hawaiiwith the Marine Corps and Army MSBL

Transition to JPACE, JIG, SOF, and JCBE

Impacts:

Reduced thermal stressReduced logistics burdenIncreased CB agent protectionEliminated dependency on charcoal adsorbent

Chemical Agent Test Results (Cumulative Penetration)

SPM 1 SPM 2 AUIB Gore-Tex® Fabric(20 hrs) (20 hrs) (21 hrs) (4 hrs)

20

15

10

5

0

>40

0.6

3.5

HDTGD

SPM 1: Polyallylamine-Based SPM 2: Cellulose-BasedAUIB: Aircrew Uniform Integrated Battlefield (Carbon loaded foam + Gore-Tex fabric)

µg/cm2

TGD/VX Breakthrough

level

HD Break through

level

1.31.0 < 0.1<0.1

VX

<0.1

Nyl

on F

abri

c

Nor

mex

Pla

in F

abri

c

Bat

tle D

ress

Ove

rgar

men

t(B

DO

)

US

Mar

ine

Cor

ps S

arat

oga

Ove

rgar

men

t N

omex

Pla

in F

abri

c w

ithC

hem

ical

Pro

tect

ive

Und

erga

rmen

t (C

PU

)C

amou

flage

Pri

nted

Nom

exFa

bric

with

CPU

Flu

orop

olym

er-B

ased

Mem

bran

e/Fa

bric

Sys

tem

SP

M2

- C

ellu

lose

-Bas

edPo

lym

er M

embr

ane/

Fabr

icSy

stem

SPM

1 - P

olya

llyla

min

e-B

ased

Mem

bran

e/F

abri

cSy

stem

Shap

e M

emor

y P

olym

erM

embr

ane/

Fabr

ic S

yste

m

0 .0E+00

5.0E+05

1.0E+06

1.5E+06

2.0E+06

2.5E+06

3.0E+06

3.5E+06

Ave

rage

Par

ticle

Cou

n(M

ean

Siz

e: 3

.5 m

icr o

Aerosol Penetration Through Various Fabrics

AEROSOL PROTECTION

SPM 1 JSLIST+BDU

337

99

400

300

200

100

0

Ave

rage

Tot

a l P

rote

ctio

n Fa

ctor

@2h

rs, 1

00 m

g/m

3 M

eS C

halle

nge

JSLIST: Joint Service Lightweight Integrated Suit Technology

SPM 1: Polyallylamine-Based

BDU: Battle Dress Duty Uniform

DPG: Dugway Proving Ground, Utah

MIST: Man-In-Simulant System Vapor Test

DPG MIST Data

VAPOR PROTECTION

In trin s ic W aterV ap o r R es is tan ce

(m 2.P a /W att)

C hem P ak F ab ric II

In trin s ic Th e rm al R es is tan ce

(m 2.K /W att)

C hem pak F ab ric II

C hem ica l P ro tec tive F abric IC hem ica l P ro tec tive F abric IIC hem ica l P ro tec tive F abric III

C hem ica l P ro tec tive F abric IV

C hem pak F ab ric I

C hem P ak F ab ric I

0 .0270 .027

0.0340.063

0 .065

0 .075

7.077.15

9 .1810 .65

12 .5913 .83

E V A PO R A T IV E C O O L IN G PO T E N T IA L S o f S P M s v s. V A R IO U S C B F A B R IC S Y S T E M S

C hem ica l P ro tec tive F abric IC hem ica l P ro tec tive F abric IIC hem ica l P ro tec tive F abric III

C hem ica l P ro tec tive F abric IV

C h em ical Protective F ab rics I-IV : V arious C B Fabric Sy stem s

High Pressure Hydrostatic Resistance

300

275

250

225

200

175

150

125

100

75

50

25

0Hig

h Pr

essu

re H

ydro

stat

ic R

esis

tanc

e, lb

/in2

PerformanceGoal

Semi-permeableFabric(Gore-Tex®)

SPM 1 SPM 2 CarbonLoadedFoam/Fabric

> 35 (Goal*)

*Being Waterproof

LIQUID PROTECTIONREDUCED HEAT STRESS

•Many Tests and Evaluation have been conducted to evaluate SPM fabrics; however, NOISE AND SIZING REMAIN SIGNIFICANT BARRIERS TO OVERCOME.

•Problems: Noise and Sizing

•Capability/Enhancement:

•Reduce/Eliminate multiple size requirement•Conformable Clothing•Reduce logistic concerns, and improved operational readiness•Reduced Noise when “being quiet” is important

StretchablePerm-selectiveMembrane

•Material Concept:

-Multiple sizes

-Many concerns (Costs, Weight, Logistic, Comfort, Mobility, etc.)

-Many variations of chemical protective clothing

Technical Approach --- Prepare dendrimer containing membranes

Dendrimer Packing and Cross

Linking shows reactive binding

polymer molecules for further

filtration efficiency

Blocking efficiency for dendrimers as a function of the density of the peripheral groups.

Experimental Results: Dendrimer containing membranes

ElastomericTo be doneTo be done5. PU dispersions mixed with ICET proprietary polymer

Not elastomeric0WSPC: 0 after 3 hrs

3,000WSPC: 2,000-2,500

4. Self-assembled dendrimer

Elastomeric0WSPC: 0 after 3 hrs

3,000WSPC: 2,000-2,800

3. Incorporate dendrimers in ICET water based proprietary polymer

Elastomeric2,000 – 3,00019,0002. Estane Cross linked dendrimers

Elastomeric10,0002,0001. Estane Coated with dendrimer

Elastomeric10,000 to 20,0001,000 – 2,000Hytrel/Noveon Membrane (Control –2mil thick)

Special NotesTCE Permeation (E96-BW) (g/m2/day)

MVTR (E96-BW) (g/m2/day)

Methods

Natick’s Water/Simulant Permeation Cell (WSPC) Test Results

Method 3. Incorporate dendrimers in ICET water based proprietary polymer

Water/Simulant Permeation Cell (WSPC) Test Results

Method 4. Self-assembled dendrimer

Static Permeation Test Results

Static Moisture Vapor Permeation Data (E96-BW)

1000

2000

19000

3000 3000

19000

2000

0

5000

10000

15000

20000

Control M-1(Method 1) M-2(Method 2) M-3(Method 3) M-4(Method 4) M-5(Method 5)

Material

Flux(g

/m2/da

Static TCE Vapor Permeation Data (E96-BW)

10000 10000

2000

0 0

6000

20000

3000

0

5000

10000

15000

20000

25000

Control M-1(Method 1) M-2(Method 2) M-3(Method 3) M-4(Method 4) M-5(Method 5)

Material

Flux (g/m

2/da

Discussions:Dendrimers are highly hydrophilic and viscous materials. They are very expensive.

The direct coating on elastomers through anchoring by surface interactions

resulted in coatings that never cured.

Direct incorporation of dendrimers into polymeric dispersions results in

tough but flexible membranes.

Using optimal cross-linking of a thin coating appears to over come this

difficulty while dramatically improving the moisture vapor permeation and

dramatically reducing cost of the eventual commercial products.

This could be a preferred way for optimization for achieving better perm-selectivity.

Conclusions:•Extremely thin coating of cross-linked dendrimer were achieved on water vapor

Permeable polyurethane elastomers.

•Such coatings improve water vapor transport properties significantly while

maintaining resistance to organic vapors.

•Further optimization work are underway with ICET, Inc. to develop elastomeric

SPMs for resistance to both polar and non-polar molecules.

Recommendations:•Follow on work will be on developing dendritic polymers cross-linked coatings

where the cross linking agent is flexible PEO segments with reactive end groups

on water vapor permeable polymer materials such as TPU latexes modified

with ICET fillers and formulations

Acknowledgments:

Dr. Shantha Sarangapani, Innovative Chemical and Environmental

Technologies, Inc. (ICET), Norwood, MA for her dedication in working to

Support the US Army Natick Soldier Center’s needs to protect our soldiers in

Various R&D work since 1985.