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MTL TR 92-58 



AD-A256 844 ad 



FLAMMABILITY CHARACTERISTICS OF 
FIBER-REINFORCED EPOXY COMPOSITES FOR 
COMBAT VEHICLE APPLICATIONS 


DOMENIC P. MACAIONE 

POLYMER RESEARCH BRANCH 


DTIC 



ELECTE 
NOV 6 1992 




August 1992 


Approved for public release; distribution unlimited. 



MATERIALS TECHNOLOGY LABORATORY 


92-28895 

_..... ■•ii* (till till 111 



U.S. ARMY MATERIALS TECHNOLOGY LABORATORY 
Watertown, Massachusetts 02172-0001 


92 11 04 059 




The findings in this report are not to be construed as an official 
Department of the Army position, unless so designated by other 
authorized documents. 

Mention of any trade names or manufacturers in this report 
shall not be construed as advertising nor as an official 
indorsement or approval of such products or companies by 
the United States Government. 


DISPOSITION INSTRUCTIONS 


Destroy this reoort vyhen it n no onger needed. 
Oo not return it to the originetor 






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REPORT DOCUMENTATION PAGE 

READ INSTRUCTIONS 

BEFORE COMPLETING FORM 

1. REPORT NUMBER 2. GOVT ACCESSION NO. 

MTL TR 92-58 

3. RECIPIENT'S CATALOG NUMBER 

4. TITLE (and Subtitle) 

5. TYPE OF REPORT & PERIOD COVERED 

FLAMMABILITY CHARACTERISTICS OF FIBER- 
REINFORCED EPOXY COMPOSITES FOR COMBAT 

Final Report 

VEHICLE APPLICATIONS 

6 PERFORMING ORG. REPORT NUMBER 

7. AUTHOR^) 

8. CONTRACT OR GRANT NUMBERS 

Domenic P. Macaione 


9. PERFORMING ORGANIZATION NAME ANO ADDRESS 

U.S. Army Materials Technology Laboratory 

Watertown, Massachusetts 02172-0001 

SLCMT-EMP 

10. PROGRAM ELEMENT. PROJECT, TASK 

AREA & WORK UNIT NUMBERS 

D/A Project: 16263102D071 

11. CONTROLLING OFFICE NAME AND ADDRESS 

U.S. Army Laboratory Command 

12. REPORT DATE 

August 1992 

2800 Powder M.ll Road 

Adelphi, Maryland 20783-1145 

13. NUMBER OF PAGES 

18 

14. MONITORING AGENCY NAME & ADDRESS (if different from Controlling Office) 

15. SECURITY CLASS, (of this report) 


Unclassified 


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SCHEDULE 

16 DISTRIBUTION STATEMENT (of this Report) 


Approved for public release; distribution unlimited. 


17. DISTRIBUTION STATEMENT (of the abstract entered in Block 20, if different from Report) 

18. SUPPLEMENTARY NOTES 

19. KEY WORDS (Continue on reverse side if necessary and identify by block number) 


Composite materials 

Fire resistance 

Polymers 


20. ABSTRACT (Continue an reverse side if necessary and identify by block number) 


(SEE REVERSE SIDE) 


nn FORM A M-m EDITION OF 1 NOV 65 IS OBSOLETE 

UD 1 JAN 73 1473 

_ UNCLASSIFIED _ 


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Block No. 20 

ABSTRACT 


The use of composites in U.S. Army systems as a means of decreasing weight and 
enhancing survivability, without reducing personnel safety, has been considered for some 
time. The U.S. Army Materials Technology Laboratory (MTL) successfully demonstrated 
in an earlier program that a ground vehicle turret could be fabricated from fiber-rein¬ 
forced composite material. TTiis technology was successfully extended to the fabrication 
of a composite vehicle hull in an earlier phase of the current program. 

Organic polymers are one of the major constituents of fiber-reinforced composites. 
As components of military systems these materials are expected to survive combustion 
and pyrolysis processes associated with fires. It is, therefore, necessary to develop an 
understanding of the flammability behavior of composite materials in the early design 
stages of a military vehicle such as the Composite Infantry Fighting Vehicle (CIFV), the 
Advanced Systems Modification (ASM), or any future U.S. Army combat vehicle. 

The present study attempts to characterize the flammability behavior of composite 
materials associated with Phase III of the CIFV Hull Program in terms of accepted fire- 
resistant material evaluation parameters. 


1MCLASSIE1EI1 


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CONTENTS 


Page 


INTRODUCTION.. . . 2 

EXPERIMENTAL 

Thermal Analysis .2 

Oxygen Index.. 

Temperature Dependence of Oxygen Index.2 

Smoke Density Measurements.2 

Pyrolysis-Gas Chromatography/Mass Spectrometry. 3 

RESULTS 

Thermal Analysis .. 

Oxygen Index/Temperature Dependence of Oxygen Index.5 

Smoke Density Measurement. 5 

Pyrolysis-Gas Chromatography/Mass Spectrometry.7 

DISCUSSION. . 

CONCLUSIONS. . 

ACKNOWLEDGMENTS. is 




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INTRODUCTION 


Fiber-reinforced composite materials are used extensively because of their physicochemical 
properties and their high strength/weight ratio. The use of composites in U.S. Army systems as 
a means of decreasing weight and enhancing survivability, without reducing personnel safety, has 
been considered for some time. The U.S. Army Materials Technology Laboratory (MTL) has 
successfully demonstrated in an earlier program 1 * 3 4 5 that a ground vehicle turret could be fabricated 
from fiber-reinforced composite material. That technology was subsequently applied to the 
fabrication of a composite hull for the Composite Infantry Fighting Vehicle (CIFV). 2,3 

Organic polymers are one of the major constituents of fiber-reinforced composites. As 
components of military systems these materials are expected to survive combustion and pyrolysis 
processes associated with fires. It is, therefore, necessary to develop data, and an understanding 
of the flammability behavior of composite materials, in the early design stages of a military vehi¬ 
cle such that assessments can be made of potential hazards and the type of protection that may 
be required. This report describes the results of a study on fiber-reinforced epoxy composite 
materials (see Table 1) which was undertaken to quantify data and gain an understanding of the 
processes associated with combustion, pyrolysis, fire propagation, and fire extinguishment. 


Table 1. CANDIDATE COMPOSITE MATERIALS 


Sample No. 

Fiber/Resin 

Ratio 

Comments 

MTL #6 

S2/Epoxy 

65/35 

Ferro Corp. CE-321R 

MTL #7 

S2/Epoxy 

65/35 

ICI-Fiberite MXB 7701 

MTI #8 

S2/Epoxy 

65/35 

American Cyanamide CYCOM 5920 (X920) 


NOTE: Fiber-reinforced composites for Phase II, MTL #1 through #5, were characterized and reported earlier. 4 - 5 


In the study, laboratory scale techniques were used to quantify the following: thermal 
response by thermal analysis techniques, ease of ignition by oxygen index and its dependency on 
temperature, smoke generation by smoke density (SD) measurement, and pyrolysis effluent 
composition by pyrolysis-gas chromatography/mass spectrometry (GC/MS). Simultaneously, an inde¬ 
pendent evaluation of the same composite materials was initiated by Factory Mutual Research 
Corporation (FMRC), under contract to MTL, to further define the flammability characteristics of 
fiber-reinforced composite materials by laboratory methods unique to that organization. 

At FMRC the composite material test specimens will be evaluated in terms of critical heat 
flux (the minimum heat flux at or below which there is no ignition), thermal response of the ma¬ 
terial expressed in terms of ignition temperature, thermal conductivity, density, specific heat, heat 
of gasification, chemical heat of combustion and its convective and radiative components, lire 
propagation rate, yields of various chemical compounds (c.g., CO, CO* total gaseous hardrocarbon. 
soot particulates), and optical properties of smoke, flame radiative heat flux (expected in large 
scale fires), and flame extinction using Halon 1301. The results of that evaluation will be re¬ 
ported by FMRC in a technical report prepared for MTL at the conclusion of the contract. 

1. SULLIVAN, F. R. Reinforced Plastic Turret for M2IM3. FMC Corporation Final Report, Contract DAAG46-83-C-0041, U. S. Army Materials 
Technology Laboratory, MTL TR 87-39, August 1987. 

Z WEERTH, D. E Composite Infantry Fitting Vehicle (CIFV) Progam ■ Phase I. FMC Corporation Interim Report, Contract DAAL04-86-C-0079, 
U.S. Army Materials Technology Laboratory, MTL TR 89-23, March 1969. 

3. PARA, P. R Composite Infinity Fitting Vehicle (CIFV) Progam - Phase II. FMC Corporation Interim Report, Contract DAALM-86-C-0079, 

U.S. Army Materials Technology Laboratory, MTL TR 91-34, September 1991. 

4. MACAIONE, D. P. Flammability Characteristics of Fiber-Reinforced Composite Materials for the Composite Infamy Figuring Vehicle. U.S. Army 
Materials Technology Laboratory, MTL TR 90-45, September 1990. 

5. TEW ARSON, A. Characteristics of Fiber-Retnfonoed Composite Materials. Factory Mutual Research Corporation, TR JI0P2N1.RC070( A), June 1990. 


I 









EXPERIMENTAL 


Thermal Analysis (TGA, OTG, 10) 

A thermogravimetric analysis (TGA) system, consisting of a TA Instrument 9900, computer 
controlled, thermal analyzer, and 951 TGA module was employed to determine sample mass 
loss as a function of temperature in a flowing gas atmosphere (air or helium) as appropriate at 
a preset flow rate of 100 cc/min. Experiments were conducted in both the dynamic and isother¬ 
mal mode. The resultant data indicates the thermal stability of the material being examined. 

In general, materials that are thermally stable are less flammable than those that are thermally 
labile, since the concentration of low molecular weight combustible fragments is decreased at 
any given temperature up to the point where major decomposition of the material occurs. 

The isothermal decomposition experiment is a variation of the dynamic TGA measurement 
described above. The same apparatus is employed with the same atmosphere existing within 
the apparatus; however, in this experiment the thermal level is fixed and the change in sam¬ 
ple mass is recorded as a function of time. The experimental results indicate the ability of 
the test specimen to withstand a sudden exposure to elevated temperatures at preset levels. 

Oxygen Index (Ol) 

As a measure of susceptibility to ignition, values of OI were determined for the compos¬ 
ite material specimens employing a Stanton-Redcroft FTA Oxygen Index apparatus. Speci¬ 
mens were evaluated according to the provisions of ASTM D 2863. The results indicate the 
minimum concentration of oxygen that is required by the material being examined to sustain 
equilibrium combustion. Materials with low oxygen indices (21% or less) can be expected to 
burn readily in normal atmospheric conditions. Materials with moderate oxygen indices (from 
21% to 27%) may be expected to ignite, with some increasing difficulty, and to self-extinguish 
upon removal of the flame source or in normal atmospheric oxygen concentration. 

Temperature Dependence of Ol 

To evaluate the change in OI as a function of temperature, a series of experiments for 
each material was conducted with a Stanton-Redcroft HFTA apparatus. With this system it 
was possible to repeat the OI determination with the test specimen at temperatures between 
ambient and 300°C. The results indicate the change in oxygen requirements to sustain com¬ 
bustion of the sample as the exposure temperature is allowed to increase. By determining 
the OI at several temperature levels it is possible to plot a profile of the change in ignition 
behavior of the material as OI versus T. 

Smoke Density (SD) Measurements 

To determine the SD values for each material, measurement of smoke generation was con¬ 
ducted in an NBS Smoke Chamber. Specimens were evaluated in smoldering and flaming 
modes according to the provisions of ASTM E 662. In the smoldering mode the test speci¬ 
men is subjected to the thermal energy of a precalibrated electric heating element adjusted 
such that the sample surface receives 2.5 watt/sq. cm, at which level the surface temperature is 
approximately 350°C. In the flaming mode the smoldering conditions are augmented with a six- 
jet propane burner oriented to impinge flame on the lower portion of the test specimen. The 
SD value is determined by the decrease in light transmission as measured by a photometer. 
Values of optical density are quoted, as appropriate, with larger values indicating more 
smoke produced by the sample being tested. 


2 



Pyrolysis-Gas Chromatography/Mass Spectrometry (GC/MS) 


To evaluate pyrolysis effluent composition samples of approximately 2 mg mass were pyro- 
lyzed in flowing helium using a Chemical Data Systems (CDS) platinum coil pyrolysis probe, set 
at 900°C, controlled by a CDS Model 122 Pyroprobe in normal mode. Effluent components 
were separated on a 12 meter fused capillary column with a cross-linked 5% phenyl, 95% methyl- 
siioxane stationary phase. The GC column was temperature programmed from -50°C to 350°C. 
Component identification was accomplished with a Hewlett-Packard Model 5995C low resolution 
quadrupole GC/MS system. Data acquisition and reduction was accomplished using a Hewlett- 
Packard Model 1000 E-series computer running revision E RTE-6/VM software. 

RESULTS 


Thermal Analysis 

Data representative of the dynamic thermogravimetric analysis experiments are presented 
in Table 2. Graphic plots of mass loss as a function of temperature are shown in Figure 1. 
Presentation in this format permits direct comparison of experimental results. 

Table 2. THERMOGRAVIMETRIC ANALYSIS RESULTS 


Sample No. 

Temperature 

ro 

Event/Condition 

Wt.(%) 

MTL #6 

Amb-200 

Steady State 

0.0 


200-500 

Mass Loss 

21.5 


500 - 800 

Mass Loss 

14.5 


900 

Steady State 

64.0 

MTL #7 

Amb-200 

Mass Loss 

0.5 


200-500 

Mass Loss 

25.5 


500 - 800 

Mass Loss 

12.0 


900 

Steady State 

62 0 

MTL #8 

Amb-200 

Steady State 

0.0 


200-500 

Mass Loss 

21.0 


500 - 800 

Mass Loss 

10.0 


900 

Steady State 

69.0 


Data representative of the results of isothermal decomposition experiments are presented 
in Table 3. A graphic plot of mass loss as a function of time for one of the composite speci¬ 
mens, MTL #7, is shown in Figure 2. 

Table 3. ISOTHERMAL DECOMPOSITION PERCENT MASS LOSS DURING FIVE MINUTE EXPOSURE 


% Residue 


Sample No. 

300° C 

400°C 

500° C 

500°C 

MTL #6 

1.0 

12.0 

29.5 

70.5 

MTL #7 

3.0 

19.0 

27.0 

73.0 

MTL #8 

1.0 

21.0 

28.0 

72.0 





Nalght 



Figure 1. Dynamic thermogravimetric analysis, MTL #6, #7, and #8. 



Figure 2. Isothermal decomposition erf glass fiber-reinforced epoxy resin MTL #7. 


4 





Oxygen Index (OI)/Temperature Dependence of 01 

The results of experimental determination of the OI and the temperature dependence of 
OI are presented in Table 4. Graphic plots are shown in Figure 3. 


Table 4. THE OXYGEN INDEX AND TEMPERATURE 
DEPENDENCE OF OXYGEN INDEX 


Temperature 

TO 

MTL #6 

MTL #7 

MTL #8 

25 

38 

50 

43 

100 

43-44 

59-60 

54-55 

200 

34-35 

49-50 

47-48 

300 

17-18 

24-25 

27-28 



TEMPERATURE (O 

Figure 3. Temperature dependence of 01, MTL #6, #7, and #8. 


Smoke Density (SD) Measurement 

Table 5 contains the results of SD measurements made with samples of MTL #6 through 
#8. A representative graphic plot of smoke generation as a function of decreasing light 
transmission is shown in Figure 4. 


5 









Table 5. SMOKE DENSITY OF S2/EPOXY COMPOSITES 



Smoldering 

Flaming 

MTI #6 - FERRO CE 321R S2 Glass/Epoxy 

Time to Ds = 16 

6 - 7 min. 

1 - 2 min. 

Time to Ds = 264 

11-12 min. 

2 - 4 min. 

Maximum Density 

600 - 700 

600 - 700 

SD/g 

120-140 

92-108 

MTL #7 - ICI-Fiberite MXB 7701 S2 Glass/Epoxy 

Time to Ds = 16 

2 - 3 min. 

1 - 2 min. 

Time to Ds = 264 

4 - 5 min. 

1 - 2 min. 

Maximum Density 

> 700 

> 700 

SD/g 

> 135 

> 113 

MTL #8 - American Cyanamid CYCOM 5902 S2 Glass/Epoxy 

Time to Ds = 16 2-3 min. 

1 - 2 min. 

Time to Ds = 264 

4 - 5 min. 

2 - 3 min. 

Maximum Density 

400 - 630 

600 - 740 

SD/g 

40-63 

81 -100 


Notes: (1) Time to Ds = 16 is the time required to reach 75% light transmission. Time to Ds = 264 is the time 
required to reach 1% light transmission, (2) Test specimen surface temperature in smoldering mode is 350°C (662°F), 
(3) SD/G = smoke density/gram = Dm(corr)/unit mass of sample. 



6 











Pyrolysis-Gas Chromatography/Mass Spectrometry (GC/MS) 


The results of pyrolysis-GC/MS experiments performed as a means of assessment of pyroly¬ 
sis effluent composition are shown in Tables 6 through 8 and Figures 5 through 7. Pyrolysis 
was performed at 900°C, in helium, because an oxidative atmosphere is not compatible with 
the analytical system at the present time. A total of 25 or 26 separated/identified constitu¬ 
ents was obtained from each of the three composites. Many compounds appeared to be con¬ 
stituents of more than one resin formulation which is not unexpected. 

Table 6. PYROLYSIS-GAS CHROMATOGRAPHY/MASS SPECTROMETRY 
OF MTL #6, FERRO CE 321R; 900°C IN HELIUM 


1. Carbon Dioxide 

2. Propene 

3. Ethylene Oxide 

4. Bromomethane 

5. Propenal 

6. Acetone 

7. 2-Butanone 

8. Water 

9. 2-Propenyl ester of Acetic Acid 

10. Toluene 

11. Benzofuran 

12. Phenol 

13. Methylphenol 

14. Bromophenol 

15. Methylphenol 

16. Methylbenzofuran 

17. Dimethylphenol 

18. Ethylphenol 

19. Dimethylbenzofuran 

20. Isopropylbenzene 

21. Methoxy styrene 

22. Dibromophenol 

23. Bromo-t-butylbenzene 

24. Dichloroaniline 

25. Dichloroquinoline 






Table 7. PYROLYSIS-GAS CHROMATOGRAPHY/MASS SPECTROMETRY OF 


MTL #7, ICI-FIBERITE MXB-7701; 900°C IN HELIUM 

1 . 

Carbon Dioxide 

2. 

Propene 

3. 

Ethylene Oxide 

4. 

1,3-Butadiene 

5. 

Bromoethane 

6. 

Propenal 

7. 

Acetone 

8. 

Water 

9. 

Propenol 

10. 

2-Propenyl ester of Acetic Acid 

11. 

2-Methyl-2-Propenoic Acid, Methyl ester 

12 . 

Toluene 

13. 

Benzofuran 

14. 

Phenol 

15. 

Methylphenol 

16. 

Bromophenol 

17. 

Methylphenol 

•18. 

Methylbenzofuran 

19. 

Ethylphenol 

20. 

Isopropylphenol 

21. 

Methoxy styrene 

22. 

Dichloroaniline 

23.- 

24 Dichloroquinonne 

25. 

Hydroxyphthalic Acid 

26. 

4-{1 -Methyl-1 -Pheny lethyl)Phenol 


8 







Table 8. PYROLYSIS-GAS CHROMATOGRAPHY/MASS SPECTROMETRY OF MTL #8, 
AM-CY CYCOM 5920; 900°C IN HELIUM 


1 . 

Carbon Dioxide 

2. 

Propene 

3. 

1,3-Butadiene 

4. 

Bromoethane 

5. 

Propenal 

6 . 

Acetone 

7. 

Water 

8. 

Benzene 

9. 

2-Propenyl ester of Acetic Acid 

10. 

Toluene 

11. 

Xylenes 

12. 

Styrene 

13. 

Isopropylbenzene 

14. 

1 -Propenylbenzene 

15. 

Benzofuran 

16. 

Phenol 

17. 

Methylphenols 

18. 

Bromophenol 

19. 

Methylbenzofuran 

20 

Ethylphenoi 

21. 

Dimethylbenzofuran 

22 

Isopropylphenol 

23. 

Methoxy styrene 

24. 

Dibromophenols 

25. 

Hydroxyphthalic Acid 


9 








* 

m 




10 


Figure 5. Pyrolysis-gas chromatography/mass spectrometry of epoxy-glass composite, MTL #6. 























12 











DISCUSSION 


The results of the dynamic thcrmogravimetric analysis experiments, presented in Table 2 
and Figure 1, demonstrate that composite samples MTL #6 through MTL #8 sustain little, if 
any, thermal damage below 200°C (392°F). The major mass loss occurs between 200°C and 
800°C (392°F and 1472°F) due to decomposition of the matrix resin. In all compositions the 
maximum rates of mass loss occur at two temperatures; initially, 350°C (662°F) and again at 
approximately 525°C (977°F). 

The results of the isothermal decomposition experiments, presented in Table 3 and Figure 2, 
illustrate the response of the composites when suddenly exposed to temperatures in the 300°C to 
500°C (572°F to 932°F) region. Although most of the thermal damage to the composites occurs 
within the first five minutes at the higher temperatures, the results demonstrate that the material 
will withstand a temperature of 300°C (572°F) quite successfully for a longer period of time. 

The results of the experimental determinations of 01 and the temperature dependence of 
01, ?.s shown in Table 4 and Figure 3, indicates the degree of resistance to ignition and sus¬ 
tained combustion exhibited by MTL #6 through MTL #8. To keep the results in perspec¬ 
tive, it should be remembered that normal atmosphere contains 21% oxygen. Therefore, any 
material whose OI is equal to, or less than, 21% would be expected to ignite and burn under 
normal atmospheric conditions. Materials whose OI is greater than 21%, but less than 26%, 
will ignite with more or less difficulty but would most probably self-extinguish upon removal 
of the flame source. Materials with oxygen indices greater than 27% would not be expected 
to ignite under normal conditions. Thus, it is not likely that any material examined in this 
evaluation would ignite under normal atmospheric conditions. 

The importance of the temperature dependence data is realized when one considers that 
in a fire the thermal environment of a material will normally elevate due to the combustion 
of surrounding structures. The behavior of the material under examination, at elevated tem¬ 
peratures, then becomes important. In general, the oxygen requirement for sustained combus¬ 
tion will decrease as the temperature of a material increases; i.e., the OI decreases. When 
the OI falls to the level of oxygen present, at a given temperature, a flashover will occur and 
the material will combust. The overall fire load will be increased to the degree that new 
combustible material becomes involved. 

If wc consider the data shown in Table 4 at temperatures between 100°C and 300°C 
(212°F and 572°F) one can be certain that composite MTL #6 would sustain combustion at 
300°C (572°F) and beyond. MTL #7 and #8 would have to reach a temperature in excess 
of 300°C (572°F) in order to sustain combustion since their OI values arc somewhat higher 
at that temperature level. The increase in OI of composites MTL #6 to #8 in the 100°C 
(212°F) region is behavior similar to that noted earlier 6 with other polymers. 

The smoke generation characteristics of MTL #6 to #8 are presented in Table 5 and 
a representative data plot is shown in Figure 4. Data for time to Ds = 16 indicates the 
amount of time available before it would be difficult to locate an escape route on the order 
of 10 feet away. Time to Ds = 264 indicates the time before a light transmission level is 
reached where vision is no longer possible. The value of maximum optical density (Dm) 
obtained can be used as a general indicator of the smoke generation classification of the 
material under evaluation. The order of magnitude values would be: 

6. MACAIONE, D. P. Flammability Characteristics of Some Epoxy Resins and Composites. U.S. Army Materials Technology Laboratory 
AMMRC TR 83-53. September 1983. 


13 






• Low Smoke Generation — Dm = < 200 

• Moderate Smoke Generation — Dm = 200 - 450 

• High Smoke Generation — Dm = > 450 

The exact numerical values may be academic once a value of Dm = 264 is exceeded; 
however, the maximum SD does indicate the relative smoke load produced by each 
material. 

Perhaps a more instructive parameter is the value of SD per gram (SD/G) because it pro¬ 
vides a direct relationship between a quantity of material and the level of smoke generation. 
Of the materials evaluated in this study, MTL #8 produced the lowest value of SD/G. The 
value of time to Ds = 264 was, at least in smoldering mode, shorter by a factor of two for 
MTL #8 when compared to MTL #6. Under these conditions, valuable escape time would 
be lost during a fire. 

Attempts to evaluate the toxicity of combustion effluent from burning organic materials 
have resulted in an ongoing debate within the fire science community. Apart from the fact 
that the thermal environment of a fire produces a complex set of reaction conditions that 
may seldom be duplicated in any two successive events, the combustion of organic material 
will always produce carbon monoxide and carbon dioxide, in large quantity, in addition to all 
of the other species produced. For these reasons we have elected to take an instrumental 
approach to evaluating the potential toxicity of combustion effluent generated by organic 
materials. The experimental results obtained can then be reviewed for the presence of 
particularly hazardous species. 

Within this context, the data presented in Tables 6 to 8 and Figures 5 to 7 indicate 
that the components of the effluent resulting from the pyrolysis of MTL #6 to #8 are 
quite similar. In fact, of the 25 or 26 compounds detected in the pyrolysis effluent of these 
composites, nearly half of them are found in all three specimens. No halogen acids (HC1 or 
HBr), nor HCN, were detected in the effluent under our reaction conditions. 

CONCLUSIONS 

The fire survivability of a U.S. Army combat vehicle and crew has been a major concern 
and obstacle to the general application of structural composites by the military. An under¬ 
standing of the flammability behavior and overall fire tolerance of organic materials is crucial 
to the proper selection of materials which must occur in the initial stage of vehicle design. 

The study described in this report was undertaken to assess the flammability characteris¬ 
tics of fiber-reinforced epoxy composite materials in view of their potential application in com¬ 
bat vehicle systems. Three fiber-reinforced composite compositions were evaluated. Considering 
the potential hazards due to fire and the generation of heat and combustion products the re¬ 
sults indicate that these would most probably be limited to the ignition zone. The perfor¬ 
mance of the composites evaluated, although acceptable, could be enhanced by co-curing an 
outer layer of phenolic composite; e.g., MTL #5, to the basic epoxy material which would 
function as a structural core. 


14 





Based upon the results obtained in this investigation it has been shown that a military 
vehicle fabricated from these fiber-reinforced composite materials would not represent an 
unusual fire hazard solely by virtue of its construction and that composites such as the ones 
examined in the current study would most likely respond in such a manner as to increase the 
fire survivability of the system. 


ACKNOWLEDGMENTS 

The author gratefully acknowledges the technical assistance of Mr. David A. Bulpett who 
conducted the pyrolysis-GC/MS experiments; the assistance of Mr. Michael Meagher, during 
his tenure as a Northeastern University Cooperative Education Student Trainee, with OI and 
SD measurement; and the assistance of Mr. William Haskell, III, and members of the 
Materials Exploitation Division for the preparation of the test specimens employed at MTL 
and FMRC. 


15 







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To 


Headquarters, Department of the Army, Office of the Assistant Secretary of the 
Army OASA(RDA), The Pentagon, Washington, DC 20301 
1 ATTN: SARO-TR, Mr. G. Singley (Rm 3E484) 

Commander, U.S. Army Materiel Command, 5001 Eisenhower Avenue, Alexandria, 

VA 22333-0001 
1 ATTN: AMCDL 

1 AMCPO-PT (Mr. Alan 0. Elkins) 

Commander, U.S. Army Laboratory Command, 2800 Powder Mill Road, Adelphi, 

MD 20783-1145 
1 AMSLC-IM-TL 

1 AMSLC-CT 

Commander, U.S. Army Tank-Automotive Corrmand, Warren, MI 48397-5000 
1 ATTN: AMCPM-ABSM, Col. J. Longhouser 
1 AMCPM-M113 

1 AMSTA-R 

1 AMSTA-T, Mr. D. Cargo 

1 AMCPM-BFVS, Mr. G. Chamberlain 

1 AMSTA-RSK, Mr. S. Goodman 

1 SFAE-ASM-SS, Col. Wm. Miller 

Director, Ballistic Research Laboratory, Aberdeen Proving Ground, 

MD 21005-5066 

1 ATTN: SLCBR-TB, Dr. C. Kitchens 
1 SLCBR-TB, Dr. B. Burns 

1 SLCBR-TB-A, Dr. W. Gillich 

Commander, Defense Technical Information Center, Cameron Station, Alexandria, 
VA 22304-6145 
1 ATTN: DTIC-FDAC 

Defense Command Agency, Technical Library Center, Washington, DC 20375 
1 ATTN: Code 204 

Commander, Army Research Office, P.0. Box 12211, Research Triangle Park, 

NC 27709 

1 ATTN: Information Processing Office, Associate Director, Materials 
Science Division, 

Dr. Andrew Crowson 

Commander, U.S. Army Test & Evaluation Command, Aberdeen Proving Ground, 

MD 21005 
ATTN: AMSTE-CT-C 

Commander, U.S. Army Natick Research, Development & Engineering Center, 

Natick, MA 01760 
1 ATTN: Technical Library 

Commander, U.S. Army Armaments, Munitions & Chemical Command, Dover, NJ 07801 
1 ATTN: AMDAR-LCA, PLASTEC, Director 

Director, Benet Weapons Laboratory, Watervliet Arsenal, Watervliet, 

NY 12189 

1 ATTN: AMSMC-LCB-TL 

Commander, Harry Diamond Laboratories, 2800 Powder Mill Road, Adelphi, 

MD 20783 

1 ATTN: Technical Information Library 
SLCHD-NW-RA, Mr. R. Lingebach 

Commander, U.S. Army Yuma Proving Ground, Yuma, AZ 85364 
1 ATTN: STEYP-MTD (TECH LI8RARY) 







No. of 
Copies 


To 


Director, U.S. Army Human Engineering Laboratory, Aberdeen Proving Ground, 

MD 21005-5066 

1 ATTN: Tech Reports Library 

Commander, U.S. Army Armor Center, Fort Knox, KY 40121-5000 
1 ATTN: ATSB-CD-ML 

Commander, U.S. Army Infantry Center & School, Fort Benning, GA 31905-5000 
1 ATTN: ATSH-CD, COL R. Kauffman 
1 ATSH-CD, MAJ C. Andre 

1 ATSH-CD, LTC P. Sowa 

Commander, MG C. Ostett, Combined Arms Center, Fort Leavenworth 
KS 66027-5000 
1 ATTN: ATZL-CA 

Naval Sea Systems Command, Marine Corps Assault Amphibian Office, 

Washington, OC 20362-8412 
1 ATTN: PMS310, MAJ C. Nans 

•David Taylor Naval Research & Development Center, Marine Corps Program Office 
(Code 1240), Bethesda, MD 20084-5000 
1 ATTN: Mr. W. Zeitfuss 
1 Mr. R. Swanek 

1 Mr. R. Peterson 

Chief of Naval Research, Arlington, VA 22217 
1 ATTN: Code 471 

Commander, U.S. Army Aviation Systems Conwand, Aviation Research and 
Technology Activity, Aviation Applied Technology Directorate, 

Fort Eustis, VA 23604-5577 
1 ATTN: SAVOL-E-MOS 

Defense Advanced Research Projects Agency, 1400 Wilson Boulevard, Arlington, 
VA 22209-2308 

1 ATTN: TTO/JPO, COL Pat Sullivan 

David Taylor Research Center, Annapolis, MD 21402 
1 ATTN: Mr. A. Marchand, Code 2843 

1 Mr. U. Sorathia, Code 2844 

Commander, U.S. Army Materials Technology Laboratory, Watertown, 

MA 02172-0001 
1 ATTN: SLCMT-TML 

1 Author 




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