UNCLASSIFIED

AD 296 018

ARMED SERVICES TECHNICAL INFORMATION AGENCYARLINGTON HALL STATIONARLINGTON 12, VIRGINIA0

UNCLASSIFIED

NOTICE: When goverament or other drawings, speci-fications or other data are used for any purposeother than in connection with a definitely relatedgovernment procurement operation, the U. S.Government thereby incurs no responsibility, nor anyobligation whatsoever; and the fact that the Govern-ment may have formalated, furnished, or in any waysupplied the said drawings, specifications, or otherdata is not to be regarded by implication or other-wise as in any manner licensing the holder or anyother person or corporation, or conveying any rightsor permission to manufacture, use or sell anypatented invention that may in any way be relatedthereto.

296 018o" PRODUCTION

.1NEKII/ VLOmEN ,fNIREERIN

RESEARCHI

TECHNICAL MEMORANDUM 1107

DETERMINATION

OF

AVAILABLE STABILIZER

IN

AGED PROPELLANTS CONTAINING EITHER

DIPHENYLAMINE OR ETHYL CENTRALITE

BY

MILTON ROTH

COPY NO. i JOF 66,7 FEBRUARY 1963

PICATINNY ARSENAL - DOVER. NEW JERSEY

TECHNICAL MEMORANDUM 1107AMMUNITION GROUP

DETERMINATIONOF

AVAILABLE STABILIZERIN

AGED PROPELLANTS

CONTAINING EITHERDIPHENYLAMINE OR ETHYL CENTRALITE

BY

MILTON ROTH

FEBRUARY 1963

REVIEWED BY. APPROVED BY: -

D. KATZ] *.. jMATTChief, Process il, AmmunitionEngineering Laboratory Production & Maint.

Engineering Division

TABLE OF CONTENTS

Page

INTRODUCTION 1DISCUSSION OF RESULTS 3CONCLUSIONS 4PROCEDURE 4DETERMINATION OF AVAILABLE STABILIZER CONTENT 5DETERMINATION OF AVAILABLE DIPHENYLAMINE 5DETERMINATION OF AVAILABLE ETHYL CENTRALITE 6REFERENCES 7

APPENDICESA. Figures Al-6B. Tables BI-10

TABLE OF DISTRIBUTION i

(i)

ACKNOWLEDGEMENT

The author wishes to thank Mr. M.R. Younginer, of the Explo-sives and Propellants Laboratory, Feltman Research Laboratories, for pre-paring, distributing and analyzing the samples and standards used in the roundrobin. His assistance and cooperation have been of great benefit to thePanel and the chairman of this round robin.

INTRODUCTION

Since stabilizer content is considered an indication of safe storage life,the problem of determining the stabilizer content of aged propellants has beenthe object of considerable study. In general, stabilizers function by undergoingchemical reaction with propellant decomposition products. Therefore theanalytical method must be able to distinguish between the original material andthe products of reaction. A number of methods have been described to theAnaI,<-al Panel (References 1-5) and a preliminary evaluation of these methods(Reference 6) was conducted by several laboratories under a cooperativeprogram.

Based on results from these screening tests, the Picatinny Arsenalspectrophotometric methods for available stabilizer and primary degradationproducts were selected for further study. The initial phase of this programwas an attempt to standardize the necessary spectrophotometric factors.It waz, found that significant differences, in regard to the factors obtained,exiscd between laboratories. It was expected, however, that these differenceswoaild be cancelled in the analysis of samples if each laboratory used the fac-tor appropriate to its spectrophotometer (Reference 7). Therefore, the Panelrecommended that a round robin be conducted on aged propellants containingeither diphenylamine (DPA) or ethyl centralite (EC).

The results of this round robin (Reference 8) were disappointing in regardto interlaborator agreement. Inspection of data revealed that most of thelaboratories had used the average of the spectrophotometric factors obtainedfrom the previous round robin. In view of this defect, and the fact that arelated round robin (Reference 9) further emphasized the importance of deter-mining the factor corcurrent with the analysis of samples, it was recommendedthat the round robin be repeated. For the repetition however, the method waslimited to the determination of available stabilizer only, rather than to its com-ponents.

The following laboratories participated in this round robin:

1. Canadian Armaments Research & Development EstablishmentQuebec, Canada

2. Frankford ArsenalPhiladelphia, Pennsylvania

3. Hercules Powder Company(at)

-I-

a. Allegany Ballistics Laboratory

Cumberland, Maryland

b. Kenvil PlantKenvil, New Jersey

c. Radford ArsenalRadford, Virginia

4. Naval Propellants PlantIndian Head, Maryland

5. Picatinny ArsenalDover, New Jersey

The required materials, distributed by Picatinny Arsenal, consisted of:

1. Diphenylamine and ethyl centralite for use as standards indetermination of spectrophotometric factors.

2. Samples representing lots of propellant as shown below.

Lot No. Type Stabilizer Nominal Cont. % Year of Mfg.

SUN-19243 M6 DPA 1.0 1945

RAD-60310 M10 DPA 1.0 1954

OKLA-29220 IMR DPA 0.7 1945

RAD-60326 M2 EC 0.6 1954

RAD-38145 T238 EC 6.0 1956

RAD- 34616 M17 EC 1.5 1954

Instructions and data sheets were also sent to all participating laboratories.In this report the data has been statistically analyzed, a number of conclusionshave been drawn and actions arc being taken to fully use the method,

DISCUSSION OF RESULTS

Tables I-IV are a compilation of the results submitted by the cooperatinglaboratories, Table V and VI summarize this data for the standards andsamples, respectively. Table VII is a summary of the reported working andelapsed times.

To evaluate the data quantitatively, statistical analyses were made. First,the absorptivity valies reported for the standards were subjected to an analy-sis-of-variance. From this analysis (Table VIII) it is seen that the averagesvary more than would be expected from chance alone. Thus, the laboratoriesdo have significant differences between the reported averages. These devia-tions can be attributed to the materials, the method, the analysts or the instru-ments. In all probability, however, the instruments are the principal causeof the disagreement since the materials (DPA and EC) were too carefullypurified and mixed and the method is too straightforward (weighing, dissolvingand diluting) to cause any confusion.

In Table IX and X, similar statistical analyses of the propellant resultsare given using the instrumental factors determined concurrently with thesample analyses. The statistical analyses indicate that with the exception of Lot60326, of six investigated, the averages do not differ more than would be expectedfrom chance alone. The DPA-stabilized propellants give results which are re-producible between laboratories, within the 950 level of confidence, while theEC propellants are within the 99%6 level.

The results obtained with the samples show much better agreement betweenlaboratories than do the results obtained with the standards. This finding con-firms the hypothesis stated earlier -- that the instruments used in the variouslaboratories are not standardized. A similar finding was evidenced in the roundrobin for determining admixtures of DPA and EC (Reference 9).

The data from each laboratory was plotted in Figure 1 to illustrate thevariability in absorptivity. Then the graph was divided into four quadrants --by horizontal and vertical lines drawn through the overall average obtained forDPA and EC. The pattern of points will be circular if only chance errors arepresent (Reference 10). A pattern in which the points form a long, narrow oval,as in Figure 1, indicates that nearly all the laboratories are departing from thestandard conditions. The location of point four and six indicates that theselaboratories have particular need for standardizing their spectrophotometers.

Despite the interlaboratory variability found with the determination ofabsorptivities, the sample results are considered to be in agreement. This isparticularly true with the DPA-stabilized propellants. Somewhat greater

-3-

variability is exhibited in the case of the EC-stabilized propellants, but onlyLot 60326 significantly exceeds the variability due to chance. However,this sample has such a low EC content and the results show such goodreproducibility, that the statistical test measure of significance is considered

impractical (Referenc 11). The total spread of results on Lot 60326 was

about 0.2%, which is well within the reproducibility of the method.

CONC LUSIONS

1. The spectrophotometric method for the determination of availablestabilizer content (as DPA or EC) is suitable for inclusion in the MIL-STD-Z86A(Propellants, Solid: Sampling, Examination and Testing) and Panel Handbook.The speed and simplicity of the method make it suitable for newly manufacturedas well as aged propellants.

2. The spectrophotometers used in the participating laboratoriesdiffer significantly in their response to the same material. Standardization ofresponse would greatly simplify writing of specifications.

Action Taken:

1. The spectrophotometric method for determination of availablestabilizer is being coordinated with the military services for inclusion inMIL-STD-286A.

2. A round robin designed to standardize spectrophotometers will beproposed at the next Panel meeting.

3. Propellants that show red fumes in less than 20 days (when stored0

at 65, 5 F) are being analyzed for available stabilizer content to establish aquantitative relationship between storage stability and stabilizer content.

PROCEDURE

Diphenylamine

Accurately weigh 50 mg. of standard DPA and transfer to a 500-ml.volumetric flask. Dissolve in and dilute to volume with 95% ethanol. Transfer1, 2, 4 and 5-ml. aliquots to separate 100-ml. volumetric flasks and dilute tovolume with ethanol. Measure the absorbance of the solutions at 285 n using aBeckman DU spectrophotometer, or equivalent, with ethanol in the referencecell. Calculate the absorptivity from the ratio:

-4-

a = A/c

whe re:

a = Absorptivity

A = Absorbance of standard (corrected for celldifferences)

c = Concentration of standard, mg/lO0 ml

Ethyl Centralite

Accurately weigh 100 mg of the standard EC and transfer to a 500-ml.volumetric flask. Dissolve in and dilute to volume with 95% ethanol. Trans-fer 3, 5, 8 and 10-ml. aliquots of this solution to separate 100-ml flasks anddilute to volume with ethanol. Measure the absorbance of these solutions at247 mp using a Beckman DU spectrophotometer, or equivalent, with ethanolin the reference cell. Calculate the absorptivity in the same manner as forDPA.

DETERMINATION OF AVAILABLE STABILIZER CONTENT

Separation by Steam Distillation

Place an accurately weighed 5-gm portion of sample (1 gm. if the nominalstabilizer content is more than 1% DPA or 2% EC) in the 1-liter balloonflask in a steam distillation apparatus similar to that in Figure 2. Add ZOO mlof 15% NaOH to the flask and steam distill at the rate of 7-9 ml/min until 400* 25 ml. of distillate is collected. Start the distillation with the tip of theadapter just below the surface of 50 ml. of ethanol in the receiver. Uponcompletion of the distillation, wash the condenser and adapter with ethanol,collecting the washings in the receiver. Transfer the contents of the receiverquantitatively to a 1,000-ml volumetric flask with the aid of ethanol, cool toroom temperature and dilute to volame with this solvent. From this stocksolution take aliquots as directed for the determination of available DPA or EC.

DETERMINATION OF AVAILABLE DIPHENYLAMINE (DPA)

From the stock solution transfer a 20-ml. aliquot to a 100-ml. volumetricflask and dilute to volume with ethanol. Determine the absorbance of thesolution at 285 rnmp using ethanol in the reference cell. Calculate the availableDPA content as:

-5-

Available DPA,% = A 100

aW

where:

A = Absorbance of solution at 285 mP.

W = Wt of sample in final aliquot, mg.

a = Absorptivity of DPA at 285 mp.

DETERMINATION OF AVAILABLE ETHYL CENTRALITE (EC)

From the stock solution transfer a 20-ml aliquot to a 100-ml volumetricflask and dilute to the mark with ethanol. Determine the absorbance of thesolution at 247 my using ethanol in the reference cell.

Calculate the EC content as:

EC,%= A 100

aW

whe r e:

a = Absorptivity of EC at 247 my.

A = Absorbance of sample at 247 mp.

W = Weight of sample in final aliquot, mg.

-6-

REFERENCES

1. M.A. Laccetti, M.R. Younginer and M. Roth, SpectrophotometricMethod for the Simultaneous Determination of Actual EC and ItsPrimary Degradation Products in Propellants, Picatinny ArsenalGeneral Laboratory Section Rpt. No. 57-HI-519, 21 March 1957.

2. M.A. Laccetti, and M.R. Younginer, Improvement of the Spectrophoto-metric Method for Analysis of Diphenylamine and Its Primary Degrada-tion Products, Picatinny Arsenal General Laboratory Section Report No.58-HI-648, 12 June 1958.

3. M.A. Lacetti and M.R. Younginer, Colorimetric Determination ofAvailable DPA by Diazo Coupling, Picatinny Arsenal Technical Memo

No GL-4-59, April 1959.

4. M. Roth M.A. Laccetti and M.R. Younginer, Abridged Spectrophoto-metric Method for Determination of Available Stabilizer and Applica-tion to Prediction Safe Life of PropellantsPicatinny Arsenal TechnicalMemorandum No. GL-8-59, June 1959.

5. J. Meyers, Determination of Total Nitrosamine Content in Propellantsand Determination of Effective Stabilizer Content in DPA StabilizedPropellant (Spectrophotometric Method),CARDE letter to M. RothReply No. CARDE 193-60/761-6, 3 September 1958.

6. M.A. Laccetti and M. Roth, Evaluation of Methods for the Analysis ofDPA, EC and Some of Their Degradation Products, Picatinny ArsenalTechnical Memorandum GL-6-59, June 1959.

7. M. Roth, Interlaboratory Determination of Spectrophotometric Factorsfor DPA, EC and Their Primary Degradation Products Pic atinny ArsenalTechnical Memorandum ACS-2-60, May 1960.

8. M. Roth, JANAF-PACSP Round Robin No. 21, Determination of Avail-able Stabilizer in Aged Propellants containing Either DPA or EC,Picatinny Arsenal Laboratory Report No. AL-P-3-62, February 1962.

9. M. Roth, JANAF-PACSP Results of the Evaluation of the PicatinnySpectrophotometric Method for the Determination of Admixtures of DPAand EC in Propellants, Picatinny Arsenal Analytical Chemistry SectionReport No. AEP-344-6Z.

-7-

10. W.J. Youden, Materials Research and Standards, p. 86Z-867,November 1961.

11. R.H. Pierson and E.A. Fay, Anal. Chem. 31, 25A, 1959.

-8-

10. W.J. Youden, Materials Research and Standards, p. 862-867,November 1961.

11. R. H. Pierson and E. A. Fay, Anal. Chem. 31, 25A, 1959.

-8-

APPENDICES

APPENDIX A

FIGURES

Im

I tL

il.

I f i l l f i l l

!II,ifA-i

CC)S

4

-4

-2

0

A U)33

012

C.)C.43

I-a 0

O~0 L:6

o) 0 0O

.0 ~~~ ~.~4O0.JO

u .0

A-3

* *1~I

Mo43

I

N.A-4

11IN.IN

I I -4

42

431 4

I ~~44.-biV

ulA-5

Remarks

TimeRequredbra/am4l

Tite Rqiehesml

Dates

A-6

APPENDIX B

TABLES

NNNNOn NNN N NN(N3r4114 O % NNI nO

to

---- ( 0 --- N 0 -0 00,o

N CN

r- 00

tILn

00

0L~ 0 0

z (

0LN U N

U,

*B-1

a,0 0 -0 N NN gNO0 0 I a''ca'a' Ia, 00Ia N

N0 a

-4 -

A NN (nV ,4 NO 10'aO0 01100aN IIX00 4-- 00 -4-0 00 N N 4-4 0 ~ 4 N7 N, -40 f)0

p 4 _4 04 -440 N-4--4-4-1 0 - 44 -0

41

0 '

U oU)

: 0

04 Lf L i t

B-2

71 -- _ _100e

~~~~ M~N0~~~

-4H 0' N C0';;C

C;1> IX) o IxU 0 c0~N~ U(j)

-4 00000 00 00 000000t-e r oa

<Z

00

00

'-4

H

Lfn

0 U w 'o N

o M)0 NN

040

P-4 c N N

~~B--

0 1

o ~ ~ 0n L n L 4N 0 n nl -c n n

NNNNNO 00cya'00m

LA) I

~2CI;U 04

-e-

P4 000000

P4,

rn U

00

z

00U

0

Z: 0

P4

00

B-5

LL~ N

a,000 00 00 000 0 qm(nC0 0000L L L 0

0000L L) f 0 0 00 00 00 000 00 NN

O LANN-r r - C N~ 0O ON NO ~N

000 0r n0 0000 00aN Y 00 00 00N

000CD0 00 0 00 0 00 0000 00

10 LA'.0 %0 %0 o ~Ln Ln LAN m m r ()LALALALA LAO U)' 0 !O - - N N NN NO0

000 0 0 0000, %ja 00 00 00 00 1

0 0 00 00 0 0 00 00 0000 00

zr- f-D -q 'D. LA'0DLA) 1 LA ~N N~ qtHn n LL LL LAO0 (- r- r- - - 0 N N NN NO

zz

cn 0

0B-N

000 00f N m m cn A '00 .-4

% , , %0 O'0 NLLl' Co' M

0000 00ttlft O

a, a,--~ ao aoo aC~ oe) oa' L)L 0 0

0000 L) n f 0 0 Ll0r0 tr 0C f o ' f

arflr~ r 0 000- C na% CCV 4c 00 NN NO

C 0000 r 00 r-r-flU)t tf o -4-'0f)

SLnrtt (n qJ1 -4 14 0 0 -4

U) ) o L- tLA -4l 00vv14 C 0'N04~ 4"4

a, N -r - eLn N '0'c 0 atr- N cf'0

-4) 000 00 trL) r-tN 00 0

IXw IX IX

0; 00

00

B-7

- N Lo~ N Lt) Lf) M (n~ -4

CT N ' . -

0000000

0

en -- ) No Lf Lflr- Lf)ID I '0

0

CY)

U) Z 0

0 N

0 a

HD LnWU) 0000 00

M~~ ~ ~ d4L 0 -WO

U)f

N 0 a, 'DOo N -o 0 ~N

a,' i nLnL o' NLtn Ln

B-8

CLnO

00

00 c*

00u'00

w ' 0 0)

U) Q LnAL C

az LoU

PL Z1- Q aNO

040l C'

H--- -- L

coo

PZ4 aa

Q C;4 ,0cw0

U) 0 co ~ Z

0 >4 u

.14 0Z 0 - .

-I

-4I$4

B-9

0, 't.0

NO LA~

H 00 L r2 -

a. 4 0 .a

N .4 -N

'V4 -

H ~ H ~ z 0055

z w'

NO Ni 4 I

NOO 0-40

~Z4 - 9-4 r-O N NN

a, a% a'

0 00 Z 0 00C-~P -4IZq

H 0

0 0

44-

4-) 4 * C I I

B-10

TABLE OF DISTRIBUTION

TABLE OF DISTRIBUTION

1. Commanding Officer Copy Number

Picatinny ArsenalDover, New JerseyATTN: SMUPA-VA6 1-5

SMUPA-DB 6SMUPA-DC7, Mr. A. Sokol 7SMUPA-I 8SMUPA- IA 9SMUPA- 10 10SMUPA-G 11-12SMUPA-DX1 13-14SMUPA-DX3 15-16SMUPA-NR2 17-18

2. Commanding General

U.S. Army Materiel CommandWashington 25, D.C.

ATTN: AMCRD 19

3. Commander

Armed Services Technical Information AgencyArlington Hall StationArlington 12, VirginiaATTN: TIPDR 20-29

4. Commanding OfficerFrankford ArsenalBridge & Tacony Streets

Philadelphia 37, PennsylvaniaATTN: Materials Engineer Division 30-31

5. Chief. Bureau of OrdnanceNavy DepartmentWashington 25, D.C.ATTN: AD3, Technical Library 32

6. Commanding GeneralAmmunition Procurement and Supply AgencyJoliet, IllinoisATTN: SMUAP-AM 33

SMUAP-AI 34SMUAP-AIDA 35

TABLE OF DISTRIBUTION (CONT'D)

Copy Number

7. Commanding OfficerRadford ArsenalRadford, VirginiaATTN: Mr. J. Horvath 36-37

8. DirectorOrdnance Materials Research OfficeWatertown ArsenalWatertown, Massachusetts 38

9. Commanding OfficerDiamond Ordnance Fuze LaboratoryConnecticut & Van Ness AvenuesWashington 25, D.C. 39-40

10. Armour Research FoundationBuilding 61-7Joliet ArsenalElwood, IllinoisATTN: R. Remaly 41-42

11. Atlantic Research CorporationShirley Highway at Edsall RoadAlexandria. VirginiaATTN: Mr. B.W. Black 43

12. E.I. duPort deNemours & Co.Carney Point Process LaboratoryP.O. Box 152Penns Grove, New JerseyATTN: Mr. C.I. Johnson 44

13. CommanderAir Force Flight Test CenterEdwards Air Force Base, CaliforniaATTN: FTRSC

Lt. H.V. Bankaitis 45

ii

TABLE OF DISTRIBUTION (CONT'D)

Copy Number

14. Allegany Ballistics LaboratoryP.O. Box 210Cumberland, MarylandATTN: Mr. W.E. Kight 46

15. Hercules Powder CompanyKenvil, New JerseyATTN: H.A. Read 47

16 National Research Corporation70 Memorial DriveCambridge 42, MassachusettsATTN: Dr. J.H. Atkins 48

17. Commanding OfficerU.S. Naval Ordnance LaboratoryWhite Oak, Silver Spring, MarylandATTN: Dr. J.M. Rosen 49

18. Commanding OfficerU.S. Naval Propellant PlantIndian Head, MarylandATTN: Mr. H.L. Stalcup 50

Dr. Mae Fauth 51

19. HeadquarterfOgden Air Materal AreaHt1 Air Force Base, UtahATTN: Mr. Neal M. Hansen 52

20. Olin Mathieson Chemical CorporationP.O. Box 508Marion, IllInoisATTN: Mr. R.J. Thiede 53

21. Commanding GeneralU.S. Army Missile CommandRedstone ArsenalHuntsville, Alabama 54

iii

TABLE OF DISTRIBUTION (CONT'D)

Copy Number

22. Sandia CorporationP.O. Box 5800Albuquerque, New MexicoATTN: Mr. R.J. Buxton, Code 1625 55

23. Stanford Research InstitutePoulter LaboratoriesMenlo Park, CaliforniaATTN: Dr. R.F. Muraca 56

Dr. Eugene Burns 57

24. Commanding OfficerU.S. Naval Ammunition & Net DepotSeal Beach, CaliforniaATTN: QE Laboratory, Technical Library 58

25. Commanding OfficerU.S. Army Chemical Corps Engineering GroupArmy Chemical Center, MarylandATTN: CMLEN-WSS-R,

Mr. Charles G. Hain 59

26. Defence Research MemberCanadian Joint Staff (W)2450 Massachusetts Avenue, N.W. 60-63Washington 8, D.C.

27. British Defence StaffBritish Embassy3100 Massachusetts Avenue, N.W.Washington 8, D.C.ATTN: Scientific Information Officer 64

28. Chemical Propulsion Information AgencyThe Johns Hopkins UniversityApplied Physics Laboratory8621 Georgia AveSilver Spring, MarylandATTN: Mr. S.S. Miller 65-67

iv