Characterization of ageing of NC based gun … function between retention volume Ve and molar mass M...

—————

2012 Bohn 1

© Fraunhofer ICT, Pfinztal, Germany

Characterization of ageing of NC based gun propellants by molar

mass degradation of nitrocellulose and its modelling by random

chain scission models

Dr. Manfred A. Bohn

Fraunhofer-Institut fuer Chemische Technologie, ICT

Pfinztal, Germany

Presentation on the

NDIA Insensitive Munitions and Energetic Materials Technology Symposium

Event # 2550 May 14-17, 2012

Las Vegas, Nevada, USA

—————

2012 Bohn 2


Motivations and Objectives

Nitrocellulose (NC) is an important ingredient in gun and rocket propellants, also in recently

developed ones, having improved IM characteristics, as the DNDA-RDX-NC based GP from

Fraunhofer ICT /1, 2/ or the ECLTM series of Nitrochemie Wimmis.

This means NC has properties which are not reached by other energetic binders up today.

Nitrocellulose decomposes slowly intrinsically and after some induction time also

autocatalytically, because of low kinetic energy barriers

The autocatalytic decomposition can be supressed by stabilizers, but not the intrinsic one

The intrinsic decomposition of NC leads to scissioning of the NC chains, expressed as

decrease in mean molar masses with time-temperature load

Chain scissioning of NC is accomponied by NOx formation, which consumes stabilizers

The chain scissioning is very sensitive to decompostion: already decomposing of one chain

element leads to roughly half of the original chain length

With decrease of chain length the mechanical strength of NC products is reduced

Therefore: Determination of NC chain degradation is a sensitive monitoring for NC products

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2012 Bohn 3


Determination of NC chain length degradation

NC STANAG: STANAG 4178 “Assessing the Quality of Nitrocellulose Deliveries from

one NATO Nation to Another”, Edition 2 /8/.

Generally the chain length degradation of a polymer is best determined by GPC (Gel Permeation

Chromatogrphy) also called SEC (Size Exclusion Chromatography)

This is the case also with NC.

At ICT this method was introduced in the early 1980s and several publications have been

published on the early results and on later work /3, 4, 5, 6/.

Also at Nitrochemie Wimmis (NCW) the GPC method was introduced at the same time and

some early RR on GPC have been performed between ICT and NCW. End of the 1990 AWE has

started a lot of GPC work on NC and HMX bonded by NC /7/.

With time the importance of this method was increasingly recognized and finally found its

expression in the implementation of the GPC method in the recently updated NC-STANAG.

For this an applicable method was worked out and especially adapted for analysing NC

by collaboration between: AWE, Univ. Cranfield-Shrivenham, Fraunhofer ICT, Nitrochemie

Wimmis, TNO-Rijswijk /9, 10, 11, 12/.

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2012 Bohn 4


How to use GPC results on NC degradation

First, one gets the elugramme of the size-separated NC chains, means a frequency distribution

of chain length versus retention volume Ve.

This elugramme is tranformed to a molar mass distribution function (MMD), by use of a

calibration function between retention volume Ve and molar mass M of a calibration substance.

Then the characteristic quantities of this molar mass distribution (MMD) are calculated:

Mean molar masses Mn, Mw, Mz and polydisperity D = Mw/Mn

Mn: averageing done by polymer fractional mol number to weigh the fractions

Mw: averageing done by polymer fractional mass to weigh the fractions

Mz: averageing done by polymer fractional z-weight to weigh the fractions

Mp: molar mass at peak maximum of the MMD

These data can be established as function of ageing of NC or the NC in a propellant respectively.

Here the degradation of NC in the triple base gun propellant Q5560 (19 hole, 27mm maschine

gun) is presented.

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2012 Bohn 5


Not only NC polymer chain degradation....

Random chain scissioning of polymer chains is widespread.

Hydrolysis of polymeric esters

Attack on thermoplastic elastomers by ‘aggressive’ substances as

ADN, HNF, nitric acid plasticizers as nitroglycerine, TMETN, BTTN, NENA,..

Attack on binders as GAP and HTPB by CL-20, RDX,...

Polyvinylnitrate (PVN)

...... M.A. Bohn, J. Aniol, M. Dörich, K. Hartlieb, H. Pontius

Stability, Ageing and Usetime Prediction of Polyvinylnitrate (PVN).

Paper 73, pages 73-1 to 73-18 in Proceedings of the 37th International Annual Conference of ICT 2006, June

27 to 30, 2006, Karlsruhe,Germany. Fraunhofer-Institut für Chemische Technologie (ICT), D-76318 Pfinztal.

Bohn M.A., Dörich M., Aniol J., Pontius H., Kempa P.B., Thome V.

Reactivity between -CL20 and GAP in Comparison to -HMX and GAP.

Paper 4, pages 4-1 to 4-30, in Proceedings of the 35th International Annual Conference of ICT, June 29 to July

2, 2004, Karlsruhe, Germany. Fraunhofer-Institut für Chemische Technologie (ICT), D-76318 Pfinztal-

Berghausen, Germany.

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2012 Bohn 6


Mean molar masses Mn, Mw, Mz and MMD-peak Mp as function of ageing

degradation of NC in GP Q5560

ageing at 90°C

0

200000

400000

600000

800000

1000000

1200000

1400000

0 5 10 15 20 25 30 35 40

ageing time [d]

Mi [g/mol]

0

1

2

3

4

5

6

D [-]

Mn [g/mol]

Mw [g/mol]

Mz [g/mol]

Mp [g/mol]

D

Mw

Mz

D

Mp, M at peak

Results for the NC degradation in gun propellant Q5560, 27 mm, triple base

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2012 Bohn 7


Relative mean molar masses and MMD-peak Mp as function of ageing

GP Q5560

aged at 90°C

relative degradation of mean molar masses, Mn, Mw, Mz

and of MMD peak molar mass Mp

0

0.2

0.4

0.6

0.8

1

1.2

0 3 6 9 12 15 18 21 24 27 30 33 36 39

ageing time [d]

Mx(t)/Mx(0) [-]

Mn(t)/Mn(0)

Mw(t)/Mw(0)

Mz(t)/Mz(0)

Mp(t)/Mp(0)

If the data are measured and evaluated well, all the mean molar masses nearly coincide in relative

representation /8, 9, 10, 11, 12/.

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2012 Bohn 8


Use of GPC results

Determine NC degradation as function of time and temperature

90°C, 80°C, 70°C, 60°C,…

Which ageing times can be chosen – orientaion can be obtained from:

time temperature loads given in AOP 48, which are adapted for NC-based materials

generalized van’t Hoff extrapolation /15/

own ageing experience

ageing times chosen for basic investigations

literature data

Time-temperature data can be kinetically parameterized, with NC-based material by

Arrhenius

Generalized van‘t Hoff (GvH)

Necessary for this is the determination of rate constants

H GvH pre-factor

FT scaling factor with regard to chosen T

T temperature

T temperature scaling interval, mostly 10°C

Z expon. pre-factor

exp Euler number e

T temperature (absolute)

Ea activation energy

R general gas constant

T/T

TGvH FH)T(k

RT/EaexpZ)T(k Arrh

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2012 Bohn 9


Description of two-step ageing of NC based material with GvH

This two step mechanism for NC-based materials is included in STANAG 4582 and AOP 48, Ed. 2 /13, 14/

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2012 Bohn 10


Description of two step mechanism by two Arrhenius rate constants

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2012 Bohn 11


Description of two step mechanism by generalized van’t Hoff (see /15/)

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2012 Bohn 12


Choosing the type of temperature parameterization

The scission process is chemically based

Arrhenius behaviour can be expected for the rate constants.

If intrinsic dual mechanistic behaviour occurs, as it is assumed with NC-based materials

(see AOP 48 and STANAG 4582), then the generalized van’t Hoff parameterization is of

advantage /15/.

Manfred A. Bohn

Prediction of equivalent time-temperature loads for accelerated ageing to simulate preset in-storage ageing

and time-temperature profile loads.

Paper 78, pages 78-1 to 78-28 in Proceedings of the 40th International Annual Conference of ICT on

‘Energetic Materials – Characterization, Modelling, Validation’, June 23 to 26, 2009, Karlsruhe, Germany.

ISSN 0722-4087.

Fraunhofer-Institut für Chemische Technologie (ICT), D-76318 Pfinztal-Berghausen. Germany.

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2012 Bohn 13


Kinetic models to describe NC chain scission and molar mass degradation

Model based on random chain scission (CS) by bond scission between chain elements (BS)

no material is lost, no mass loss; model CS-BS

Model based on random chain scission (CS) by chain element decomposition (ED)

material is lost, mass loss occurs; model CS-ED

Model based on random chain scission (CS) by bond scission between chain elements (BS)

and recombination of chains (CR)

no material is lost, no mass loss; model CS-BS with CR

Model based on random chain scission (CS) by chain element decomposition (ED)

and recombination of chains (CR)

material is lost, mass loss occurs; model CS-ED with CR

The model must be able to describe the whole course of Mx = f(t) as precise as possible

The model should have a true kinetic base, developed from the type of scission process of

NC chains

Only this ensures a correct extrapolation

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2012 Bohn 14


Which molar mass is the right one for the kinetic description of chain

degradation in polymers

Kinetic processes in chemistry describe reaction of atoms or molecules and between them.

The adequate quantity followed is a concentration, means ‘particle’ number per any unit

(volume, mass,…)

Conclusion

The right mean molar mass is the one which ‘counts’ particles, means which is based on mol

numbers – this is Mn

So the models are formulated with Mn, which is the center of gravity molar mass of the

distribution function hn, the fractional mol number related MMD

Remark:

With RI and UV detectors the distribution function hm is determined, the fractional mass

related MMD;

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2012 Bohn 15


Use of kinetic modelling to get rate constants

degradation of NC in GP Q5560 at 90°C

10000

20000

30000

40000

50000

60000

70000

80000

90000

100000

110000

120000

130000

0 5 10 15 20 25 30 35 40

ageing time [d]

Mn [g/mol]

0

1

2

3

4

5

6D [-]

Mn [g/mol]

D

The Mn data obtained from the MMD of NC in GP Q5560 are used for modelling

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2012 Bohn 16


Elugrammes of the NC degradation of GP Q5560, obtained by RI detection

Concentration related elugrammes of the NC of GP Q5560, obtained by referactive index (RI) detection

to maximum normalized elugrams

NC of Q5560

ageing at 90°C

-0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1

9.5 10 10.5 11 11.5 12 12.5 13 13.5 14 14.5 15 15.5 16 16.5

Ve [ml]

RI [aU]

unaged

2d-1

8d-1

16d-1

28d-1

35d-1

zero

unaged

2d

8d

16d28d

35d

Low molar mass

end, increase of

concentration by

ageing of the NC

in the GP

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2012 Bohn 17


Area normalized molar mass distributions hm of NC degradation

Frequency

distribution of

the fractional

polymer parts

as function of

molar mass

molar mass distribution of NC of Q5560

polymer fraction mass related

ageing at 90°C

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.0E+03 1.0E+04 1.0E+05 1.0E+06 1.0E+07

M [g/mol]

hm(lgM)unaged

2d

5d

8d

12d

16d

22d

28d

35dunaged

2d

5d

12d

8d35d

28d

22d

16d

Low molar mass

end, increase of

frequency by

ageing of the NC

in the GP

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2012 Bohn 18


Model with chain scission by bond splitting between chain elements

B(t): number of bonds between chain elements in polymer sample

Nm(t): number of chain elements in the polymer sample

nc(t) number of polymer chains in the sample, nc(t) = Nm(t) / (Mn(t)/m)

Mn(t) mol number averaged mean molar mass

m molar mass of one chain element of the polymer

t)T(kexp)0(B)T,t(B 1B )t(Bkdt

)t(dnc1B

Model set-up

Formation rate of new chains is proportional to the present number bonds B(t) between

chain elements Nm(t).

Splitting of one bond splits a chain. This process is of first order.

The number of bonds B(t) decreases to reaction of first order. The number of chain

elements stays constant. No mass loss.

1tkexp)0(Mn

m

tkexp

m

)t(Mn

1B

1B

Model CS-BS See also /18/

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2012 Bohn 19


Model with chain splitting by chain element decomposition

B(t): number of bonds between chain elements in polymer sample

Nm(t): number of chain elements in the polymer sample

nc(t) number of polymer chains in the sample, nc(t) = Nm(t) / (Mn(t)/m)

Mn(t) mol number averaged mean molar mass

m molar mass of one chain element of the polymer

t)T(kexp)0(N)T,t(N 1M

Model set-up

Formation rate of new chains is proportional to the present number of chain elements Nm(t).

Destruction of one chain element splits a chain. This process is of first order. Number of

chain elements decrease steadily. Mass loss occurs.See also /7, 8/

)t(Nmkdt

)t(dnc1M

tkexp1)0(Mn

m

tkexp

m

)t(Mn

1M

1M

First derived by Norbert

Eisenreich at Fraunhofer ICT in

the 1980s

See also /16, 17, 18/

Model CS-ED

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2012 Bohn 20


Results: model with chain element decomposition: Q5560 at 90°C

The description

with model CS-

ED (or CS-BS) is

not satisfying.

The description

must be done in

two steps, to get

adequate

modelling.

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2012 Bohn 21


Results: model with chain element decomposition: Q5560 at 80°C

The description

with model CS-ED

(or CS-BS) is not

satisfying.

The description

must be done in

two steps, to get

adequate

modelling.

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2012 Bohn 22


Model chain splitting by bond scission with chain recombination - kB2(n(t)-n(0))

Model set-up

1. Formation rate of new chains is proportional to the present number of bonds B(t) between

chain elements Nm(t).

Splitting of one bond splits a chain. This process is of first order.

The number of bonds B(t) decreases to reaction of first order. The number of chain

elements stays constant. No mass loss.

2. The loss rate of chains is proportional to the number of chains n(t)-n(0) already formed.

The active ends arising by splitting are radicals and attack the reservoir of chains.

The second reactant of this bimolecular reaction is nearly constant and is included in the

reaction rate constant kB2

)0(n)t(nck)t(Bkdt

)t(dnc2B1B

t)kk(exp1kk

)0(Mn

mkk

t)kk(exp)0(Mn

m

1

m

)t(Mn

2B1B2B1B

2B1B

2B1B

)0(Mn

mkk

kkm)te(Mn

2B1B

2B1B

Model CS-BS with CR

Mn(te) =plateau value in

Mn at t versus ; Note:

Mn(te,T) is T-dependent

via the kB1(T) and kB2(T)

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2012 Bohn 23


Model chain splitting by element decomposition with chain recombination- kM2(n(t)-

n(0))

Model set-up

1. Formation rate of new chains is proportional to the present number of chain elements Nm(t).

Destruction of one chain element splits a chain. This process is of first order.

The number of chain elements decrease steadily. Mass loss occurs.

2. The loss rate of chains is proportional to the number of chains newly formed already, n(t)-n(0).

The active ends arising are radicals and attack the great reservoir of chains. The second

reactant of this bimolecular reaction is nearly constant (in initial conversion range) and is

included in the reaction rate constant kM2.

)0(n)t(nck)t(Nmkdt

)t(dnc2M1M

1)tkexp()0(Mn

mtkkexp1

kk

k

)0(Mn

m

tkkexp

m

)t(Mn

2M2M1M2M1M

1M

2M1M

t)T(kexp)0(N)T,t(N 1M

Model CS-ED with CR

Mn(te,T) = 0 at t versus at every T

Means all chain elements will be decomposed

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2012 Bohn 24


Comparison of models: CS-BS versus CS-BS with CR

comparison

model CS-BS: chain splitting (CS) by bond scission (BS)

model CS-BS with CR-kB2*(n(t)-n(0)): CS with chain recombination

0

0.2

0.4

0.6

0.8

1

1.2

0 20 40 60 80 100 120 140 160 180 200

time [d]

Mn(t)/Mn(0)

0

0.2

0.4

0.6

0.8

1

1.2

B(t)/B(0)

Mn(t)/Mn(0) kb1 kb2

Mn(t)/Mn(0) kb1

B(t)/B(0) kb1 kb2

B(t)/B(0) kb1

kB1 = 9.0 E-5 1/d

kB2 = 5.0 E-3 1/d

m = 279.96 g/mol

Mn(0) = 112548 g/mol

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2012 Bohn 25


Comparison of models: CS-ED versus CS-ED with CR

comparison

model CS-ED: chain splitting (CS) by chain element decomposition (ED)

model CS-ED with CR-kM2*(n(t)-n(0)): CS with chain recombination

0

0.2

0.4

0.6

0.8

1

1.2

0 20 40 60 80 100 120 140 160 180 200

time [d]

Mn(t)/Mn(0)

0

0.2

0.4

0.6

0.8

1

1.2

Nm(t)/Nm(0)

B(t)/B(0)

Mn(t)/Mn(0) km1 km2

Mn(t)/Mn(0) km1

B(t)/B(0) km1 km2

Nm(t)/Nm(0) km1

kM1 = 9.0 E-5 1/d

kM2 = 5.0 E-3 1/d

m = 279.96 g/mol

Mn(0) = 112548 g/mol

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2012 Bohn 26


Comparison of models: CS-BS with CR versus CS-BS with CR

comparison

model CS-BS with CR-kB2*(n(t)-n(0)): CS by bond sicission and chain recombination

model CS-ED with CR-kM2*(n(t)-n(0)): CS by element decomposition and chain recombination

0

0.2

0.4

0.6

0.8

1

1.2

0 20 40 60 80 100 120 140 160 180 200

time [d]

Mn(t)/Mn(0)

0.5

0.6

0.7

0.8

0.9

1

1.1

B(t)/B(0)

Nm(t)/Nm(0)

Mn(t)/Mn(0) kb1 kb2

Mn(t)/Mn(0) km1 km2

B(t)/B(0) kb1 kb2

B(t)/B(0) km1 km2

Nm(t)/Nm(0) km1kB1 = kM1= 9.0 E-5 1/d

kB2 = kM2 = 5.0 E-3 1/d

m = 279.96 g/mol

Mn(0) = 112548 g/mol

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2012 Bohn 27


In T-scan: Comparison of models: CS-BS versus CS-BS with CR

comparison in T-scanning mode

model CS-BS

model CS-BS and CR with CR-kB2*(n(t)-n(0))

-0.15

0

0.15

0.3

0.45

0.6

0.75

0.9

1.05

1.2

20 50 80 110 140 170 200 230

T [°C]

Mn(t)/Mn(0)

Mn(te)/Mn)0)

-0.15

0

0.15

0.3

0.45

0.6

0.75

0.9

1.05

1.2

B(t)/B(0)

Mn(t)/Mn(0) kb1

Mn(t)/Mn(0) kb1 kb2

Mn(te)/Mn(0)

zero

B(t)/B(0) kb1

B(t)/B(0) kb1 kb2

m = 279.96 g/mol

Mn(0) = 112548 g/mol

kB1

ZB1 = 8.0 E+14 1/d

EaB1 = 133 kJ/mol

kB2

ZB2 = 8.0 E+10 1/d

EaB2 = 87 kJ/mol

T0 = 25°C

h = 0.6 °C/d

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2012 Bohn 28


In T-scan: Comparison of models: CS-ED versus CS-ED with CR


model CS-ED

model CS-ED and CR with CR-kM2*(n(t)-n(0))

-0.15

0

0.15

0.3

0.45

0.6

0.75

0.9

1.05

1.2

20 50 80 110 140 170 200 230

T [°C]

Mn(t)/Mn(0)

-0.15

0

0.15

0.3

0.45

0.6

0.75

0.9

1.05

1.2

Nm(t)/Nm(0)

B(t)/B(0)

Mn(t)/Mn(0) km1

Mn(t)/Mn(0) km1 km2

zero

N(t)/N(0) km1

B(t)/B(0) km1 km2

m = 279.96 g/mol

Mn(0) = 112548 g/mol

kM1

ZM1 = 8.0 E+14 1/d

EaM1 = 133 kJ/mol

kM2

ZM2 = 8.0 E+10 1/d

EaM2 = 87 kJ/mol

T0 = 25°C

h =0.6 °C/d

—————

2012 Bohn 29


In T-scan: Comparison of models: CS-BS with CR versus CS-BS with CR


model CS-ED

model CS-BS

model CS-ED and CR with CR-kM2*(n(t)-n(0))

model CS-BS and CR with CR-kB2*(n(t)-n(0))

-0.15

0

0.15

0.3

0.45

0.6

0.75

0.9

1.05

1.2

20 50 80 110 140 170 200 230

T [°C]

Mn(t)/Mn(0)

-0.15

0

0.15

0.3

0.45

0.6

0.75

0.9

1.05

1.2

Nm(t)/Nm(0)

B(t)/B(0)

Mn(t)/Mn(0) km1Mn(t)/Mn(0) kb1Mn(t)/Mn(0) km1 km2Mn(t)/Mn(0) kb1 kb2zeroN(t)/N(0) km1B(t)/B(0) km1 km2B(t)/B(0) kb1 kb2

m = 279.96 g/mol

Mn(0) = 112548 g/mol

kM1 / kB1

Z1 = 8.0 E+14 1/d

Ea1 = 133 kJ/mol

kM2 / kB2

Z2 = 8.0 E+10 1/d

Ea2 = 87 kJ/mol

T0 = 25°C

h =0.6 °C/d

—————

2012 Bohn 30


Results: Description of data by model CS-ED with CR

The description

with model CS-

ED with CR is

now satisfying.

—————

2012 Bohn 31


Results: Description of data by model CS-BS with CR

Also the

description with

model CS-BS

with CR is now

satisfying.

At isothermal

conversions not

to high both

models are nearly

equal in

descrption

quality.

But from

mechanistic point

of view model

CS-ED with CR is

the right one

—————

2012 Bohn 32


Comparison: chain scission alone versus scission and recombination

GP Q5560

aged at 90°C

NC degradation

0

0.2

0.4

0.6

0.8

1

1.2

0 10 20 30 40 50 60 70 80 90 100 110 120

ageing time [d]

Mn(t)/Mn(0) [-]

0

0.2

0.4

0.6

0.8

1

1.2Nm(t)/Nm(0) [-]

Mn(t)/Mn(0)-1k

Mn(t)/Mn(0)-2k

Mn(t)/Mn(0)-exp

Mn(te)r

Nm(t)/Nm(0)

decrease of chain elements

Nm(t)/Nm(0)

decrease of Mn, one k

experimental data decrease of Mn, two k,

leveling to Mn(te)Mn(te)/Mn(0)

Correct description is achieved with model CS-ED with CR;

illustration here done with model CS-BS with CR in order to get the value for Mn(te) at t →

—————

2012 Bohn 33


Summary and Conclusions

Decrease of NC chain length is a very sensitive probing of ageing of NC based materials

Decrease of chain length of polymers can be well determined by GPC (also named SEC)

The chain degradation of NC is expressed in decrease of the mean molar masses

To use the data, suitable modelling is applied to extract the rate constants of the

degradation process

Models using chain splitting by chain element decomposition are nearest to the reality of the

splitting process for NC

With NC it seems that besides chain splitting also recombination of chains occur.

Best model for NC: chain splitting by chain element decomposition with recombination of

chains

—————

2012 Bohn 34


Acknowledgement

To my colleague Dr. Norbert Eisenreich

For the development of the model ‘chain splitting by chain element decomposition’

in the early 1980s.

For always helpful discussions in set-up and handling of kinetic models.

To my colleagues in the ‘stability group’ at ICT

providing me with measurement results of high quality:

Manuela Doerich, Heike Pontius

Kerstin Wimmer, Monika Raab, Juergen Hickmann

—————

2012 Bohn 35


References – part 1 of 3

1/ M.A. Bohn, D. Mueller Insensitivity aspects of NC bonded and DNDA plasticizer containing gun propellants

2006 Insensitive Munitions & Energetic Materials Technology Symposium, April 24-28, 2006, Bristol, UK. /2/ D. Mueller, M.A. Bohn, W. Langlotz

LTC propellants based on DNDA plasticizer.

Paper on the 33rd International Pyrotechnics Seminar July 16 to 21, 2006, Fort Collins, Colorado, USA. Organized and proceedings by International Pyrotechnics Seminar USA, Inc. and the International Pyrotechnics Society.

/3/ M. A. Bohn, F. Volk.

Aging Behavior of Propellants investigated by heat generation, stabilizer consumption, and molar mass degradation.

Propellants, Explosives, Pyrotechnics, 17, 4 (1992) 171 – 178. /4/ F. Volk, M.A. Bohn, G. Wunsch.

Determination of chemical and mechanical properties of double base propellants during aging.

Propellants, Explosives, Pyrotechnics, 12 (1987) 81 – 87.

/5/ M.A. Bohn The Use of Kinetic Equations to Evaluate the Ageing Behaviour of Energetic Materials – Possible Problems.

Proceed. 11th Symp. on ‘Chemical Problems Connected with the Stability of Explosives’ (held in Båstad, May 24 to 28, 1998),

pages 89-151. Editor: Jan Hansson, Ola Listh. 1999, Sundbyberg, Sweden. /6/ M.A. Bohn, J. Aniol, M. Dörich, K. Hartlieb, H. Pontius Stability, Ageing and Usetime Prediction of Polyvinylnitrate (PVN).

Paper 73, pages 73-1 to 73-18, in Proceedings of the 37th International Annual Conference of ICT, June 27 to 30, 2006, Karlsruhe,Germany. Fraunhofer-Institut für Chemische Technologie (Fraunhofer ICT), D76318 Pfinztal, Germany.

/7/ C. L. Bauer, P. R. Deacon, R. N. Garman, A. M. Emsley, J. R. Jones.

Low Temperature Non-Isothermal Aging of Nitrocellulose.

Propellants, Explosives, Pyrotechnics 30 (2005), No. 3.

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2012 Bohn 36


References – part 2 of 3 /8/ GPC method described in

STANAG 4178 “Assessing the Quality of Nitrocellulose Deliveries from one NATO Nation to Another”, Edition 2.

/9/ H. Pontius, M. Dörich, M.A. Bohn. Gel permeation chromatography of nitrocellulose (NC) and NC containing substances.- I. Parameter study for preparation of NC

solutions and chromatogram evaluation.

Paper 69, Pages 69-1 to 69-15, in Proceedings of the 39th International Annual Conference of ICT, ‘Energetic Materials – Processing and Product Design’, June 24 to 27, 2008, Karlsruhe, Germany. ISSN 0722-4087. Fraunhofer-Institut für Chemische

Technologie (ICT), D-76318 Pfinztal-Berghausen. Germany. /10/ Manfred A. Bohn.

Gel permeation chromatography of nitrocellulose (NC) and NC containing substances. - II. Remarks on calibration, molar mass distributions and mean molar masses.

Paper 70, pages 70-1 to 70-22, in Proceedings of the 39th International Annual Conference of ICT on ‘Energetic Materials –

Processing and Product Design’, June 24 to 27, 2008, Karlsruhe, Germany. Fraunhofer-Institut für Chemische Technologie (ICT), D-76318 Pfinztal-Berghausen, Germany.

/11/ Heike Pontius, Manuela Dörich, Manfred A. Bohn. Gel permeation chromatography of nitrocellulose (NC) and NC containing substances. - III. Recent results from a continued parameter study on the GPC of NC samples.

Paper 80, pages 80-1 to 80-12 in Proceedings of the 40th International Annual Conference of ICT on ‘Energetic Materials – Characterization, Modelling, Validation’, June 23 to 26, 2009, Karlsruhe, Germany. ISSN 0722-4087. Fraunhofer-Institut für Chemische Technologie (ICT), D-76318 Pfinztal-Berghausen. Germany.

/12/ P. Deacon, A. Macdonald, P. Gill, N. Mai, M.A. Bohn, H. Pontius, M. Van Hulst, W. de Klerk, C. Baker

An update on the Round Robin test to evaluate the nitrocellulose SEC method in STANAG 4178 (Ed.2).

Paper 81 in Proceedings of the International Annual Conference of ICT, 2009, Karlsruhe, Germany. /13/ NATO Standardization Agreement (NATO STANAG) 4582 ‘Explosives, Nitrocellulose Based Propellants, Stability Test

Procedure and Requirements Using Heat Flow Calorimetry’

Military Agency for Standardization, NATO Headquarters, Brussels, Belgium.

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2012 Bohn 37


References – part 3 of 3

/14/ NATO Allied Ordnance Publication (NATO AOP) 48, edition 2

Explosives, Nitrocellulose-based Propellants, Stability Test Procedures and Requirements Using Stabilizer Depletion.

Military Agency for Standardisation, NATO Headquarters, 1110 Brussels, Belgium.

/15/ Manfred A. Bohn Prediction of equivalent time-temperature loads for accelerated ageing to simulate preset in-storage ageing and time-temperature profile loads.

Paper 78, pages 78-1 to 78-28 in Proceedings of the 40th International Annual Conference of ICT on ‘Energetic Materials – Characterization, Modelling, Validation’, June 23 to 26, 2009, Karlsruhe, Germany. ISSN 0722-4087. Fraunhofer-Institut für Chemische Technologie (ICT), D-76318 Pfinztal-Berghausen. Germany.

/16/ A. Pfeil, H. H. Krause, N. Eisenreich.

The Consequences of Beginning Slow Thermal Decomposition of the Molecular Weight of Nitrated Cellulose.

Thermochim. Acta, 1985, 85, 395. /17/ N. Eisenreich and A. Pfeil.

Non-linear least-squares fit of non-isothermal thermoanalytical curves: Reinvestigation of the kinetics of the autocatalytic decomposition of nitrated cellulose.

Thermochim. Acta 61 (1983) 1 – 13.

/18/ Manfred A. Bohn und Norbert Eisenreich.

Kinetic modelling of the change of molar mass distribution function of nitrocellulose during ageing.

Paper 86, pages 86-1 to 86-24 in Proceed. of 41th International Annual Conference of ICT on ‘Energetic Materials – High Performance, Insensitive Munitions, Zero Pollution’, June 29 to July 2, 2010, Karlsruhe, Germany. ISSN 0722-4087. Fraunhofer-Institut für Chemische Technologie (ICT), D-76318 Pfinztal-Berghausen. Germany.

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2012 Bohn 38


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