hossam6006
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Performance measure for Nitrocellulose
There are countless procedures for preparing NC, I usually do it this way:
- mix 5kg of HNO3 (conc 65%) with 8kg of H2SO4 (98%) slowly with cooling under 25c.
- gradually add 1.5kg of medical cotton to the acidic mixture while mixing with a PPR pipe.
- wait 2 hours, take off the cotton.
- squeezing, washing with water (6 times).
- boiling with 10% sodium bicarbonate solution for 2 hours, squeezing (2 times)
- washing with water, squeezing (2 times)
This produces a very nice nitrocellulose, but "nice" is not a word in science.
The washing process may look sufficient but it's not.
In industry they boil NC for up to 40 hours! and they may also add some stabilizers (1-2%), like diphenylamine, to remove any traces of the acid and
enhance the cotton stability and prevent performance deterioration over time.
remember NC in military rockets remains stable over decades !
while I can't afford to buy expensive diphenylamine, I can live happy knowing the actual performance of my NC, so I can use the right amount of it for
my ballistic application.
My question is:
What is the way to measure it's performance, to determine the deterioration rate over time and also define its nitrogen content?
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Dany
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A good reference for nitrocellulose and derivatives is found in volume 2 of Encyclopedia of explosive and related items, Vol.2, page C-100 to C-125,
there are useful information on synthesis, characterization, and properties of this material.
Dany
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plante1999
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That's a very very large scale synthesis!
Try to find how to use a nitrometer, and build one. With such a device, you will know the nitrogen content, nitrocellulose at maximum purity is 14.14%
Nitrogen I believe.
I never asked for this.
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mayko
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I made nitrocellulose in polymer chem in high school; I'll see if I can dig up my notebook but I seem to remember that we used the change in mass to
assess the degree of nitration.
There are a couple of things I might try to assess performance. One of the things that characterizes NC performance is the speed it burns; I've heard
you can put good NC on a small pile of gunpowder and light it without igniting the pile. You could measure this perhaps by laying out a foot of NC
thread and timing its burn time as a fuse.
Another measure might be gas released per mass. This could be assessed with an electric igniter and a flask connected to a graduated gas trap.
At the scale you're operating on, you could measure deterioration by setting aside a large sample in the storage conditions being modeled, and then
periodically test it.
al-khemie is not a terrorist organization
"Chemicals, chemicals... I need chemicals!" - George Hayduke
"Wubbalubba dub-dub!" - Rick Sanchez
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golfpro
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Are you using the NC as a rocket proppelant?
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hossam6006
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@Dany:
Thanks. very informative refrence!
@plante1999:
Yes, cotton is cheap 
looks like nitrometer is unavailable/expensive/impractical for me.
@mayko:
nice info.
I'll dig for more about what you said.
@golfpro:
yes I am willing to do so, but first I want to reach a satisfactory synthesis procedure.
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VladimirLem
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What? I'm always making 3 up to 4 kg HMTD in one step.
Whers the problem?
@Thread: Such a waste of good acid
and, once i made some NC the same way and used even more H2SO4 and it burned very very solw...that sucks...without HOKO i wouldnt go for it, even as
an propellant
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plante1999
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3 to 4kg HMTD seams very safe...
I would never make 10g of primary, lets alone kg. I have nothing again large scale nitrocellulose synthesis.
I never asked for this.
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hossam6006
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@VladimirLem:
I wouldn't do large-scale primary ... I know someone who make ~2kg of acetone peroxide in one batch! but this shouldn't be done, remember your first
error is the last one.
If your NC is burning slow, it's either wet or not properly washed from the acids.
my synthesis works great and produces NC of the same quality of industrial NC (when freshly used).
What do you mean by "HOKO" ?
@plante1999:
NC is not primary and there should be nothing wrong doing it even at larger-scale.
the problem is that of washing the cotton: very exhaustive!
using a customized washing machine you can do up to 7kg in one batch at home.
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mayko
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(from my notebook)
Dried (oven-roasted, I believe) cotton of mass 0.5389 g was nitrated (no details, sorry). It was then massed at 0.9787 g.
This gives a mass increase of (0.9787-0.5389)/0.5389 = 81.6%.
By comparison, the trinitrated product has a molar mass of 594 g/mol, compared to 324 g/mol of cellulose monomer. This gives a mass increase of (594 -
324)/324 = 83.3%
The mononitrated and dinitrated products have mass increases of 27.7% and 55.5%, respectively.
al-khemie is not a terrorist organization
"Chemicals, chemicals... I need chemicals!" - George Hayduke
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Fantasma4500
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i would say nitrate it for a total max of 24 hours, this is the max, i found out about this just lately, peroximane92 on youtube states that after 24
hours it has a chance of starting to disintegrate / decompose due to acidity
his video also shows 1, 2 and 5 hours deflagration difference
also im not sure whether your solution is completely stoppered with cotton, but you should try to suck it all up with cotton to improve yields
also, how do you manage to pay for such massive nitrations..??
for propellants, you might want to consider adding sorbitol hexanitrate dissolved in ethanol to the cotton and let it dry out, i suppose this is one
way to get it evenly scattered in the NC, with respective quanities, wrong quanities might just remove everything you consider using as barrell and
what not (:
i think you should however consider trying a small scale 100 mL H2SO4 where you test nitration times against each other..
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hossam6006
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@mayko:
I think the calculation isn't correct.
Trinitrate has a molecular weight of 828.56 (Encyclopedia of explosive and related items, vol.2, page c-100)
but I got the idea ...
@Antiswat:
there's something wrong peroximane92's tests.
I once made cotton similar to the 1 hour sample, it burned slowly leaving a black dust, after investigating I found this is because of bad washing, I
rewashed it and it worked like charm.
this should never happen even if nitrating for 15 mins only.
Sure, my cotton is fully saturated with the acid mixture.
I'm thinking of making double phase propellant: bending NC with ethanol & ether mix, adding nitroglycerin, bending even more, casting or extruding
the paste to get something like drinking straw, drying for few days, then using it.
I didn't try that yet, but I think it will work just fine.
I'm using such a large sample to be able to thoroughly test portions of it over a period of up to 6 months.
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VladimirLem
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Quote: Originally posted by plante1999  | 3 to 4kg HMTD seams very safe...
I would never make 10g of primary, lets alone kg. I have nothing again large scale nitrocellulose synthesis. |
 
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Fantasma4500
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well hossam, thats quite interesting actually..
can you make video proof of the unwashed vs. properly washed NC??
and if so...
how would 24 hours nitrated NC perform when fully washed?!
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