Sciencemadness Discussion Board

Stabilising additives

Ral123 - 13-1-2014 at 10:27

We all know many of the commercial energetic materials have added stabilizers. As far as I know CaCO3 and other carbonates are used for cheap dynamites. Diphenylamine is used to stabilize NC and double base propellants. Urea is also used sometimes. The problem with urea is that it generates water when reacted with NOx and water aids decomposition of some nitric esters, I've read about NC to be precise. How would you stabilize RDX, TNP, PETN and others? A storage test of mine showed the R-salt alone sucks totally for storage. UN didn't do bad, blew up after a year poorly sealed and torture dried to begin with (till melted and decomposed here and there).

Pard - 13-1-2014 at 14:06

I know with lead azide, dextrin is used. (though I believe you know this, iirc you have a video of it produced) Sodium carbonate for dynamite. For PETN, I've heard of Urea being added as a stabiliser. Actually urea being used as a stabiliser in a few things.

Could you give details on this urea nitrate going off, sounds interesting.

Hennig Brand - 13-1-2014 at 15:39

RDX, TNP and PETN are all very storage stable even without added stabilizers, when well purified, relative to dynamite and NC. The dextrin added to lead azide is not for storage stability, but to inhibit crystal growth, as far as I know. Larger lead azide crystals tend to be more dangerous to handle. Just recently in the Cheddite thread there was talk of using lecithin to prevent recrystallization and hardening of Cheddite charges in storage. I guess different compounds or mixtures can change in different ways and that there are different ways of slowing those undesirable processes.

Ral123 - 13-1-2014 at 23:45

Quote: Originally posted by Pard  
I know with lead azide, dextrin is used. (though I believe you know this, iirc you have a video of it produced) Sodium carbonate for dynamite. For PETN, I've heard of Urea being added as a stabiliser. Actually urea being used as a stabiliser in a few things.

Could you give details on this urea nitrate going off, sounds interesting.

https://www.youtube.com/watch?v=37q_QyKDrGA

I have the feeling NC has similar stability to PETN. How about calcium carbonate of sodium carbonate for let's say ETN. If these had very good stability without additives, why the industry still adds stabilizers? I'm not sure if it's done with RDX.

Pard - 15-1-2014 at 14:32

I'd say they add more to the still stable because they like to be extra careful. They have to factor in for human error and people having off days.

I've also heard of lecithin being used for PETN and RDX as well as mixtures of the two. I was told used for to help forming of larger crystals

Ral123 - 23-1-2014 at 13:38

I wonder isn't MgCO3 superior to Na2CO3 due to it's lower agressiveness? Also, has anyone thought of using erithritol as a stabiliser, it would get partially nitrated with the decomposition products.