Fire vs. Handgrenade

[Darth Wong]

I thought the stabilizing effect of a substrate for nitroglycerine had to do with the prevention of the bubble formation mechanism that was thought to initiate detonation, not with any changes in real or potential energy states.

[Admiral Valdemar]

Hmm, may be so. Given I used "bond" rather than "energy state" whilst writing that last night and confused TNT and Dynamite, I was probably tired enough to misread the use of stabilisers in explosives. Now I'm going to have to try and fish out that chem site again.

EDIT: All I can find is what I read originally, that the stabiliser (diatomaceous earth originally) simply buffered the nitro absorbed in, so any physical shock didn't directly hit pure nitro which will happily react from even gentle touches at times.

[Darth Wong]

OK, let's find a source:

NG, an oily liquid, is extremely sensitive to initiation by shock. The sensitivity is due to the presence of bubbles of NG vapor, which are usually present throughout the liquid. Alfred Nobel discovered and patented the technique of absorbing NG in a porous medium that suppressed the effects of the bubbles and allowed the mixture to be safely handled. Originally, Nobel used kieselguhr (diatomaceous earth) as the absorbent. Today a wide variety of absorbents are used, along with any number of other additives. Some of the other additives are used to provide water resistance and to adjust oxygen balance and density. Sometimes halogen salts are added in order to suppress the formation of a large and hot fireball from the detonation. This is done to lower the chance of the dynamite igniting flammable and explosive gases present in some mines. Such dynamites are called "permitted".

From Explosives Engineering by Paul W. Cooper, Wiley-VCH 1996

The text goes on to list all manner of additives, and also reveals the interesting fact that US military dynamite uses no nitroglycerine any more. It is apparently made of a mixture of TNT, RDX, cornstarch, and engine oil. This was done to eliminate problems with freezing, oozing, and extruding. Apparently, US military dynamite remains usable even after 24 hours of submersion in water.

[Admiral Valdemar]

Most all militaries use RDX or PETN for munitions, with various mixtures depending on what you're wanting as a result e.g. RDX can form the "safe" C-4, or you can use PETN and another catalyst to produce Primacord which is more volatile but less stable. For big bangs such as Daisy Cutters, you use ammonium nitrate with aluminium powder and polystyrene, while FAEs can vary from liquid to gas to solid explosives. The cool thing about the plastic based explosives, like C-4 and its relatives and Semtex, is that you can chuck a chunk in burning fuel or shoot it, and it won't go off. It has to have that electrical charge go off inside it because the plasticiser is so good at stabilising. I guess the suppressing of vapour bubbles is the missing detail in my previous posts, since pure vapour bubbles will react easier than NG in some solid buffer.

In this day and age, the last thing you want is sappers or infrantrymen dealing with what we used in the 19th century. Even when Dynamite was mixed with a stabiliser, it was prone to degradation if not stored well. TNT I believe is used exclusively in controlled demolitions today and clearing mines.

[drachefly]

not with any changes in real or potential energy states.

What do you mean by 'real energy'? Kinetic?

[Darth Wong]

not with any changes in real or potential energy states.

What do you mean by 'real energy'? Kinetic?

I was thinking of internal energy, actually.

[Sea Skimmer]

How fast would the fire reignite? And what would a thermobaric grenade do to a fire?

Instantly if its going to at all. As for a thermobaric warhead, within a limited radius it would snuff out any fire, but the whole point of a thermobaric device is that it’s a very fast moving fire caused by a fuel, not a detonation of an explosive compound. So outside that limited radius it will start fires REALLY well. In the few videos I've seen of them being used there is always a lingering fire after the warhead goes off at the point of impact, even if there wasn't much of anything to be set on fire. So that would be a bad option.