meltable explosive mixtures

[Oktogen]

Sorry for making a new thread but I searched for similiar topic. There were some topics about nitrating naphtalens but not about melting explosives. :cool:

For about half a year I'm looking for a meltable waterproof mixture with a high VoD (needed for liner shaped charges) containing at least 50%PETN, the rest should be ammonium nitrate and some easily meltable nitro compound(TNT, TNX or other).

TNT is the best for such a mixture because it's stable, has a low melting point, but on the other hand nitrating toluene is very hard, every NO2 group inhibits the benzen ring for electrophil substitiusion of next NO2 groups, so in the last step only using 60% oleum (solution of SO3in H2SO4) and 99% HNO3 and nitrating DNT in high temperaturs can give pure TNT with a good yield.

Making TNX (trinitroxylene ) is better but commercial xylene from a hardware strore sold as solvent is a mixture of different isomers, and contain only 50-60% of b-xylene which is the only isomer stable during last step of nitration (o- and p- isomers oxidise ).

TNP, picric acid synthesis is really easy, TNP is 20% more powerful than TNT but don’t forget that it’s a strong acid !!! It can’t be melted together with nitroesters like PETN because it can make them unstable and cause their decomposition. The last one i think of is the best one... nitronaphtalenes...

In the next days (I’ve broken my hand and in the weekend I go to hospital to cut the gyps bandage ;):):] ) I’ll try nitrating naphtalene to mononitro, then dinitro form. Today I’ve bought moth balls, with some aroma (smells like ordinary naphtalene so it shouldn’t be a problem.) I’ll nitrate it with 40ml HNO3 65%, 40ml H2SO4 96% for every 50grams C10H8. It should give 60 grams of MNN.

Then I want to melt 15% MNN with 75% AN and 10% PETN or just 15%MNN and 85%AN. It should work fine as a substitute of ordinary ANFO or amonal. I’m a bit scared of melting large ammounts of highly flamable mix, and I don’t know if such a tiny ammount of MNN can sink in so much AN. Next thing I am going to do is to make DNN and also try to melt it.

Have you guys any experience in melting high explosives, especially based on PETN or MNN/DNN/TENN ???? I’ll send you photos of synthesis (it should be safe , but I hate this NO2 red fumes just hate them ! ! ! :mad: ).

[Cordtex]

Oktogen:
IMHO I do not think that there are waterproof explosive mixtures made by NH4NO3. And in case if you want to melt MNN, DNN, DNT, TNT for any reason, you can just use a hot water bath or steam, which is pretty safe and there won't be
any decomposition (i.e. you won't smell any NO2). For PETN, sorry never tried to melt or cast it, PETN MP = 141.3 celcius.

[Boomer]

This *has* been covered, but mostly in threads about *one* explosive. I.e. melt-castable ETN/PETN mixtures were discussed in the ETN + PETN threads, pentolite in the TNT thread and so on. So IMO this thread is not redundant, as we can compare the different mixes here. :)

Firstly, are you sure that the o+p xylenes are oxidised during the tri-nitration? I thought they only stopped at the di-stage because further nitration was inhibited too much?
Secondly, I thought the three isomers were approx. present in equal parts. 60% meta would not be bad for making TNX, as you can use the leftover o/p dinitros for AN explosives. Thirdly, TNX has a melting point of 181C, much higher than picric. You definitely do *not* want to melt it. It has a use as a melting point reducer for PA and TNT though.

There is some contradiction in your plans: You look for a high VoD, with at least 50% PETN, and then speak about 75-85% AN with 15% MNN and 0-10% PETN only. Or are that two different projects? Plus, even the originally mentioned mix with 50% PETN will not be too water resistant if there is AN in it. It will be fairly resistant for quite a time, but the AN crystals may eventually dissolve out of the matrix.

Have you thought of simply adding NG to the PETN? Varying the percentage between 10 and 40%, you will get any consistency from a hard mass that softens just enough at 55C to allow pressing, to a pourable liquid at 55C that hardens just enough at room temp to retain its shape. The same is true for MHN and ETN, with MHN being least stable, once at 55C for some time it needs a stabilizer for storage. ETN is castable as-is, but a few % NG lower the melting point to a more nerve-friendly level. All these mixes benefit from addition of a crystalline HE like RDX, they tend to det low order otherwise if unconfined. Even HDN, less sensitive than the other components, works in this way if not too much is added.

[Oktogen]

bingo,
making a high VoD mix with 50%> PETN is one task for me, making AN/MNN mixes is the other. I'm going to use ANMNN for simplier cases such as blowing concrete blocks, rocks or trees ;) . high VoD explosive would be used for cutting steel in shaped charges. two months ago I tried plastic composition, I made it with following ingredients:
60% PETN,
36% EGDN
4% low nitrated nitrocellose
tomorrow I'll try to upload a film of kneeding this plastic, it's hardly initiated :eek: but fantastic :D . It's density is around 1,7g/ml so in heavy confinement it could give 8300m/s :D
In my opinion, AN/MNN/PETN would be waterproof because crystals of MNN would coat and cover AN/PETN powder. More interesting for me is if PETN and MNN or DNN can make an eutectic mixture (mixture of two compounds that melts in lower temperature than two compounds apart). If so, it would be the simpliest meltable explosive.
PS,
addition of AN to all the mixes is applied to improve oxygen balance of MNN/DNN

[Myrol]

Oktogen: Umm, you're looking for a powerful meltable HE? What about DNT with AN and Al? Because I have now around 700g DNT waiting for his wash ready I can make a lot of this mix and TEST some at the Weekend! The mainproblem is just the worse initiateability with cast AN-mixes!

I hope I dont get a misfire with my pretty DNT. But hey....you're right Nitrated Naphthalenes are less cancerogen than DNT....but because I just love DNT I'll stick to that Energetic for a while. TNT is a possibility, but for that effort...I think it isn't worth to waste it with AN together....if you need more Info's for a TNT-Synthesis look in the TNT-Synthesis Thread....I'll posted something wich could be helpful

[Blackout]

Octol 30% TNT 70% HMX
Cyclotol 25% TNT 75% RDX
Comp. B 39% TNT 60% RDX 1% wax
Baratol 76% barium nitrate 24% TNT
Boracitol 60% boric acid 40% TNT
Picratol 60% TNP 40% TNT (I'm not sure of the %)
Pentolite 50% TNT 50% PETN

[Microtek]

TNT isn't all that difficult to make; you don't need oleum for the final nitration step, it's just more convenient. Without oleum, just using nitric acid 95% and H2SO4 96% you have to separate the DNT from the spent acid of the previous nitration before adding it to the fresh mixed acids.
If you have oleum, you can just add the oleum and fuming HNO3 to the mix of DNT and spent acids, and the SO3 will react with all the water present to form H2SO4.

An additional separation step obviously adds to the work load, but not by too much once you get it organized.

[Rosco Bodine]

Cast compositions offer the ultimate in terms of bulk density
and velocity , to deliver the most energy from the smallest package .
But the tradeoff encountered with cast compositions is that as a rule
a cast composition is two or three times as hard to initiate as a pressed
composition of particles of the exact same material . To secure the
high output , high velocity detonation of which the cast composition is
capable , requires a much stronger detonator or intitiating charge ,
The critical diameter also increases so generally the scale of the device
for efficient operation is much larger than for pressed charges of the same
material .

For cast compositions to function efficiently in relatively small scale devices ,
the more sensitive materials like nitrated polyols are the most practical .
ETN , PETN , MHN , and probably other nitrated polyols , can form low melting
mixtures which are useful . It is important that purified and stabilized forms
of the nitrated polyols be used in such melts since heating of such materials
adversely affects their stability . Working quickly with the purified and stabilized
materials used to form the melt is necessary , so that the exposure to the
elevated temperature is limited in its negative effects upon the storage stability
of the finished cast composition .

[Oktogen]

the insensitivity of cast explosives can be useful :) but to overcome the problem of good initiation, i'll drill or simply make with a plastic container a hole, 2-3cm in diameter, with a volume similiar to camera film container in which I will press several grams of PETN, and put a hmtd/petn Bcap in center of it. According to the fact that this mixture will contain at least 50% PETN, the rest beeing high nitrated aromatic explosive, TeNN, TNT or as I said just DNN it will be quite sensitive. Just imagine a shaped charge made from a HDPE(hardened poliethylene) pipe 50mm in diameter with 150grams cast high explosive with briliant VoD and a big 20grams PETN detonator and 500mg HMTD B-cap , liner made from 1mm copper sheet ... :D :D :D it would be one of the most advanced steel cuting device on this forum...IMHO it would...

[Diabolique]

Is a melt-castable explosive really necessary? The US military is getting away from them and is using plastic bonded explosives instead.

These use materials such as polystyrene, Estane 5702-F1, Exxon 461, DOP and CEF to bond explosives such as RDX, HMX and TATB into solids. The process is simple, but time consuming.

The primary explosive is mixed with water into a slurry. The temperature of the slurry is raised to around the boiling point of the solvent to be used. The bonding agent is disolved in a solvent, such as benzene, and added to the slurry with a lot of agitation. The bonding solution is added slowly over time, and the solvent driven off by the heat. The bonding agent deposits on the particles of explosive. Toward the end, the explosive clumps into beads. When all the solvent has been driven off, the product is washed with water and dried.

These beads are fed into a plastics injection molder where they are compressed into shape at 12,000 to 20,000 psi under vacuum. The vacuum is the secret for their high performance, it makes for a high density product. The same is true for plastic explosives, like C-4. The vacuum processing eliminates voids that cause low density, and thus low detonation velocity (the new texts list VoD as simply D).

The PBX's have several advantages. No molten explosives that cause burns and are quite shock sensitive. No cracks forming during solidification. No problem with explosives decomposing with heat. The insensitive explosives, like TATB and LLM-109, are not made sensitive by being cast in TNT (TATB is stable at temperatures near those that melt lead!).

I have heard that 5% DIPAM has been used by Germany in WW1 to reduce shrinkage of TNT when cast. However, DIPAM is a skin irritant.

[cutefix]

I have heard that 5% DIPAM has been used by Germany in WW1 to reduce shrinkage of TNT when cast. However, DIPAM is a skin irritant.

IIRC. its HNS being used with TNT for the same reason as DIPAM?

[Diabolique]

Cutefix: I understand that HNS is used to reduce TNT's melting point. It may have the same effect. I prefer the nitamines and esters rather than TNT - too much work or too much material, depending on how it's made.

Oktogen mentioned blasting and steel cutting. There are many manuals on blasting, DuPont's is about the best, if you can get it.

Steel cutting is a subject in itself. Steel plate is cut by either a ribbon charge (use 3X the steel's thickness in high brisance explosive, its width 3X its thickness) or linear shaped charge. LSC's use a lot less explosive.

A chain or rod is best cut with a diamond charge, if you have the time. Make a diamond shaped charge 2.5 cm thick of plastic or sheet explosive. The long axis is the circumferance of the steel rod, the short axis is half the circumferance. Wrap the long axis around the rod's circumferance, and initiate with two electric detonators at the apex's of the short axis. The colliding detonation waves tear the steel rod apart.

Shaped charges are very hard to make, if you are looking for high penetration (over 3X the diameter of the charge). A single void will cause the detonation wave to become mis-shaped, and disrupt the formation of the penetration rod. Munitions plants load these with vacuum cycling to scavenge gas bubbles that form voids.

PETN is soluble in TNT. The military's standard pentolite is 50%-50%, which is very near the eutectic for the mixture. What I;ve heard of pentolites, do not go over 65% PETN. At high PETN levels, the mixuture is used as a propellant, not an explosive. It may become insensitive to standard initiation.

Has anyone tried TNT-PETN-RDX in equal amounts? The TNT-PETN forms a eutectic matrix for the RDX crystals.

Also, stay away from oleum (beyond cost, availability and danger), it can inhibit the trinitration of toluene. Urbanski recommends a few percent of water in the nitration mix for TNT, it helps form sulfation ions that attach to the benzene ring of the toluene, and are replaced by nitro groups. I gave a lecture on this in college. Even acetic anhydride needs a tiny amount of water to activate the RDX production reaction (that absorbed from air is usually enough).

[cutefix]

“Cutefix: I understand that HNS is used to reduce TNT's melting point. It may have the same effect.”

Why would you reduce the already low melting point of TNT which is already causing problems in melt cast explosives due to exudation?

AFAIK the primary importance in the presence of small amounts of HNS was to reduce shrinkage of melt cast explosives containing TNT.
But the main importance of HNS is its high temperature stability having a higher melting point than most stable explosives.
HNS melt at 316-319 deg C.
Compare that to RDX which is ca. 200 -205 C;HMX ca. 270 deg C.

“I prefer the nitramines and esters rather than TNT - too much work or too much material, depending on how it's made.”


The primary reason for such preference is the higher explosive performance of certain nitric esters if compared to common nitroaromatics like TNT.
As an example compare the explosive performance data between Trotyl and penthrite.
The primary benefit of TNT is its best performance as a carrier for other explosives for melt casting into explosives compositions such as Composition B, Cyclotol-hexotol, tritonal,picratol,octol etc.

From previous Los Alamos Science Laboratory files in California if these explosives are to be made in volume quantities say in 40000 lb quantities, TNT cost only $0.65 per pound, PETN cost only $2.08 per lb. RDX cost $ 6.00 a pound. HMX cost $ 9.72 per pound to produce.

Therefore melt cast explosives cost cheaper as TNT is not expensive but PBXs are expensive being based primarily on nitramines bound with both plastic inert and energetic binders and plasticizers;plus the fact that the manufacturing systems ,are time consuming to do.
One thing also the nitramines such as RDX used in melt cast compositions had fallen to lower acceptability were sensitivity hazards during storage of ammunitions resulting in several deaths and severe damage to infrastructure occured.
In recent years RDX are largely superseded by newly discovered heterocyclic explosives like NTO.
If you look at the current explosive fillers for modern bombs there are still melt cast explosives to replace composition B but NTO is used as a replacement for RDX due to its compliance to insensitive munitions classifications and keep in mind TNT is still the carrier.
Meaning PBX may dominate in specialized explosive formulations but the simpler cost effective melt cast explosive formulations cannot be just abandoned for simple application such as filling common artillery shells.


”Oktogen mentioned blasting and steel cutting. There are many manuals on blasting, DuPont's is about the best, if you can get it

Steel cutting is a subject in itself. Steel plate is cut by either a ribbon charge (use 3X the steel's thickness in high brisance explosive, its width 3X its thickness) or linear shaped charge. LSC's use a lot less explosive.”

Regarding blasting and steel cutting there are good literature references from Dupont and the US army technical manuals which are even cited in the Literature sections of this forum.



”Shaped charges are very hard to make, if you are looking for high penetration (over 3X the diameter of the charge). A single void will cause the detonation wave to become mis-shaped, and disrupt the formation of the penetration rod. Munitions plants load these with vacuum cycling to scavenge gas bubbles that form voids.”

If shaped charges are difficult to make how come there are many improvised methods of producing it without the need for high precision equipment? There are literatures that are found in the net which are even known by many members of this forum.
Besides there is another way around for anti armor applications such as the explosively formed projectiles( EFP) which are simpler to design if compared to SC.

”PETN is soluble in TNT. The military's standard pentolite is 50%-50%, which is very near the eutectic for the mixture. What I;ve heard of pentolites, do not go over 65% “

Not really...
If you look closely how pentolites are made in recent years for industrial explosive boosters, the PETN particles are coated with TNT then the resulting mixture is cooled under rapid stirring and then dried out at 75 deg C.
Dissolution is not practical as the fact is at the casting temperature of around 90 degree C only 20% of PETN can be found to ‘ dissolve’ in TNT hence will likely stratify. In addition to that you need a particular PETN grain morphology and size to enhance better dispersion in the pentolite composition

“ At high PETN levels, the mixture is used as a propellant, not an explosive. It may become insensitive to standard initiation.’

I have not heard of any double base compositions for propellants containing penthrite. So its likely that….
PETN is not used as an energetic enhancer for high performance propellants if compared to its cousin nitric esters NG and NC are.
its is because it has lower burning rate specially in solid form .In fact it was proven in past experiments that PETN is difficult to ignite at STP and its slow burning in solid form but if liquefied it can burn in the same way as Nitroglycerine and nitrocellulose.
But liquid PETN does not exist for practical applications.

”Has anyone tried TNT-PETN-RDX in equal amounts? The TNT-PETN forms a eutectic matrix for the RDX crystals.”

Well regarding that case PETN has fallen into low popularity in military applications if compared to RDX; whatever applications made with eutectic mixtures of PETN-TNT-RDX is superfluous as the nitric esters can’t provide any advantages in terms of explosive performance in the presence of RDX.
The main reason why PETN is included practically is its cheaper and it can extend RDX.


”Also, stay away from oleum (beyond cost, availability and danger), it can inhibit the trinitration of toluene. Urbanski recommends a few percent of water in the nitration mix for TNT, it helps form sulfation ions that attach to the benzene ring of the toluene, and are replaced by nitro groups.”


Yes that might be true in the mono and dinitration of toluene to mono and dinitrotoluenes- water is really added there
But its common knowledge that Oleum is used in the majority of plants (worldwide )devoted to TNT manufacture.
Therefore its confirms that higher nitration requires higher acid concentration which can be supplemented with the use of oleum during the later stages of nitration.
It was found out from other experimenters that the presence of water in higher nitration will increase the amount of trinitrobenzoic acid impurity during the trinitration stages.
.