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Author: Subject: How to plasticize ETN with SBR (styrene-butadiene rubber)?
ManyInterests
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[*] posted on 11-1-2024 at 21:12


https://shorturl.at/vGWZ3

Would something like this work? I tried to find a seller of litmus powder, but they were either not shipping or prohibitively expensive. Would this work? Also what if I just made the mixture of the oil and rubber cement, then used a pH strip? If the liquid is neutral, then it all should be good, right?
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[*] posted on 11-1-2024 at 22:37


Quote: Originally posted by ManyInterests  
https://shorturl.at/vGWZ3

Would something like this work? I tried to find a seller of litmus powder, but they were either not shipping or prohibitively expensive. Would this work? Also what if I just made the mixture of the oil and rubber cement, then used a pH strip? If the liquid is neutral, then it all should be good, right?

I have another idea. Ethanol is miscible both with petroleum solvents in rubber cement and with mineral oil. You can extract anthocyanines from, say, hibiscus tea. And add that alcohol solution to rubber+oil mix.




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[*] posted on 12-1-2024 at 00:55


Denny, when you say:

Quote:

There are also many silicone-based adhesives, but as far as I know, silicone polymers are not the best choice for plastic explosives due to their strong negative effect on the detonation rate.


Do you have any sources for that? From the papers I've read, it seems that silicone based plastiques are technically about as good as hydrocarbon polymers, but the price is higher.
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[*] posted on 12-1-2024 at 09:34


I'll be honest, I wrote this because I remembered an ancient discussion on a dead forum. I found it in the web archive, and unfortunately the opponents didn't leave a list of references to sources :(

So my thesis unfortunately smells of an appeal to authority. It's just that those guys were in 2000-2003 (up to 2012) essentially the founders of the hobby of making HEDM at home. But the posts themselves date back to 2006. Actually here are these comments:

"It is equally significant that organosilicon polymers give lower velocity characteristics in plastic explosives (negative influence of Si atom) than hydrocarbon polymers (gross formula of ALT glue[-C4H8-]n ), for example, in PETN/Binder 87/13, in the case of silicone, the calculated velocity increase in porous explosives is 0.39 km/s, while with ALT it is 0.86 km/s."

"Somewhere there were official data on impromptu with PETN and ligaments with the same content. Butyl rubber is the leader in terms of detonation speed, followed by polyisobutylene, and polysiloxane (i.e. silicone) is the worst of all, showing itself almost 0.5 km/s worse.In any case, it is better to use what you can buy at the market than to go to the chemical stores"

So forgive Microtek for not being able to provide any more substantial evidence, I can of course dig the internet for 2000-2007, but that may not make sense. And the archive page itself is here, in general, you can find these comments there too, if you need (https://web.archive.org/web/20160418142955/http://www.explod...)

[Edited on 12-1-2024 by DennyDevHE77]
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[*] posted on 12-1-2024 at 14:02


The silicone binders are also not moldable I assume. So they’d be horrible if you want a ‘plastic’ plastic explosive. If you’re just casting though, they’d be fine.
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[*] posted on 12-1-2024 at 17:42


Quote: Originally posted by EF2000  
Quote: Originally posted by ManyInterests  
https://shorturl.at/vGWZ3

Would something like this work? I tried to find a seller of litmus powder, but they were either not shipping or prohibitively expensive. Would this work? Also what if I just made the mixture of the oil and rubber cement, then used a pH strip? If the liquid is neutral, then it all should be good, right?

I have another idea. Ethanol is miscible both with petroleum solvents in rubber cement and with mineral oil. You can extract anthocyanines from, say, hibiscus tea. And add that alcohol solution to rubber+oil mix.


Now THAT sounds more fun and dooable. Also a lot cheaper.
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[*] posted on 13-1-2024 at 18:38


[I edited this comp from 0.3 to 0.45g low MW PIB(or mineral oil) since it dried out a little over storage]

Around 50ml Mineral spirits (any aromatic paint thinner), 3.6g SBR (Shoe Goo), and 0.45g low MW PIB (substitute for mineral oil) can be mixed together well in an aluminum bowl.

*This mix won’t completely dissolve, but will swell the SBR; it’ll need to be kneaded into the solids*

Then 22.7g all purpose flour (combustible material) can be added to the bowl and thoroughly mixed with the liquid mixture. The ‘dough’ should afterwards be strongly mixed with a spatula every 20min for about 2 hours or until the mineral spirits completely evaporate - a stand mixer might be preferable for a task like this. Gentle heat can be applied but air drying or sitting under a fan is recommended.

The resulting composition is perfectly pliable, tacky, leaves no residue on surfaces, and has a good amount of stretch before tearing.

Ratios can be adjusted to meet users’ needs, but this mix is straight from the hardware store and preps in <4hrs. I haven’t measured density or seen long term storage stability yet.

[Edited on 14-1-2024 by dettoo456]

[Edited on 14-1-2024 by dettoo456]
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[*] posted on 13-1-2024 at 23:38


Quote: Originally posted by dettoo456  
Around 50ml Mineral spirits (any aromatic paint thinner), 3.6g SBR (Shoe Goo), and 0.3g low MW PIB (substitute for mineral oil) can be mixed together well in an aluminum bowl.

*This mix won’t completely dissolve, but will swell the SBR; it’ll need to be kneaded into the solids*

Then 22.7g all purpose flour (combustible material) can be added to the bowl and thoroughly mixed with the liquid mixture. The ‘dough’ should afterwards be strongly mixed with a spatula every 20min for about 2 hours or until the mineral spirits completely evaporate - a stand mixer might be preferable for a task like this. Gentle heat can be applied but air drying or sitting under a fan is recommended.

The resulting composition is perfectly pliable, tacky, leaves no residue on surfaces, and has a good amount of stretch before tearing.

Ratios can be adjusted to meet users’ needs, but this mix is straight from the hardware store and preps in <4hrs. I haven’t measured density or seen long term storage stability yet.


Thanks for the instructions. I like stuff like that. I assume the 0.3g low MW PIB (you haven't told me what MW means) can be substituted with bar and chain oil or another motor oil?
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[*] posted on 14-1-2024 at 00:40


MW = molecular weight. Usually is number among 10.000 - 1000.000 Repeated search failed to find MW for Scapa 2501.



Development of primarily - secondary substances CHP (2015) Lithex (2022) Brightelite (2023) Nitrocelite (2024)
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[*] posted on 14-1-2024 at 06:26


Scapa has too high MW (and viscosity) I believe. You can substitute the low MW PIB for mineral oil and perhaps chain or motor oil. I think chain and/or motor oil might be have too low viscosity though.

If anyone knows also, can stabilizers like DPA, 2-NDPA, or centralite-1 be added to PBXs (nitrate ester based) and still have the same stabilizing effect or would they be useless in that case? Compounds such as DPA, 2-NDPA, and centralite are all soluble in acetone but insoluble in water, so I figured a co-mixture with ETN or PETN could be produced fairly easily via the anti solvent method and the resulting solid would have better stor-ability.

[Edited on 14-1-2024 by dettoo456]
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[*] posted on 14-1-2024 at 07:55


Quote: Originally posted by dettoo456  
Compounds such as DPA, 2-NDPA, and centralite are all soluble in acetone but insoluble in water, so I figured a co-mixture with ETN or PETN could be produced fairly easily via the anti solvent method and the resulting solid would have better stor-ability.
[Edited on 14-1-2024 by dettoo456]

DPA is soluble in acetone, insoluble in water, but soluble enough in acetone-water mix. I had problems with this. Other way insert DPA to PETN is need.
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[*] posted on 16-1-2024 at 15:51


Quote: Originally posted by dettoo456  
[I edited this comp from 0.3 to 0.45g low MW PIB(or mineral oil) since it dried out a little over storage]

Around 50ml Mineral spirits (any aromatic paint thinner), 3.6g SBR (Shoe Goo), and 0.45g low MW PIB (substitute for mineral oil) can be mixed together well in an aluminum bowl.

*This mix won’t completely dissolve, but will swell the SBR; it’ll need to be kneaded into the solids*

Then 22.7g all purpose flour (combustible material) can be added to the bowl and thoroughly mixed with the liquid mixture. The ‘dough’ should afterwards be strongly mixed with a spatula every 20min for about 2 hours or until the mineral spirits completely evaporate - a stand mixer might be preferable for a task like this. Gentle heat can be applied but air drying or sitting under a fan is recommended.

The resulting composition is perfectly pliable, tacky, leaves no residue on surfaces, and has a good amount of stretch before tearing.

Ratios can be adjusted to meet users’ needs, but this mix is straight from the hardware store and preps in <4hrs. I haven’t measured density or seen long term storage stability yet.

[Edited on 14-1-2024 by dettoo456]

[Edited on 14-1-2024 by dettoo456]


This composition dried out too much during storage out in the open at room temp. I handled it multiple times over the course of 3 days to test plasticity and I believe that too much oil was absorbed into my skin or transferred away.

It still remained pliable and soft but was simply too dry. I will replace (either fully or in part) the low MW PIB/mineral oil with Vaseline and maybe beeswax to see if they produce a product with better results.

If anyone has any insight on SBR PBXs please feel free to add or critique.
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