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Author: Subject: Interesting plasticizer observation
aromaticfanatic
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[*] posted on 30-12-2020 at 17:55
Interesting plasticizer observation


I have come up my my very own PBX that works well utilizing rubber cement and motor oil. It's properties are a little stiffer when cold but relatively malleable when warm. It would roll out nicely and wouldn't crack or anything. Never reeked of solvent either. It was high density too.

The major drawback was that I had to use acetone as the solvent for plasticizing. It dissolves the ETN destroying the previous crystal size and has a higher risk of detonation when shaving due to the larger crystals that form.

I attempted the same ratios that work perfectly for my acetone method but this time used naphtha to allow better incorporation of the ETN. It worked but what I found was that the end result did not bind together too well. It was much crumblier and was more prone to crumbling apart when rolled out. My acetone version rolled out like regular dough.

On top of that I had to use much more oil than usual to combat that crumbling issue (it ended up being semi futile and all it did was give it properties that I remembered my other plastic having if I used too much oil). It is much softer but more crumblier and still reeks of naphtha even though I can been hitting it with a hair dryer while constantly kneading for around an hour.

This is my last HE experiment so I won't try again.

I just wanted to share and see if anyone else knows why this happens? The ETN was pH neutral and recrystallized into the same crystal size/density as usual. Only difference was the solvent. ETN was a free flowing powder.

My guess on what happened here is that the dissolution of ETN into the acetone allowed for a much better incorporation of the ETN throughout the latex plastic allowing for much better properties. The naphtha simply dissolved the latex and seemed to not "grab" the ETN as well and as intimately. What are your guys' thoughts?




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aromaticfanatic
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[*] posted on 1-1-2021 at 02:03


Aaaand it didn't detonate. Not exactly surprised. The detonator had some changes to it and because of the lie of ETN being easily hand pressed to 1.2g/cm^3 it caused my cap to have half the usual amount of ETN at much lower density. Of course it didn't detonate the plastic. Sad day but whatever. I hated dealing with HE again and I can't wait to make benzoic acid instead.



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[*] posted on 1-1-2021 at 08:01


Ugh, when I read this post the other day, seeing ETN was repellant. I guess if you could phlegmatize it, the dangers are reduced. One question, why is acetone required? Aren't there other solvents that could soften rubber cement? I never found much success beyond the patent PIB dioctylsebacate blend. Works great. Oddly enough amazon was selling DOS recently, kind of amusing. And you can find the PIB tape, not cheap but not the major constituent.

As far as detonation, what percent was the ETN in the final blend?

Also, best practice here is to edit posts over repeat posts.




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aromaticfanatic
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[*] posted on 1-1-2021 at 12:18


ETN when properly prepared is not as sensitive as you may think. I am very cautious as is and would never have made this much if I didn't know how to handle it or if I didn't know how sensitive it truly was. The only thing you really need to watch for is sources of heat shock. I was able to absolutely slam a hammer onto some wrapped in aluminum foil and only got a detonation 30% of the time. Free of acid and small crystal size is key. But using a lamp that could fall onto or crack and send hot glass onto the drying pile would be unwise.

The plastic is very insensitive which is why I plasticized as soon as possible. Plasticizing is one form of phlegmatizing. A detonator went off inside of the plastic and it still didn't detonate. If that doesn't attest to its stability, I don't know what does.

The ETN in the end was likely very low. I believe I had 25 grams of ETN in there and the final weight was 33grams. Like I said I had to use much more oil than usual to prevent it from getting crumbly. Add on top of that that the plastic still smelled strongly of solvent, I'd say that's partially added to the failure. My money is that the detonator was far too weak. I have gotten reliable and successful detonation with straw and aluminum sheet confinement using 800mg of melt cast ETN, 200mg of pressed ETN, and 200mg of SADS. I had used 600mg of pressed ETN before with 200mg SADS and that also failed to detonate the plastic. That was using just a plastic straw for confinement. The other detonators always set it off. This go around was 500mg of pressed ETN and 200mg of SADS in a metallic tube. It was bound to fail. I know that the pressed ETN did detonate because the plastic was completely splattered and from experience I know that was not just the SADS by sound. The SADS part of the detonator was sticking out of the plastic and the ETN part was inside which was also another indicator of ETN going off.

Something else I should say is that I have been able to detonate various plastic formulas even with poor OB and lots of oil and they still retained incredible power.

I say acetone was seemingly required as the plastic produced from the acetone method had impeccable properties (high density, good OB, high brisance, and good malleability). When the binder was dissolved in naphtha the properties were pretty horrendous (low density, poor OB, but better malleability). As I said, I think it was due to better and more intimate contact between the binder and ETN as the solvated ETN was able to get inside the binder much better than solid form.

I can't edit the post as there is a time limit on editing and deleting. Or else I would.



And yes I would have loved to make a new plastic formula with PIB (I was thinking about extracting some) but since my old formula using rubber cement gave such great results I saw no need to. It was supposed to be one last hurrah. I had even prepared methyl ricinoleate (one of the best plasticizers that amateurs can easily make) but like I said I never made the new plastic.



[Edited on 1-1-2021 by aromaticfanatic]




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