Sciencemadness Discussion Board


ceasemcb - 10-2-2012 at 13:10


Long time lurker, first time poster.
I've been making energetic materials for quite some time now, going one two years soon, and this forum has helped me learn a lot. But one thing I haven't been able to understand is plasticization. I know what it is, but not how to do it; right now I have some PETN and RDX, and I want to plasticize them together. Could someone help me with the process?

Use The Forum Search Engine

Bot0nist - 10-2-2012 at 19:05

<a href="">Read this for a start.</a> A great thread. Reminds you that crystal structure plays a significant role in effective plasticizing. Some tit-bits to get the mouth watering.



fter experimenting a bit with some fresly made methylricinoate I come to believe that the hydrophillic moment of the plasticizer is very import in determining the "stickyness" and "stiffness" of the plastique, especially with low % plasticizer, high density plastique...

Whereas using motoroil alone as plasticizer gives an almost rocksolid plastique at 5-10% plasticizer, replacing 60-70% of the oil by methylricinoate makes it perfectly kneedable while not sticky, even at very small particle sizes.
It is no coincidence that all plasticizers contain some hyrophillic groups. My theory is that the reppellant action of these groups towards the hydrophobic environment allows for a much better separation of the long chain molecules of the polymer to be plasticized, giving them far better mechanical properties. I noticed though that above a certain percent of methylricioate the plasticizer mix seems to become cloudy, probably due to some precipitation, or emulsification, of the PIB. Adding some oil, analogous to the C4 composition can overcome this and makes the plastique stiffer...

Anayway, I'm quite pleased to have made 12% plasticizer plastique at 1.60-1.62 g/cc which has better mechanical properties than plah-doh. You can press it with your fingers to 0.5 mm thick without any cracking or tearing! :o

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After drying the milled crystals, I add about 2.8% PIB and 6% plasticizer containing 60% methylricinoleate and 40% motoroil in gasoline as a solvent. The gasoline solvent must be completely evaporated before your start rolling the plastique. At this point the mixture deliberately contains too little plasticizer, because the stiffer the plastique is, the better is the crystal shaving you mentioned and erosion process upon rolling. Smooth surface to roll on is a must, I use a glass bottle filled with water for rolling on a glass cutting board.
The rolling has to be continued for a VERY long time, and this is really not the fun part. I reckon for industrial manufacture this is done by mechanical means, but since this is out of reach for most amateurs there is no other option than to roll by hand.:(
As you keep on rolling the plastiqye, you will see it becoming more brittle in the beginning. This is due too an excess of air that works as a plasticizer, that is removed from the plastiqe, but after prolonged rolling you will notice that very gradually the plastique will become more cohesive again, due to rouding of the crystals by abbrassing against eachother. The longer you roll, the more pliable it will become...

When all of that is done, (and you have probably put more energy in working on the plastique than is in the plastique itself :P) You add another 3.5-4% of methylricinoleate, depending on the crystal size, to make it really pliable...

Methylricinoleate can be replaced by ethylricinoleate (or better, even higher alcohols) For transesterification I found the PDF attached very helpfull. (Tried to link to it, but didn't work :()

[EDIT]: For all clarity, ricinoate esters are derived from ricinoleic acid, which makes up 90% of the fatty acids from castor oil. The rapeseed oil PDF was just a guideline for the proper transesterification reaction conditions...

[Edited on 22-12-2006 by nitro-genes]

Attachment: EthylEsterofRapeOil.pdf (666kB)
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In the future please use the forum search engine or "Google site: search" SciMad, so as to not seem like you want a spoon-feeding. Your next stop should also be the forum library. Lots of good publications.

Good luck and be safe. ;)

[Edited on 11-2-2012 by Bot0nist]

ceasemcb - 11-2-2012 at 08:44

Quote: Originally posted by Bot0nist  
<a href="">Read this for a start.</a> A great thread. Reminds you that crystal structure plays a significant role in effective plasticizing. Some tit-bits to get the mouth watering.

In the future please use the forum search engine or "Google site: search" SciMad, so as to not seem like you want a spoon-feeding. Your next stop should also be the forum library. Lots of good publications.

Good luck and be safe. ;)

[Edited on 11-2-2012 by Bot0nist]

Thanks a million for the advice mate; I didn't even see the search function!

freedompyro - 12-2-2012 at 18:16

I have a ridiculously simple and non back-breaking way of plasticizing. Doesn't make the best plastique, but it works underwater, propagates evenly, and does everything needed for experimentation.

I just use *Fine Powder (Eg, ETN, RDX, etc..)*/NG/NC/PIB. With the ratios of *70*/23/1/6. The PIB tacifier is known as tangle-trap. It's petroleum based.

It's a bit more sensitive than your average putty plastique but if your just experimenting with small amounts this technique works fine. Use acetone to dissolve the NG/NC/PIB together and mix/evaporate.

It's slightly more brittle than I would optimally like though. It forms cracks when one one inch ball is pressed thinner than 5mm. Does anyone know of a simple solution to solve that little problem?

[Edited on 13-2-2012 by freedompyro]


idiotabroad - 20-2-2012 at 11:20

I realize this a topic that has been discussed at great length here, and I have read all the pertinate posts (or so I believe). That being said, I happened upon an OTC material today for use in the seal of ducts and conduits. Packing states it's nontoxic, nonhardening, adheres to any surface. I pulled the manufactures MSDS, no with while information with the exception of flash point >232 C, and had no luck with patent information either. So long story short, does anybody have any experience with this material or something similar as a plastic's base? Or am I dreaming that this could be a short cut (which is more the likely the case).

chemrox - 25-4-2012 at 19:19

a name for the product?

grndpndr - 1-5-2012 at 02:31

It would seem a search reveals all thats needed in the way of energetics,crystal shaving and the chemistry of plasticizing.

What I havent seen addressed is how best to physically incorporate
these carefully made materials into a dense finished product.The only methods ive heard of involve elbow grease and beer bottle rollers.First thought that came to mind was the old wringer wash machine.Perfect except thier almost collectables.Preppers wash tubs and hand wringers?$160-$200 for the wringer alone.Then I looked at a second hand bread making machine and how it kneaded/worked the dough.Seemed near ideal for tireless hi torque incorporation
of the plastic into a hi density mass.The kneading arm and dough container are inert.Made of SS and covered w/teflon.
I attempted to stop the kneading arm by hand,instead it would have broken fingers.Mine was a gift from a friend that was moving but I expect with a bit of searching a useable one could be found for $5-$10 hi side.
Final rolling to desired thickness could be accomplished with the beer bottle after the repetetive kneading/working needed to shave crystals and work the material to max density.I wouldnt be at all suprise if near commercial density/minimal inerts wouldnt be possible with a machine intended to make bread.
I dont have the desire or skills needed to make an energetic
plastic material but I suppose the concept could be borne out using inerts such as powdered sugar/% mineral oil,etc.

The machines also have a warming feature, I assume for bread rising which should also be useful for plastic.Just a thought!:)

[Edited on 1-5-2012 by grndpndr]

[Edited on 1-5-2012 by grndpndr]

[Edited on 1-5-2012 by grndpndr]

grndpndr - 3-5-2012 at 00:56

Along this general popular topic line(LOL)there are inexpensive
hand crank
polymer clay rollers designed for hobby use advertised on ebay in the $25-$35 range that couldnt help but assist in achieving the highest density possible from a homemade
product over using water wieghted beer bottles as a makeshift 'rolling device'.Inexpensive considering the investment in time and money some have gone to achieve hi performance from a homemade product.But maybe thats the allure of the beer bottle rollers.:P

[Edited on 3-5-2012 by grndpndr]

[Edited on 3-5-2012 by grndpndr]

Hennig Brand - 4-5-2012 at 18:43

Sounds like they might be useful. How about a link and/or picture of what you are talking about.

Something like this would maybe appeal to you.

Mixer with Dough Hook. There are of course other attachments to choose from.

I was at a fairly large bakery one day and caught a glimpse of the operation out back. They had two of these things mixing & kneading dough, but they were large industrial/commercial versions. I could have had a bath in one of the bowls.

I am sure one of these things could knead anything you wanted kneaded. Maybe the machine would have to be a heftier version, or the batches kept smaller when handling denser more viscous things.
The beer bottle however is zero investment, probably safer and for small batches the effort required is not much worse than kneading some dough for a pizza or bread.

Obviously for large scale production a machine of some sort is the way to go. A mixer/kneading machine might even be useful on the small scale, but truthfully I don't find kneading for 10 minutes or so a big deal. Actually, I kind of like it.

[Edited on 5-5-2012 by Hennig Brand]

Hennig Brand - 8-5-2012 at 07:37

The more I think about it, some kind of hand mixer might be a good idea. These are probably what you were referring to grndpndr.

Those rollers look very similar to the machines used for rolling out lasagna pasta. The pasta machines are available at some walmarts and stores specializing in kitchen accessories.

Check out this article discussing various methods of kneading dough. From reading some of it, many of the considerations regarding bread dough seem directly related to explosive putty kneading as well.

Here are a couple snip-its from the page.

"But what about machine kneading? Can that really replace hand kneading?

As with every other possible variable, using a machine to do your kneading changes the outcome. While a food processor or a stand mixture does a fine job of developing the gluten in dough, neither one of them perfectly mimics the motion of hand-kneading.

A stand mixer straddles the line between hand kneading and a food processor. It eliminates the hand work, and while it’s slightly faster than hand kneading, it’s nowhere near as fast as a food processor"


"The action of the food processor is also the most violent, cutting some of the gluten strands as it kneads. It’s also violent to bread add-ins, so if you want large chunks of anything or unmolested seeds, it’s best to add them by hand after the dough is kneaded.

Since the stand mixer isn’t as fast as a food processor, it allows the baker to watch the development of the dough and add ingredients along the way. It isn’t as violent as the food processor and doesn’t cut gluten strands. It’s also less damaging to bread add-ins, so you can add seeds, nuts, and dried fruit and expect that most of them will remain intact.

While the stand mixer heats the dough a little bit, it doesn’t get nearly as warm as a dough kneaded in a food processor, so you can knead for a much longer time without any fear of overheating the yeast."

There are other good points on that page to consider as well. Here is the link,

Man I am getting hungry!

[Edited on 8-5-2012 by Hennig Brand]

grndpndr - 9-5-2012 at 19:29

Those hobby clay rollers were exactly what I had in mind for a roller type machine.The +'s include various consistent thickness's
for those who wanted to mimick something like deta-sheet.

If anyone has an opportunity to look at a HH bread making machine lokk at how the dough kneading arm rotates around the container it mimic ks hand kneading where the dough arm closes with the side of the container 2x every turn,working the plastic dough.It has a relatively slow RPM, Im guessing 75-100 RPM of the arm and I noticed a heating feature that warmed the container perhaps making the plastic easier to manipulate.If It gets very hot I cant say but it should be able to be shut off.
Only real dowside I could see was it would require maybe 1/2-1lb or more of a claylike material for the machine to be full enuf to function as designed.

[Edited on 10-5-2012 by grndpndr]