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Author: Subject: Method to make polybutylene for plasticizing my PETN!?
csm9420
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sad.gif posted on 27-4-2010 at 21:30
Method to make polybutylene for plasticizing my PETN!?


Now I was trying to make PETN and made it
but i was hoping to be more like a plastic explosive
and i just knew it needed plasticizer and blinder!

Do I need both plasticizer and blinder or do i need just 1 of them?

and someone posted how to make polybutylene out of ducktape but i don't get it;;

Can anyone help me through this:(

(Sorry, My english is bad:))
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hissingnoise
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[*] posted on 28-4-2010 at 03:02


Quote:

and someone posted how to make polybutylene out of ducktape but i don't get it;;

There is a self-fusing tape but it's silicone-based, IIRC. . .
http://www.google.com/patents?id=NhxVAAAAEBAJ&printsec=a...

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csm9420
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[*] posted on 28-4-2010 at 05:17


Quote: Originally posted by hissingnoise  
Quote:

and someone posted how to make polybutylene out of ducktape but i don't get it;;

There is a self-fusing tape but it's silicone-based, IIRC. . .
http://www.google.com/patents?id=NhxVAAAAEBAJ&printsec=a...



thanks!!! that helped me lot!! :D
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quicksilver
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[*] posted on 28-4-2010 at 05:52


One does not use PIB if a choice is available ; the material of choice is polybutene (the material used for repelling birds because it's sticky on their perch area but harmless...sold in tubes). and added to it is a sebacate material. The use of the proper materials coat the particulate as well as provide a plasticizer and a "tackafier" -Yes; there are two materials combined to produce a truly professional end result.

You see, you need to use a plasticizer and a "tackafier" - two materials to make a really professional result. you don't want a blob or plastic-mass. You want a mold-able explos. that is tacky and adheres to objects. The other choice is a synthetic liquid rubber & silicone oil combination. These are the "C4 & Semtex" bonding materials for what is often called plastique.

There is quite a bit written about this subject on the board if you search. The keys are : silicone oil, Castor oil, & sebacate> There are quite some many threads on just about every detail.
If you can't find the threads, PM me & I'll help you as best as I can. But this is a really well trodden road (and is actually a boarder-line subject w/ the moderators as it's implementation as opposed to illustrative science). I do have some of my old notes at this station so I'll copy some for you:


(from thread)
"You can get self-vulcanising tape from every DIY store, just ask someone, say you need it for your aquarium to make a watertight seal for the pump hoses. Say you need the tape that melts into itself and forms one piece of rubber after some time."
(Begin note): 5/16/04
Buy the "bird repellant" (Polybutene) & save the work... That way you may get the correct material.
However PIB is not as effective as the mil-spec poybutene which is a "bird repellant". Only uncrosslinked PIB (which is polybutene and a Methylricinoleate) can do this, to if you find it you can be sure you have the right stuff. The gasoline extracted product is a slightly yellowish, clear elastic rubbery mass and behaves exactly as medium weight pib is described in information datasheets!


(Important)
The plasticizer is homemade, it's made by transesterification of castor oil and methanol to yield methylricinoleate. Ricinoleates are almost as good as sebacate or adipate plasticizers and are used as a more environment friendly plasticizer for rubbers, vinyls etc. If you use less than 20% plasticizer you really need the ricinoleate as the plastique with motor oil alone becomes extremely brittle with more pib + less oil and incredibly sticky with less pib + more oil (the oil is NOT an organic lubricant....it's synthetic!). The hydrophillic moment of plasticizers like sebacates or ricinoleates is extremely important in maintaining mouldability and coherency for dense, low% plasticizer plastiques. I was skeptical as well at first, but believe me, with motor oil (synthetic) alone (w/ a tackifier, etc) you won't anywhere near as good results as with ricinoleates. I use 75% methylricinoleate and 25% motor oil as the plasticizer mix. The finer your crysals are, the more surface area, and the stiffer your plastique becomes. For really fine crystals I use 4.5 times as much plasticizer as pib to overcome this, while for coarser fractions you could use 3-3.5 times as much plasticizer realtive to the pib. There is no such thing as the perfect plastique I think. The larger your crystals are, the less % plasticizer you can use to still obtain maximum density of the plastique. Unfortunately, this comes at the expense of a higher critical diameter, and more important a less homogeneous detonation pressure so to say. I tried a shaped charge with some of the 5% plasticizer plastique with 200 micron PETN at 1.69 and although you have a CJ pressure of 277 kbar at your disposal this way, to my surprise it didn't penetrate very deep, although the entrance hole was quite wide. I guess these large particles result in small differences in detonation pressure along the liner surface, disturbing the jet. That is why I only experiment with extremely fine PETN crystals fractions, obtained by careful milling of recrystallized PETN with 40% water (milling or shaving is actually accomplished in industry via rollers; you can do the same). These small crystals need at least 15% plasticizer though, as less will result in lower densities. These small crystals have a much less mass than the larger ones, making them very difficult to abrade against each other to become rounded. That is why the finer the crystals become, the longer you have to roll your plastique. But it is still powerful enough though, I got a program from someone to calculate critical diameter, VoD and detonation pressure for plastiques at a given density, plasticizer %, and crystal size. The fine milled PETN with 15% plasticizer and density of 1.53 is at 210 kbar with a critical diameter of less than 1 mm unconfined.
Testing noted on seperate note 3/30/04


Plastique
Poybutene 80%
Methylricinoleate 20% (castor oil 70% methanol 30%)
PETN - as much as would be absorbed via kneeding
________________________________________________


15.24USA - Polyisobutylene / Polybutene - U.S. Adhesives

MIL-P-9121 (both are labled 9121 but the Polybutene is the one used by Olin subsidiary in the Czech Republic)


The terminology used in this raw material market report can be somewhat confusing, since it embodies three different types of polymers: polyisobutylene, poly n-butene, and copolymers of 1- and 2-butene. These three categories are described below:

Polyisobutylene
Polyisobutylene is a linear polymer of isobutylene of varying average molecular weights. This straight chain paraffinic hydrocarbon varies from a soft, tacky, viscous liquid to a tough elastomeric solid. Polyisobutylene is chemically inert and, therefore, possesses excellent resistance to oxidation and thermal degradation. It is used as a permanent flexibilizer and tackifier in pressure sensitive and hot melt adhesives. It is particularly useful where low temperature flexibility is a requirement. The straight chain hydrocarbon structure of polyisobutylene also contributes excellent moisture and barrier properties and specific adhesion to certain hard to wet surfaces (e.g., polyolefin). Low shelf life ( <5 yrs)

Polyisobutylene adhesives are commonly formulated using a variety of plasticizers and modifiers. Typical modifiers include petroleum oils, waxes, hydrocarbon resins, rosin esters, phenolics, etc. Modifiers are selected on the basis of desired end use properties (i.e., specific adhesion, melt or solution viscosity, and/or cost). The majority of polyisobutylenes are used as modifiers and tackifiers to other elastomers and polymers and many grades have FDA clearance. Exxon is the only domestic company that manufactures polyisobutylene. BASF imports less than 5% of the total polyisobutylene demand.

Polybutene
Polybutene is a viscous, non-drying, liquid polymer, which results from the copolymerization of 1- and 2-butene with a small quantity of isobutylene. Polybutene is colorless, has little or no odor, is chemically stable and resists oxidation by light and moderate heat. High shelf life.

An important characteristic in adhesive applications is polybutene’s tackiness, which increases with increased molecular weight. Polybutene acts as both a tackifier and plasticizer and is used to extend the viscosity range and to control the tack and cohesive strength level of adhesives. Polybutene is sold in a wide variety of molecular weights and the viscosity grades range from light oils to highly viscous fluids.

Polybutylene
Polyisobutylene is the term (first used by Shell Chemical aka Resolution Performance Products) used to describe a family of homopolymers of n-butene. They are supplied in a granule form and used in hot melt formulations. They are compatible with polyolefins and capable of extending their high temperature and low temperature service range. This resin classification market report on polyisobutylene / polybutene estimates 2003 demand with a historical perspective back to 2000 as well as forecasts through 2005 and 2010 within the U.S. Adhesives Industry. $400.00 Very high shelf life.
User Agreement

2/21/04
Ok, that's an interesting proposal, I'll give it a try as well, though the fineness is not everything, when you dump a saturated PETN/acetone solution rapidly in ice cold water supposedly you get these small and irregular plates, which are quite different from needle shaped ones, and this can even be seen with the naked eye. Though it is impossible to go to less than 15% plasticizer with this while obtaining theoretical density for the plastique. Maybe I can take some photographs at the university from these crystal fractions under a microscope...

Making the plastiser yourself from Castor Oil / or a sebicate is important BECAUSE only uncrosslinked PIB can do this, to if you find it you can be sure you have the right stuff. The gasoline extracted product is a slightly yellowish, clear elastic rubbery mass and behaves exactly as medium weight pib is described in information datasheets! But why try to work with PIB when you can buy Polybutene?
***This is really important to the finished product! Actually a commercial sebicate makes a more consistent product. Side by side comparison shows....

The plasticizer is homemade, it's made by transesterification of castor oil and methanol to yield methylricinoleate. Ricinoleates are almost as good as sebacate or adipate plasticizers and are used as a more environment friendly plasticizer for rubbers, vinyls etc. If you use less than 20% plasticizer you really need the ricinoleate as the plastique with motor-oil alone becomes extremely brittle with more pib + less oil and incredibly sticky with less pib + more oil. The hydrophillic moment of plasticizers like sebacates or ricinoleates is extremely important in maintaining mouldability and coherency for dense, low% plasticizer plastiques. I was sceptical as well at first, but believe me, with motor oil alone you won't anywhere near as good results as with ricinoleates. I use 75% methylricinoleate and 25% motor oil as the plasticizer mix. The finer your crysals are, the more surface area, and the stiffer your plastique becomes. For really fine crystals I use 4.5 times as much plasticizer as pib to overcome this, while for coarser fractions you could use 3-3.5 times as much plasticizer realtive to the pib. There is no such thing as the perfect plastique I think. The larger your crystals are, the less % plasticizer you can use to still obtain maximum density of the plastique. Unfortunately, this comes at the experience of a higher critical diameter, and more important a less homogeneous detonation pressure so to say. I tried a shaped charge with some of the 5% plasticizer plastique with 200 micron PETN at 1.69 and although you have a CJ pressure of 277 kbar at your disposal this way, to my surprise it didn't penetrate very deep, although the entrance hole was quite wide. I guess these large particles result in small differences in detonation pressure along the liner surface, disturbing the jet. That is why I only experiment with extremely fine PETN crystals fractions, obtained by careful milling of recrystallized PETN with 40% water. These small crystals need at least 15% plasticizer though, as less will result in lower densities. These small crystals have a much less mass than the larger ones, making them very difficult to abrade against each other to become rounded. That is why the finer the crystals become, the longer you have to roll your plastique. But it is still powerful enough though, I got a program from someone to calculate critical diameter, VoD and detonation pressure for plastiques at a given density, plasticizer %, and crystal size. The fine milled PETN with 15% plasticizer and density of 1.53 is at 210 kbar with a critical diameter of less than 1 mm unconfined. Quite fun stuff to play with..


concept:

The use of DBSP to both stabilize and reduce crystal size in PETN.
During re-crystallization the introduction of DBSP in the acetone may play an important role in both.

concept:

The use of HEAT (high temp) to mix binder and tackifier to the powder.
The issues are that the binders (plasicizers) and tackifier NEED to be heated to a near liquid for the complete
joining and mixing of the above. It is very important that the mix be done a little at a time. it is a time
consuming affair bit worth it if the material is to be molded to a greater degree. The introduction of the powder
must be done a small amount at a time. The powdered material should be as tiny particulate as possible. Hot
water (boiling) can be used for this as a bath and to solidify the final product. However a very small percentage
is possible if extensive molding of the plastique is not needed.

concept:

PIB does NOT appear to be as effective as polybutene. The tackiness of PIB is a bit higher than polybutene
and PIB does a better job holding at a very small percentage. Polybutene does a better job holding for a very
moldable final product. As binder/tackifiers they appear to do two different jobs. If used together percentage
becomes the determinate of if the final product is flexible. note that if PIB is used the attempt at making
the product highly flexible will amount to a VERY tacky material. (too tacky to be practicable) If polybutene is used with a methylricinoleate
made from Castor oil and methanol the yield will be a material similar to modeling clay in flexibility.

{More to follow by request}




[Edited on 28-4-2010 by quicksilver]
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roXefeller
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[*] posted on 10-12-2013 at 17:53


I want to try out the method from the patents where the crystals are spherodized, combined with fines, and mixed in a two-phase pot of xylene/water to coat with lacquer in order to improve plastic effects with minimal binder. I'm sure I'm going to mess it up the first time though and I don't want to botch it with an expensive batch of HE. I was thinking I could simulate doing it with a cheap off the shelf crystalline product that doesn't break my heart to pour out, I always expect failed first attempts. It needs to have the right solubilities/insolubilities though. Any suggestions? I've thought about mono- and disaccharides, naphthalene, para-dichlorobenzene, acetylsalicylic acid, salicylic acid. ASA is about the only one I've got to lean on so far, but I'm still researching it.
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DubaiAmateurRocketry
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[*] posted on 10-12-2013 at 19:19


You should take a look at this topic.

http://www.sciencemadness.org/talk/viewthread.php?tid=27095.

My suggestion is you need both, plasticizer usually have higher energy and density, such as BTTN, EGDN, DEGDN, TEMTN. They also make your binder more ''strong'' and ''flexible'', like a pencil rubber.

I've researched and made different types of binders such as polyurethane/ urea based, epoxies, and so on before, without plasticizers, it would be more like a piece of rough rock(more impact and friction sensitive).

energetic binders such as GAP, NMMO, BAMO, NHTPB, GLYN, so on, are much harder to synthesize and expensive, polyurethane binder is bad at mixing with energetic plasticizers therefore I suggest you sythesize your own GAP, its one of the easiest/cheapest binder to make, and energetic. However the procedure is long and you might need to buy a new range of solvents, equipments and chemicals



[Edited on 11-12-2013 by DubaiAmateurRocketry]
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