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Rosco Bodine
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| Quote: | Originally posted by HMTD
IMO, there is no difference between cubic and needle crystal shape for certain applications. I use PETN mostly for PBX, and it’s crystals is always
needle-shaped, which are produced from hot acetone and water. These crystals are not convenient for using in PBX directly, so I crush them with
mortar/pestle in presence of water and antistatic agent (commercially available static strain remover spray) . Time of procedure determines the
resulting crystal size. After drying the PETN looks like slightly yellowish(depends on color of antistatic agent) fine powder with more or less
observable no-more-needle-like crystals, which no more electrifies. Of course, I made for one time not more than 50 grams, but there is no problem to
make more. The greater part of this PETN I use for producing PBX, the rest for hand-pressed boosters to this PBX. Using 14% - 5 % of polybutylene
as binder, the resulting measured density varies from 1.56 to 1.65. When I need PBX with small critical diameter ( less than mm), I use raw PETN
after above mentioned procedure, 86/14 has about 1.51 and quite stable, it detonates in 0.5 mm sheets. |
I don't say this very often because of preserving a certain decorum ....
but you are full of bullshit .
The critical diameter of fine mesh PETN compressed and heavily confined in a glass tube is more than 1 mm ,
so it would be miraculous for your .5mm sheet plastique
having a diluent of a soft inert plasticizer to detonate
as you describe .
If you have good data to share , then by all means share , but if you come here to this forum to tell kewl tales ......then just STFU and keep kewl in
" Moscow , Russia "
LOL .....
as if I believe that load of bullshit either .
[Edited on 12-10-2006 by Rosco Bodine]
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nitro-genes
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I know about the production of C4. The increased density is mainly about crystal size control (has little to do with the plasticizer or binder used),
screening of the two exact particle sizes, strict crystallization procedures, vacuum removal of solvent, after which the granules are sold as a loose
powder which can be pressed directly, like a PBX or kneeded into a clay consistancy. The extra steps in it's manufacture make that semtex is much
cheaper and commercially available, though on the other hand it doesn't produce the detonation pressures of the latter. Semtex is mostly used as a
booster, so for this purpose the extra amount of pressure sqeezed out would not be worth the cost. Only metal accelarating purposes as EFP's, shaped
charges, or hard target demolitions this is necessary, hence army usage...
But enough on the practical side, after seeing some examples of 90+% PETN plastiques at densities of more than 1.60, I was just curious if there was
any info available about different crystallization procedures for PETN.
HMTD does have a point about manually "milling" the coarse crystals until they become a more free-flowing powder. It is difficult to judge when this
exactly is, and it is a lot of work, but after a quick try I was able to get to a density of 1.51-1.53!
8 grams of coarse crystals of about 5 mm long and 0.5 mm thick were crushed gently under water until it was the consistancy of rather fine sand. To
this was added about 4 grams of very fine, instantly precipitated PETN from acetone, and 12% of plasticizer. The coarser particles made the plastique
much more sticky and to overcome this, another 2 grams of the fine PETN was added. (Actually, more PIB should have been added but this was more work
 ) The density was considerably higher, my scale can measure down to 10
milligrams and it was done three times to get an accurate reading. A density of 1.65 seems a bit of a stretch though! And the process is considerably
more work. Moreover the coarse particles give it the feeling of plasticized sand and results in greatly reduced moulding properties. The finished
product starts to tear at about 1-2 mm thickness and doesn't have a good density homogenity. With only PIB in a PBX formulation you should be able to
go thinner though...
Since no one has heard about di-PEHN and tri-PEON as crystal modifiers to make life a little more easy, I will experiment a bit further with the
milling method. Although I don't really like the milling procedure, the goal was to make a SAFE, non-toxic, high brisance and small critical diameter,
storage stable, cheap, insensitive and versatile explosive! 
Thanks for the all the repies! 
[Edited on 12-10-2006 by nitro-genes]
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Rosco Bodine
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Realistically .....if you can get a *homebrew* PETN plastique with an inactive
binder with a fine enough consistency and good enough aggregation to have a critical diameter of 2.0-3mm , then you are probably doing damn good !
To get it smaller you will likely have to explore MHN
or HNI as additions to the mixture , and *sensitive* energetic plasticizers which leads to compositions which really depart the PBX designation and
are gelatins or fillered gelatins .... maybe designate it GBX ?
Yepper when PBX just won't cut it .... upgrade to GBX .
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HMTD
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Rosco Bodine, I didn’t outrage you! 0.5 mm sheet (not “bullshit”) was with ULTRA fine PETN which wasn’t re-crystallized! And you probably
know, that the critical diameter ( just as critical width of expl. sheet) depends on conditions of its detonation. In my case it was located in 0.5
mm steel sheet (which was damaged), so the critical width is twice less than in case of free sheet in air. And 0.3 mm sheet in contact with the
previous one didn’t set off. In my way of production PETN ( Urbansky’s 96% H2SO4+70% HNO3, then filtering, neutralization, boiling for 1 hour in
1 % Na2CO3 ) gives flour-like crystals, then I mill them with antistatic agent to free them from the extra in-crystal acid, and it gives me even finer
powder.It is known that critical diameter depends on crystal size. And I know industrial samples of PBX (ELAS-2) based on 85% of 5 – micron size
PETN crystals with inert plasticizer that have cr.diam. of 0.5-0.7 mm. I am sure, that milling process can’t give such a fine powder, probably they
use some sort of re-crystallization, I don’t know. With the better plasticizer ( polyisobutylene+heavy oil from some old putty ( like blu-tak I
think but yellow) 88/12 PBX(density not known) detonated in elongated charge (section 0.6 mm * 1.2 mm rectangle) . With 0.9 mm * 1.2 mm section
charge I had measured VoD about 7848 +-250 m/s ( was measured time between breaking two wires on the charge’s ends). It is to be told that this
ultra-fine non-re-crystallized PETN powder based PBX surely to be less stable and dense then one produced from re-crystallized, so it can be used
mostly in special purposes I mentioned and shouldn’t be kept long. I have number of videos of testing such small-critical-width plastique, maybe
later I would share some of them.
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quicksilver
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I am always interested in crystal modifiers, so if you do find the info by all means please post it. I just looked at some LA stuff and couldn't find
anything on di-PEHN and tri-PEON at all....
However the phenomenon of crystal shaving via mix manipulation is such that I would bet once the granularity is established one could refine such a
thing to reduce the overall size (where a needle shape would be impossible to work with).
I was taken off track frankly; I just thought you wanted to posit differnt shapes per se' but then I post with my morning coffee and I'm mostly not
awake.
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Rosco Bodine
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@HMTD
I simply don't believe you because the scenario you
describe is inconsistent with published limitations
concerning these type compositions .
I also doubt the veracity of your reported chronographic data . I feel like you are pulling my leg so hard that
my hip joint has been dislocated .
The numbers and scenario you are describing are
simply not believable .
Even if you got below a millimeter using microfine PETN
pressed in a capillary providing strong confinement and
an optimum density to achieve a sustainable detonation ,
the velocity would drop way off , and that situation would quickly be worsened by the presence of an inert binder diluent , and worsened further by
the absence of confinement for a thin sheet or ribbon . What you describe simply doesn't ring true for a PIB bonded plastique . Hell it might not
even go that low as a
viable section for NG plasticized PETN where the binder
is active . 0.5mm thickness is like a heavy coat of varnish
in thickness , the thickness of a paper matchbook cover .
Does it sound reasonable that even a sensitive secondary like PETN is going to sustain detonation in
an unconfined layer that thin , when not even all of
the primary explosives could match that performance ?
Even pure NG has its limiting diameter .
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HMTD
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“It is impossible because it can’t be true” – this is like your words, Rosco Bodine, sounds to me. Just try the things I’ve described –
you’ll see. Or maybe nitro-genes could try, he seems to be more practical person. Here some data from official sources (I can give you the all
article if you want in Russian).
“Russian chemical magazine”
The magazine of Russian Chemical Community named after D.I. Mendeleyev
Vol. XLI
“ High energy substances”
Part 2
4,1997
Article “ Elastic explosive materials” by A.A. Kotomin
“ A.A. Kotomin – Doctor of Technical Sciences, professor of department of Chemistry and Technology of organic nitrogen compounds of
Saint-Petersburg State Technological Institute.”
“
Explosive composition ELAS ( developed in assistance with candidate of Technical Sciences S.A.Dushenok)
ELAS-1/ELAS-2 Contains ( % by mass )
PETN 85 / -
RDX - / 85
Butadiene-nitrile rubber 6.5 / 6.5
Butadiene-styrene rubber 6.5 / 6.5
Polytetrafluoroethylene(Teflon) 1.5 / 1.4
Antioxidant 0.5 / 0.5
Carbon(soot) - / 0.1
Properties
Density, g/cm^3 1.57 / 1.59
Critical diameter, mm 0.5-0.7 / 3.0-3.5
Temperature when intense decomposition starts, °C 170 / 210
Flash temperature ( after 5 sec delay) °C 230 / 280
VoD , km/s 7.5 / 7.6
Sensitiveness to impact, % of explosions 52 / 48
Sensitiveness to friction(low limit), MPa 168 / 217
Sensitiveness to initial blast wave, kBar 15 / 28
Lead block expansion, cm^3 400 / 380
Brisance ( 25 g) , mm 16 / 18
Detonation Pressure, kBar 210 / 225
Breaking strength , MPa 4.0 / 3.0
Chemical stability ( 110 °C for 14 hrs) ,mercury mm 10-25 / 10-25
Application interval , °C from -55 to +80 / from -55 to +160
”
And here is some data about the critical diameters ( measured and [calculated]) of different crystal fractions of RDX, PETN and HMX at the 98-99 % of
crystal density from the same article :
“
RDX (high dispersed, 3-5 micron) 0.27 [0.27]
RDX (fraction 0-60 micron) 1.7 [1.5]
RDX (fraction 90-160 micron) 2.4 [2.35]
RDX (fraction 200-250 micron) 3.3 [3.45]
RDX (fraction 250-350 micron) 3.8 [4.1]
PETN (high dispersed, 5-7 micron) 0.2 [0.2]
PETN (fraction 0-90 micron) 0.86 [0.85]
HMX (fraction 0-90 micron) 1.5 [1.45]
HMX (fraction 90-160 micron) 2.1 [2.05]
HMX (fraction 200-250 micron) 3.1 [3.05]
HMX (fraction 400-500 micron) 4.8 [4.4]
”
This data can be used to determine cr.diam. of PBX composition based on mentioned explosives ( method of calculation described in article). Later
I’ll try to share some movies/photos which should prove my words, I hope.
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Rosco Bodine
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Oh I'm a practical person , and detaflex and detasheet
have been around for forty years .
That's the DuPont comparison of your " ELAS-1" .
The stated minimums on these highly specialized PETN
based products is about 2 mm for the inactve bindered
product and about 1 mm for the active bindered material .
But the products as used are increased well away from those minimums .
So maybe the Russian manufactured detaflex and detasheet is better stuff ?
I still doubt it .
What is the KGB doing these days , trying to get a
roll of detonating cord miniaturized to the point it can
be concealed as a spool of sewing thread
No wait ....dental floss and toothpaste ! That must be it .
[Edited on 13-10-2006 by Rosco Bodine]
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quicksilver
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ahhemmm....just for the record I want to reiterate what you all are talking about here. I'm just waking up so I'm sort of fuzzy & I am not a
trained scientist but we are talking about a non-energetic PBX, at a thickness of 1/2 a mm detonating at what speed? I also didn't know they had
Blu-Tac in Russia. Damn; this board has some new stuff every time I turn around.....I was always under the impression that energetic materials needed
to have a critical diamiter and that the binder in a PBX (if non-energetic) would further reduce the density of said material. If the material is
reduced in particle size oil will not keep it binded; thats why butyl styrenes are used - so it seems logical that if one reduces the thickness,
density will suffer.....no?
When I think about it - it occured to me that "6 grain" det cord (the yellow shit) would be thin as Hell BUT that is det cord and packed down via a
machine and utilizing no binder. The objective being to simply transfer shock from point A to point B. Would a material's energetic responses be
altered by volume as well as density? Certainly some would, others would not. But deta sheet's usage woud almost preclude the desire for super thin
sectioning; it's area coverage material, to move a larger mass. Unlike a cylinder, the purpose is to shove (or smack, however you like) a larger
area.....no? And IF one were to develop a super thin deta sheet how do you get the thing into a fine, small, thin area, if the purpose (the only one
left) is to insert same into a tiny crack between large surfaces (like large scale building rubble)???? But that's not the point of the discussion, so
I'll drop that. But I was under the impression that PETN and RDX had similar stats but that if one used LESS material PETN would be more appropriate,
yet the above sited material includes both and HMX as well. Perhaps this is a "lab-only" scenerio wherein the conditions are controled to such a fine
extent that they could almost never be reproduced in industry.
Now the only reason I even bring this up (which I possibly shouldn't) is that I have been reading Rocsoe's posts for well over two years now and have
not remembered him calling something bullshit. I have followed his suggestions in many areas and all of them have been on the money. But I also know
that shaving of crystaline particulate is possable and that the above sited patent makes it clear that the granular particles can be mesh sized up or
down. The siting of published material is a well respected method of debate however I also know that journal material may be taken out of context or
non-peer reviewed (such as the clinical reference to "sexual additiction" which has a journal but is not peer-reviewed, nor part of the clinical
references in the DSM-IV). Thus angels dance on the head of a pin for many in this world and for many they just don't exist.
OK...I'm ready to be flamed now...
[Edited on 14-10-2006 by quicksilver]
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Boomer
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Rosco, have a look at the Los Alamos handbook, a PBX called XTX8003 (from memory) has a critical dia of under a mm, IIRC around 0.5mm *unconfined*.
It is PETN based, with an inactice binder. XTX8004 is identical but RDX based and needs over a mm.
These two are also mentioned in Cooper.
Sheet explosive comes in 1mm thickness too, and they would not sell something that's on the edge of not working. Again, the mil version with RDX
starts at 2mm.
He may well be right, even though I doubt his 'measured' VoD (ionization probes are better than breaking wires, I once got 20 km/s for BP because the
hot gas conducts as well, fooling the timer)!
EDIT: His material was confined: "it was located in 0.5 mm steel sheet, so the critical width is twice less than in free air"
[Edited on 14-10-2006 by Boomer]
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Rosco Bodine
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I get it that the lower limits of propogation can be explored , but I would be doubtful about the consistency
of any high velocity performance on this material unconfined , particularly an improvised material not
made in an industrial setting .
When you are out a distance of about 100 times
the thickness or diameter of a charge that is close to
critical , the propagation reliability isn't there anymore ,
and the detonation can drop to a low velocity figure or
drop out completely . At a thickness of 0.5mm , that
would give you a couple of inches of reliable propagation
and then a big question mark as to what happens further out .
Anyway , I am highly skeptical about these microscale
microfine structured materials . I do not trust the reliability or practicality of these things that operating near to minimums , and I sure don't
have confidence in any improvised compositions . We could go on forever
arguing about it , but I doubt the credibility of confirmatory claims for an improvised composition which
parallels work done at DuPont or Los Alamos to produce
something so specialized .....it just seems far fetched .
But by all means , anyone drag out their ball mill and screens , their blu-tak and solvents , stir sticks and
tell me all about it .......
I still don't believe it .
I would have to see it to believe it ,
and then see it replicated a few times just to be sure .
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nitro-genes
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After a few tries I got to 1.69 g/cm3, using 7-8% plasticizer, and estimated avarage PETN particle size of about 20 micron. A little more oil was
required to make it soft and pliable. Like HMTD said also, using finer material will result in lower densities, but better sheet material properties.
Supposedly, this ultra fine PETN can be made by spraying an acetone/PETN mixture under high pressure in icecold water. Partilce size was something in
the nanometer range... It is mentioned in some article that I am unable to find
again.
Probably the figures given by HMTD are not that unbelievable. Regular semtex at a density of 1.40 g/cm3 is said to have a critical diameter of 3 mm.
Though I have reliably fired it at 1.5-2 mm, and this was with fairly coarse PETN recrystallized from acetone! The failure diameters given are likely
to be the "worst case senario" limits. Though an alternative explaination may be that there is a certain run up distance. I have seen it before with
tubes filled with NG...
[Edited on 18-10-2006 by nitro-genes]
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Boomer
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I took the time to look up several plastic bounded (PBX...) and extrudable (XTX...) formulations using PETN in Los Alamos and LLNL files: *Many* are
under 1mm either in critical diameter of in wedge test failure thickness. Only RDX comps are above 1mm. And Rosco, those peaple *do* replicate their
test before publishing results.
BTW semtex has some 30% plasticiser, the kreml crooks probably sold the cheapest shit to terrorists that barely went bang. I once read there's two
kinds, semtex 'H' for 'hardly detonable', and semtex 'A' for 'adultered'.
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franklyn
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The mesh size of crystal formation is a function of time.
The comparatively slow precipitation from a chilled solvent
can be avoided by spray aeration, as from a paint gun.
On page 382 of COPAE _
"extremely fine powder may be procured by the rapid cooling of
a mist or spray of hot nitroguanidine solution, either by spraying
it against a cooled surface from which the material is removed
continuously, or by allowing the spray to drop through
a tower up which a counter current of cold air is passing"
It would be easy to rig a vacuum cleaner with a spray nozzle
inside of a fine wire mesh cylinder ( of the type used for coffee
filters ) introduced inside the vacuum's bag, fitted to seal the
opening where the hose normally attaches. The partial vacuum
created will draw mist inside from the differential with
atmospheric pressure, flash volatilizing a high vapor pressure
organic solvent to produce the desired fine dust of the solute.
The solvent can be reclaimed from a condensor fixed to the vacuum's
exhaust. This entire arrangemnt works best if there is very minimal
air present so initial venting of fumes to purge the space is
advisable.
Of course then the greater insensitivity of the resulting product
would have to be addressed for a given application.
_______________________________________________
This is just an after thought. To explore the practicle limit for
thickness of sheet explosive. One may obtain good quality " rag "
writing paper of the type used for personalized stationary. Treat
this with mixed acids to produce "flash paper" ( nitrocellulose )
neutralize residual acidity, then place onto a piece of window glass
to dry without crinkles. Now using the spray gun approach one can
spray paint an explosive onto this substrate in the desired
thickness, although a combined one milimeter thickness would be
something of a reach.
.
[Edited on 22-10-2006 by franklyn]
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quicksilver
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{Not that I doubt it} but 30% binder is unique to my limited knowlege in a commercial PBX. That would certainly explain the "A" & "H" - I can hardly imagine a material going bang at that level. And this brings to mind
questions that I have had for awhile now....What is "Gulf Crown" oil - it's viscosity or equivilant ? And from what I have seen Silicon Oil is
extremely expensive; does the value of it's use as a binder comes from it's viscoity or some other characterisic?
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Boomer
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Quote from a 1995 post on a.e.e.
Source is:
"Analysis of Semtex Explosives" J.R.Hobbs.
Chapter 39. p.409-428 in " Advances in Analysis and
Detection of Explosives" edited by Jehuda Yinon
Kluwer Academic Publishers ISBN 0-7923-2138-3 (1993)
Name Semtex H Semtex A
% PETN 49.8 94.3
% RDX 50.2 5.7
Dye Sudan I Sudan IV
Antioxidant N-phenyl-2- N--phenyl-2-
naphthalamine naphthalamine
Plasticizer n-octyl phthalate n-octyl phthalate
butyl citrate butyl citrate
Binder styrene-butadiene styrene-butadiene
rubber rubber
Table 2. Gravimentric Analysis
Sample size 1.0194 1.1061
Weight oil 0.0811 0.0994
% oil by weight 7.9 9.0
weight rubber 0.0920 0.1036
% rubber by weight 9.0 9.4
weight explosives 0.7029 0.7029
[ rest of table omitted ] (end quote)
See that last line. It is not % but grams out of 1.0194 and 1.1061 grams. I go on quoting (Jerry btw. alias Gerald L. Hurst - should ring a bell,
think Astrolite/Kinepack):
"If comrade Vladimir
gets Col Khadaffi's order for a few tons of plastique, and
Vlad finds he is out of PETN from the Chernobyl plant, does
he apologize and not fill the order because he doesn't have
the "minimum" 21 percent PETN? Or does he simply manufacture
"Semtex U," short for USA, a material remarkably like C-4?
As long as these guys can get their hands on either PETN or
RDX individually or in a mixed ordnance scrap pile, they will
continue to manufacture "Semtex" and people will continue
to ask "What is the composition of Semtex?" I would be
willing to bet that there is plastique "Semtex" out there
adulterated with TNT, HMX (They should be so lucky) and tetryl
as well and probably a good bit of it cut with inerts to the
cap-sensitivity limit.
According to your gravimetric analysis table II, the total
explosive contents of Semtex "A1" and "H" respectively
are 64 and 69%. The corresponding oil/rubber contents are
17 and 18% for totals of about 81 and 87%. Based on the ratios
in table 1, the RDX would be 5.7*.64 = 3.6 percent which is
far less than the material not accounted for."...
"So, Mr. Entrepeneur formulates his plastique in the cheapest
way possible using PETN and all the passive materials he can
put in without losing cap sensitivity. He is not at all
concerned about the strength of his product as long as it
shoots.
Time passes and our businessman gets his hands on some price
competitive RDX. His first new batch of "Semtex" is a dud, it
won't shoot. He could raise the concentration of RDX up to 91
percent to make "Semtex C-4", but that would raise his costs
significantly. Then he finds a happy compromise. He blends in
enough PETN to allow the retention of cap-sensitivity at
higher inert dilutions.
Batches containing about 50/50 PETN/RDX can tolerate a hefty
30 percent or so of inerts while material with 95 percent
PETN handle a whopping 35 percent.
Without a rather sophisticated laboratory, your average
terrorist is unlikely to be able to tell 50/50 from 95/10, but
he can estimate the total explosive content by noting a couple
of solubilities (acetone and ligroin), so our vendor puts
labels on the material: "H" for "hardly detonable" and "A" for
"Awfully adulterated." This act of honesty helps assure the
manufacturer that he won't receive any "returns" from his
customers...." (end quote)
Good old times when there was intelligent discussion on a.e.e.
Discussion between professional blasters, veteran EODs, and people from the explosives industry like said Jerry. Now it's overrun by kewls and the
pros keep silent/have given up. Sad world...
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quicksilver
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Yes indeed.
Thanks for digging that up; I do remember some interesting interaction back many years ago on UseNet A>E>E. It's now getting to be MANY years
ago....
RE: butadiene styrene: it seems like a pretty damn good binder (toluene is the solvent as I remember). Seems it's sold in nearly pure form as an
adhesive in the US.
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Boomer
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I am not that familiar with the old english names, but should a polymerized ...-dien not be named ...-tylen? That would close the link between
poly(iso)butylene (PIB in C-4) and (poly-(styrene-))butadien in semtex.
These may be OTC via self-amalgamating tape or bubble gum, or rubber glue or whatever. But where does John Doe get WTF-phthalate/citrate and
OMG-(ethyl-hexyl)sebacate OTC?
I have seen a barrel of IIRC octyl phthalate half a mile from my door in the backyard of a factory. Never went for a late-night-sample though.
The most surprising thing about C-4, apart from how they cram in 91% RDX without loosing coherency (hint: bimodal crystal size), is the high content
of softener compared to rubber binder (1/50th part!):
Polyisobutylene 2.1
Motor oil 1.6
Di(2-ethylhexyl) sebacate 5.3
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nitro-genes
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You certainly don't want to use triethylcitrate! God knows why this is used,
since TEC is pretty water soluble, eliminating the possibility of underwater usage. There is nothing really special about sebacates IMHO. The
hydrophyllic moment (detergent action) of the ester groups and the linearity of the molecule as a whole give it slightly better plasticizer
properties, the resulting advantage is mainly that sebacates show no exudation whereas using motoroil alone does exudate at high rates from
plastiques. Nowadays they often use low molecular weight polymers to plasticize, these are very long and linear molecules virtually eliminating
exudation. The affinity of the sebacate ester groups towards the nitramine groups from RDX could also reduce exudation...
Ricinoates share the same properties as sebacate plasticizers (linearity and hydrophillic moment) and both are derived from castor oil (92% ricinic
acid). The caustic oxidation process of castor oil to yield sebacate is rather difficult, needing high temperatures and pressures and Raney nickel as
a catalyst. An attempt to do so produced an IMMENSLY strong "fungus like odour" throughout the entire building! Probably due to octanols and other high C esters produced... (Their low volatility
ensured days of pleasure... )
Never seen my girlfriend that mad before, I wonder why?!
Ricinoate esters on the other hand are much easier produced. I tried the methyl and ethyl esters by transesterification reaction (Vogel) of castor oil
and methanol/ethanol under reflux. the methyl/ethylricinoate seperates as an oily layer at the top. These plasticizers are somewhat less good solvents
for PIB and need some 20% of motoroil added for better properties. Seeping of plasticizer is much reduced, but there is no other real advantage that I
noticed... (Although I never tried with very low % of plasticizer)
[Edited on 25-10-2006 by nitro-genes]
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quicksilver
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| Quote: | Originally posted by Boomer
These may be OTC via self-amalgamating tape or bubble gum, or rubber glue or whatever. But where does John Doe get WTF-phthalate/citrate and
OMG-(ethyl-hexyl)sebacate OTC?
I have seen a barrel of IIRC octyl phthalate half a mile from my door in the backyard of a factory. Never went for a late-night-sample though.
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I didn't want to create a run on the place or give it a bad rep but the hardware store chain that begins the letter A (I feel a little foolish saying
that but I really would like to keep it available). The MSDS for a specific bulk adhesive reveiled amazing results. Look for related posts on Rogue
Sci; I think I even posted the SKU number as well. It's not that big of a deal but it seemed to fall out of the sky....a canned bulk adhesive that
could be used as is. Indoor floor adhesive.
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nitro-genes
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Wow! The increase in brisance is amazing with increasing density!
Following HMTD's advice, very fine PETN was produced by pestling wet recrystallized PETN in a mortar. To 4.50 grams of this was added 0.50 grams of
plasticizer/binder to give a density of 1.59.
A spun formed 0.5mm thick, 60 degree coppercone with rounded apex of 17 mm in diameter was glued to a 25 mm long piece of 17 mm innerdiameter PVC
tubing. The 5 grams of plastique was loaded into the container by hand. Headheight was about 0.5 times conediameter, but I figured the rest of the
headheight would be provided by the detonator...
Whereas the usual plastique penetrated only about 3.5-4.0 cm with the same setup, this one penetrated the entire 5 cm block of steel and about 6 cm of
soil!!! The much smaller critical diameter of this plastique must have helped too. I Made some really nice pictures of them that I will upload as soon
as I figure out how the ftp of sciencemadness works...
Just to set the standard: 4.5 grams of HE --> over 6 cm penetration in steel!
Moehahahaha Beat that!
[Edited on 26-10-2006 by nitro-genes]
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Rosco Bodine
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Pentaerythritol and other polyols also form other esters
than the nitric acid esters , and some of the organic acid
esters may be useful as modifiers / plasticizers when added to the energetic nitric ester . There is a patent
concerning the use of the tetralactate IIRC in this regard ,
as a densifier and modifier for the tetranitrate .
There are a series of organic acid esters of the polyols
which are synthetic lubricants , synthetic " ester oils "
blends of which are used as refrigeration compressor oils and as synthetic engine oils . Some of these may have
a sufficient solvent or colloiding effect upon PETN to be useful in small quantity as a component of any binder
system . Of course the non-energetic esters will not
contribute to the power of the composition except by
physical improvements as a blending agent which exceeds their negative effect as a diluent . But it may be the case that even a small addition of
such esters can
have significant effect on increasing the percentage of
the other energetic materials which may be " packed " at higher density into a composition , so that the net effect
is increased performance .
Anyway , when I see these compositions which use a small amount of motor oil as a component , it just may be that a particular oil is superior to
others , depending upon how
it interacts with both the binders and with the PETN .
Also , certain of the silicone oils can may have superior properties in the same regard , so these should be looked at
as possibly better than just ordinary " motor oil " ..... as this particular " minor ingredient " may be more significant than
some would think in defining the physical properties of
the final composition . The component called " motor oil "
may be a proprietary ingredient which is highly specific in
its effect on the finished composition .
[Edited on 26-10-2006 by Rosco Bodine]
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nitro-genes
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| Quote: | Originally posted by Rosco Bodine
The component called " motor oil "may be a proprietary ingredient which is highly specific in its effect on the finished composition.
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After 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!
[Edited on 20-12-2006 by nitro-genes]
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quicksilver
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| Quote: | Originally posted by nitro-genes
]
After 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!
[Edited on 20-12-2006 by nitro-genes] |
I have been VERY interested in this issue for as long time as well. Could you please post your "nuts & bolts" methodology in regards to what
materials you used and the methods of mixtrure?
THANKS!
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nitro-genes
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First I recrystallize the PETN slowly from acetone, to give needle shaped crystals of about 5 mm long. These are GENTLY crushed with at least 40%
water in a strong bowl until there are no needle shaped crystals left. This is the tricky part, if you keep on milling too long, the crystals will
become smaller and the density of the final product will go down, if you mill too short on the other hand, there will still be needle shaped crystals
left, also reducing the final density.
I'm not happy about the milling step, and I advise everyone attempting this to use extreme caution, and only small amounts at the time! (few grams or
so) I'd rather go with better recrystallization control of crystal shape, but no luck with that untill so far...
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 ) You add another 3.5-4% of methylricinoleate, depending on the crystal size, to make
it really pliable...
ps:
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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