Styrene-Butadiene Rubber

[stanfield]

These days, my work was trying to plasticize some PETN...This wasn't an easy task because I wasn't be able to find a (cheap) source for polyisobutylene and I asked MANY corporations all over the world. No luck... the only source I found is ACROS organics but 100g of polyisonutylene cost 60€ + 25€ of shipping taxes, so, about 80$ for 100g of rubber ! argh !

Now, I'm thiking... no ! I'm HOPING that "Styren Butadiene Rubber" (used in semtex A & H) will come easier although a simple search on google gave me lesser results than polyisobutylene. So, where do I need to search ? I know that Styren Butadiene Rubber is used in car tyres but I know too it's impossible to "extract" it... don't give me this possibility, please !

thanx for all !

<small>[ October 11, 2002, 10:28 AM: Message edited by: stanfield ]</small>

[stanfield]

I've just found that SBR is used in thermoplastic elastomer which is (are?) available everywhere but, the same question always remains : is there a way to dissolve it ? in toluene/unleaded gazoline/... ?

<small>[ October 11, 2002, 10:35 AM: Message edited by: stanfield ]</small>

[stanfield]

ok, I've finally found a source for Styurene Butadiene Rubber. In fact, this chemical is VERY common but you'll need to lookf for "SBR rubber" (common name), and you'll quickly see there is many sources for this one...

So, I phoned some of them and they asked my how much percentage of styrene do I need (is it correct english?). They said 23,5% is the most common choice because this SBR is used to make car tyres, shoes,...

So, what do you advise me ? how much % for semtex ? In my acros catalog, they sell SBR rubber with only 5% of styrene, I think this is too low...

see ya !

[nbk2000]

Ask them for small samples in 5% steps from 5% to 25%.

I can't imagine using 23.5% for making a plastique if that's the percentage used for tires and shoe soles...way too stiff. Though for sheet explosive... <img border="0" title="" alt="[Wink]" src="wink.gif" />

[stanfield]

Ok but they will send me a non polymerised form of SBR so, it will be modelable... no ? car tyres are SBR with added polymerisant (is this word exist ?). Furthermore, I've already asked him to send me 1kg of SBR with 23.5%...so, I'll see !

Another question on SEMTEX :
My reference page is e-detonator simply because no other pages on the web are "chatting" about semtex composition...

So, on this web page, I can see :
n-octyl-phtalate, butyl-citrate: 9% , what does this mean ?

- n-octyl-phtalate + butyl-citrate ?
- n-octyl-phtalate OR butyl-citrate ?
- 1% n-octyl-phtalate AND 8% butyl-citrate ?...

And my last question :
Antioxidant and dye : (N-phenyl-2-naphtylamin, Sudan IV), Sudan IV is relatively available everywhere... but, N-phenyl-2-naphtylamin is a very not common chemical ! I didn't found him in my acros catalog ! which has a damn huge collection of chemicals ! Could it be substitued ? if so, what's the chemical ?

thanx for all ! and sorry for my bad english...

<small>[ October 18, 2002, 11:45 AM: Message edited by: stanfield ]</small>

[nbk2000]

n-octyl-phtalate + butyl-citrate = 9% total composition weight. Ratios...who knows.

Sudan IV...why bother. It's not like your going to be storing the stuff for decades, right?

If you need an anti-oxidant, you might try Vitamin C or EDTA, both cheap and available.

[stanfield]

ok, but Sudan IV is the funniest thing in semtex since it's a colorizing ! :) Red semtex, like military ! muhahaha ! Maybe it could be substitued by any other polymer "colorizant" (again, does this word exist ?)

EDTA ? There is a lot of EDTA in my acros catalog, one is 2,2'-Diaminnobibenzyl, that's what you mean ?

thanx for all !

EDIT : by the way, I have 250 mL of "ethyl hexyl adipate" , could I use it instead of "n-octyl-phtalate + butyl-citrate"

<small>[ October 19, 2002, 09:22 AM: Message edited by: stanfield ]</small>

[nbk2000]

Found an article on recovering the polymer faction from discarded tires, using dilute nitric acid.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532006000300027

[Jacks Complete]

Can you not simply use rubber cement? The type that sets into rubber once the volatiles are evaporated off?

Also, there are a great many silicones out there these days, something from that range might work very well. Or does the rubber act as a fuel?

[Charles Owlen Picket]

The OTC thread has addressed some of this issues. I once was fascinated by the whole process so I did some hunting around....SBR is certainly available but not always th best choice depending on what energetic material is being used.

Rubber cement is (generally) a common latex. Therefore the resultant would not be continually formable and at some point would firm up. So if the desired result is to have a moldable material that continually stays pliable, it may not be suitable. On another point, I found out some unique issues with polyisobutylene (most of the generalized issues being in the OTC thread). Source material sited is from Los Alamos research in plastic energetics. They start with polybutene (yes, the bird repellent). Results with polybutene and true sebacates yield some fantastic "play-doh" like material that shoots at gram level.

[nbk2000]

SX-2 A military explosive which comes in thin sheet form, and contains 88.2% RDX, 8.2% polyisobutylene, 2.2% Di(2-ethylhexyl)Sebecate

US Patent 6932878, A plastic mouldable explosive composition

Previous discussion about SBR, polybutadiene, PIB, etc.:

http://www.roguesci.org/theforum/showthread.php?t=2655