Florine Donors and PTFE based stars

[AustralianPyromaniac]

Because of the limited availability of pyrotechnic chlorine donors in much of the world (they can be sourced it is just difficult), I’m interested in doing some tests with chlorate based blue stars, with PTFE as the halogen donor. PTFE powder is easily available as a lubricant powder. It is milled to air float for this use. The cost is around $50 AUD per kg, which is much higher than other options, but it may be convenient and give a good colour. PVC cement is the only other OTC chlorine donor which actually works well, but it is painful to work with. 

Compared to the most direct chlorine equivalent, PVC, PTFE has a higher density than PVC (2.2 vs 1.4 g/cm2) and a higher halogen percentage (76% vs 56%). The decomposition is much the same as PVC, beginning at 350c and ending around 550c, more than low enough to be functional. The spectral emission of the mono-fluoride species CuF SrF BaF also seem good. 
 

Does anyone have an experience with formula along these lines? Or just fluorine based formula in general? I have also struggled to find an emission spectrum for the mono-fluoride species. Hardt gives a table with values, but no relative intensity, so not very useful. Would anyone know where to find these graphs? 
 

AP. 

[CountZero]

https://onlinelibrary.wiley.com/doi/abs/10.1002/prep.201500231

 

Quote

Copper(I) fluoride is a poor emitter with a very narrow green band centered at λ=493 nm only. 

CuBr looks more promising, perhaps some pool chemical can provide the Br?

[AustralianPyromaniac]

Hmm ok… I’ll have to take another look at that.

I have seen those experimental bromine based formula. Copper Bromate looks like it works great, which could be made using a standard chlorate cell, much the same as barium chlorate is made for good OTC greens. Not sure about bromine donors from the pool section, I think they’d all be reactive and strongly basic. Maybe as a precursor of bromine to form the bromate. Did you have a particular chemical in mind? 

[cmjlab]

My guess is he's referring to using the pool chemical Bromine as a reactant to make the Copper Bromide. Wish I could be more help but I lack an intensive chemistry background, I definitely respect the difficulty you guys in Australia have to get pyro chems.  Good luck, I look forward to what you come up with.

Edited December 15, 2023 by cmjlab

[cmjlab]

Out of curiosity, is it a major offense if you receive a package from friends/family in a different country with chemicals you can't buy with out a license in your country?  

Now that I write it out, it certainly looks like it would be, but my question still stands...

Edited December 15, 2023 by cmjlab

[AustralianPyromaniac]

From what i understand all chemicals are “legal” here except those for drug manufacturer, which have legislated restrictions on possession. In the EU, there are some legislated limits which we don’t have here. No peroxide solutions above 12% in water, and no perchlorate salts above 50% in solution with water for example, break those limits and you are breaking the law.
 

We have lab supplies who will sell pyro chemicals, although they’re expensive. Nitric, sulphuric and hydrochloric acid are quite easily available OTC, and peroxide solutions up to 50% can be bought easily at brick and mortar stores. 
 

Manufacturing high and low explosives is illegal here. But I think having chemicals shipped here wouldn’t be an issue assuming you followed shipping regulations, of course the cost would be prohibitive. But you certainly might have some people asking questions if they opened a package, and if you got a visit from the police it would be a charge of explosives manufacturing rather than the chemicals themselves that you’d have to deal with. 
 

Chlorine/ halogen donors are an interesting case where you could probably get them shipped internationally. We have one source of PVC and parlon in Australia, very expensive, and the PVC is very poor quality. How long this supplier will be in business we don’t know. When people are starting out in pyro, in restrictive places, you don’t want to be shipping chemicals internationally, even inert ones. I think there’s a lot of value in having simple compositions  that perform well and can be made with a good foundation in chemistry, rather than relying on international imports. 

Edited December 15, 2023 by AustralianPyromaniac

[Mumbles]

I have never actually tried this, and if I've talked about it in the past, it's probably from the same information in Hardt that you referenced.  There are a few, but generally pretty specialized, applications of teflon in pyrotechnics.  The majority of information I've seen is typically utilized in military flare applications with magnesium.  There is also some occasional use of other fluorinated polymers or binders as a casting agent or binding agent.  Teflon is one of those things that's extremely non-reactive, until it isn't.  There are some reports that a Mg/Teflon mixture is a fairly sensitive, quite powerful flash powder like mixture.

As far as that paper goes, check out the supporting information for a bit more detail on the compositions.  The thing that catches my eye is that the fluorine composition is a high temperature mixture being primarily Mg based and what I assume to be copper powder.  The chlorine, bromine, and iodine analogues are low temperature mixtures and use basic copper carbonate.  I wonder if that had anything to do with the spectral output or intensities.  

Be careful if you're experimenting with any of this.  As previously mentioned, teflon compositions with metals, can be more reactive than you might think.  The smoke from these compositions also has the potential to produce some pretty nasty by-products as well you probably wouldn't want to be breathing in.  

[CountZero]

On 12/15/2023 at 5:33 AM, AustralianPyromaniac said:

Did you have a particular chemical in mind? 

Sorry, I have just noticed this "chlorine free" stuff in the pool Isle. Probably to reactive to use as is in a composition, but could be useful as a precursor to ...something. Not too versed in chemistry

I dont know if it exists, but a block of pure PVC(no additions or filler) for machining would not be something that would raise any concerns with customs. Pressing PVC powder in a heated form could possibly work. Getting it to a powder state again would take some work... 

[AustralianPyromaniac]

Pure PVC powder is sold by plastics companies as something called PVC dry blend, but it comes in 25kg sacks, it's around 40 mesh and quite hard to mill. We can get PVC and Parlon here from one pyro supplier, but it's hard to know how long they will be in business. I think in Europe there is no good supplier. I don't think there is any need to import it, I just get joy out of finding new ways to make stars with easily available chemicals. 

OTC blue stars can be made with PVC cement, which is around 25% PVC and 75% MEK. 

9 hours ago, CountZero said:

Sorry, I have just noticed this "chlorine free" stuff in the pool Isle. Probably to reactive to use as is in a composition, but could be useful as a precursor to ...something. Not too versed in chemistry

I dont know if it exists, but a block of pure PVC(no additions or filler) for machining would not be something that would raise any concerns with customs. Pressing PVC powder in a heated form could possibly work. Getting it to a powder state again would take some work... 

 

[AustralianPyromaniac]

On 12/16/2023 at 8:41 AM, Mumbles said:

I have never actually tried this, and if I've talked about it in the past, it's probably from the same information in Hardt that you referenced.  There are a few, but generally pretty specialized, applications of teflon in pyrotechnics.  The majority of information I've seen is typically utilized in military flare applications with magnesium.  There is also some occasional use of other fluorinated polymers or binders as a casting agent or binding agent.  Teflon is one of those things that's extremely non-reactive, until it isn't.  There are some reports that a Mg/Teflon mixture is a fairly sensitive, quite powerful flash powder like mixture.

As far as that paper goes, check out the supporting information for a bit more detail on the compositions.  The thing that catches my eye is that the fluorine composition is a high temperature mixture being primarily Mg based and what I assume to be copper powder.  The chlorine, bromine, and iodine analogues are low temperature mixtures and use basic copper carbonate.  I wonder if that had anything to do with the spectral output or intensities.  

Be careful if you're experimenting with any of this.  As previously mentioned, teflon compositions with metals, can be more reactive than you might think.  The smoke from these compositions also has the potential to produce some pretty nasty by-products as well you probably wouldn't want to be breathing in.  

I have seen those comps but do not read much into them. The Teflon and the magnesium produce enormous amounts of heat and IR when burned, and the magnesium is probably the only fuel that can get the Teflon to act as an oxidizer and sustain the reaction. In stars, the Teflon would not be expected to do nearly as much work as in an IR flare.

I've read the paper, they said "As metal fluoro-carbon combustion flames are rich sources of volatile metal fluoride species" which is why they picked the metal-based comp as opposed to an organic one, but it would have been nice had they tried both. I don't think the magnesium would be necessary to release fluorine, but it might be. In any case, surely it would all be burning way too hot! They also say "although Grandsen et al. did not find any signals for CuF in their study of the same composition 6. The chemical equilibrium calculation with EKVI-4.5 7 (see Supporting Information) however indicates formation of CuF."

It's not clear to me they made the right species, but really they probably did, and it is not viable. I'll make some up and give it a shot. The CuBr emission do look very promising though!