Sciencemadness Discussion Board

How does Mg burn in/with PTFE?

RogueRose - 19-9-2018 at 00:22

I was watching a video of some magnesium flares and one video showed someone supposedly burning Mg and PTFE.

I did some research on it and came across this PDF

http://www.vti.mod.gov.rs/ntp/rad2009/1-09/bosk/bosk.pdf

It looks like it is research from a Russian government site so IDK why it is published in english. I haven't read the whole thing but just looking at the equations makes me wonder a little.

It theroises that Mg or Al + PTFE will burn very hot and produce a lot of gas - it was researched as a solid rocket propellant. It haven't seen any mention of an oxidizer used in this reaction and I would think that relying the metal to burn in air with the PTFE (which is very resistant to burn, but IDK if so at those temps)
http://www.appstate.edu/~clementsjs/journalarticles/zeus_fla...

The PTFE would melt and restrict the amount of atmospheric O2 that can get to the metal to burn.

Am I missing something here about Fluorine? I know Chlorine is used in some pyrotechnics (PVC) and am not sure how it is used either. Can these two elements "burn" w/o O2 or is there some other reaction that is going on?


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j_sum1 - 19-9-2018 at 00:32

Quote:
It theroises that Mg or Al + PTFE will burn very hot and produce a lot of gas


No time for a full answer but…
https://youtu.be/SYucLGUr2MQ?t=1m47s

It is more than just theory.

RogueRose - 19-9-2018 at 02:40

Quote: Originally posted by j_sum1  
Quote:
It theroises that Mg or Al + PTFE will burn very hot and produce a lot of gas


No time for a full answer but…
https://youtu.be/SYucLGUr2MQ?t=1m47s

It is more than just theory.


Wow, that was impressive! I wonder if it could be used as a flare material or if it would burn too fast?

Also, have you ever thought about doing video narration professionally? I listened to some of your other videos and it was nice to hear a chem video that wasn't a computer, electronically altered, a kid or someone stumbling/mumbling their words. Your Aussie accent isn't real thick or harsh like some of them and most foreigners would probably find the same. Good job on the vid's!

j_sum1 - 19-9-2018 at 03:06

Well for start, I am not an aussie. I still have a bit of my own accent left.

And I find narration difficult. Put me in front of a classroom or a crowd and I am fine. Point a camera or a mike at me and I get flustered and trip over my words. It's not logical but it is real.

I do intend to get better. (And I do intend to finish off the electron series within the next three weeks - before the end of the next holiday break.)

It is always encouraging to get positive feedback. Thank you.

RogueRose - 19-9-2018 at 05:19

Quote: Originally posted by j_sum1  
Well for start, I am not an aussie. I still have a bit of my own accent left.

And I find narration difficult. Put me in front of a classroom or a crowd and I am fine. Point a camera or a mike at me and I get flustered and trip over my words. It's not logical but it is real.

I do intend to get better. (And I do intend to finish off the electron series within the next three weeks - before the end of the next holiday break.)

It is always encouraging to get positive feedback. Thank you.


I wouldn't have thought you had any "issues" with speaking into a mic. I wonder if that is more psychological (well kind of obvious) but what I mean is some people get a "stage fright" in front of those things, I completely understand and feel similar - but I couldn't tell is what I am trying to say. I found the benzaldehyde narration very "soothing" for a chem video and better than many BBC or PBS documentaries I hear.

IDK if you partake in alcohol, but maybe have a couple of your choice before starting, I find that helps even though people say that it is not "correct" and a crutch. People take pills right and left for that stuff, it allows you to quiet any inner voice that is making you have second thoughts. Just a thought.

macckone - 19-9-2018 at 12:16

Aluminum or Magnesium will strip fluorine from the PTFE.
This is a very exothermic reaction.
It is similar to the thermite reaction.

https://patents.google.com/patent/US5372069

Pyronol is Aluminum, Nickel, Iron Oxide and PTFE.

In the patent they don't mention what the "solid material which will decompose to form a gas when exposed to the heat of the reacting fuels" is but it is PTFE which also reacts with aluminum or magnesium and the carbon strips oxygen from the iron oxide giving an iron nickle mixture with carbon dioxide and an aluminum fluoride flux.

A perfect example of how a patent leaves out a CRITICAL piece of information.

j_sum1 - 19-9-2018 at 14:42

That's actually a really clever idea to add a bit of flux and heat to a thermite mixture via ptfe.

macckone - 19-9-2018 at 15:27

Clever ideas are what make them patentable.

Texium - 19-9-2018 at 17:35

When Brain&Force (our resident LANTHANIDEZ guy) came to visit, we lit off a couple small PTFE mixtures with ytterbium and samarium filings, which were brilliant green and red respectively!

j_sum1 - 19-9-2018 at 18:17

Quote: Originally posted by Texium (zts16)  
When Brain&Force (our resident LANTHANIDEZ guy) came to visit, we lit off a couple small PTFE mixtures with ytterbium and samarium filings, which were brilliant green and red respectively!

OOh! I might have to do that. I will have some nice Yb coming at some stage.
Actually, it could make a nice rare earth series for a video...

Herr Haber - 20-9-2018 at 03:17

Quote: Originally posted by RogueRose  


Wow, that was impressive! I wonder if it could be used as a flare material or if it would burn too fast?


https://en.wikipedia.org/wiki/Magnesium/Teflon/Viton

Interesting that you didnt find your way to some pyro book or page.
I might be wrong, but I think Conklin's book contain a few words about these flares. I cant really remember the details but they're very intereting in the way they work.

NeonPulse - 21-9-2018 at 17:38

I actually explored these kind of mixtures with pleasing results. The Ti/PTFE was especially hot and Al/Mg powders were much like flash powder but harder to ignite but once they got going they weee hot and bright: see here: https://m.youtube.com/watch?v=qZkmAjLp2-k&autoplay=1