What is the most flammable common plastic?

[jaubert]

The question pretty much says it all.
This has to do with a pyrotechnic flare device. Looking for a tube type case that will burn away rapidly with the flare composition. In searching the web, it appears polystyrene may be the most likely candidate.
Any suggestions would be appreciated, thanks.

 

[Demon3]

Don't use PS you'll get tons of black acrid smoke.

PE and PP will burn away as cleanly as a candle.

Chris DeArmitt PhD FRSC CChem

 

[Compositepro]

Cellulose nitrate can be made at various degrees of nitration to control flammability. But usually waxed paper is used for your type of application. Paper will not melt, but burns away cleanly. You generally do not want the casing to melt or drip before burning away, or to continue burning after the flare is done. A puddle of melted plastic can burn for a long time and the molten plastic is more of a burn hazard than a flame.

 

[patprimmer]

I agree with all the above but would like to add:-

1) Acetal burns very well but has very noxious fumes as it burns.

2) Acrylic burns very well and has a sweet smell.

3) Any cellulose ester burns very well, but especially cellulose nitrate which can actually be used as a propellant for bullets or as an explosive. It used to be used as film for movies and resulted in a number of theater fires.

Of course as mentioned before, all flammable thermoplastics can produce flaming blobs of dripping molten plastic.

Regards
Pat
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[Compositepro]

I'll add one thing to what Pat said. Although acetal breaks down into formaldehyde as it burns, which is noxious, it is actually about the cleanest burning plastic there is. It burns with a smokeless blue flame with little odor because the formaldehyde burns very well. I've even considered using scrap pieces of acetal as a camp stove solid fuel. Trioxane is used as fuel pellets and that too break down into formaldehyde as it burns.

 

[Pud]

PP will burn away as cleanly as a candle

Ans smell just as nice...

If you want to test cellulosics, get hold of a Fender(tm) guitar pick - the marbled ones, and try that!

h

http://www.tynevalleyplastics.co.uk

 

[jaubert]

Celluloid type plastics are not very common any more. Otherwise, I would use it. As far as nitrocellulose goes, it’s a little to flammable, even explosive. I have ordered some virgin 100% Acetal, PP & PE resin beads. Which I will deliver to the injection mold people to make a few tubes & we will try each out, to see which suits our needs. Thanks all.

 

[Demon3]

Cellulose plastics are fully available on commercial scale from Eastman. E.g. CAB and CAP. No reason not to use them.

Chris DeArmitt PhD FRSC CChem

 

[jaubert]

RE: Cellulose plastic resin:

Commercially available is in-part the issue. At most we would need 10 or 20 lbs of resin beads to make prototype tubes from, just to use in burn off tests.

The only place on line (I can find) that handles it, either is foreign (India- China, etc), or sells by the ton. Any idea where a small amount, even 50 lbs can be found domestically (preferably west coast)?

 

[KENAT]

Maybe you need to actually talk to someone at the resin folks, explain you need samples for testing and see what they say. This may require use of telephone or perhaps email etc. rather than just looking at a standard price list or order form.

Or maybe, talk to a bunch of molders and see if they have some on the shelf etc. left over from a production lot.

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[Compositepro]

Anything that can be injection molded must melt and flow which I think would be undesirable for a flare casing. I've never seen thermoplastics used in pyrotechnic devices where they are exposed to flame. There are thermoset molding compounds would work. That is what circuit breaker casings are made from.

 

[patprimmer]

Cast cross linked acrylic would work

Regards
Pat
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[Demon3]

Contact Eastman Chemical who will probably point you to their distributor.

Cellulose acetate proprionate (CAP) or

Celloluse acetate butyrate (CAB)

or look on

http://www.matweb.com

where they normally list every material and where to get it.

Chris DeArmitt PhD FRSC CChem

 

[patprimmer]

CAP is better than CAB for this I think as CAB can really smell bad when stored in confined spaces or when heated. It gives off butyric acid which literally smells like rancid butter or vomit.

Regards
Pat
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[Demon3]

Very good point Pat. I once used butyric acid to surface treat some filler. The smell in the lab was horrible for several days.

Chris DeArmitt PhD FRSC CChem