[blakeud]

Hello,
Would putting liquid paraffin (C_nH_2n+2) in either a polyurethane or polyethylene bladder (such as a camelbak hydration bladder) create any compounds that have a higher toxicity than that of paraffin itself?   I know that all petroleum distillates act as weak solvents and I'm curious as to whether paraffin will dissolve the above (and if so, is it an issue?)

Thank you,
Blake

[Polytriazole]

I would first be concerned that the liquid paraffin would plasticize or outright dissolve the polyethylene.  Most commercially available polyethylene is not crosslinked, meaning that rather than swelling with a liquid like a crosslinked polymer would and becoming a gel, the polyethylene bag would simply fail. 

The polyurethane is more likely to be crosslinked, so material failure is not as big a concern.  Polyurethanes are made from toxic monomers, though, so any unreacted starting material left in the finished plastic could be leached out by the paraffin and be a problem.

Of course, commercial plastics often have additives like colors, plasticizers, etc. that can be toxic.  For an item like a Camelbak bladder, this is less of a concern because they are intended to carry potable water, but there still might be compounds present that are leached out by paraffin (very nonpolar solvent) and not by water (very polar solvent).

I'm curious as to why you want to store paraffin this way.  You'd probably have much better luck in a high-density polyethylene or polypropylene container, or use glass or metal.

[blakeud]

Thank you for your excellent answer.  I'm actually part of a fire dancing troupe and we use paraffin as the least toxic (excepting alcohol) fire breathing fuel we can find.  I want to have a compact way to store it for ~1hr at a time, because the current method of using bottles is rather inelegant and takes up hand space.   From your response I will probably go with Camelbak (the PU) rather than Source (the PE) bladder.

[Polytriazole]

I'd actually test both, if you can, because I'd expect any possible toxins to come from the polyurethane and would use the polyethylene if at all possible.  However, if you're not actually swallowing any of it and make sure to rinse your mouth well, the risk is probably minimal.

Good luck with the fire eating!

[Enthalpy]

Use a metallic flask. Make sur it has no polymer liner inside.