Sciencemadness Discussion Board

Dissolve Styrofoam? Nah...

johncena - 25-3-2016 at 01:24

Hello everybody! I want to make and study a little bit of the priorities of styrofoam dissolved in a solvent (acetone, gasoline or a non-polar one). Well, I tried doing it, but...
Firstly, I used nail polish remover containing acetone and i put it in a beaker and next I added the styrofoam ot it. Nothing really happened. Next, I made an another batch using Lighting Gas - paraffin hydrocarbons (probably long chains of alkanes and cycloalkanes). I'm not really sure what this actually is, but I think it might be kerosene. Ok, good, I have it. As for the acetone try, I repeated evrything and expect what... again nothing! The only visible change I was able to see was that the styrofoam broke apart and there were many floating balls of it on the top of the gasoline.
So, my question is - why did nothing happen? All the solvents were non-polar as the styrofoam is, but why didn't the long chains of it broke? (Sorry for my English, I'm currently really busy, so I'm not really paying attention of what I'm writing).

Ozone - 25-3-2016 at 04:19

I'm thinking that if it won't dissolve in acetone, it isn't styrofoam, e.g. expanded polystyrene. The form fitting foam for packing is polyurethane, and it is resistant (a mixture of dimethylformamide, methanol, and maybe DCM will soften it for removal from packed items). Starch packing peanuts, not at all. I you have starch, they will dissolve in water.

And, the chains do NOT break upon dissolution--they slowly relax, and they swell. Eventually, if lucky, they dissolve-but, the chains are intact.

Look up good vs ideal (theta) solvents for polymers. https://en.wikipedia.org/wiki/Theta_solvent

O3

ave369 - 25-3-2016 at 04:42

If it's really styrofoam, acetone or gasoline should first turn it into jelly or putty. This "fire jelly", essentially solid napalm, is useful for starting campfires.

Another reason why it failed to dissolve is mislabeled lighting gas. In my country, denatured ethanol is often sold as lighting gas, and the label says "paraffin". If you have denatured ethanol, styrofoam will not dissolve in it.

100PercentChemistry - 25-3-2016 at 09:24

It probably isn't styrofoam. Although I put styrofoam in acetone nail polish remover(not 100%) and nothing happened.

johncena - 25-3-2016 at 11:06

Thanks for the replies! I'm sure that the lamp oil is something like gasoline or kerosene, because it has the distinctive smell of them. It's highly flammable, too. As for the styrofoam - I really don't think it's something else - I took 2 different pieces of styrofoam (a small one from an old toy and a bigger one from the package of my new TV).

hyfalcon - 25-3-2016 at 16:10

Try using gasoline straight from the pump. If it's styrofoam, it will dissolve into mush that you are capable of repairing fiberglass with in a pinch.

careysub - 25-3-2016 at 18:24

Genuine styrofoam, expanded polystyrene (EPS) will dissolve in acetone or hydrocarbon solvents very, very well. This is a convenient test for whether it is polystyrene.

Foams that are not polystyrene that are commonly encountered are polyurethane, polyethylene and PIR (polyisocyanurate, those rigid silver foil covered panels). These do not dissolve in those solvents.

The effect of acetone or gasoline (etc.) on expanded polystyrene makes a very impressive demonstration (it is included in one of Shakhashiri's chem demo books), a large chunk of styrofoam will vanish into a small quantity of solvent since the solubility is high, and the density of the foam low (as low as 0.016).

This makes things filled with polystyrene vulnerable to ruin in any solvent ever gets into them. I have used EPS in several projects, using thin plywood sheet, fiberglass, or carbon fiber to make very light, rigid, inexpensive structures (a book shelf, work tables, router tables, telescopes). But I have been having second thoughts due to the possibility of solvent exposure by accident. Using spray paint or spray adhesives on a structure made with EPS is a no-no if there is any possibility of penetration. Once any solvent gets into a foam structure it can undergo considerably collapse over time, not necessarily al at once.

Texium - 25-3-2016 at 20:00

Yeah, quite often if I have a lot of styrofoam to dispose of, I'll first reduce its size a lot by breaking it all down with acetone. I take an oven tray, pour just enough acetone in it to cover the surface, and then keep adding chunks of styrofoam. It looks quite comical, just shoving huge blocks of the stuff into the tray. Afterwards, I pour off the excess acetone (which can be reused to break down more styrofoam) and squeeze as much as I can out of the polystyrene goop. Then I spread the PS out on the oven tray and let it sit in the sun for a few days. By the time it's done that, you're left with a sheet of dense, brittle, white plastic. It's easily broken up into small pieces, so I think I will use it to make styrene when I have time to.

MrMario - 26-3-2016 at 02:24

Maybe offtopic, but is it possible to obtain styrene from polystyrene?

karlosĀ³ - 26-3-2016 at 03:11

@MrMario:
It is, by destructive distillation
This thread http://www.sciencemadness.org/talk/viewthread.php?tid=7641 showed up first on a quick search, altough another subject, styrene from polystyrene is discussed.


j_sum1 - 26-3-2016 at 03:27

The thread MrMario linked contains a lot of other discussion.
If you want the patents related to extracting the styrene monomer...
Here are the links.
http://www.freepatentsonline.com/3901951.pdf
http://www.freepatentsonline.com/6018085.html


I haven't read them through but a quick glance at the newer of these suggests it is relatively straightforward.
(Isn't that always the way with patents?)

MeshPL - 26-3-2016 at 03:59

It is possible yhat your nail polish remover contained little or no acetone? I heard that in some new polish removers ethyl acetate is main ingredient...

chemrox - 27-3-2016 at 13:29

Styrofoam + gasoline = napalm? So would no-ethanol gasoline and/or white gas be better?

http://www.instructables.com/id/Easy-to-make-and-safer-to-br...

[Edited on 27-3-2016 by chemrox]

PHILOU Zrealone - 27-3-2016 at 16:51

Quote: Originally posted by chemrox  
Styrofoam + gasoline = napalm? So would no-ethanol gasoline and/or white gas be better?

http://www.instructables.com/id/Easy-to-make-and-safer-to-br...

[Edited on 27-3-2016 by chemrox]

Napalm refers to Sodium (Na) Palmitate, it is a anionic carboxilic acid soap used to somehow gellify gasoline...for the military incendiary purpose...
Styrofoam has nothing to do with it...

chemrox - 27-3-2016 at 17:24

Actually there are a number of compositions called, "napalm." The Norwegian army made one using fish oil. Napalm B was made for the Vietnam war using polystyrene and gasoline + benzene. It made for a stickier and longer burn than the palmitate "soap" version. This latter lead to an urban legend that napalm could be made with soap flakes and gasoline. For all know there might be a composition of the right soap and gas that gels. I believe the term "napalm" has evolved to include any gelled flammable mixture including natural oils. It was apparently used in ancient times as "Greek fire." http://military.wikia.com/wiki/Napalm