Stefan Trethan wrote:
> On Tue, 28 Nov 2006 13:44:32 +0100, AnaLog Services, Inc.
> <wireline@...> wrote:
>
>> Most peculiar. I originally noticed this with denatured alcohol. The
>> denaturing agent is usually methanol. I ∗THINK∗ I have seen the same
>> effect
>> with PGA ethanol, but now I am questioning my sanity. I will do some
>> experimenting down in the lab later today.
>> I did come across a mention of 0.37% solubility of polystyrene cup
>> material
>> in PGA, but not much else with a web search.
>
>
> Polystyrene foam cups are virtually non-existent here. I can't remember
> ever seeing one in my life.
> Coffee machines use polystyrene cups, but not foam, they are vacuum formed
> sheet with a rolled edge, or some cardboard polyethylene composite
> material.
>
> But still, expanded or extruded polystyrene should be the same all around
> the world, since it is shipped as packing material everywhere. My ethanol
> did not do anything to that, or vacuum-formed sheet polystyrene cups.
> Acetone or laquer thinners will eat all that though.
>
> ST
>
I would suggest you may both be right. I was curious about this so I
popped down to the garage and tried some polystyrene foam in both IPA
and denatured ethanol. Neither had any noticeable effect upon the
polystyrene foam. This is perfectly reasonable. Imagine a world where it
was not possible to go to those classy parties where you get to drink
beer and wine from polystyrene cups for fear that they dissolve in your
hands.
On the other hand, the monomer styrene is soluble in ethanol apparently.
see
http://www.oehha.ca.gov/air/acute_rels/pdf/100425A.pdfbut should not be present in any quantity in polystyrene. I really don't
know how much might be there. The styrene monomer is toxic. Table 6 in
this paper:
http://www.mindfully.org/Plastic/Polystyrene/Polystyrene-Foods-Styrene-Monomer.htmindicates that even then, the amount of styrene you would get out is
tiny and that the polystyrene cup is not destroyed in the test.
If Everclear - which claims to be a non-toxic ethanol product - really
can dissolve polystyrene I would be worried either about the quality of
the polystyrene or exactly what can be present in small proportions in
Everclear that can wreak such havoc with polystyrene.
Pete Harrison