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I did a science fair project once in elementary school. My project was to see what materials would break down styrofoam. I took a big chunk and broke it into pieces, leaving each in a jar of different liquid (and burning one). As one would expect, burning it worked really well, but of course let off a ton of black smoke.

But you know what else fully dissolved the styrofoam? Coke. One week in a jar of coke and it was gone.

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If you want to dissolve polystyrene (styrofoam) then acetone or any other organic solvent (even gasoline) does a much faster job. And because the foam is mostly air you can get rid of quite a lot of it before the solution becomes completely saturated. This solution can be used as a sealant, or to fill molds and produce plastic parts, although it's advisable to use a vacuum chamber to recycle your solvent and help with the degassing.

12 year old me made napalm with the dissolved styrofoam

I was just melting styrofoam with acetone sprayed from syringe.

Fun ended when I decided to include lego minifigure and found out that acetone also dissolves abs plastic. Legos were expensive, hard to get and treasured when I was a kid so result was much undesired.

>Legos were expensive, hard to get and treasured when I was a kid so result was much undesired.

By the time I had children of my own, they were cheap enough to be used as caltrops.

I once tried to spray-paint styrofoam black for a school project. The solvent in the paint ate away at the plastic and left it not foamy immediately.

Next time put a thin layer of plaster of paris on the styrofoam first before painting.

Or PVA (aka "wood") glue. You can even thin it with water fairly substantially to make a poor "sealer."

Gasoline works great. And with enough styrofoam you get the Anarchist’s Cookbook version of napalm as a bonus.

Solvent-based methods have some unfortunate side-effects, and are difficult to scale [1]. Low and slow heat appears to work. I'm still trying to find reports of anyone who takes end user styrofoam and turns it back into desired styrofoam shapes with carbon dioxide as a foaming agent, entraining it into the closed cells. I've yet to hear of people who reduce styrofoam into polystyrene being able to turn it back into styrofoam again, but can't tell if that is an outcome of the chemistry/thermochemistry (very difficult to address), or lack of foaming equipment (addressable with enough expertise, space and capital).

Ideally, I'd like to figure out a way to take all styrofoam entering say a neighborhood as end user packing gets continuously turned into standardized insulation interlocking blocks that is continuously, incrementally installed into buildings that are pre-built with say, 2-4 meter thick wall cavities for incrementally build up the insulation over time. The styrofoam that enters our lives as packing material for a brief period and becomes unwanted detritus ends up in multi-decade and hopefully multi-century building insulation.

I want to do the same with the polyethylene used for most bags, though for those I'd want to turn them into sheets and use them for endlessly making Kaizen foam to organize, protect and store my tooling.

[1] https://davehakkens.nl/community/forums/topic/has-anyone-tri...

Styrofoam isn't safe for household insulation. It's very flamable and produces heavy black toxic smoke.

Is it not the same thing as ubiquitous foam board insulation? https://www.homedepot.com/b/Building-Materials-Insulation-Fo...

Somewhat. There's multiple types of foam board used for insulation in buildings. The most common types are EPS, XPS, and polyisocyanurate. EPS and XPS are Expanded and eXtruded PolyStyrene, respectively. Both are closed-cell foams.

EPS is styrofoam, and is made by putting a bunch of polystyrene beads in a container, and then heating it up so they expand into a big block either in the desired final shape, or later cut into the desired size and shape.

XPS is foamed up with a blowing agent, previously an hyrdoflourocarbon gas (I don't know what's used currently), and then extruded into its desired shape.

Polyiso is its own animal, but I know little about it, other than it's not polystyrene.

Apparently acetone or any organic solvent work well to dissolve styrofoam also.

https://sciencing.com/acetone-styrofoam-experiment-2768.html

Though, that's probably not elementary school safe.

It doesn't remove the Styrofoam though. The Styrofoam is broken down into long chains of molecules which remain in the solvent.

Could this mean it's a bad idea to drink Coke from a styrofoam cup?

Only if you plan to leave the coke in there for a week beforehand.

Coke doesn't contain acetone or alkanes like in gasoline so you will be fine. You should be more worried about your teeth and blood sugar.

Don't these cups have some kind of inner coating?

They do not. You are thinking of paper cups with a plastic or wax coating.

They used to have a wax coating, in just the past decade that has disappeared almost entirely and any recently manufactured cups have a polyethylene (not styrene) lining. Many cups made for hot drinks have polystyrene on the outside, some are multi-layer paper and some have a cardboard sleeve.

It's generally a bad idea to drink coke, or to drink from a styrofoam cup.

>It's generally a bad idea to drink coke

Not really, it's not worse compared to many other things people consume.

Some people I know lecture me about drinking too much soda while their kid chugs cup after cup of orange/apple/grape juice.

https://www.forbes.com/sites/nancyhuehnergarth/2015/12/14/wa....

> Not really, it's not worse compared to many other things people consume.

Yes really. Other things being worse is whataboutism to derail from the issue.

Coke, specifically, from can bottle. If you drink the brown sugar suspension that is fountain soda, you are just marching toward diabetes. The chemistry is unique between these products.

Coke isn't limited to sugary coke.

> Could this mean it's a bad idea to drink Coke from a styrofoam cup?

> It's generally a bad idea to drink coke

All coke colas (and most other products) are insanely high in fructose. The distinction to "drinking coke" is that it's a coke carbonated cola product. The conversation isn't nuanced that a distinction is being made.

>All coke colas (and most other products) are insanely high in fructose

by "Coke isn't limited to sugary coke.", I'm guessing the parent commenter was talking about the sugar free variants eg. diet coke or coke zero.

Yep.

Uhhh no, diet coke and the various kinds of coke zero are NOT high in fructose.

Why is this downvoted. I'm quite sure that many soft drinks like "coke no sugar" use aspartame instead.

If you look at my posts, I seem to be on the "downvoted every post list" from a few unhappy members as I frequently find my posts instantly downvoted for no reasons...

Most fruit juices sold have very similar amounts of sugar to non-diet sodas.

Coke is a fairly strong acid, and somewhat notorious for its cleaning properties viz: https://www.airtasker.com/blog/15-ways-clean-coca-cola/

This admittedly might be pedantic however when it comes to acids "weak" and "strong" are reserved words, if you will, in chemistry; phosphoric is a weak acid. This may be a confusing notion at the outset as hydrofluoric acid, for example, is terrifically corrosive yet considered "weak".

The distinction lies in whether the acid's molecules fully disassociate into ions in solution, or only partially.

What is a better way to describe acids with higher or lower pH in a non-technical context?

Apparently the USDA uses "strongly acidic" to mean soil pH of 5–5.5 https://en.wikipedia.org/wiki/PH#Classification_of_soil_pH_r...

Yes, but "strongly acidic soil" and a "strong acid" are not the same thing.

Coke contains phosphoric acid whic is a weak acid. It is just an acid that is pretty good at removing rust and other oxides in a relatively safe way. Phosphoric acid is also really good at decalcifying your teeth... Leave a tooth in coke for a few days if you want to see what I mean.

To which the head scientist of Coke responded in the 70's - don't keep coke in your mouth for days on end.

What does it turn into?

Polymer degradation of polystyrene through chain scission, if I recall correctly. Phosphoric acid results in a whole bunch of H+ ions floating around in the coke. Those can attach to the C of both ends of each piece of a broken polymer chain or to the aromatic rings on the chain. So the styrofoam breaks into shorter and shorter chains until they are simply floating in solution invisible to the naked eye.

I wonder if that makes it easier for the mealworms to digest it.

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