This is only a simple starting point guide, most of the molds i made were mostly just proof of concept, I was preparing for the 7th Annual Albuquerque Mini Maker Faire, where i showed off my Styrofoam re-creations and a bunch of my experiments that lead me up to this point, (in the process i tried a lot of other solvents, xylene, toluene, acetone, gasoline, naphtha, lacquer thinner, M.E.K.) lots of them melt it, but all are less pleasant to work with than D-limonene and in some cases such as acetone, my end results were super bubbly, Note: although its possible to get PS to fall out of acetone solution by adding water. (which may be useful for some resuses)

below are some of my more random notes and links i found during my research.

Here is a instructable about using just acetone i think i ran into early on in my research, and is totally worth a credit. https://www.instructables.com/id/How-to-%22make%22-plastic/

About Solvents: https://www.masterorganicchemistry.com/2012/04/27/polar-protic-polar-aprotic-nonpolar-all-about-solvents/

Why so many organic solvents are bad for you..

http://www.rroij.com/open-access/health-hazards-of-organic-solvents.php?aid=57418

Acetone: Works great, turns it into a slurry of dissolved polystyrene that will eventually evaporate thicken and then finally harden, most of the gas is lost, but the acetone gets trapped eventually and blows bubbles into the slowly solidifying stuff, making it bubbly and less than ideal to cast with. Interesting note, water makes the eps crash out of the acetone, but make a odd milky slushy eggdrop soup like stuff. I've not really worked with water crashed out eps much yet, did it two times and all, may try baking it after drying it to see if it will melt back into a puck.

Xyline: also dissolves the product fast, but takes a good long time to dry, and is stinky and bad for many reasons.

M.E.K.: (methyl ethyl ketone) also dissolves the product fast, ends up with a fairly bubble free end result, but is also stinky, and bad for many reasons.

Lacquer thinner: slow, does soften it and degasify it, but not fully dissolve it, and is stinky and bad for many reasons. End result foams and puffs up as it dries. And dries white, one neat thing is its totally not sticky. And i don't think much of any is being pulled along in the solvent, making it possibly the most solvent friendly. Might be good for just strictly commercial use, this may also vary by formulation

D-limonene: works great on plain white ps, will dissolve quite a lot per oz, nice smell, not known to be toxic, leaves the ps very clear (sometimes a slight yellowing) virtually no bubbles, long glass transition. (verrrrry long transition, can take months to feel like thick rubber. And stay that way at elevated heat (80F and plenty of circulation for months.) when solid, re melts at about 104C/220F(seriously this is like easy bake kids oven temperatures! and flows nicely. Casts with relatively few bubbles*http://katu.com/news/local/tigard-company-plans-to-recycle-tons-of-hard-to-recycle-styrofoam-plastics. Cons, very long dry time. And relatively expensive Pros, not known to be toxic, nice smell, good clean results, not much shrinkage, re-meltable and flows well, stays glassy

Toluline: works much like limonene stinkier but faster has many more health risks. and bad for many reasons.

Gasoline: works but dirty, very yellow stinky foamy result in the end... and is stinky and bad for many reasons.

White gas/ Naphthalene: works to degas and shrink it to some degree but does not soften or melt the EPS.

Links: misc.

Experiments in mixes of acetone and D'Limonene

Cool tool! https://www.hansen-solubility.com/HSP-science/sol... Looks like 87% d-limonene to 13% Acetone by volume should do the best melt. According to the above site. Theoretical mix RA of 3.8 (lower= better)

But 25% d'limonene to 75% M.E.K has a theoretical RA of 3.7

Or 21% Xyline to 79% acetone gets us down to ra of 3.2 which is the best i've pulled from the above table. Sofar. Other experiment notes and links:

Tried this mix, using a 50ml test tube filled it with 43ml acetone and about 7ml limonene, and absorbed EPS until it stopped accepting more. Let it tsit 30 min, and then mixed in 45ml of distilled water and mixed. Milky thick eps crashed out of the slurry and the acetone was absorbed into the water. kicking out about 55ml of liquid although im estimating since i spilled some, wound up with a slightly milky 50 ml of liquid, im letting see if any settles, ideally in the future id love to try and absorb the water out, (perhaps with water beads? Can't recall if they dissolve in acetone/limonene,) or distil off and recover the acetone, and see if we can do it again. I have also not investigated only using acetone vapors, perhaps a bucket with a pie tin in it with acetone under it, and ps, and a lid. Or eventually a condensing chamber i can pipe in ther hot distilled acetone? The end result was a sticky ball of wet ps. It’s self sticky and very thick, but it is handleable, (standard disclaimers for solvents on skin, gloves are not a great solution, because the stuff sticks more to them than skin) and shapes like putty, i kneaded it a bit to get out the water/acetone, and proceeded to leave one blob to dry, and one blob mushed into a small mold and i will see how it dries. Im suspecting this version will still contain a fair amount of solvent, and may still take some time to dry End result was fairly white and milky with teeny bubbles, workable. Should be able to distil out the acetone from the water for reuse.

Limonene sadly is not water absorbable so not sure how mixes of acetone/limonene will work, and results of drying lomonine under water have lead to very milky results and super slow drying time.

Polysevert uses Cymene to do what im doing with limonene info on the solvent here. https://en.wikipedia.org/wiki/P-Cymene

more on Cymene (thyme/Lavender terpene) https://link.springer.com/article/10.1007/s10086-009-1073-x

Abstract

We examined the dissolution of polystyrene into p-cymene and related substances to develop an alternative method for the recycling of expanded polystyrene. The dissolving power of p-cymene [212.0 g (100 g solvent)−1] to polystyrene at 50°C compared favorably with those of 2-p-cymenol [156.7 g (100 g solvent)−1], (R)-limonene and its structural isomers [181.7–197.1 g (100 g solvent)−1], and Abies leaf oil [84.7 g (100 g solvent)−1]. The favorable solubility of polystyrene into p-cymene can be explained by the solubility parameter. p-Cymene and polystyrene can be recovered almost quantitatively from the polystyrene solution by simple steam distillation.

Carrier, a term for something like a solvent, may be what im needing for the end reprocessing, folks are suggesting toluline, but, in the process im hearing about making conductive ps mixes, using toluene as the carrier,

http://www.afinitica.com/arnews/sites/default/file...

Related links

My ebay source for 99% pure clear d-limonene https://www.ebay.com/itm/D-Limonene-100-FOOD-GRAD...

https://www.cnn.com/2018/03/09/world/miranda-wang-...https://www.cnn.com/2018/03/09/world/miranda-wang-...

https://upload.wikimedia.org/wikipedia/commons/1/1...

https://www.fastcompany.com/1277458/dissolving-sty...

News:

http://katu.com/news/local/tigard-company-plans-to-recycle-tons-of-hard-to-recycle-styrofoam-plastics

My Youtube Growing playlist of plastic recycling links mostly EPS but some PET, some PP and others…https://youtu.be/CoNd-QbVlqw

For more information or questions email

adric@quelab dot net Or tweet @killbox