Hey guys, Ive been looking into ways of dissolving styrofoam to make a putty that can be hand molded. Acetone is not very environmentally friendly so Im thinking about trying D-Limonene. Has anyone had any experience with this? Does the oil ‘ruin’ the plastic?
Im a fine artist so im planning on making art objects from them- it leaves a lot of flexibility because even ‘bad’ qualities can dictate the design of the object.
Thank you! 
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I’m trying to find ways to handle Styrofoam and #2 bag types of plastics for work. I do the recycling for my facility and expanded polystyrene is so unwanted that our recycling vendor will landfill other recyclables if they see Styrofoam or a bunch of bags included. This has led to a lot of experimentation.
D-limonene is basically Orange oil. Tiny amounts of it will cause polystyrene to break down into an amorphous goo. Just about any organic solvent will do the same: Acetone, toluene, and I’ve heard gasoline works as well. These yield a VERY flammable mixture which is rather napalm like. There are also contact and inhalation hazards that are no joke. If you pursue this path, download the SDS for your specific product. Read it and understand the hazards BEFORE proceeding. PPE will be required.
I have done a few trials. Orange oil type products dry VERY slowly, plan for a month or so. The nastier solvents set more quickly, like say a week, but they are much more likely to create a fire hazard, kill some irreplaceable brain cells, or maybe give you a little cancer.
The picture is of a still spongy 2 week old trial. I filled a 5 gallon bucket with packing peanuts. Then I added 2 cups of Orange oil. I let it set up for a couple days then pulled a pancake of broken down polystyrene out of the solution. I used the pictured silicone soap mold as a form. So it’s very formable, but dealing with residual solvent is a necessary issue.
A few little notes from my googling and trials: glacial acetic acid, which is essentially vinegar is supposed to “deactivate” the Orange oil. I tried that in that trial. The color changed and the super strong citrus scent all but disappeared. My hands still smell of oranges after handling the resulting molded product. I also tried resting a medallion on the top of the product. An increase in local temperature from 50F to upper 70’s softened the polystyrene enough that the medallion settled through and the residual Orange oil stripped the enameled paint and that paint can now be seen as a circular discoloration in the product.
I think the compression machine might address the degassing problem. Unfortunately that’s far enough down the project list that I can’t see it happening before the end of next year. I might be able to take and fab up a little pressure / vacuum chamber out of some 6″ cast iron pipe stock with a few fittings.
I guess my goal is to take this stuff that’s technically recyclable, but in practice is not recycled because of its’ form, and make it easily recycled not just by the tiny percentage of folks that have industrial level equipment, but to most folks that will put forth a little effort. I’d like to see it be like composting, relatively simple to do once you put in a few hours of set up time.
So anyway, here are some pictures which I think show the general color, translucency, and brittleness of styrofoam (note the cracks in the larger piece) reduced to polystyrene with heat.
the commercial guys use extrusion machines with compression screws. they extrude into filament and chop into pellets
Yeah, it does the dissolving without adding heat. And yes I added the vinegar after the polystyrene dissolved. It’s an interesting experiment but the ventilation requirements and inherent flammability of any of the solvent methods make them of reduced utility for accomplishing this on any scale with usable results. And of course the orange oil type dissolved product has a REALLY long set up time.
I wouldn’t recommend putting a lot of effort into the solvent methods. Heat seems more efficient. Simply taking a basic toaster oven with a thermostat on it, (not a 1-10 scale), and a little bread pan, or whatever you can fit in there, 300-350 degrees F will exceed the glass transition point and drastically reduce your volume. The trick I would argue is scaling that process up. With the toaster oven method it took me a whole afternoon to reduce a refrigerator size volume of eps to about a 2″ thick cake in my bread pan. . . just gradually breaking pieces off of larger pieces and letting them reduce. Meh. Tedious, but if you were to be in a jamb like say you bought a couple things with a bunch of styrofoam in them like say a computer or a tv that would take all your garbage space, this would let you reduce the volume. And let’s not gloss over that detail, anytime that you can take and reduce a volume of waste by say 95%, that’s pretty remarkable.
Other things come up . . . like it’s difficult to degas the resulting polystyrene. The bubbles look like imperfections. I suspect using either a pressure chamber or maybe a vacuum chamber while it’s pliable could minimize or maybe eliminate those bubbles. It has an appearance not too different from say amber or carnival glass. It’s VERY thick when still pliable. It’s brittle when it cools into shape.
I could envision maybe using this for a low heat output , (like say an LED) light fixture cover, a fly in amber type trinket or beads, a moderate or smallish size vase, or maybe a tinting cover for a photo frame. It’d have to be something that would tolerate the brittle nature of the material. . . things that wouldn’t absorb much abuse, or would, if made of glass instead not be problematic. It’s been a while since I did that. I’ll try to dig it up and post a picture here of my little polystyrene cake in case anyone’s interested.
Nice Mikel, I have a couple of questions:
-does Dlimonene solve the styrofoam whithout adding heat?
-Regarding the vinegar, you add it mixed with Dlimonene or after the material was desified?
I’ve been making lots of trials….you can see in my profile a couple of pictures of some rustic flowerpots I made.
