V4 Find a solution for Styrofoam waste
Hi all! My name is Adrián and I am in Eindhoven with the PP V4 team!
Styrofoam is going to be one focus for the 4th version of the project. In the beginning, styrofoam was a commercial name for XPS (Extruded Polystyrene), later becoming a more casual name for EPS (Expanded Polystyrene). At their core, both materials have the same root which is PS (Polystyrene) so both work in a similar way. There are some differences between them, because they are made with different processes, so there are some slight differences.
This post will explain what are we doing here with this focus, so that we can share our knowledge, to solve the problem of EPS and XPS all together.
Any tips or help is welcome, all experiences are a bonus for us and extra knowledge is always good!
Here’s a summary of the options that we have for recycling EPS:
I think that we can make a few alternative processes; To return the EPS and XPS to its earlier form, by melting it and converting it into PS. Or… by working with EPS and XPS to find solutions without changing its properties too much. Two other options could be to convert EPS and XPS into active carbon for filtering and cleaning water (see: https://archive.googlesciencefair.com/projects/en/2016/2ca4f4c493f29dff24dd2d14ff404868348cb44abb782f5dba8089a40c1c7caf )or even to feed to mealworms in our ‘beyond plastic’ research (see: https://www.plasticula.com/ you can also ask Jannis @dasjannis who is also part of our army!)
Focussing now on turning EPS or XPS into PS, we have two types of process; involving heat or chemicals.
– Chemical process with which the molecules of PS react, causing the material to melt
– Terpenes such as D-Limonene, which is part of the group of monoterpenes, it could be extracted from essential oils in citric fruits. I do not know if it could work also with other monoterpenes. Like Pinene (pine), Myrcene (hop) Linanool (lavender). If someone has tried with them it could be interesting to know how they work.
– Acetone and esters
– Saturated aliphatic hydrocarbons
– Diesel oil
– Thermal process : The temperature that we are working with now is in-between 160ºC and 180ºC. Although from 100ºC (glass transition temperature) we notice some changed to the characteristics of EPS and XPS.
To keep working with EPS and XPS we also have two types of mechanical process; shredded or un-shredded.
Once shredded we can use the pellets in the following ways:
– Using it for filling textiles (pillows etc.)
– Making bricks by mixing the pellets with concrete (the down-side of this option is that it will be really difficult to recycle it again)
– Some agricultural applications, mixed with soil (we have the same problem with difficulty to further recycle)
Un-shredded, we can use the material in the following ways:
– We can cut, and sand it in an easy way, depending on the density of the EPS we have. (The issue with this option is that the process leaves leftovers. This is aimed towards reusing rather than recycling)
-We can also make molds with it, then fill the sand with melted aluminium and burn the EPS. However, this is not a very eco-friendly system. (see: https://www.youtube.com/watch?v=tH-PaNugz9w )
I have been shredding Styrofoam and I have found some problems… Could be great if someone can share their experience shredding this material.
First of all, I was shredding some EPS which I could collect at electronic & electrodomestics shops. It was very clean because it was used only for transporting new devices inside a cardboard box. They gave me a good amount of what I wanted without problem (Nice place to do it!).
I have to say that I have made a big mess doing it 🙂 because:
– I couldn´t use the mesh. This EPS was too light to use with the mesh that I had, and it wouldnt go down. So I thought that it was better to remove the mesh and try without it. (one problem is that big pieces go down without being shredded) My collegue @caroespinozaj was also trying to do it and the styrofoam gets stuck in the shreder and the styrofoam melts on it.
– It was also quite messy because EPS is too light, so when the pellets go down, they start flying everywhere ( so I have changed the box for the collecting bag attached with clamps, so it works much better…) It is also electrostatic…which means that is going to stick everywhere after shredding it… (: It was like being in Christmas!
– Another key point to shredding styrofoam… More density is easier to shred. The shop gave me two Pre-Pressed blocks made by them for an easier transport, these two blocks worked so much better in the shreder. With the low density EPS, I had to apply pressure the whole time because it was not enough heavy to go in to the shreder, the Pre-pressed blocks were so much easier to shred because of their weight and density.
This is the machine which I was using
A couple of images of the mess…:)
Trying to find a way to work with the Styrofoam, so I decided to start melting it as my first test. My tools for experimenting are not the best quality so the results which I am showing are quite rough. I only used two types of EPS: one with a density of around 15kg/m3 and the other from the shop which is around 25 kg/m3. I was using the oven of the compression machine which has some tricky things which jeapardized the tests. For example, it only heats on one side and does not have a ventilation system, also the temperature is not really precise.The first experiment is shown in the first table that I have attached, the second one is on the second photo. The original brick for the second one was 30mm x 50mm x 100mm around 2,20grams and 15kg/m3.
After these two experiments, I can say that the EPS reacts differently depending of its density and on its shape. So I would say that it is a tricky plastic to work with… (nothing new)
I have noticed that the material changes really quickly changing its original properties. It first starts to shrink and then hardens. It then becomes harder and also breakable/brittle, it continues to be light in weight and isolant, but less so than the original material.
After these tests, I started to mould it in different ways, I do not want to melt so I don´t lose the original properties that EPS has in front the PS properties.
Testing the compression machine with shredded and non-shredded material. First at all I would say that we need a really big amount of material to fill the mould and compress it in a good way. Shredded material is more difficult to melt, the timing and the behaviour is different than non-shredded material. I have tested both and I have not found a good way to mould it… (any suggestions?). I have also experimented with cold and hot moulds: if the mould is too hot after being in the oven, the material is going to stick to it (be carefull!).
After testing moulds in the compression oven, we tried to go to hand moulding it. It was tricky to know the exact moment to do it, so I suggest to do it just when the material starts to bend. Another thing to consider is the surface on which you are melting the EPS. If it is a normal tray it is not going to be heated on the bottom part of the material, so we finally decided to melt it on a mesh, where the hot air can pass through easily to heat this bottom part. This make the material melt better.
More photos of the proccess
Hey I have had a little bit to do with it and I used the method of encapusaltion ( putting it in concrete bricks ).
1 shredder is no good to use need to use .. see video https://www.youtube.com/watch?v=1myXa8zZHWs
2. once you have a uniform shape of bead try using steam to but a sheet together refer to this link http://epsa.org.au/about-eps/what-is-eps/how-is-eps-made/
3. Use a vacuum system at all points of process to stop it from going everywhere.
Hope this helps.
I will post more if you want me help with some research or just pm me
I would advise against shredding this material as as you have realized it is ridiculously light. I would recommend trying ball Milling a small batch to see if that process would give you better results. the other benefit for Bowl Milling in the circumstances you can ball mill this material wet, that would also allow you to keep it together and prevent dust from getting kicked up.
hey @acoira !
push on the experiments with the ironing !! (i’ll be trying the technique out this week at work) and see what ar the limits to fusing 😀
my only experience with dealing with PSE was use of chemicals such as acetone to turn it into some very strong glue (but then we want physical solutions, not chemical ones :p)
Was very interesting to share with you on the subject @ the PPV4 workshop; keep up all the awesome work !
nick (& eric & green :p)
It seems to me that what you are trying to do is too subtle. You need to just barely nose up into glass transition range, and do so with uniform heat, reform your material, and then cool for what you want. But there is Such a huge mass loss as the EPS hits those points that it’ll shrink to unusable dimensions for you, as long as you are trying to leave it as EPS. If you took a tiny handheld extruder, you might be able to cut your pieces into the 6 wall sides and the base and essentially weld it together. Not sure that the results would justify the effort required though. Gotta agree with other folks suggesting skipping shredding too. Do the least work to get the necessary results.
I’m of the opinion that for home users, folks without gasifying extruders, working with eps will be easiest if fully converted to polystyrene form first. A glass like sheet stock seems doable. Shiny things like trophies and crystal like pendants seem plausible. (If I can just get the stuff degassed) Next time I get out to harbor freight I want to take a look at one of those plastic welder air compressor add ons. If they could be made to work with polystyrene that could yield some forming options.
@plastikfantastik I have already seen this proccess but the problem, as @mikel says it´s that it is not an easy machine to find and the “home users” aren´t able to use it, so I have discarded this option. Aswell I have discarded the option of the bricks mixed with concrete. In the next life stage/cycle of the product we are not going to be able to separate the EPS from the concrete…
For now I am trying to skip shredding because of the mess and also because I have noticed that the behaviour after shredding is different. Also for the volume of material that I am going to lose by heating it I think that the best way is to use as less energy and processes as I can. In terms of this I do not know if it is worthly to convert it on PS again, cause this means that we are going to spend much energy for having a little amount of PS, but it is not a discarded option, I will explore it as well. First I am trying to use the EPS as EPS keeping its properties.
Okay so here is an idea for an experiment what about using a vacuum to pull it into shape like those space saving bags. Get the eps to a warm temperature (forming temperature) and then put it in a vacuum sealed bag and form it. or will it form to a shape with the vacuum bag alone?
or you could just use a vacuum forming machine
That was a cool video. But geez, the effort, skillset and tooling required to replicate that endeavor, and still then just have a replicated thing as opposed to a wonderful “hey look at how cool I am, now throw money at me, throw ALL THE MONEY AT ME” sort of marketable invention.
I see a pretty decent sample of a single facilities waste stream, not colossal, not like a big urban city sort of volume, but a lot. There are things that can be handled fairly adequately by the existing system and things that can’t. I want to pay attention to the things where there’s just this huge volume of stuff for which the existing system has no effective remedy. Plastic bags are one thing. Even our current practice of collecting recyclables generates more bags that the system does not want. They clog up the big wheels in the sorting machines. So paying attention to that makes sense. Styrofoam, EPS, or XPS is another. It is ridiculously huge for the weight of the stuff. When we put a bunch of it into a compactor, what it does is temporarily compress and then when the ram comes back it re expands like nothing happened. It can totally clog up the compactor. Technically recyclable, but no vendor wants it. So all we can do is landfill the stuff. So from my perspective, heat reducing is something. Not enough, but something. From the perspective of waste volume, reducing the volume of a type of waste by 90-95% is huge. But it’s not sexy. It’s hard to sell the idea of budgeting for floor space, for foundations, for electrification, ventilation, purchasing, installing, maintaining, training shifts of folks to operate something that won’t and can’t make us money. At least not on the scale that justifies the effort to the place.
Here’s a thing that generates loads of indifference when I suggest its’ like: https://youtu.be/PXWNButIZ60
All it’ll do is make it smaller. Meh. I keep going back to just what it’s attributes are: what’s it do? It’s a good insulator. It floats. It absorbs impacts.
So here’s a thing, basically a dock or a floating platform: http://benchmarkfoam.com/products/benchmark-foam-dock-floats/
That’s a product. Someone could survive off of churning things like those out. Make some plastic lumber out of #2, some bulk flotation matter out of styrofoam or eps, work out some coloring method for a half way decent looking product, name it, market. I still find myself unenthusiastic, like looking into the fridge and not seeing anything that I want to eat. Maybe a couple really small platforms and some accompanying pugil sticks. Whack the heck out of your buddies. Something more like this: http://bedfordandbowery.com/2016/07/art-gangs-had-rifts-on-rafts-at-the-battle-for-mau-mau-island/
@mikel the vacuum formers look like a nice process for this material and also for the material which I am working with now. Maybe it doesn’t work properly for EPS, because I think that is only going to melt on one side, so it means that the other side of the sheet is going to break. So I will explain you what we were doing in the last few weeks.
First I have made a hot wire cutter, because cutting styrofoam always makes a mess. This tool makes it cleaner and more precise. This tool is really easy to build, there are lots of tutorials on the internet talking about it. We have made a quite big model of it, because we want to cut big pieces of styrofoam which we are collecting to work with them easily, so we need it to be high and deep. To build it we only need an electricity regulator , a wire which is going to work as a resistence (usually made of nicrom, I am using a 0,5mm diameter, because I am cutting hard and big styrofoam, if not it is going to break more often) a plug, two cables ( + and -),a couple of screws, and the table or shape which we think is better adapted to our necessities. If you need more information, just ask.
As iI was saying, I am now working with a different state of the material. It is not pure EPS, but it is not pure PS neither. So I am trying to work in a middle state of it. I think that this state could be useful for different applications, and I also think that is an easier way to work with Styrofoam. This material is lighter than PS but heavier than EPS. I believe that in the future I will be able to make proper sheets of it so it could be really useful for the people to work with. Also its volume is considerably less than EPS so it is going to be easier and worthwhile to transport it (one of the biggest problems of Styrofoam) It is easy to cut and to bend, so it gives us more freedom for designing with it. It has some interesting properties as it is light and hard, also very breakable, it also has a funny property which is its sound. The touch sense is quite similar to porcelain and could work as it in some products because it is also waterproof…So lets make EPS precious…
The way to obtain this middleway material is heating it and pressing it. I first tested it with a clothing iron at maximum heat at 150ºC. After passing the iron a couple of times you will see how the material starts to reduce its volume and becomes harder, you can make it as thin as you want. After seeing how the iron works, I am trying to work with the sheetpress, trying to get proper sheets with a big amount of material and in this way recycling as much plastic as I can in less time.
After making these sheets I have noticed that I can cut it and mould it easily. To cut it I am using the hot wire with a higher level of amperage. To mould it I am using the heat gun at roughly 300ªC (be careful, if you stop with the heat gun you are going to shrink the material and make holes on it, so try to keep the heat moving and keep bending it at the same time, follow your feelings when you think that is going to break or when it is bendable)
I will show you my tests with the sheet press soon. I am currently trying to process different shapes of Styrofoam trying to fused them together cheap, quick and easy. I want to know what you think about it or if you have any tips about working with EPS on the sheetpress.
Hot wire cutter
Examples of works with this material
@mikel Thank you for all your inputs. The main problem for the examples that you gave me is to fuse the different parts of EPS that I have and then shape it…
On the other hand, this machine that you show me is amazing, I wonder how it works. For the way to convert it in PS again looks very nice.
Actually I am thinking in shred this thin material and try to melt it, maybe in the extruder could work.
This is what current recycling co’s are using to compress the material.
Baling – Balers use hydraulic ram to compact EPS waste either vertically (from above) or horizontally (from the sides). The resulting bales are tied with a strap or twine to keep them together and for easier handling and transport.
Cold compaction – The volume of EPS is reduced without using heat. EPS waste is fed to a pre-breaker where it is broken into flakes of roughly 1 to 2 inches in size. Using an auger or screw compactor, it is then compacted hydraulically into “logs” or blocks, achieving a reduction in volume of up to 98%. The compacted polystyrene can be broken into size or transformed into pellets.
Thermal densification – Thermal densifiers such as StyromeltTM use heat to melt EPS and liberate trapped gases. The melted resin is then allowed to cool into briquettes or strands. This process achieves a greater compaction rate than most hydraulic compactors and results to a product that is sterile. There is, however, the issue of the release of vapours in the workplace and the smell created once EPS is heated. Most manufacturers resolve this by installing air filters on the equipment.
Another technique, as they are doing with wall isolation , is to inject the uncompressed eps with a glue under high pressure. You could do this also in a closed mall to make thick sheets or maybe shapes of the uncompressed eps pearls. That could be reused again to isolate houses.
On my exprerience with styrofoam, i’ve being trying different ways of melting this material:
First I tried the most common one, acetone, and by the way I think it was the worst result (first picture), it get a fragile, rough and irregular material, because when it gets dry it deforms a lot.
Then I tried another type of solvent, but now with some heat. I used cooking oil in a pan. The results were a lot better, but the molding process was very dangerous and difficult to control without burning myself (second and third picture).
The last way I tried to transform the material was only with temperature (160° to 180°C) in an oven, it was a pretty cool result, but it delay a lot more to transform than with the other techniques.
And about my shredding experience, as Adrian said, the material melted in the shredder but it was because of the mesh I was using in that moment, the hole’s diameter were too little for the low weight of the material, (4mm) then, because of the friction it started melting, so now i’m trying different diameters to know wich is the best one to work with.
melting with cooking oil
So just as a warning to others, call this material Foamed Polystyrene (or Expanded Polystyrene Foam (EPS) if you want to get REALLY technical). This is because Styrofoam is copyrighted and this can possibly get you in trouble if you use their “property” etc.
Hope thhis helps!
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