Turning a plastic soda bottle into foam

most plastic water and soda bottles are made from a polymer called PE T which stands for polyethylene terephthalate it's a very useful and versatile plastic but every year millions of tons of it are produced and it represents a huge amount of waste a small portion of it is recycled though and it's generally done in two main ways either mechanically or chemically when it's done mechanically it's collected shredded cleaned up and melted then from a liquid it can be extruded spun into fibres and so on in general though it can't be used to remake drink bottles because there's often contamination that makes it not safe for food when it's recycled chemically it isn't just melted and reshaped and it's instead degraded these degradation products can then be used to build into new polymers I found a book that outlined two common chemical methods and I wanted to try them out in the first one it's used to make polyurethane foam for things like insulation and in the other one it's used to make fiberglass resin for this video I'm gonna be focusing on the polyurethane one but in the future I will cover the other procedure as a quick side note for those of you who are waiting the last part of my prescient blue series should be out in the next couple weeks I originally wanted it to be this video but I ran into some problems that ended up delaying it in any case for the first part of this project these are all the chemicals that I used the ones labeled Sigma were purchased well from Sigma the two black ones were from ebay and the castor oil was from my local pharmacy besides the chemicals I of course also needed a plastic bottle pretty much all water and soda bottles should work but it is a good idea to check that it's actually PE tea this is very easy to do by just looking for the recycling number and it should either say one or sometimes it's even just literally written P et I took off the label cleaned off all the glue and then chopped it into pieces using scissors I also waded out and in total there were 22 point five grams of plastic hair into a flask I added some boiling chips that had got by smashing a porcelain plate then I added all the plastic which ended up kind of being a pain because the pieces kept getting stuck in the neck this was totally my fault though and it was just because I didn't cut them up small enough in any case when it was eventually all inside I added magnesium acetate and manganese carbonate which were the catalyst for the reaction then on top of all of this I poured in 15 milliliters of diethylene glycol to get the reaction going I needed to heat it to its boiling point so I placed the heating mantle below it and above it I attached a condenser column to prevent any vapors from escaping I cranked on the heating and over the course of an hour the plastic slowly disappeared P et plastic is a long repeating chain of ethylene glycol and terephthalic acid groups all bound together by ester bonds and what i'm doing here is breaking apart this chain in a process called transesterification with strong heating and in the presence of the manganese catalyst the diethylene glycol starts to attack the PE T it competes with the ethylene glycol for the terephthalic acid and it's able to kick it out and replace it this makes a new ester bond between the terephthalic acid and the diethylene glycol and the PE T chain is broken at this point as the reaction continues this happens in more and more places and the polymer is slowly degraded after about an hour I took away the heating mantle to check its progress as it cooled a bit it became cloudy because some of the plastic was separating from the solution this told me that the polymer chains were still too big so I boiled it for another hour this time it cooled all the way to room temperature without any cloudiness for the next step I had to get rid of the manganese catalyst and I was originally planning to filter it however I found that it was a lot easier to just reheat the resin to make it a bit more liquidy and then to pour it off into another flask by doing this carefully and slowly I was pretty much able to separate out all of it when it was all in the new flask I let it fully cool to room temperature then I poured in seventy 7.4 grams of caster oil and I added a stir bar I tried to set up my stir plate and to mix this all together but I ran into some problems the sir bar that I used was too big and the mixture was way too thick so it kind of just got stuck and did nothing I thought that maybe it would work with a smaller one so I took this one out using a magnet and dropped in the other one not only was this swap kind of a mess but it also didn't pay off at all it was actually able to spin this time but it was so slow that there was no hope in mixing anything I ended up just having to do it the old-fashioned way which was how I should have done it from the beginning when I felt that I had a relatively even mixture I put it back on the stand then into this I poured my entire bottle of tall alene to four die Oh cyanate or just TDI for short just as a quick safety note TDI is relatively toxic especially by inhalation so it's really important to work in a well-ventilated area anyway right after adding it I quickly swirled it around then about 30 seconds later when it looked nice and even I put it back on the stand what was good this time was that the isocyanate actually thinned it out enough that the stir bar was able to work over the next 20 minutes or so the temperature slowly rose and it started to bubble the TDI has two isocyanate groups and each of them can react with an alcohol to make a urethane the castor oil that was added is almost entirely a triglyceride of rice and oleic acid and it can react in three places also each fragment of the de polymerized PE tea can react on either end with all these ingredients added together the castor oil and the PE tea fragments start attacking the TDI this builds a new polymer chain containing many urethane groups and it's generally referred to as a polyurethane an excess of TDI was used here though so it didn't fully polymerize and most of the strands didn't get very long a lot of them also have free isocyanate groups on the end and you'll see in a bit why that's important all the foaming that's happening here is from another reaction between the isocyanate and water the water attacks the isocyanate which leads to the formation of an amine and carbon dioxide gas the aiming that forms can then attack another isocyanate and polymerize things further this reaction doesn't make urethane bonds though and it instead makes dye substituted ureas one final thing that i think is important to talk about is why I even added the castor oil it didn't mention it at all in the procedure and I couldn't find any info online but I think it's because the D polymerize PE T alone just makes bad quality polyurethane the phone made from castor oil is a much higher quality though so I think in industry the general idea is to just use the recycled PE T as a cheap additive to cut down on cost when it's kept in relatively low percentages maybe around 10 or 15% it'll still give a high quality foam but it's just cheaper to make as the reaction continued the temperature kept rising and it eventually peaked at 86 C when this happened the flask was placed into a vegetable oil bath that I had pre heated to 120 see the increase in temperature quickly kick-started some more bubbling but it wasn't nearly as vigorous as before I kept it here for about an hour and then they took it out of the bath and I put it in some cold water in hindsight though while it was still hot I should have poured it into a beaker the cooled resin was extremely thick and it got completely stuck in the flask to get it out I had to invert it in a beaker and blast it with my heat gun it slowly goood its way out of the flask and I thought that it looked like really thick honey after several minutes of working at it it was all eventually out so I got rid of the flask sealed the top with some plastic wrap and the pre polymer was now ready however before I tried making the phone with it I'm just gonna give a quick shout out to Skillshare for sponsoring this video skill shares an online learning community that offers lessons on almost everything from drawing to running a business signing up for premium cost less than ten dollars a month and it gives you unlimited access to all their classes which at this point is over twenty one thousand in one of my recent videos the one on Prussian blue I made my own oil paint and I attempted to use it as I expected I wasn't very good but it genuinely made me interested in learning how to paint and to draw in general I've been using Skillshare for the past week or so to do this and so far I honestly really liked it I personally think that I've improved quite a bit and in a future video if you notice that my drawing and stuff isn't terrible well this is the reason why so with that being said if you're interested in learning some new things and supporting my channel at the same time you should definitely try out Skillshare what's also great is that the first 500 people who sign up using my personalized link will get a two month free trial anyway with that being said let's get back to making the foam to do this I needed a few ingredients and they're all shown here the first step was to make a buffered catalyst solution by adding seven grams of diethyl amino ethanol followed by 10 mils of 10 percent hydrochloric acid I swirled it around a bit to really mix it up and then I placed it on the side in a plastic cup I weighed out about 5 grams of the pre polymer and in the beaker on the right I prepared the catalyst mixture I added about half a mil of water two drops of silicone oil and point one seven five mils of the buffered catalyst that I just made with everything added I gave it a quick mixing and I dumped it into the pre polymer I then stirred it around for a couple minutes and it slowly got whiter and whiter due to the production of co2 gas when I felt like it was evenly mixed I took out the spatula and I let the reaction do its thing the initial reaction was between water and some of the unreacted eyes of cyanate groups which converted them to a means it also produced co2 gas which caused it to slowly puff up these a means then went on to attack other isocyanates forming urea linkages this caused the polymer chains to slowly increase in size and for it to eventually solidify this combination of co2 production and polymerization is how a lot of polyurethane foams are made when it was done I thought it was going to be impossible to get out of the cup but it was actually quite easy I tried jamming my thumb into it and it seemed relatively tough but then it just kind of exploded I took one of the pieces and crushed it in my hand and it easily fell apart into a powder okay so now that I knew my foam actually worked I wanted to try molding it into something so I whipped up a relatively large batch and started putting it into some silicone molds I just bought the one on the Left from Amazon but I made the one on the right myself using a silicone kit at the bottom of it there's an imprint of a caffeine molecule and I wanted to see if it would turn out when it was all transferred over I started a time-lapse and I waited for about 30 minutes when it was done I started by de molding the caffeine one and I saw that it kind of worked it was actually able to get in and mold the molecule but when I took it out a portion of it just got stuck inside despite this though I still kind of thought that it was cool I then moved on to D bolding the other pieces the first one didn't have much to work with but the other three had a lot of excess foam so I was able to shape them using a razor blade in the end this was the final result and I was pretty happy with how it all turned out although the majority of the reaction was over it can take up to a month or longer for the polyurethane to fully cure because of this drink testing it right after making it wasn't really fair and it doesn't show the true strength of the polymer so I waited a couple months and then tested it again and the results were very different I tried as hard as I could to jab my finger into it and then to crush it in my hand but basically nothing happened I also tried flattening it but that didn't really work either so I just resorted to smashing it it was able to take several good hits and still kind of stay together the foam here was definitely way stronger and it really showed me why it was important to let things cure anyway I think that's about it for this project one thing I want you to keep in mind though is that this was just one method of recycling PE t-to polyurethane and there are a whole bunch of other ways that it could be done it's possible to use many different catalysts solvents and even another alcohol instead of castor oil a lot of these changes though will alter the final properties of the polyurethane for example it's possible to make a foam that's instead soft and spongy that can be used for things like cushions the foaming process can even be inhibited altogether so it instead forms a dense solid that can either be rigid or flexible it's an incredibly versatile family of polymers and I think I'm gonna try exploring it in a bit more detail in a future video and one other thing that I might try is redoing this prep but without adding the castor oil I honestly really don't know how it'll turn out and I'm really curious to see what will happen as usual a big things goes out to all my supporters on patreon everyone who supports me can see my videos at least 24 hours before I post them to YouTube also everyone on patreon can directly message me and if you support me with $5 or more you'll get your name at the end like you see here [Music]

Channel: NileRed

Views: 1,072,320

Rating: 4.9297667 out of 5

Keywords: nile, red, science, polyurethane, foam, pet, bottle, plastic, recycle, recycling, chemistry, nilered, soda, turning

Id: xLftqtsiFBs

Length: 14min 58sec (898 seconds)

Published: Thu Jun 21 2018