Making bakelite plastic (Part 1)

today I'll be making some bakelite which is a very interesting and useful polymer in the past it was used to make a lot of things like telephone casings knobs kitchenware toys and jewelry however as new plastics were discovered it was slowly phased out bakelite was developed by a Belgian American named leo baekeland in the very early 1900s and it's one of the first synthetic plastics ever made it's made from reacting phenol with formaldehyde and it's a thermosetting polymer this means that polymerization is induced by heat but once the final bakelite is formed it can't be remoulded and heating it again won't soften it before baekeland there were many attempts to make phenol formaldehyde polymers but they usually ended up as brittle and useless solids the reaction between formaldehyde and phenol generates a lot of heat in gases and this causes the polymer to puff up and become something like a hard sponge the key discovery by baekeland was how to control the reaction he found out the reaction between formaldehyde and phenol went through three main stages which he called a b and c in stage a the resin was viscous or solid but it was still soluble in solvent the stage B resin was a hard material that was no longer soluble but it could still be softened by heat he found that both a and B stage resins to be isolated by carefully controlling the temperature when the a and B stage resins were heated again they would go to stage C which was the fully cured polymer the stage see polymer was still brittle and puffed up though so to solve this issue he invented a machine called a bake eliezer bakelite is formed above 100 C and it produces water as a by-product under normal conditions the water is boiled off and it puffs up the polymer the bake eliezer was a high-pressure steam vessel which both heated the resin and suppress the bubbling when placed in the bake Lizer the result was a very useful and durable plastic when it comes to formaldehyde phenol resins there are two main types Razzles and nova lacks resins are made by using more formaldehyde than phenol as well as a base catalyst when resin is heated to around 70 C it thickens to a reddish brown material but polymerization is incomplete the resolume R can then be transferred directly to a mold and heated to about 120 C which results in complete polymerization Razzles are typically known as one-step resins because they don't need any additives to fully polymerize on the other hand nova locks use less formaldehyde than phenol and an acid catalyst instead of a base the pre polymer that results is a hard and brittle material that can be crushed and made into a powder because it's a powder it's common to mix in fillers to change its final properties or things like colorants like the result it then needs to be reheated to be fully polymerized however unlike wrestles which can be directly heated we need to add a curing agent to nova Lacs because it can't cure on its own and we need to add in this extra stuff it's referred to as a two-step resin this video is going to be a two-part series in the first part I'll be doing the classic bakelite demonstration and making resulallah making the novolac just as a disclaimer before I start I don't have a bake eliezer or anything similar so I'm not going to be making any beautiful bakelite products I do think that the stuff I make is still cool though to start things off I'm going to do the typical classroom bakelite demonstration to do this we're going to need a few main ingredients phenol formaldehyde glacial acetic acid and concentrated hydrochloric acid okay so I add some phenol to a beaker and then I pour in formaldehyde solution I turn on the stirring and I wait for all of the phenol to dissolve it has a yellow color because my phenol is a little bit dirty when there was no phenol left I added the last ingredient which is glacial acetic acid I let it stir for about 30 seconds and then I replace it with a smaller beaker into the smaller beaker I add about 25 milliliters of the solution that was just made I then pour in about 12 milliliters of hydrochloric acid the hydrochloric acid is a strong acid and it will catalyze the reaction between the formaldehyde and the phenol although we have a seat ik acid present acetic acid is a weak acid and it's not strong enough to catalyze the reaction on its own after the hydrochloric acid is added the formaldehyde in the phenol will slowly react and the solution will heat up at some point polymerization rapidly occurs and the bakelite is formed the formation of the bakelite can sometimes be quite violent and shoot out of the beaker I tried several times to get it to explode but unfortunately it never really worked for me because the reaction is so vigorous the final polymer that forms is all puffed up this was the problem that people were having when they were first trying to make phenol formaldehyde plastics the polymerization reaction produces water and due to the heat of the reaction it's boiled off and puffs things up just for fun I wanted to see what would happen if I added all of the acid and then quickly turned off the stirring without the stirring the reaction seemed to be a little bit more violent you I tried it again hoping that it would be violent enough to pop out of the beaker but unfortunately it wasn't for the final run with the I have I decided to add the hydrochloric acid slowly because of this the reaction was allowed to occur over a longer period of time and the polymerization wasn't nearly as violent the bakelite that ended up forming was much more dense than the previous runs the product from each run was washed thoroughly with water and then allowed to soak for a few days as it soaked the color slowly faded and became an orange yellow a few days later they were taken out of the water and placed into a strainer to dry they were occasionally rotated and allowed to dry for about a week and it dried now the orange color slowly disappeared and it reverted back to being pink they were transferred to a piece of paper and I tested their properties basically by trying to break them this first one was the most dense and it was made when I added the hydrochloric acid slowly it was actually quite tough and using just my hands I wasn't able to break it the more puffed up ones were very brittle and very easy to crush with my hand you so coming back to the denser one it was actually pretty tough and I needed pliers to break it you just for fun I decided to hit the piece with a hammer and again it was surprisingly strong anyway after smashing it I moved on to making bakelite the proper way starting with res all to make the razzle I'll be using phenol-formaldehyde and a little bit of sodium hydroxide to make the wrestle I mix 20 grams of phenol with 25 grams of formaldehyde solution if you recall from the introduction razzle is made with an excess of formaldehyde the ratio that I'm using here is about 1.5 moles of formaldehyde for every mole of phenol once all of the phenol had dissolved I add several drops of 10% sodium hydroxide which will act as a base catalyst I turned on the heating and I tried to heat it to between 70 and 100 C as the solution is heated the formaldehyde will slowly start to react with the phenol because we have an excess of formaldehyde each phenol can react with more than one and this leads to a mixture of products each of these individual phenol formaldehyde units are generally known as pre polymers in terms of the mechanism I'll quickly explain what's going on the base catalyst first takes a proton from phenol to form a free pair of electrons which is denoted by the negative charge the free electrons on the oxygen moved to form a double bond and the electrons are transferred to the ring due to something called resonance these electrons can move around the ring and exist in three major positions the product that forms in the reaction depends on the position of the electrons on the ring when they attack the formaldehyde for this mechanism I'll just assume it's in the para position in the first step the electrons attacked the formaldehyde and form an intermediate a water molecule comes along and protonates the oxygen to form an alcohol group and this regenerates the base catalyst the base then swings back around and picks up a hydrogen the electrons from the hydrogen are donated to the ring and the double bond on the oxygen opens up this marks the end of the first addition and the process can be repeated to form dye and try products to a certain extent the pre polymers can start to react with each other and the more this happens the thicker the resin will get I continue to heat things and I waited for it to thicken the solution slowly took on a brown color and it looked like it was becoming more viscous it started to bubble a lot more so I turned off the stirring and I took it off the hot plate immediately after taking it off the hot plate it was still quite liquidy but it very quickly starts to thicken as it cools before it became too viscous I poured as much as I could into a silicone mold one thing to point out here is that there's very little water left because most of it was evaporated in the proper production of razzle the temperature control is much better and they use things like condensers to prevent the water from escaping also they run it for a longer time and usually at a lower temperature than I did it at it can be made in batches or continuously where the resin is siphoned off as it's made anyway I wasn't able to transfer everything and some stayed stuck in the beaker the silicone kind of acted as an insulator and the heat in the one on the left started to build up the heat caused it to pulverize more which generated more heat and resulted in a positive feedback loop eventually it stopped reacting and I let it sit overnight when I poked at the left one the next day it was a hard solid chunk the one on the right didn't go crazy so it's still soft and gooey the stuff that was left in the beaker was soft and gooey as well this can all be cleaned out pretty easily using a little bit of acetone in the intro I mentioned that there were three main stages of phenol formaldehyde resins a B and C the stuff in the beaker can still be dissolved in solvent so it means that it's currently in stage a now it's time to take the resins out of the mold and it's pretty easy to do so at first I thought this was a failure but it turned out to be pretty cool the center is red because it's fully cured but the outer part is yellow because it didn't get heated as much if I were to heat this again I could fully polymerize the yellow part and it should turn red in terms of the stages the center part would be stage C because it's fully cured but the outer part would be stage B stage B means that it's solidified and it's no longer soluble in solvents but it's still not fully polymerized it's pretty tough though and I definitely wouldn't be able to break it with my fingers however you can see that it's still quite porous from all of the bubbling that occurred I then de-mold the other stuff and it's clearly a lot softer the texture of it was kind of interesting and it felt almost exactly like a gummy candy if somebody randomly gave me this and said nothing I would probably try to eat it anyway with great difficulty I jammed it back into the mold and I'm going to try to cure it so when it comes to results which are known as one-step I don't need to add anything here and I can simply just heat this gummy pre polymer and it will form the final bakelite to cure it properly it would have to be heated and kept under high pressure unfortunately I don't have something like a baked Eliezer to do this so I just tried to do it using a toaster oven I slowly cranked up the heat and I held it at what was supposed to be around 120 C as it warmed up the resin liquefied again and started to bubble I lowered the temperature to try to keep the reaction under control but it didn't really work in terms of what's going on what we're doing is cross-linking all of the pre polymers that were made in the previous step the linking of the pre polymers is done in two major ways where we either form carbon-carbon bonds or ether groups in the first way it's a reaction between the ring of one pre polymer and the formaldehyde attachment of another so the first thing that happens is the base comes along and pulls off a hydrogen the electrons are shuffled around and we form a carbon-carbon double bond known as an alkyne this alkyne is then attacked by the ring of another pre polymer to form a carbon bridge a hydrogen is then picked up by the base to form water and regenerate the double bond in the second way the formaldehyde attachments are directly attacking each other the hydroxyl group of one attacks the carbon of another and a bond is formed a proton transfer then occurs and the water molecule is kicked off both of these reactions are occurring when making the pre polymer and this is why it's really important to control the heat because we don't want it to polymerize too much so just to summarize the major idea with results is that at least one formaldehyde group has been attached to each phenol when it's heated each pre polymer is capable of attaching to multiple other pre polymers and we build up a densely linked Network however as you saw in the mechanism both of the reactions produce water and unfortunately because polymerization requires more than 100 CE to occur the water is boiled off and things get puffed up the bubbling slowly became more and more vigorous and it eventually got out of control I didn't do anything to stop it and I kind of just let it run its course when it stops bubbling it was this yellow solid which is probably stage B as a heated it more it slowly cured to the final bakelite I continued heating for about 15 or 20 minutes and then I figured it was done I turned off the toaster and pulled out the tray and let things cool I test it out by hitting it with my finger a few times and it's pretty hard when I flip it around I see probably one of the worst quality mouldings I've ever done the molded part is black because I burnt it a little but when I push on it it seems pretty strong the rest of the stuff is also strong but it's so thin and porous that it's pretty easy to break apart so the conclusion here is that I heated it way too quickly and I let the temperature get way too high I think if I had more careful heating and temperature control it wouldn't have puffed up so much and I would have probably gotten a much nicer moulding anyway I wasn't really expecting to get a top quality moulding and it was mostly to explore the properties of Razzles so just to summarize the Rezo is a base catalyzed process which forms a pre polymer that's kind of like a gummy candy the resin that's formed is also known as a one-step resin because no additive needs to be added it can be simply directly heated to form the final bakelite anyway this marks the end of part 1 in part 2 I'm going to be making novolac and you're going to see the big difference between these two types of resins you

Channel: NileRed

Views: 943,039

Rating: 4.9286551 out of 5

Keywords: nile, red, chemistry, bakelite, demonstration, plastic, formaldehyde, phenol, science, how to, organic chemistry, nilered, resole, novolac, polymer, making

Id: phNLecfyWS8

Length: 18min 23sec (1103 seconds)

Published: Fri Apr 21 2017

Reddit Comments

[u/SuBj3cT]

Love NileRed

[u/buddythegelfling]

Yes but is it special Bakelite?

[u/Firstprime]

Serious Eva vibes if you pause at 17:15. Kinda looks like a face. Reminds me of Sachiel's face when it's all messed up during the fight with Unit 01.