Polymers - Chemistry online class

In this video is going to run through polymers, it's going to cover the whole of the section of polymers from the MDA to specifications. This is still. This is unit for polymers. Then, sir, what are polymers now polymers came up a little bit in a s in the AAS. I think it was unit two but not to a great extent, but most people, I would guess, do do the GCSE where polymers do come up. I thinking all specifications. So polymers, what are they well long-chain molecules, and they really are quite long sort of you know thousands of sort of a thousand thousand atoms long long chain molecules made from many monomers. So monomers are the things that go together that joined together to make to make polymers, so lots of monomers come together to make a polymer chain of this long chain molecule. There are two flavors of polymers in in the a to specification. They are addition polymers and they are condensation. Polymers addition tends to be the one that people do lower down sort of a year ten year, eleven somewhere, like that, the English system. So addition polymers they're condensation, we new to most people, but nothing particularly difficult about condensation. Polymers at all, I'm going to start wishin then going to condensation then end with a bit of a disposable polymers which is really going to be a table just for you guys to solve, to look at and to copy down the first one dition polymers. So the term addition so addition, what does addition mean? Well addition means that when it, what addition reactions are, when you add two or more molecules produce one molecule, there is no or there are no other products formed at all, so there's no war to perform. There'S no methane, no hydrogen chloride, there's nothing else. Patoot form performed formed. Even so. Two things go together to form one molecule or two or more. I should say so in the case of addition, polymerization we're dealing with alkene so, for example, we're dealing with ething. So, let's draw something so here's my ii theme now i'm saying that n numbers of ething could be any number it could be. A million could be three relatives. Probably you know several thousand tens of thousands. That goes to form me a strand of poly ething, or, if you think, about plastic bags and clean plastic bags and things then polythene is the same thing, a polyethylene. It'S also called - and that looks something like this now. This means this part here. This portion is going to repeat repeated n number of times, so it's completely dependent upon how many initially things go into this. So a thousand these things would make a thousand lots of this portion here now, the buzz word or the buzz phrase in in the a 2 chemistry with relation to the polymers. Is this term repeating unit? So I'll just rub those and gives me a little bit extra room, so this term repeating unit. This is not a repeating unit, and I can't stress that enough. That is not a repeating unit. If you are asked for repeating unit - and you draw that you are not going to get them out, that is not a repeating unit, they often will let it go once. But if there's another question you do it like this, they will penalize you. Okay, often they let it go once the repeating unit is actually a little more simple Lisp, it's very, very similar. So in the case of the poly a thing the repeating unit is going to be that, and that is it. This is the repeating unit and that's going to be the same, no matter what time penalization looking at no brackets no ends. It'S just the this or bare bones of the molecule that the part, that's being repeated, note the trailing bonds, though that is incredibly important. If you were to do this, just like that, you're going to lose yourself a map, because that can't actually repeat can it, you need those trailing bonds, because it shows you've got understanding and therefore the repetition can occur. That would be the repeating unit of polyurethane. Another example of an addition parameter polymer. You might talk a little bit more difficult, so you might get something like they might give you a monomer, give you the alkene expected to draw the repeating unit so from a past paper. There was this, so it was molecule like this. So what's this 1 2 3 4 5 pent tooing so pent to in and they were asking for the repeating unit. So if we were to look at what this would form well, it would form a polymer like this just bring these bonds at right angles and it makes the whole thing very, very easy. So ch3 ch2 ch3 there. So that's what it would form. That'S what the that's the reaction for the formation of the polymer. This is the polymer here obvious. You can't draw it out its entirety. The repeating unit, the other hand, will just be listening again without the brackets, so carbon hydrogen carbon, hydrogen, ch3 ch2 ch3 trailing bonds. That'S is the repeating unit and again, as I said earlier on note, that there are no extra products formed here. We just have the, however, many of this going into make a one huge, long molecule and that's addition, polymerization quite straightforward, a simple type, polymerization sort of them to lead you into it. The next type, then is, of course, condensation polymerization and condensation polymerization again it. It seems that it's a lot, but it isn't overly difficult. So it's going to remember a little bit more than with addition, polymerization so condensation, I say condensation polymers, so condensation polymers is when two or more molecules react to form one molecule plus water. Now the number of water is obviously dependent upon how many initial molecules you've got, but water is its produced here and that's where this term condensation comes in. It'S a nice sort of reminder in a condensation water is going to be produced. What we tend to find and I'm going to show you some examples and you'll see you'll see what I mean here so we'll take an example of something like this. So we've got a molecule here. Oh it's group on one end, we've got ya, go with that. That'S a molecule, and this could be a molecule why, as it was in an exam paper, question actually, so this is why, right here and what the question was was basically draw the repeating unit that would occur when, when the polymer is made from Y, something like That so again, you could go through and if you do, you find your calculation all the rest, but this is actually quite straightforward. The lenses work, and if you can remember this, it will speed this up greatly, basically way. All of these condensation polymers work is. We have a reaction between an H group and an H and that's where this water comes from. So that's how the polymers actually linked - and you can see on the ends of here we this case you have 208 groups, so we're going to end up forming, is and I'll draw this out as the repeating unit and then explain sort of what's happening afterwards. So there's you CH, there's your C double bond o and then we're going across. This is the repeating unit for this molecule here now there are a couple of options here of what you could do this, but in the middle must stay the same. I could put the O there, but then I would have to remove it from this side. If I want to put the O this side, I can I'm on this side the reason being that that oxygen, we're assuming that either the O H, is going to be removed from this side. Reacting with the H of the next molecule or the O. H of this side is going to be it's going to react with the H of the next molecule and that's got to stay constant. So if I have eyes on each side that is actually now incorrect. That'S not right! Because, actually, if you think about it that couldn't possibly forming water when it reacts with the next, the next thing so actually you've got to have the O on one side or the next. It doesn't matter which side, but it must appear on one of them again with these trailing bonds, and in this case here, when one of these reacts, we would obviously produce water again and that's the --. That'S this. This part here is the Oh H. Group is reacting with the h of a pre of the next molecule, or the H on this side is reacting with the a to the next molecule. It doesn't matter if I want to show you I'll just draw this out, so you can actually see what I mean just throw one more molecule for you, so that will be the next molecule. Basically, what I'm suggesting here is that, in the case of what I've drawn here, the repeating unit would be this reacting there. So my H coming off as h2o. If I wanted to switch this and put the O on the other side, then I would be suggesting there that in fact the that would be happening so very slight difference very, very slight difference, but at the same time it's important to make sure that o is Present on one end, particularly in these cases, what I've formed here, this is a poly ester, so it's an ester linkage. This part here is ester linkage. That'S going to connect up our of each one of our monomers to form it the overall polymer. So it's polyester ester linkage and that's obviously they do tend to the way. Certainly, do ask you that occasionally kind of what kind of what kind of polymer would this be, etc, etc, and that's obviously important that you you can specify that this type here is a polyester. Now these way to remember that is that we have an alcohol group, an O, H group here, reacting with a carboxyl group, and that's really, if you remember back to sort formation Investor's, we have alcohols and carboxylic acids coming together to form an ester. So what you're forming is a polyester lots of esters joined together. Really so that's your first time and that's just a generic one, there's nothing there. That was just an application really of a molecule that was given to you and expected. You were expected there to draw the the next thing from it. Then this one, however the formation of terylene or PE T, as it's also known this is a reaction you're expected to be able to remember so. You need to know this. One is know the reactants and you need to know obviously that it produced terylene now the reactants in this example as follows: we have benzene one for died, carboxylic acid and we're going to react to that with an alcohol. So again, this is a polyester rather than alcohol, so which group here we're going to write to it with ething 1/2 dial. All right, all I would say here is make sure you get that e there. They love that in an exam to penalize you for East, an 1/2 dial must haven't either and they could actually give you a big one. That'S not in the case of terylene, that's formed from this. They could give you a longer alcohol and expect you to name it, in which case it would stand true. If there were four carbons here, it would be butane with the OHS. On the end, it would be butane one for dialogue, but, of course, this one here, just the two carbons - it's ething one to dial numbering - is obviously very important there as well. Don'T think that all we should include the numbers because of see it's dictating, that the RH groups are on either end of the molecule. Now, when these come together same kind of reactions before happens, I'm going to draw the repeating unit and the repeating unit I'm going to do it this way, but again you could switch it over and I'll explain what I mean by that in a second. If you've, if you don't understand so there's our benzene ring there C double bond to the oh. We have an O ester linkage linking us to the carbon carbon, the hydrogen, hydrogen hydrogen and then, on this side. I'M going to have my oh now, I'm choosing for this time to say that the O is because of this hydrogen being joined to the O H there. I could flip it around and say I'll have. Oh there and I'll only have the blank there. It doesn't matter I just quite like to draw it with the o. This way again, with the trailing bonds doesn't matter how no, in this case the repeating unit. Is this entire thing, because we've not got one Moloch, one molecule react and we've got two different molecules. Coming together to form one repeating unit, so this entire thing here is the repeating unit. So don't try just drawing half of it, because that obviously isn't correct. Repeating unit is the entire thing from carbonyl group right through to Oh and obviously the trailing bombs there as well. So, as I said, this is terylene, then this is an example. You are expected to know Plus Hadj water, of course, there again and you're expected to know this, and then it's a polyester and the reactants here, the benzene one for dicarboxylic acid and the ething one to dial. That is very important right. Next, one double polyesters: now we're going to move on to look at some poly, amide and polyamides. The first way place, you'd have seen polyamides or poly omadd's, also how proteins form so amino acids coming together to form polyimides so dipeptides and all the rest. They are poly amide not going to look at those now. We look at two specified examples and those are Kevlar and nylons the first one. Then the production of nylon 66, so nylon, 6-6. Interestingly nylon coming from supposedly where it was made new york and london. Some of our own up there you go nylon. 66 is made from two similar molecules. We have hexane diavik acid, so something like that. It'S easier to abbreviate the central portion you're by all means can draw it out, but obviously you've got it's going to take. You extra time and then on this side, we've got one six diamino hexane a couple of points. I'D like to write work, one real main point here: I've, so I've abbreviate the central portions be aware that this is ch2 four, whereas this is ch2 six. If you appreciate to four there, that's going to be one for diamino butane, it's got to have those six there. The reason only the four here so obviously we're capping it. Each side with our carboxyl group, one which provides as a carbon so do not make that arrow there. That would be an absolute schoolboy freedom to do that so make sure they're drawn out fully names for these. Just so you are, you can see those hexane, dioic acid and one six die amino hexane. These are going to join as a as is this go slow, different, color there we go similar to before, but with a with a reasonably large difference, actually go through here. Ch2 4c: Oh notice, there is no oxygen there we're going straight to the bottom and it looks slightly neater like that. There is no need have any oxygen here left over the HDH come together in their entirety, so there is no needs just c2n going across here. Nh and then this trailing bond there, so each side with a carbonyl group on one side and this partial amino group here and, of course, what we have in the middle here. We have amide linkage, and this is where we get this term poly amide from so the aiming group being that carbonyl with the amino group added on to it and that's exactly what we hear amide linkage. So it's not an ester, a polyester either poly amide. Specifically this one being nylon 6-6, you are expected me. I draw the repeating unit, which is this entire thing here, and you are also expected to know the products of that as well. So a bit of a trick. You want to do once. Remember the names, though the actual we're going to do is remember the names, the molecules that they're making I'm gon na remember how it forms, because that's pretty straightforward, you can just do it on the fly next, one we'll struggles on the side here get rid of That next bit, then, is going to be another poly amide, this one's going to be Kevlar, so Kevlar is a polymer. It'S a poly, amide polymer used in obviously vest and all the rest protective clothing, also used in various wear. High strength is required. Where else you use Kevlar now, possibly in sports equipment as well - maybe but certainly in bulletproof, jackets, stab-proof, vests and all bulletproof jackets - is that right, but it professed whatever they're called so Kevlar again you're expected to know the names of the initial molecules. The first one a dicarboxylic acid over here, so there we have that nice aromatic structure which we actually used earlier on and then the next part is again because we're producing and poly amide we have to have an amine based molecule and again it has aromatic portion To it with the obviously, the nitrogen, the hydrogen and the hydrogen now in terms of names, for these, our names are going to be benzene, one for die, carboxylic acid. So exactly the same as what was used in the formation of terylene same initial product there. I'M sorry no seminal molecule and this one here benzene, one for die aiming named as such, because if we have this one, two three there's a corner there, it's terribly wrong but corner one: two, three: four and again one two, three four. So the amino group is on the first carbon, the four from this one. The carboxyl is on the first and the fourth coming together to form our repeating unit. As with all the rest same because it's a poly a might, we have got to worry about oxygens. So carbon carbonyl group, benzene ring carbonyl groups straight through to nitrogen, could go up or down. I tend to draw it down, I think it looks nicer. Ring nitrogen hydrogen boom trailing bond, there you go and this guy here this is Kevlar and, as I say, used in stab vest and all the rest very useful good. Now, once again you need to know the example of Kevlar. You need another example of Forgotten. It was now already you need to know the example of nylon, the other poly a might need to know the example of terylene or PT as the polyester. Those are specified in the specification, so you need to have them down both drawing the repeating units on this. But the key thing is to remember the names of the reactant molecules. Now the fun of it really with polymers is um. Is the idea of the disposal of polymers and it's a section which I don't thoroughly enjoy? It'S that idea of sort of it's the itty-bitty kind of the bits of chemistry that come up every now and again through thee through units 1, 2, 4.

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