 See this is one type of classification we have which is based on the structural unit present. Okay. Classification of polymer is also there on the basis of source. Write down the next one classification based on I'll just write down the second one here. The heading is classification based on source based on source. We have two types of polymers. One is natural polymers which exists naturally. That's the name suggest. Write down just one line polymers which are found in nature like animal plants are natural polymers. Okay. Like starch example I'll write down here. Natural polymers examples are starch, cellulose, protein, proteins, nucleic acid, nucleic acid, etc. Nucleic acid we haven't done in biomolecules. No sir that part was left out. I'll do that. Nucleic acid. It takes half an hour. Okay. We'll finish that. It's not that important for you know chemistry point of view but we'll go through once. Okay. We'll do that. Okay. These are natural polymers. Second one is synthetic. Synthetic means what? Manmade. Any example of synthetic polymers? Nylon. Yes. Nylon, polythene, polystyrene, PVC, beccalite, dechron, write down all these examples. Nylon, polythylene, polystyrene, PVC, polyvinyl chloride, beccalite, dechron, DAC, RON. Okay. Now another type of classification we have which is based on structure. I'm not giving you this as you listen to me. Based on structure we have linear polymers, branched chain polymers and three-dimensional polymers. Okay. In three-dimensional polymers there are cross-link. I'll just draw the structure here. You see the first one we have like, here I am not giving you. Just you draw the structure because these are not important. Based on source, classification based on source you write down. See one thing I'll tell you here that for these chapters. Okay. Like we have polymers, biomolecules to a certain extent, biomolecules to a certain extent, then surface chemistry, chemistry in everyday life. For these chapters, NCRT is more than enough. You don't have to read any other book, okay, from beginning to end. The focus should be on NCRT. They prepare questions directly from NCRT. They pick one or two lines and they prepare questions from that. Okay. So my suggestion is I'll cover everything here in the class. But when you want to go through on your own, just read NCRT. For questions you can refer the assignments or any other book. Okay. But for theory part, don't go to any other book that you have. NCRT is more than enough for theory. Okay. So theory part will focus on whatever theory given in NCRT, not more than that. Okay. Based on structure we have three types of polymers. The first one is linear polymer. The name suggests linear polymer will have a linear structure. It should be based on structure. Based on structure. Yes. It is source I have written by mistake. Make it a structure. It means you are not sleepy. Yes, Paras. Sir. Based on structure. Okay. So like I said here, there is linear polymer. There is no branch. It's a linear polymer like this. So it's just a one layer. So you can have another layer like this one. So it is a linear polymer. Oh, it looks good. Second one we have branched chain polymer like the names are just in this. We have branches also. For example, you see this is the polymer. We have suppose and in this we have branches present like this. This is branched chain polymers. Third one is we have three dimensional sheet structure three dimension network polymers also we call it as three dimensional network polymers three dimension network polymers in this we have cross linking right down in this we have cross linking cross linking means what suppose this is the layer one another layer. We have another layer like this. All these layer like here. These are linked together by some bonds. Cross linking see this one is cross like this the cross linking web present. Okay. So write down this is the cross linking. So because of this cross linking their strength increases a bit. Okay. So these kind of polymers are really hard is it? And so can you give an example for 3d thing? Okay. I'll give you write down these are hard rigid and brittle. The example of this is beccalite urea formaldehyde polymer write down urea formaldehyde polymer beccalite melamine formaldehyde polymer. I'll give you examples for all three. Because examples important here for this it is polythene nylons polysters nylons polysters for this one. We have a glycogen amylopectin amylopectin is there in amino acids will discuss that to one type of amino acid. And this is beccalite urea formaldehyde and melamine formaldehyde polymer. So what kind of starch? Sorry. Starch comes under which category sir? The starch comes under the third one. Because amylose and amylopectin. Yes. Yes. Because all these starch proteins you know cellulose they have very very very complex structure. Okay. Very large huge complex structure we have. In all these we have cross linking right. Last class we were discussing no proteins how they forms there will be cyclic you know helical structure because of hydrogen bonding and all. But there are cross linking present in all these kind of molecules starch cellulose proteins and all. All these comes under three dimensional network. Okay. Yes sir. Okay. Okay. Now there are few examples will discuss like I said other you know classification also we have classification based on synthesis. Okay. How the polymers forms two types of reaction generally we have addition and condensation. Right. So that we call it as addition polymerization and condensation polymerization addition polymerization two molecules joins together. Okay. In condensation are like molecules like H2O and H3 goes out and they joins together. Okay. That will discuss in reactions involved in polymerization. So that is also one kind of classification. And we say this as what based on synthesis means what reaction we are using for the synthesis of one kind of polymers. This also comes under classification but we will do that in reactions involved in polymerization. Okay. So before going into that there are few examples that we should know the examples. The first one is H2C double bond T H2. What is the name of this molecule? Ethene. Ethylene. Okay. Both we can see. It goes under polymerization. It gives you what it gives you polyethylene polyethylene or polyethene also you can say which is which we use in plastic bags. So this is ethylene and on polymerization it gives polyethylene. Okay. What is the structure of this polyethylene? It is like this. We have CH2 CH2 CH2 CH2 CH2 CH2 and so on. In short, we can also write this as open bonds CH2 CH2 open bond. Bracket and this is actually represent that there are n such molecules present in this and that's why this is polymer. And the name of this is polyethylene. Am I clear? For polymerization what happens? We should have a definite pressure, temperature or catalyst. So whatever is required will provide you for this reaction and then the reaction takes place. Okay. So the method by which this monomer ethylene this monomer converts into polymer. Those methods are polymerization technique and this phenomenon is polymerization. Okay. What is the use of polyethylene? Use in the formation of plastic bag. You know that. Yes, sir. If you're using plastic bag, if you're carrying some goods in the plastic bag, then they can ask you for 2000 rupees. You know that the soft shell, yeah, soft molecule 5000 and the person who is taking, you know, goods into the plastic bag, they have to pay 2000 rupees. Okay. So don't use plastic bag. So this is one uses of polyethylene. Now the reference molecule is this on the basis of this only will give you the another molecules, which is this. Now if you remove one hydrogen here with chlorine, TH2 double bond CH and here we have CL. When you do the polymerization of it, what you will get? First of all, you tell me the name of this compound. The name of this compound is what? Chloroethylene. Okay. Vinyl chloride. Yes. The vinyl position we have chlorine present. So this molecule is vinyl chloride. And the polymerization of this gives you poly vinyl chloride. Italyne gives polyethylene. Vinyl chloride gives poly vinyl chloride. Got it. The structure is what? If you draw the structure. CH2 CHCl. Connected with other molecules. CH2 CHCl. CH2 CHCl and so on. In short, if I write this as CH2 CHCl and N times. Okay. The example of this PVC, sorry PVC, the user of this in making pipes. Pipes were on them. Okay. One more thing I forgot to tell you here. What is the repeating unit? What is the repeating unit here? This N times means what? This is the repeating unit we have. So like this you have to, you should know the repeating unit of the molecules. Like this one is easy. So you don't have to worry about it. They won't ask this questions also. But for others, we'll see what are the repeating units. There it is important. One kind of one, this kind of question they ask. Similarly, the repeating unit is this one here. Is there a name for these repeating units? It's vinyl chloride only for this one. Name they won't ask. They'll draw the structure. Now, if I ask you these, these two are homopolymers or copolymers? Yes, because the monomer is same. We have only one type of monomer. That's why these are homopolymers, not copolymers. Like this, you have to keep in mind that whatever examples you are looking at, you should focus on the repeating unit, what kind of polymers it is, homopolymer, copolymer. And then what are the monomers? If it is homopolymer file, only one monomer will be there. If it is copolymer, then what are the two monomers we use for the production of this? And what are the uses? These two things you must focus on.