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One of the biggest applications of organic chemistry is polymer. In this chapter, we will review the basic concepts of polymers, including their structure, bonding, and fundamental properties. By understanding the general characteristics of polymers, such as chain configuration, crystallinity, and inter-monautical interactions, we will be better prepared to see how these features translate into the specific and various applications.

for example the battery or the bioengineering even the semiconductor. So for example, for the battery, this foundation will allow us to understand why certain polymers are selected for the design batteries, how they function as a binder, electrolyte, or separator, and how their property influence the overall performance, safety, and stability of the battery system.

The term polymer originated from the Greek word poly means many, metals means part, which together means many parts. Another common name for polymer is macromolecules, which literally means big molecules. In general, a polymer from the step by step beginning with the monomer we called in Korean.

then growing into oligomer and eventually becoming polymer with a high molecular weight. A monomer can be defined as any substance that can be converted into a polymer. In polymer, if we identify the repeated unit within the structure, we can easily predict what the original monomer looks like. For example, polyethylans, which

called the P which we use very often the monomer is ethylene initially ethylene contains a double bond but during the polymerization this double bond converted into a single bond gradually forming the polymer chain in biological system proteins all the polygaptides are also polymers they are formed through the condensation reaction of the amino acid like

as one of the water molecules is go out and then the polymer is to the polypeptide. And in case of the polymerization, the polymerization process itself particularly means with two monomer joining to form a dimer. Then with the addition of another monomer, a tumor is formed. And this process continues step by step.

until high molecular weight polymers are obtained. As monomer grow, they form the oligomer. We know that origomer are low molecular weight polymerization products. And they include species such as dimer, trimer, tetramer, pantomer, and so on. And polymers are materials with a molecular weight.

about 10K are usually considered low molecular weight polymers, while those above these thresholds are classified as high molecular weight polymers. To make this concept easier to understand, let us record what we run in organic chemistry. Take arcane as an example. When the carbon chain contains only one or four carbons, the compound exists in gas.

As the chain lengths increase, they gradually become wicked and solid. When the number of carbon exceeds around 1000, the material can be regarded as a polymer such as polyethylene. The example illustrates how molecular science directly influences the physical properties of materials from the gas state to the gas.

liquid and the solid and finally the polymer. So how can you classify the structure of polymers? In general polymer structures can be divided into three major categories. Linear, branched and the cross-linked polymer. Linear polymers that is the first consideration of the concept.

These polymers do not have side branches and because of their simple chain structure, they are usually sold in the soil vents. At room temperature, many linear polymers use with elastomer, meaning they can stretch and return to their original shape. So we can imagine one of the examples of elastomer is the rubber.

we call it the chromo and then the typical example of a vinyl polymer include the polyethylene, polyvinyl chloride, we call it PVC, polymethylmetaclate, emma, polyacronitrile and the nylons is quite the famous material for the clothes. These are widely used in everyday materials and industrial applications.

Second is branched polymer. Branched polymers are often soluble in soil vents and in many ways they resemble linear polymers. However, because of their irregular structure looks like this one, they have a role tendance to crystallize. They also use a bit difficult different solution based costs compared to the linear polymers. On the other hand, the co-spring polymer

behave quite differently. They do not absorb the solvent but instead they swell. Swell means some the smaller amount of this kind of cross-linked polymer. Then they absorb the solvent. The size is changed to the huge size. So like this, when the big degree of the cross-linked is very high, the material becomes rigid, high melting point and

the even and swell the results in the solid network but then the entire of the cross-link is a key tapping in the polymer science the it plays a the critical role in the enhanced the mechanical property of polymer material making them more durable and suitable for advanced application so already we know that why the kinds of the cosmic polymer is tough and the some or sometimes good mechanical property because so for example one of the things they made

they connect it is very stable some the in the bonding some mechanism we already know covalence bonding for new product so it's not easy to some cut these kinds of the bondage in addition there are other polymarchitectures such as the statite polymer and the dendrimal type polymers these type of polymers are often used as material in polymer the battery lateralized by introducing the cross-thinking they not only enhance ionic conductivity but also improve the mechanical property of the system

As a result, such structures are frequently reported as a promising candidate for advanced battery electrolyte materials. So like a three-stubbed polymer and the stubble stendrohomal polymers. Next we are going to talk about the two important types of polymer, homopolymer and copolymer. The difference between them is very important in the polymer science and the material engineering.

First, let's start with the homopolymer. the monomer unit. That means the rifting structure throughout the chain is the same. One of the examples is holy until then.

So for example, if we polymer ethylene, we get polyethylene, a simple chain of the repeating, these kinds of units. Homo polymers are usually easier to synthesize and their properties are more uniform. So they are widely using the plastic, fiber, and the pillows. Let's look at the coal polymer. A polymer is made from the two or two.

more differentiable monomers. By combining the different kinds of the monomer, we can create material with a payload properties. Copolymer can be the classified into the different type. So one is the random copolymer. The monomer are arranged in no specific order. Random means just A, B, B, A, A, B, A, B.

The large blocks of the one monomer are connected to blocks of other like AA AA BBBBB. So let's compare the homopolymer and copolymer. Homopolymer are simpler and they usually have a predictive property but copolymer gives us the flexibility to design material with the specific

the vistic like the top points elasticity or the chemical resistance so that's why the many advanced on tackling a material today such as impact resistant plastic or specialized coatings are based on the these kinds of the co-polymers so let's look at another example the graft polymer and graft the co-polymer is tied both the polymer in each step

side chain of one kind of polymer organically attached to the main backbone of another polymer. I think you can imagine there is like a some kinds of tree. The tree, the trunk represents the main chain while the branching represents the graft side, the chains. This unique architecture allows the graft copolymer to combine the property of both polymers.

For example, the backbones may provide mechanical strength, while the side chains may introduce flexibility, biocompatibility, or conductivity. A lot of things because of these, graphical polymer are widely applied in biomedical materials, membranes, and surface multiplication. Another thing like these kinds of telechirotic polymers, these kinds of polymers,

that has a reactive functional groups located at both chain and end these kinds of chain ends like as for example we can think of an OH or COOH like this one these terminal groups are maybe a lot of the functionality the special feature of these kinds of polymers is that they can serve as a building blocks for other chemical reactions such as chain extensions, cross-linking or block of polymers indices

So from these kinds of the structure we can make a lot of things. For example, something has a COOH functional group carboxylic seed. If we add the armin base, something material, so mixing together and the heating, and then the water molecules go out, we can connect here like a COOH amine root.

this one. These are special type of the monomer that contain the two distinct reactive groups within single molecules like COH, the amines, OH, COH, amino acid NH2 and COH. Because of their dual reactivity they can participate in different types of polymerization reaction.

or even link two different polymer chains together. For example, a monomer may have both a hydroxyl group and a carboxyl function group. In this case, the hydroxyl groups could attend some reactions we can call esterification, while the carboxyl functionally could react with amines or other arcos. Another example is the amino XC, which contain both amines and carboxyls.

dual functionality is the fundamental reason why I'm actually the kind of form the peptide wound and the build some kind of proteins the presence of two different functional groups makes these more numbers buried some the function are some specific to use some the functionalities they are often using the design of the co-polymer crosswind network and the

advanced functional materials. So that is the one of the some key or the core techniques for designing some new polymer structure. To understand the polymerization we need to know about the basic reaction. The basic reaction one of these addition reactions. We are going to talk about the horny adhesion reactions.

focusing especially on the olefins and the carbonate confounds. In the poly addition, the reactions, no small molecules is filled out. That's the key difference from the condensation reactions. Condensation. So what is the condensation reaction? We already know

that. So for example some COOH and the H2O high-gob-2 functional group and then they react with some heat so whatever the H2O is go out. That means the condensation reactions. So in case of the addition of polymobidations when the reaction takes place the monomer

just add together step by step to make a big polymer chain. So what exactly is polyaddition and is a type of step by step, stepwise reaction? Two molecules with the react group meet. They add to each other and then this process repeats many times until we get a polymer of the high molecular weight. Unlike the condensation reaction, we don't see the byproducts like H2O or HCl.

of things so that's why is especially useful in the making clean polymer materials so the one of the the process of the the poly addition the reactions they are the main the pathway like is the pre radical addition and the ionic addition the reactions the pre the radical additions

but think about the atelence. So one of those good examples. If we add the radical initiator like as vanjolylperoxide like this

initiator it generates the some ready calls

radicals. These radicals attack the double bond, open it up and the transfer the vertical side to the end of the growing chain. So some initiator or like this one is better, initiator attack and they move to here. So like this one and then meet with another like this

the chain that goes as more monomer are added and finally in the terminal the termination the some step the radical combined or the underbord this preparation to staff rules I think we already know that India organic chemistry the part

Finally we will get the polyethylene materials and these kinds of reactions conversion from the double bond. So double bond consists of sigma and the pi bond but on the single bond just consists of sigma bond. So compared to the sigma pi bond and the sigma sigma bond which is the stronger

Sigma bond is the stronger and stable bond. And then another example, inside the radical, we also have the ionic polymerization. In the tationid, the polymerization, and in the strong, the oxid, like the tationid, polymerization.

around the anion polymarization. Cation polymarization, a strong acid like as BF3 has form carbocations and then the decarvocation adds to the double bond and the process keeps going. A common product is the polyisobutylene which is using the adhesive and sometimes it's a vulnerable binder for batteries and in case of the anion,

the polymerization and you hide the strong base and this part you exit like this organic reaching the compound generates a the carbon anion that cover anions protect the double board propagating the chain and then this method is used to make a polymer polystyrene opened with a very countered molecular weight

So in this section we went about the three different kinds of polymerization. One is addition reactions, the ketionic polymerization and the anionic polymerization. So repeat again the addition polymer. Addition polymer is simple monoviditions. Usually they have an unsaturated binary group.

low condensate. The same composition of monomer and polymer and fast and open the spontaneous reactions. At this case, the reaction proceeds through the several stages. The first is the initiation step. The initiate is the substance that starts the whole chain reaction without initiator.

the monomer just stay there they want polymer gains on their own so there are many type of the initiator one is the pre- radical initiator like as benzoil for oxide or the other compound we usually say the k i in the end initiator the when the heat or exposed to light they decompose and form the free radicals

already we know that the kinds of the radicals attack the double bond and of the monomer opening up and the starting chain goes. Another thing is cationic polymolidations with the cationic initiator like as the APEF3H2SO4 exit type generate carbocations. Carbocations added to the double bond and the chain goes through the success

Another thing is anionic polymerization. Organometallic compound like this. Base usually and liquid lithiums generate carbon anion. Not carbon cation, carbon anion. Carbon anion attacks the double volt and the chain continues to grow and grow.

and anionic some materials. Now let's look at some examples. The polyethylene is formed when the ethylene undergoes the addition of polymerization. EBC polyvinyl chloride comes from the monomer that has a chlorine atoms attached

So in case of the PVC, it's quite widely used in the water pipes. Polyacronitrins is coming from these kinds of monomer with the nitril groups. So we also have the polystyrene and the polyizobutylene, which is important to the material using the VAVA product. The phy softens also polymerase in the similar way through the addition and

reading to the formation of a polymer. For example, polyisophane. So we already know that the natural rubber, there are two types, C's and the trans. But I'm just the C's type of the polyisophane, we call the natural rubber. Another thing, the neofran rubber looks like this kind of structure. Next is the polytetrafluethylene.

record the PFE is quite the famous called the teflon so we can see the cooking fans some cooking fans coated with the teflon about two years is it is non stick coating usually and this kind of teflon is very stable at the some high temperatures nothing is 40 for my behind for the ultimately like this

kinds of the structure. Alright everyone, we are going to talk about the different type of the force that hold the molecule together or attack, attract them to each other. This is very important for polymer chemistry even for organic chemistry. So I think in the organic chemistry already we will learn about this one, so organic chemistry one maybe

Some of these are the primary bonds, like as covalent, the ionic bonds which are strong and formed the framework of the molecules. Others are secondary interactions, like as the hydrogene bonds, dipole interactions and the van der Waals force which are generally weaker, but very important in determining the physical properties.

Let's talk about the primary covalent bond. Covalent bond is formed when the two atoms share a pair of electrons.

Unlike the ionic bondings where the electrons are completely transferred, the cobalt bonding the atom holds the electrons together in the share space. This share allows the both atoms to achieve more stable electron configurations. So let's think about this example the hydrogen molecules. Each hydrogen atom has only one electrons in the 1s of atoms but the hydrogen is more stable when it is out shafts.

the 1-asovietal is filled with the two electrons. So when the two hydrogen atoms come closer, and then they can share the electrons, but on theirs is too close because of some repulsion, the force with the energy is increased. So the final day two at the peripheral, the bone ranks, the hydrogen atoms share the electrons,

form a single covalent bond. Now let's talk about the hydrogen bond. I think the lot of and various the application of the polymer even the organic chemistry and the battery hydrogen bonding is very common is very important. These are weaker than covalent and ionic bonds.

but still very important. A hydrogen bond occurs when hydrogen atoms already cobalt bond to highly electronegative atoms like gas or sometimes the fluorine is attracted to another electronegative atom nearby. So we often write it is the e h.

A is donor, A is acceptor. And the hydrogen bonds are stronger than the van der Waals tools or some different interactions. So they are also the directional, meaning they have a stronger when the atoms wind up almost a straight line. So one of the good examples like as the hydrogen bond is

water and also the DNA the amino acid proteins they maintain like is that helix structures because of the there are some hydrogen bonds of those kinds of things they maintain the unique structure or the in case of the some kinds of the polymer for example CO8 like as the

the oils. In that case they can form a lot of the interactions here. Next they look at the dipole-dipole interactions. The dipole interaction, what is the definition? These occur between the molecules that have a permanent dipole. That means the one side of the molecules is slightly

positive and the other side is slightly negative we call partial minus partial positive partial negative partial positive the positive and the one molecule is attract the negative and the another these kinds of the attractions like this is weaker than the hydrogen bond but also a little bit stronger than the Pandarivas fruits.

for example chloromethane CaP3Cl the carbon is partially positive and the chlorine is partially negative because of their the huge difference of the electron negativity so neighboring molecules like attract each other through the dipholic force another example the methyl liquid but then the carbon is partially

led to negative and the lithium is partially positive. Through this, we can see the partial charge is another array of things for each element. In that case, the metal-litium is partial minus charge, but in the chloromethane, the carbon is partial positive charge. So, the V must be considered in relation to the surrounding atoms and all the molecules.

Next is the van der Waals force. These are weak intermolecular forces that exist between the molecules and they find important laws sometimes in the mature science. The definition is van der Waals force are attractive or the repulsive interaction between the molecules that are not due to the covalent or ionic bond. Instead they come from the

interaction of the electron cloud like this plus minus plus minus these kinds of interactions these occur between the molecules with the permanent dipoles such as hydrogen the chloride nothing example dipole and induced dipole interaction a the polar molecules like this plus minus

eluse near the other non-pola molecules and they're creating interaction. They cause the partial minus and partial positive charge. So let's look at the one of the example the the carbon the compound in case of the arcanes one of the examples when the increased the carbon there the melting point and the boiling point increase why because of their

isn't the dipole-dipole the interactions like as van der Waals tools so temporarily it's dipoles. Next the ionic bond is a type of chemical bond that forms between a metal and the non-metals it happened when the atom can transfer electrons to another the atoms so for example is the NaCl

So the sodium is given one electron and the chlorine is gained the electrons. As a result, sodium becomes a positive ion and chlorine is a negative ion. So the strong elastro static attraction between these opposite charts plus and minus.

ionic bond. So in case of the ionic bond, sometimes create a compound like a sword or some crystal structures. So in case of the crystal structure, they have a high melting point or sometimes they can conduct the electricity when dissolved in the waters.

Thank you.