Lesson video

Hello, I am Mrs. Adcock and welcome to today's lesson on condensation polymerization.

We are going to be looking at what is condensation polymerization, how does it differ to addition polymerization? And then we are going to look at some examples of condensation polymers.

Today's lesson outcome is, I can explain the basic principles of condensation polymerization.

Some of the key words that we will be using in today's lesson include condensation polymerization, addition polymerization, polyesters, polyamides, and polypeptides.

You can see each of those keywords here written in a sentence.

It would be a good idea to pause the video now and read through those sentences.

You might like to also make some notes so that you can refer back to them later in the lesson if needed.

Today's lesson on condensation polymerization is split into three parts.

First of all, we are going to be looking at condensation polymers.

Then we're going to move on to look at two examples, polyesters, and then finally polyamides.

Let's get started on condensation polymers.

Condensation polymerization involves monomers joining together to form a polymer and a small molecule of water.

Remember, the monomers are the small molecules that join together, and when they join together, they form a polymer.

The reaction below shows how the monomers may join together to form a longer chained molecule, so a polymer, and water.

So we've got a monomer shown there and we've got another monomer shown here.

So we've got two different monomers and they can join together.

And when they join together, they also produce water.

So in condensation polymerization, we have monomers that join together to form a polymer, but they also produce a small molecule, such as water.

We can see here how that water molecule is formed.

The OH comes from one of the monomers and a H atom comes from the other monomer for us to produce water.

Here we can see how these two monomers join together and we can see this section of the polymer where these functional groups are now joined together.

And we can see in that polymer we've got the Ester functional group.

What product is or products are formed during condensation polymerization? Do we form A, a monomer and polymer? Do we form, B polymer and a small molecule? Do we form C, a polymer and a long chained molecule or do we form D only the polymer? So just have a think, what do we form during condensation polymerization? The correct answer is B.

We form a polymer and a small molecule, and we have seen how that small molecule might be a molecule of water.

Condensation polymerization produces two products, the polymer and a small molecule.

Here we can see a polymer that has been produced.

This is a condensation polymer, and we can see we've also formed water molecule.

A repeat unit from a condensation polymer and water.

Addition polymerization, this is a different type of polymerization.

This produces only one product, and in addition, polymerization, we only produce the polymer.

We can see two repeat units there from an addition polymer.

Time for a question.

How many products are formed during condensation polymerization? Do we form A, one product, B, two products or C, three products? The correct answer is B.

During condensation polymerization, we form two products.

We form the polymer and we form a small molecule.

Condensation polymerization gets its name from the fact that during this type of polymerization we have a condensation reaction where we produce a small molecule, such as water.

Condensation polymerization involves monomers with two functional groups joining together to form a polymer.

Here we can see an example of a monomer that could be used in condensation polymerization.

And this monomer has two carboxylic acid functional groups and it's known as a di, because of the two, dicarboxylic acid.

And you can see there the two carboxylic acid groups that are present on that molecule.

Monomer two has two alcohol functional groups, and it is a dialcohol.

We can see the two alcohol groups that are present in that.

Monomer one and monomer two can join together to form a polymer.

We can see here how atoms in their functional group can bond together to form our polymer.

And during this process, a small molecule, such as water is also formed.

And we can see here how we get hydrogen atoms from one monomer and OH atoms from the other monomer and that these come together to form our water molecule.

This is different to in addition polymerization.

So in condensation polymerization, we said that we have monomers with two functional groups, but in addition polymerization, we only need one monomer, which has a carbon-carbon double bond.

So we can see here that we have a monomer.

It has a carbon-carbon double bond, and that carbon-carbon double bond can open up and these monomers can join together to form an addition polymer.

So this is different.

Addition polymerization is different to condensation polymerization.

The double bond opens up to form the addition polymer and no other product is formed.

So we only form our polymer in addition polymerization.

Time for a check for understanding.

What is the lowest number of functional groups that the monomers that form condensation polymers must contain? Is it A one functional group, B, two functional groups or C, three functional groups? The correct answer is B, two.

The monomers that form condensation polymers must contain at least two functional groups.

Well done if you've got that question correct.

Time for our first practise task of today's lesson.

Question one, for each of the reactions, state the small molecule that would be produced.

You've got three questions there, A, B, and C.

And for each one, you've got two different monomers that are going to join together to form a condensation polymer and a small molecule.

And you need to see if you can work out what would be the small molecule that would be produced.

Now, don't be put off by those purple boxes.

They just represent a group of atoms that's in the middle of that monomer.

Pause the video now, have a go at answering this question and then come back when you're ready to go over the answer.

Let's see how you got it.

In 1A, we have got hydrogen from one of the monomers and OH from one of the other monomers, and these would join together to form a small molecule of H2O.

In B, we've got a atom of hydrogen and an atom of chlorine.

And these would form a molecule of HCL.

Well done if you got that one correct, that was more difficult.

And C, is difficult because we cannot see these structures drawn out.

But hopefully you were able to realise that we had a hydrogen atom from one of the monomers and an OH from the other monomer, and these would've formed a small molecule of water.

Well done if you got those questions correct.

We have had a look at condensation polymerization and seen how this differs from addition polymerization.

Now we are going to move on to have a look at polyesters.

Polyesters are condensation polymers that contain the ester functional group.

And the ester functional group is a COO.

We can see in the image there that we've got a section of a polyester chain, and hopefully you can identify that ester functional group.

Here we can see it, and again and again.

So this polyester is a polymer that contains the ester functional group.

Which functional group do polyesters contain? Is it A, a carbon-carbon double bond, B an OH group, C, a COOH group or D, a COO group? The correct answer is D, COO Group is the functional group of an ester, and therefore you will find that present in polyesters.

The C double bond C is the functional group of an alkene.

The OH is the functional group of an alcohol, and the COOH is the functional group of a carboxylic acid.

Well done if you got that question correct and you were able to identify the molecules to which those functional groups belong.

Polyesters can be made by reacting two different monomers together.

When we're making a polyester, one of the monomers may contain two carboxylic acid groups, so that would be a dicarboxylic acid.

There we can see the two carboxylic acid groups.

And the other monomer contained two alcohol groups.

So this is a dialcohol and we can see the two alcohol groups present in that molecule.

Let's see if we can remember what we've just learned, which two monomers join together to form a polyester? And a polyester is a type of condensation polymer.

Is it A, dicarboxylic acid, B, diamine, C, Dialcohol or D, water? We want two monomers that will join together to form a polyester.

The two monomers that will join together to form a polyester are a dicarboxylic acid and a dialcohol.

Well done if you identified both of those monomers.

The dicarboxylic acid and dialcohol monomers join together producing a polyester and water.

We can see here a section of a polyester chain.

When the dicarboxylic acid and dialcohol monomers joined together, water was also produced as one of our products.

We can see here this section of the chain would've come from the dicarboxylic acid monomer.

Then this section would've come from the dialcohol.

And again, this has come from a dicarboxylic acid, and we can see that C double bond O on either end.

And this section here would've come froma dialcohol.

And as this has bonded on, it would've lost hydrogen atoms, which would've formed part of those water molecules.

Time for another question.

What will be formed when dicarboxylic acid monomers and dialcohol monomers join together? Is it A, polyester, B, water, C, hydrogen? Choose any answers that you think are correct.

The correct answers are polyester and water.

Well done if you identified both of those products.

So during condensation polymerization, we always form the polymer and another small molecule.

In this case it would've been water.

An example of the overall chemical equation for producing a polyester from two monomers is, and we can see we've got N number of that dicarboxylic acid and N number of that dialcohol.

And N stands for any number.

Any number of these monomers can join together.

And then we will get this repeat unit present in our polymer N number of times.

So we've got our polymer there as the repeat unit with brackets around it and an N on the outside.

And we will also form N number of small molecules, and in this case it'll be N number of water molecules.

Polyesters can also be made from just one monomer, and that one monomer will contain both a carboxylic acid group and an alcohol group.

So rather than having two monomers that each have two functional groups, we've got one monomer here that has two functional groups.

And we can see an example of a monomer here that has a carboxylic acid functional group, and it also has an alcohol functional group when making polyesters from only one monomer.

An example of the overall equation is we can see we will have N number of that monomer, and it's a single monomer with two functional groups.

It's a single monomer with two different functional groups, and these can join together to form our polymer and we can see our polymer there.

We have the repeat unit with square brackets around it and an N on the outside.

This shows our polymer.

And don't forget, we will also form a small molecule.

In this case it's water and we will form N number of water.

And remember that N can stand for any number.

Polyesters can be made from just one monomer.

Which two functional groups will this monomer contain? Will it contain A, an alcohol group, B, an amine group, C, an alkene, or D, a carboxylic acid? If we want to make a polyester from just one monomer, then that monomer needs to contain an alcohol functional group and a carboxylic acid functional group.

Hopefully you were able to identify those two functional groups that we would need to be present in our monomer.

Time for us to complete our practise task on polyesters.

For this, you need to first of all, draw the products from the polymerization of the following monomers.

So look carefully there at your two monomers.

We are gonna join them together to form a polymer and another small molecule.

So see if you can draw the products that would be formed from those monomers.

Pause the video now, have a go at answering this question, then come back when you're ready to go over the answer.

If we start with these two monomers, we will form a polyester and you can see how we've joined the alcohol and the carboxylic acid here in the middle to form that ester functional group.

Because this is a polymer, we need to remember to add the brackets and an N so that now we have our polymer.

And because this is a condensation polymer, we will also form N number of a small molecule.

And in this case, that's H2O.

Well done if you've got that question correct.

Let's move on to question two.

Question two, draw the products from the polymerization of this monomer.

And this time we have a single monomer, which has two functional groups.

It's got a carboxylic acid functional group and a alcohol functional group.

The rectangle is just representing a group of atoms, so you can keep this and include it in your answer.

Remember to include all the products in your answer.

Pause the video now, have a go at answering this question and then I'll see you in a moment when you're ready to go over the answers.

The products from the polymerization of this monomer will be the repeat unit here.

We're gonna add brackets and N to show our polymer that we will form and we also will form N number of water molecules.

That question was more difficult, so well done if you got that one correct.

We are going to move on now to have a look at polyamides, which are another example of a condensation polymer.

Polyamides are condensation polymers that contain the amide functional group.

So we can see there the amide functional group is CONH.

Here is a section of a polyamide chain and in our chain, hopefully you can begin to spot this amide functional group.

There we've got the CONH, and here we've got it again.

And here's that amide functional group again.

Which functional group do polyamides contain? Is it A, a carbon-carbon double bond, B, CHO group, C, COOH, or D, CONH? So we're looking for the functional group that we would find in polyamides.

The correct answer is D.

So well done.

If you chose answer D.

A is the functional group from alkenes.

B is the functional group from aldehydes, and C is the functional group from carboxylic acids.

Polyamides are condensation polymers that can be made from two monomers.

One of the monomers will contain two carboxylic acid groups, so that will be a dicarboxylic acid.

And we can see the two carboxylic acid groups there.

So that's similar to when we were making polyesters.

However, the second monomer will contain two amine groups, and this is where we get those nitrogen atoms from.

So we can see here a diamine and it's got two amine groups.

Let's check for understanding.

Which two monomers join together to form a polyamide? would you need a dicarboxylic acid, a diamine, a dialcohol or water? We're looking for two monomers that we can join together to form a polyamide.

The correct answer is a dicarboxylic acid and a diamine.

So well done if you identified those two monomers.

The dicarboxylic acid and diamine monomers join together and they produce our polyamide.

So that's our polymer and our small molecule, which is water.

Here we can see a section of a polyamide chain.

When we form this polyamide, we will have a dicarboxylic acid that joins together to a diamine, and this will join together to a dicarboxylic acid.

And this will join to a diamine and so on.

And each time these join together, a molecule of water is lost.

So we also form water as our other product.

When a dicarboxylic acid and diamine react together, they form a polyamide.

And what are the product? Do they form A, a polyester, B, water or C, hydrogen? The other product will be water.

Hopefully you got that one correct.

An example of the overall chemical equation for producing a polyamide from two monomers is, and this is similar to when we looked at the overall equation for forming a polyester.

So we've got N number of our two monomers.

So in this case, we've got a dicarboxylic acid and a diamine.

And these joined together to produce our polyamide polymer and N number of that small molecule, which is water.

Polyamides can also be made from one monomer that contains both a carboxylic acid group and an amine group.

Here we can see an example of a monomer that could be used to form a polyamide.

And this monomer contains our carboxylic acid functional group, and it contains an amine functional group.

When making polyamides from only one monomer, then the overall equation may look similar to this.

So we've got N number of our monomer.

And remember this time we've just got one monomer because our one monomer contains that carboxylic acid and amine functional groups, and they will join together to produce our polyamide and our water molecules.

So we can see we've got N number of the monomer produce our polymer, and we have that repeating unit N number of times.

And we produce N number of water molecules.

Amino acids are monomers that contain the carboxylic acid and amine functional group.

Here we can see an amino acid and we have the carboxylic acid functional group and the amine functional group.

And that R just represents any atom or group of atoms. So we could change that R and put in any atom or any group of atoms that's specific to amino acids.

And then we'd have all our different types of amino acids, depending on what we replaced that R with.

Amino acids can join together to make polypeptides.

Polypeptides are a polyamide.

They are condensation polymers that are made from amino acids.

Proteins contain one or more polypeptide chains.

Which functional group or groups do all amino acids contain? Is it a A, alkene, B, alcohol, C, carboxylic acid, or D, amine? The correct answer is the carboxylic acid functional group and the amine functional group.

Well done if you identified both of those functional groups that are present in all amino acids time.

For our final practise task of today's lesson, you need to first of all draw the products from the polymerization of this monomer.

And secondly, the monomer shown is an amino acid.

What do amino acids form when they join together? Pause the video now, have a go at answering those two questions and then come back when you're ready to go over the answers.

This monomer will join together to form a polymer, and you can see the polymer drawn there and also water molecules.

So you should have N number of the monomer will produce that polymer and N number of water molecules.

Just check your structured carefully to check You got that one correct.

You should have lost an OH from the carboxylic acid functional group and a hydrogen atom from that amine functional group, and they bond together to form the water molecule.

Question two, the monomer shown is an amino acid.

What do amino acids form when they join together? Amino acids form polyamide polymers known as polypeptides and proteins contain one or more polypeptides.

Well done if you remembered that amino acids joined together to form those polypeptides.

We have reached the end of today's lesson on condensation polymerization.

Let's just summarise some of the key points that we've covered in today's lesson.

Condensation Polymerization requires monomers with two functional groups.

Condensation polymers can be made of two different monomers.

A polyester is formed by reaction of a monomer with two carboxylic acid groups, and they will react with a monomer with two alcohol groups.

In condensation polymerization, as well as the polymer, a small molecule is also formed, and this is usually water.

Amino acids contain two functional groups, the carboxylic acid and the amine functional group.

When amino acids undergo condensation polymerization, they form polypeptides and proteins.

You've worked really hard in today's lesson, so well done.

I've really enjoyed the lesson, and I hope you have too.