Lesson video

Hi there, my name is Mr. Booth and welcome to today's lesson.

In this lesson today, we are gonna be looking at polymer properties, the sources of polymers, so where we get them from, and also their stock forms. This is part of the Ergonomic design: Accessible controllers unit.

And obviously you know that most controllers, whether your games controllers or your TV remote controllers, are made from polymers.

So let's go and find out why.

By the end of today's lesson, I want you to be able to identify polymer categories.

We're gonna look at two of those.

I want you to be able to identify the sources of polymers, so where we get those from, and also the stock forms that they're available in and how that relates to how we manufacture those through the processes we use to make our products.

We have three keywords today that I want you to look out for in the lesson.

The first one is polymer.

Very obvious there.

And this is a material made of long chains of repeating units called monomers.

You might have started to do that in your science lessons.

We're also gonna look at properties, the properties of materials, and these are the the characteristics that determine how a material behaves.

And we need to understand the properties and materials to be able to select the correct materials for the job we want them to do in the products that we design.

And then the final keyword today is stock form, the basic shape or size of material that they are supplied in.

And in your design and technology departments in your schools, you will probably be able to look at variety of these and see how they are supplied.

There are three learning cycles to today's lesson.

The first one, we are gonna look at the applications of polymers.

So what do we use polymers for? That's a really important way of starting this lesson because then it'll give you a good idea of why we make them with the materials we do and the manufacturing processes that we use.

We're then gonna look a little bit closer at the properties of polymers, using some specific examples of products that you will interact with every single day.

And then finally look at those stock forms and why they are supplied in those stock forms and how that relates to the manufacturing processes.

So let's start with the applications of polymers.

Before we do anything though, it's really important to understand what the word polymer actually means.

And like many of the words in our language, it comes from Greek, meaning, roughly translated to "many parts." Let's have a closer look.

So first of all, the term poly is from the Greek polu, meaning many.

Pretty obvious.

And secondly, mer comes from meros, which means a share or a share of, or in this case, parts.

So what we can say is a polymer means many parts.

What do we mean by that? Well, actually a polymer is a long chain of small chemical units called monomers.

Here we have our monomers, they're all on their own, but when we put the monomers through a process called polymer.

polymerization, if I can get that right, then what we have is we have these long chains of polymers, which we can then make materials out of to do all the wonderful things that polymers do in our lives.

Now, polymers fall into two categories.

We have natural and we have synthetic.

Two words you are probably aware of.

Natural polymers are sourced directly from nature.

We get them from nature.

They are not made by humans.

These actually count for quite a small amount of the polymers that we use in our everyday life.

Around about 5%.

We get them from animals or plant materials.

And you might be aware of cellulose or starch.

You possibly have a 3D printer in your school or maybe even at home if you're very lucky.

And one of the filament materials that you might use to 3D print your products might be PLA.

That is a natural polymer which is derived from starch.

So there you go.

One that you might be even more aware of is of course rubber, which we get from the rubber trees, which is used for a variety of different products.

Synthetic polymers, these are the ones that you come into contact with on a very regular basis.

They are manufactured by humans and account for around 95% of the polymers we use for our products.

They are from non-renewable resources, which are limited, such as oil, coal, and gas.

And I'm sure you understand the issues that we get with these polymers.

One that you might be aware of is in your clothing, you might be wearing polyester.

But the important thing to remember is they are synthetic, they are manufactured by humans.

So a quick check for understanding.

What are the two categories of polymer? Are they synthetic, organic, natural, sustainable? Pause the video now, have a go at this.

When you've got your answer, come back to me.

So if you answered synthetic and natural, congratulations, you've got that right.

Well done.

Once manufactured, polymers can be categorised into groups, we are gonna look at two of these groups now, which are thermosetting and thermoforming.

Noticed I've highlighted parts of those words, one being set and one being form.

And we're gonna get onto the reason for that in a moment.

The materials in each category have different properties which must be considered when selecting a polymer for a product.

And we're gonna go a little bit deeper and look closely at why we would select these two different types of polymer categories for our products.

So if we first look at thermoforming polymers.

So these polymers can be repeatedly heated and remoulded.

You've probably used them in your school environment already in your lives right now.

They can be recycled because, of course, we can reheat them and remould them.

They also have plastic memory and they will try to return to their original manufactured state when they are heated.

Examples of these include: and this is a very difficult word which we abbreviate to ABS, but it's acrylonitrile, butadiene styrene.

You can see why we abbreviate that to ABS and I'll continue to call it ABS throughout the rest of this video just for ease so I don't have to repeat that again.

We also have polypropylene, slightly easier to say, but we can abbreviate that to PP.

For thermosetting polymers, they're slightly different.

They undergo a chemical change, sometimes due to heat or pressure, resulting in permanent rigidity.

That means they can't be reheated and shaped, also meaning they can't be recycled very easily, very difficult to recycle these.

Two examples of these include silicon, which I'm sure you're aware with, aware of, and also urea formaldehyde, which you might not have heard of, but we'll show you some examples of products that you certainly would've heard of in a moment.

So a quick check for understanding.

Thermoforming polymers cannot be recycled.

Is that true or is that false? Pause the video now, come up with your answer.

Come back to me when you've got that.

It is of course false, but I wanna know why.

So come up with your reason why.

Come back to me once you've paused the video.

And of course the reason is thermoforming polymers are recycled because they can be heated and reshaped into new products.

So the applications of polymers, we talked about that.

So let's have a look at what polymer uses are.

They have all sorts of different uses and in fact, I'm not even going to read all these out on the screen because there are so many you can have, and these are just some of the examples.

But one of the things that is really key to understand is they are everywhere, they are in our everyday life.

And what you are going to do for your task in a moment is you are gonna look at that and just look at how much we rely on these materials to be able to do things in our everyday life.

And here is your first task.

So what I would like you to do is take a look around your classroom or the room that you are in right now and make a list of all the items you see that are made of polymers.

Now I've given you some examples of polymers and what to look for.

So you should be able to do this quite easily.

I would like you to write down what each product is and also what the use is.

And from this hopefully you'll get an understanding that there is such a wide range of applications for polymers.

Once you've done this, come back to me.

Pause the video now.

So I had a look around my room and I found lots of different products.

One of them was a protractor because I've been doing some measuring and drawing angles.

Also, the chair I was sitting on is also made of a polymer.

And that's for sitting on.

I have my ruler with my protractor and I've been using that for measuring.

My water bottle is also made of a polymer and obviously that is to keep me hydrated so I can drink.

The handle of my scissors interestingly are made of a polymer, even though the blades are made of a metal.

And that's used for cutting paper.

I've also got a glue stick on my desk as well, that actually has multiple different polymers within it and I use that for sticking.

And then finally we've got some laminated posters maybe around your classroom.

And obviously they're displaying information.

So what you can see there is we have a variety of them.

And you probably could have done this activity for a very long time with the amount of polymers that you have in your classroom or your room.

But hopefully you've understood that there are lots of different applications of polymers.

So we're now onto our second learning cycle, the properties of polymers.

Material properties are the characteristics that determines how a material behaves.

They help us choose the right material for a specific job.

So it's important we know about those.

Otherwise, how are we gonna choose the materials to design our products out of? Some examples include: strength, and actually let's break strength down into the three different types of strength we can talk about.

We can talk about compressive strength, if I'm pushing something together or squeezing it.

We could talk about torsional strength, if I'm twisting something.

And we can also talk about tensile strength.

If I'm pulling something apart.

If materials are withstanding those types of forces, we can call it strong.

We also have flexibility, very obvious one.

So can it bend without breaking? Can it bend and return to its original shape without bending? We have hardness.

This is often a misconception.

Hardness is the ability to resist scratching.

Think about diamonds when you're thinking about that.

We also have toughness as well.

So think about an we're absorbing an impact without that material breaking or shattering.

That is a tough material.

We also have other types of properties as well, things like conductivity.

And we can talk about conductivity in terms of heat, how well heat passes through it or even electricity.

So how well electricity passes through it.

Does it allow electrons to flow through it? That's all about conductivity.

And then finally, another obvious one is transparency.

Transparency, sorry.

Does it let light through? How much light does it let through? These are examples of material.

Quick check for understanding.

Match the property to the description that we've just talked about.

So you have strength, hardness and toughness.

You have resist scratching, absorbs impact without breaking and withstands a force.

Pause the video, have a go at this.

Come back to me when you've got your answer.

So let's look at strength first.

That is, of course, withstanding a force.

And we talked about those three different types of strength.

We have hardness, which is resisting scratching.

And then finally, of course, toughness, absorbing impact without breaking.

Well done on that.

All polymers have their own unique properties, which we'll look at in a little moment.

But they do share some common ones too.

Most of them are lightweight.

They're usually lighter than metals or glass, for example.

They might not be strong as metals, but with them being lightweight, it means we can design all sorts of wonderful products using them.

They're durable.

They last a long time.

Just think about how long they take to break down in places like landfill.

And that's because they're durable.

They're flexible.

So most polymers can bend without breaking.

Just think about that chair you're sitting on and how many pupils every single day have to sit on it and lean back on it.

And that's a fantastic property to have.

They're resistant to corrosion.

They don't rust like metal or rot like wood.

And we can clean them again and again using quite harsh chemicals.

And they don't corrode.

They're good insulators.

And we can talk about again, our heat and also our electricity.

They don't conduct heat that well.

And they also don't conduct electricity that well.

So again, that gives us lots of opportunities to design products.

There're also water resistant.

They don't absorb water.

Some do, but not all of them absorb water, which again means we can use them for things like outdoor clothing.

So check for understanding.

True or false? Polymer properties only refer to the material's appearance.

Is that true or is that false? Pause the video.

Come back to me when you've got an answer.

So for this one, you should, of course, answered false.

A little bit more complicated though, I want to know why.

So again, pause the video, come back to me when you have your reason.

And this is of course, polymer properties are the characteristics that show how a material behaves and what it's suitable for when we wanna make it into a product.

Well done.

We're now gonna have a closer look at our two different types of polymer, two different categories of polymer, that being thermoforming polymers and thermosetting polymers.

So thermoforming polymers.

A nice one to look at is acrylic 'cause you probably come into contact with this in your school lives.

This is also, the chemical name for this is PMMA, which is abbreviated.

It's clear and transparent.

You can get it in all sorts of different colours, but you can also get it clear and transparent.

It's strong and impact resistant.

It's weather resistant as well.

So it's got that durability.

It's scratch resistant, it's easy to shape.

It's a good electrical insulator.

And we use it for all sorts of things, like protective screens, car headlight casings and lots and lots of school projects.

And there you have a nice example of some acrylic headlight casings.

Another thermoformed polymer we have is polypropylene and that's gonna be abbreviated to PP.

It is flexible, it's lightweight, it's tough.

Remember what tough means? It means it can withstand impact.

It's chemical resistant.

It's got a very good chemical resistance.

And for this, it can be used for outdoor seating, carpets and even those flexible folders that you use in school.

And here you can see we have a stadium seating all made of polypropylene.

In fact, there's a good chance if you are sat on a school chair right now, it's probably made of polypropylene.

Next on our thermoforming polymer list we have ABS.

It's strong and tough, scratch resistant, good for moulding, very good at moulding complex shapes through the process of injection moulding.

It's a great electrical insulator and it's often used for things like games controllers, toy building bricks, those favourite toy building bricks, car bumpers, pipes and fittings, safety helmets and suitcases.

A really wide variety of products there.

And I'm sure you have one of these or a similar one of these at home.

And this is made of ABS.

In fact, the mouse that's in front of me and even my little clicker I've got in my hand to forward on this presentation are both made of ABS.

Quick check for understanding.

I would like you to match the polymer to the product.

So we have acrylic, PMMA, polypropylene, PP, ABS.

And you have three products on screen there.

We have seating, we have a games controller and we have some car headlight casings.

I would like you to match the correct polymer to the correct image.

Pause the video, have a go at that.

Come back to me when you've got your answers.

So first of all, let's look at acrylic.

That is of course the car headlight casings.

The polypropylene is those flexible seats that we sit on.

And the ABS is of course that tough controller that gets dropped repeatedly and used every single day.

Well done if you've got all those correct.

Now let's have a look at some thermosetting polymers.

The first one is silicon.

You've probably come into contact with this.

It's non-toxic.

It's a good electrical insulator.

It's chemically resistant, it's resistant to chemicals.

It's heat resistant as well.

So it's a good heat insulator as well.

And it's non-stick, which makes it very interesting for using for cooking utensils, sealants, things like mould making and also electrical insulation as well.

And there's some nice examples here in your food and nutrition lessons, cooking nutrition lessons, you'd probably use these items and you might even have some of those at home.

They're probably made of silicon for all those reasons there.

Our next thermosetting polymer is, of course, urea formaldehyde.

You might not have heard of this one but I'm sure, again, you've come into contact with it every single day.

It's easily moldable, usually through compression moulding, a slightly different type of moulding.

It's a very good electrical insulator.

It's chemical resistant, heat resistant, but it can be a little bit brittle.

Okay? So that means it's not got a great toughness.

These are often used for electrical casings.

Sometimes it's used in adhesives, insulation materials and also saucepan handles.

And there you have it.

It's what plugs are made of.

And you've gotta think about why we make plugs of this.

Well, if we made it from a thermoforming polymer, a plug, and something went wrong with the circuitry inside that, the electrics, and it got hot, it might start to melt.

It could even open up, exposing the wires inside.

We make it out of thermosetting polymer.

It simply won't do that.

It will just blister rather than opening up and causing those issues.

So that's why urea formaldehyde is a great product for making electrical casings out of.

So a check for understanding.

I would like you to once again match the polymer to the products.

Pause the video, have a go at this.

Come back to me when you've got your answer.

So if you matched silicon to the top one, that's great.

And then urea formaldehyde would be the plug.

And also the saucepan handles.

Not the saucepan it's important to point out.

We're now onto Task B.

What I would like you to do is for each of the products you can see here, is identify the category of polymer.

Is it thermosetting or thermoforming? What I then want you to do is explain which specific properties that we've talked about make each polymer suitable for the product.

Pause the video, have a go at this.

Come back to me when you've got your answers and you can have a look at mine as well.

So for the ABS games controller, ABS is a thermoforming polymer.

It's strong and tough.

If the controller is dropped, it will not break.

And I'm sure you have dropped your controllers many times.

It's also scratch resistant so the controller won't easily get scratched when moved or placed next to other products, which keeps it looking nice.

It's lightweight so users can hold it comfortably for an extended period of time.

And it's easy to mould, allowing the creation of quite complex ergonomic shapes so it fits in your hand.

For the saucepan handle, we said it was, I said it was urea formaldehyde and that is a thermosetting polymer.

It's easily moulded and attached to the metal saucepan, making it comfortable to grip.

Urea formaldehyde is a good heat insulator, meaning that it won't melt but also it won't burn when the saucepan is heated.

The other good reason for that as well is it means if I grab hold of the saucepan handle, I'm not gonna burn my hand either 'cause it's not gonna transfer the heat from the saucepan through the material into my hand.

'cause it's insulating that heat.

It's also chemically resistant, which means it won't be damaged when cleaned using chemicals or put in the dishwasher.

And then we also have, here is the folder.

This is polypropylene, it's a thermoforming polymer.

The folder needs to bend without breaking repeatedly.

We need to open and close it, open and close it.

So that is why polypropylene is suitable.

It's also lightweight.

So what we need to do is carry it in our bags.

And we might be carrying many of these if we're at school or university.

So that means we can carry lots of them without it being too heavy.

It's also chemically resistant, which means that if you spill ink on it or you need to clean it, you can without it being damaged.

And then, of course, we have the bath.

This is gonna be made of acrylic.

Acrylic is suitable for the bath because it's strong and impact resistant.

That means if we drop stuff in the bath or we're getting in and out, it's not gonna get damaged.

That means it can also hold a lot of water and a person in there without it deforming.

'Cause water, of course, in a full bath is quite heavy.

It's also very easy to shape and it's scratch resistant.

So it can be made into curved shapes easily and won't scratch when people use it.

Well done with all that.

We're now onto our final learning cycle.

And this is polymer stock forms. So stock form means the basic shape a material is supplied in.

For example, timbers can be supplied in planks, boards, mouldings, dowels, or even veneers.

So we have some examples on here that you can see which are really useful and that's what they're supplied in.

You might even find if you are in a school environment, you'll be able to access and see some of these in their stock form.

Quick check for understanding.

What are the stock forms of timber? Pause the video, have a go.

Come back to me when you've got your answer.

We, of course have boards and planks.

If you've got those two well done.

So we know that the stock form is the basic shape a material comes in before it's processed into a final product.

So let's have a look at what the polymers come in in terms of stock form.

We have granules, we have sheet, we have rods, and we have pipes.

Most of these you have probably seen, you might not have seen granules 'cause it's probably already been made into a product by the time it reaches you.

So when designing, it's important to be aware of the available stock forms as this impacts the design decisions that you have to make.

There are four manufacturing process categories which will affect the choice of the stock forms. And these are: wasting, removing material, we have fabricating, so when we join materials together, we have deforming, so changing the material shape but not the state of the material.

And then what we have is called reforming, which is changing the material shape and the state.

So let's have a little closer look at some of these.

The first one is granules.

So polymer granules are used in what we call reforming manufacturing processes such as injection moulding.

The material shape and the state are changed, the solid granules are heated into a liquid and then they're changed into whatever shape we want.

Usually quite complex shapes like for example, your games controller, they're cooled again and that makes them a solid.

And then, of course, they are our product.

Polymer sheets are suitable for wasting, and fabricating or even deforming manufacturing processes.

Now of course you might have used these sheets in your everyday school lives.

And what pops into my head are things like laser cutting, acrylic sheets.

But also you might have done some things like vacuum forming, something along the lines of that.

Quick check for understanding.

Which polymer stock forms are suitable for reforming manufacturing processes? Pause the video, come back to me when you've got your answer.

So you should, of course, answered granules because that is what we use if we are reforming the material.

Well done if you got that.

When making design decisions about materials, we must consider a few things.

These include the properties required, the size, shape, and complexity of the design and the available manufacturing processes that we have at our disposal.

For example, if we take our games controller, again, it's a complex curved shape and this is made of ABS and it's made using the reforming process and therefore the stock form will be granules.

'cause we're gonna injection mould it.

It'll be no good trying to make this out of a sheet material.

It'd be far too complex.

But if we were gonna make our bath, so we're going back to our bath, it's a simple curved shape, and this is acrylic bath.

So it can be made using the deforming processes such as vacuum forming or thermoforming as it might be called.

And therefore the stock form would be sheets.

So we're now onto our final task.

For each of these products, I want you to identify the manufacturing process and the polymer stock form, and I want you to give reasons for each of those.

So we have a hairdryer, a yoghourt pot, a TV remote control, and a builder's hard hat.

Have a go at this, once you've got it, come back to me and we'll have a look at my answers.

So how did you get on? Well, what I said is the hairdryer and the remote control are both complex curved shapes similar to the games controller.

Therefore, they are manufactured using a reforming process, probably injection moulding, which means the stock forms is most likely to be granules.

We then have the yoghourt pot and the builder's hard hat.

They are simple curved shapes, very similar to the bath that we looked at.

They can therefore be made from sheet material and they will be deformed, possibly using vacuum forming or thermoforming.

Well done with how you got on with that.

So we're now at the end of the lesson.

So let's have a quick summary.

Polymers are long chains of monomers classified as natural or synthetic, and grouped into thermoforming or thermosetting.

Most polymers are made from petrochemicals, which are synthetic.

Polymers are lightweight, durable, flexible, water resistant, and good insulators with specific types offering unique properties.

Polymers are supplied as granules, sheets, rods or pipes, and have many, many uses.

Finally, when designing polymer products, it's important to consider the required properties, the size, shape, and complexity of the design and the manufacturing processes available.

Well done today, you've been absolutely fantastic and I'll see you again soon.