1f Designer Polymers

Chemists design polymers to suit the job they have to perform

1. Polythene – correct chemical name is poly(ethene)

Polythene is used to make _______________ and _____________________. What properties must polythene have to make it a good material for making these?

1.

2.

3.

4.

5.

2. Polystyrene

Polystyrene is used to make the packaging for hot drinks and food Suggest what properties make polystyrene fit for this purpose

1.

2.

3.

4.3. Polyester in clothing

Polyester is used to make clothes. It is fairly strong, lightweight and can be coloured easily

4. PTFE – poly(tetrafluoroethene)

PTFE is used as a non-stick coating for frying pans and saucepans. It has a very slippery surface that nothing can stick to. It must be:

1.

2.

3.

4.

5. Comparing Gore-Tex® and Nylon

Look at the picture of the climber and think about the properties that his jacket and trousers must have? Then look at the table and decide whether it would be better to make them from nylon or Gore-Tex®. You must learn this table of properties

Nylon Gore-Tex®

tough toughhard wearing hard wearinglightweight lightweightwaterproof waterproof

keeps out UV light keeps out UV light not breathable breathable

What do we mean by a material being breathable?

Why is Gore-Tex® breathable

The PTFE layer has tiny _______ that are too ________ for water to get in but large enough for _________________to pass out

The PTFE membrane is not very __________ so it is bonded to a sheet of ________ to strengthen it

In an exam, you must be able to:1. List the advantages and disadvantages of using Nylon for making outdoor

clothes. Be specific and mention the properties in the table above 2. Explain why Gore-Tex® is better than nylon3. HIGHER – explain how nylon works

How do the covalent bonds and intermolecular forces affect the properties of polymers?

The atoms in plastics are held together by strong covalent bonds.

We can explain the properties of plastics by thinking about their structures:

Higher

Higher

1. Plastics that have weak intermolecular forces between polymer

molecules have low melting points and can be stretched easily as the

polymer molecules can slide over one another

2. Plastics that have strong forces between the polymer molecules

(covalent bonds or cross-linking bridges) have high melting points,

cannot be stretched and are rigid.

e.g. If your shopping is too heavy the plastic bag might stretch – particularly on a very warm day

e.g. UPVC window frames. Window frames must be rigid. If they were flexible the glass may fall out.

Strong cross-linking bridges need a lot of energy to break to mpts are high

Weak intermolecular forces attract polymer chains.Easy to breakso mpt is low

Disposing of Plastics

Plastics are made from __________________.

It is difficult to dispose of polymers be cause most polymers are

_________________________.

Non-biodegradable means that they will not _____________ (rot) or

decompose by bacterial action.

Because they do not rot away it leads to problems with _________________

3 ways that we can dispose of polymers:

The disadvantage of this method of

disposal

Land fill sites 1. Landfill sites get filled quickly wasting

valuable land

2. Waste of a valuable resource

Burning of waste polymers 1. Burning waste plastics makes toxic

gases

CO2 – contributes to global warming dioxins - any compounds containing Cl, C,

H, O they are toxic e.g. CO

2. Waste of a valuable resource

Recycling You cannot mix different types of polymers together when they are recycled. It is difficult to sort out all of the different types