What is a polymer?

A polymer is a substance with very long molecules. A polymer had identical group of atoms, repeated many times. There are many polymers and different polymers have different properties. Their properties make them suitable for their uses.

 

Why are natural polymers useful?

Plants and animals make natural polymers, including wool, cotton and rubber. Sheep make wool. Wool fibres trap air between them. This means that wool traps heat, making it useful for jumpers and socks. Cotton plants make cotton fibres. Cotton fibre is strong, durable and absorbs sweat. it useful for summer clothing ex. t-shirts. Rubber trees produce rubber. Rubber is flexible, waterproof and durable. These properties make it suitable for tyres.

 

Why are synthetic polymers useful?

Synthetic polymers do not occur naturally. They are made in chemical reactions.There are hundreds of synthetic polymers.

 

Poly(ethene)

Poly(ethene) is the scientific name for polythene. There are two types of poly(ethene).

 

• The molecules in low-density poly(ethene) (LDPE) slide over each other. This makes it flexible. LDPE is also strong and is used for carrier bags.

• High-density poly(ethene) (HDPE) is also strong and flexible. It is harder than LDEP. It surfaces can be very smooth. HDPE is used in artificial knee joints. Artificial joints include metal, such as titanium.

Both types of poly(ethene) do not wear away or break down (decay) naturally. This property is very important for artificial knee joints. It also makes it hard to get rid of carrier bags.

 

Polymers-Summary question

Q1.  A polymer molecule has long molecules. Each molecule has identical groups of atoms, repeated many times. There are two types of polymer: natural polymers and synthetic polymers. Synthetic polymers include PVC and poly(ethene). Poly(ethene) is flexible because it's molecules slide over each other.

Q2. Polystyrene is suitable for packaging because it is a durable material and it is also lightweight, adding on to this it has a low density. It is suitable for disposable cups as it has very good insulation of heat and it is a white colour.

Q3. Poly(vinyl chloride) strength is not as good as the other two polymers, nylon’s strength is okay but acrylic strength is very good. Acrylic hardness is also very good, nylons not as good although poly(vinyl chloride) has an okay hardness. Poly(vinyl chloride) density is very good, nylons not as good with acrylic okay with density.Personally, Overall the best synthetic polymer is acrylic as its strength, hardness and density is great.