Polymers
Design & Technology: AQA GCSE, topic 1.6.4
Polymers
Polymers (plastics) are categorised into two types: thermoforming polymers and thermosetting polymers.
Thermoforming polymers
- Thermoforming polymers have the following characteristics:
- These polymers are generally more flexible especially when heated.
- These polymers are built up of loosely entangled polymer chains with few cross-links.
- They can be shaped into complex shapes and many can be re-shaped multiple times.
- They are easy to recycle.
Common uses
- They are commonly used in processes such as:
- Vacuum forming.
- Injection moulding.
- Blow moulding.
Thermoplastic
Thermosetting polymers
- Thermosetting polymers have the following characteristics:
- These polymers are generally more rigid, harder and brittle.
- These polymers are built up with many more cross-links between them which stops the molecular chains in the plastic moving.
- They can be shaped into complex shapes but once they are ‘set’ they cannot be re-shaped again.
Thermosetting polymers cont.
- They make excellent electrical insulators.
- They have good resistance to heat and chemicals.
- They are difficult to recycle as when heated they generally burn rather than melt.
Thermoset
Test yourself on Polymers
Which type of polymer is difficult to recycle as when heated they generally burn rather than melt?