2.1 Characteristics of Polymers Flashcards
What are mechanical properties?
The characteristics a material displays when subject to an external force
What are physical properties?
The characteristics associated with the actual structure of the material
What are some of the mechanical properties for polymers?
- Toughness
- Flexibility
- Elasticity
- Mouldability
What are some of the physical properties for polymers?
- Insulation
- Self finishing
- UV resistance
- Melting points
- Transparency and translucency
- Resistance to chemicals and liquids
- Ability to be combined with other polymers and additives
What is toughness?
The ability to absorb impact force without cracking
What is flexibility?
The ability to be bent or folded without breaking
What is elasticity?
The ability to be deformed and then return to its original shape when the force is removed
What is mouldability?
The ability to be shaped into a form or mould
What is insulation?
- Thermal - prevents the transfer of heat through the material
- Electrical - doesn’t allow the flow of electricity through the material
What is a melting point?
The temperature at which a material changes state from solid to liquid
How are polymers affected by UV radiation?
- UV ‘bleaches’ the colour from polymers like ABS
- It also effects the polymer’s mechanical properties, degrading it and making it more brittle
Which polymer is particularly resistant to chemicals?
High density polyethylene (HDPE), and it’s used to manufacture bleach bottles and chemically resistant piping.
Are polymers resistant to liquids?
Yes, most polymers are resistant to liquids however, the length of time they can be used varies
Why are polymer films and moulded polymer sheets commonly used in many types of food packaging?
- They hygienically protect the goods inside by creating a barrier to oxygen, liquids, foreign airborne bodies and tampering
- They prolong the shelf life, help keep the flavour and protect the quality of the contents
What does self-finishing mean?
No additional surface finishing is required - in manufacture, the surface of the mould, will dictate the surface finish
