13.1 - Enhancement Of Materials (Polymers) Flashcards
Different types of polymer enhancements (11)
- Lubricants
- Thermal antioxidants
- Pigments
- Antistatics
- Flame retardants
- Plasticisers
- Fillers
- Biodegradable plasticisers
- Bio-batch additives
- Antioxidants
- UV light stabilisers
Why would you add lubricants to polymer stock? (2)
- Adding wax or calcium steerage reduces the viscosity of the molten polymer, making it less ‘sticky’ and allowing more intricate shapes to be formed
- Lubricants also allow the moulding temperature to be lowered, saving energy
Why would you add thermal antioxidants to polymer stock?
They prevent the polymer oxidising or discolouring due to excessive heat during processing
Why would you add pigments to polymer stock?
Tiny particles that are mixed into the polymer in its molten state to give colour to the final processed product
Why would you add antistatics to polymer stock?
Antistatics reduces the likelihood of the polymer building up a static charge
Why would you add flame retardants to polymer stock?
Reduce the likelihood of combustion or the spread of fire (car engine components) or potential electrical fires such as plug sockets
Why would you add plasticisers to polymer stock? (2)
- Plasticisers allow plastics to become less hard and brittle at normal temperature use, e.g. added to LDPE food wrap, allowing the wrap to be stretched over the food product
- Plasticisers also help in processing because they allow polymers to be easily formed at high temperatures
Why would you add fillers to polymer stock? (2)
- Sawdust and wood flour provide bulk to the product, meaning that less polymer is required
- Mineral fillers such as chalk, clay and calcium carbonate help increase thermal conductivity this allows it to heat up and cool down more quickly therefore giving shorter mould cycle times
Why would you add biodegradable plasticisers to polymer stock?
Make polymer more flexible, softer and easier to break down which allows for faster degradation time
Why would you add bio-batch additives to polymer stock?
oxy-degradable, photodegradable and hydro-degradable additives help reduce degradation time from hundreds of years to a few years or even months
Why would you add antioxidants to polymer stock? (2)
- They help reduce environmental deterioration of the polymer from exposure to oxygen in the air
- They also help prevent increased brittleness, surface cracks and pigment discolouration. Often used in polymer garden furniture
Why would you add UV light stabilisers to polymer stock? (2)
- Prevents the polymer chains being broken down by sunlight. UV attack causes colour loss and brittleness
- Used in outdoor toys and play equipment, garden furniture, sports stadium seats and synthetic grass playing surfaces
