Polymers Flashcards
What are polymers?
Organic material made up of chain of single units called monomers
What are the two main sources of polymers?
- Synthetic polymers
- Natural polymers
What are synthetic polymers?
Commonly used
Chemically manufactured from carbon-based materials such as crude oil
What are natural polymers?
Processing natural materials e.g plants
latex from trees
What are the two main types of polymer
- Thermosetting plastic
- Thermoplastic polymers
Properties of poylmers
- Lower density of metals
- Not normally painted but painted pigment to them
What are thermosets formed by?
Moulding process
Why are thermosetting plastic harder than thermoplastics?
During the process of making
form many links across different polymer chains
stop movement of chains
General properties of thermosetting plastic
- good resistance to electricity and heat
What happens after thermosetting plastics are moulded?
They cannot be re-shaped
Thermosetting plastic
What is melamine formaldehyde used for?
- Impact-resistance plastic plates
- laminate covering for kitchen workshops
- cupboards
- moulding for electrical equipment
- light fittings
Thermosetting plastic
What is phenol formaldehyde?
A dark coloured brittle plastic
Thermosetting plastic
What is phenol formaldehyde used for?
- Electrical fittings e.g light sockets
- Heat -resistant parts for domestic appliances e.g handles for cookers and pans
Thermosetting plastics
What is urea formaldehyde used for?
- Coloured with artificial pigments
- Used to make electrical fittings e.g light switches
Thermosetting plastic
Epoxy resin: what is it used for?
PCB
‘cold cast’ electrical insulators
What are forms thermoset usually available in?
Powder or granular forms
How can thermoplastic be reshaped when heated again?
Do not have link between different polymer chains
more softer and flexible than thermosets
Thermosetting polymers (Metal)
Properties of polypropylene
- Softens at 150 degrees Celsius
- High impact strength for polymer
- flexed many times without breaking
Thermoplastic polymers
Where is polypropylene used for?
- Food containers
- Plastic chairs
- Children’s toys
Thermoplastic polymers
Properties of HIPS (High impact polystyrene)
- Softens at 95 degrees celcius
- Easy to mould
- Light but strong
Thermoplastic Polymers
Where is HIPS used for?
- Vacuum formed packaging and castings
Thermosetting polymers
Properties of acrylic
- Can be transparent like glass
- Coloured like pigment
- Hard wearing
- Will not shatter on impact
Thermosetting polymers
What is acrylic used for?
- Machine guards
- Plastic windows
- Bathtubs
- Display signs
Thermosetting polymers
Properties of nylon
- Low friction qualities
- Good resistance to wear and tear
Thermosetting polymers
What is nylon used for?
- Bearings
- gear wheels
- curtain rail fittings
Thermosetting polymers
Properties of HDPE (High-density polyethylene)
- Softens at 120 degree celcius
- Strong
Thermosetting polymers
What is HDPE used for?
- Bowls
- Buckets
- Milk crates
Thermosetting Polymers
Properties of LDPE ( low-density polyethylene)
- Softens at 85 degree
- Softer, more flexible and less strong than HDPE
Thermosetting Polymers
What is LDPE used for?
- Detergent bottles
- Carrier bags
- Packaging
- Film
Thermosetting Polymers
Properties of polyvinyl chloride
- Stiff
- Hard wearing
- Can be softer and rubber by adding plasticiser
Thermosetting Polymers
What is polyvinyl chloride used for?
- Chemical Tanks
- Pipework
- Coverings for electrical cables
- Wallcoverings
- Packaging
