Materials & manufacture · National 5
Plastics
7 cards · 4 quiz · 1 exam
Design & Manufacture · National 5 · mrkellydt.co.uk
What you're learning in this topic
Learning intention WALT
We are learning about plastics, specifically to understand:
- the difference between thermoplastics and thermosetting plastics
- the properties and uses of ABS, acrylic, polypropylene and polystyrene
- the properties and uses of urea formaldehyde and melamine formaldehyde
Success criteria WILF
- I can explain the difference between thermoplastics and thermosetting plastics
- I can describe the properties and uses of ABS, acrylic, polypropylene and polystyrene
- I can describe the properties and uses of urea formaldehyde and melamine formaldehyde
Two groups of plastic
- Thermoplastics: soften when heated and can be reshaped repeatedly ("plastic memory"). Recyclable.
- Thermosetting plastics: set permanently when first heated and shaped; can't be softened again. Heat resistant.
Plastics are lightweight, corrosion resistant, insulate heat and electricity, come in any colour, and suit mass production.
Plastics you need to know
| Plastic | Properties | Uses |
|---|---|---|
| ABS (thermo) | Tough, impact and scratch resistant, light, high surface finish | Toys (Lego), phone cases, helmets, 3D printing |
| Acrylic (thermo) | Rigid, clear or coloured, polishes well, scratches, brittle | Glass substitute, light covers, signs |
| Polypropylene (thermo) | Tough, chemical resistant, resists fatigue (living hinges), light | Bottle caps, crates, chairs, medical equipment, kayaks |
| Polystyrene (thermo) | Stiff, light, buoyant, insulates | Food packaging, disposable cups |
| Urea formaldehyde (set) | Rigid, hard, heat resistant, electrical insulator | Plugs, sockets, switches |
| Melamine formaldehyde (set) | Hard, scratch and heat resistant, food safe | Worktop laminates, picnic plates |
Key terms
| Thermoplastic | Softens when heated; can be reshaped and recycled. |
|---|---|
| Thermosetting plastic | Sets permanently once heated; heat resistant; cannot be reshaped. |
| ABS | Tough, impact resistant, high gloss. Toys, casings, helmets. |
| Acrylic | Rigid, clear, polishes well. Glass substitute, signs. |
| Polypropylene | Fatigue resistant (living hinges), chemical resistant. Caps, crates. |
| Urea formaldehyde | Thermoset electrical insulator. Plugs and sockets. |
| Melamine formaldehyde | Hard, scratch and heat resistant. Laminates, picnic ware. |
Quick check
1. Which plastic is used for electrical plugs?
- Polystyrene
- Polypropylene
- Acrylic
- Urea formaldehyde
Show answer
D: Urea formaldehyde. Thermoset that insulates and resists heat.
2. A flip-top shampoo lid with a living hinge is made from…
- Polypropylene
- Acrylic
- Melamine
- Polystyrene
Show answer
A: Polypropylene. Polypropylene resists fatigue.
3. Which can be reheated and reshaped?
- Melamine formaldehyde
- Acrylic
- Urea formaldehyde
- Bakelite
Show answer
B: Acrylic. Acrylic is a thermoplastic.
4. Which is the best substitute for glass in a light cover?
- ABS
- MDF
- Acrylic
- Polystyrene foam
Show answer
C: Acrylic. Transparent and shatter resistant compared to glass.
Exam-style questions
1. Describe two advantages of plastics over wood and metal for a product such as a kettle. (2 marks)
Show marking guidance
- Can be moulded into complex forms in one piece (1)
- Electrical/heat insulator so safe to hold (1)
- Range of colours with no finishing needed (1)
- Water/corrosion resistant (1)
Printable worksheet
An I do, we do, you do worksheet for this topic, with a separate answer sheet.