Thermoplastics

Question 1

What are most plastics made of and why is it bad

Answer 1

Oil, crude oil so they’re not biodegradeable and are bad for the environment

Question 2

What are some modern plastics made of

Answer 2

Plant based materials such as cellulose and starch, this is good as it means they’re biodegradable so therefore better for the environment

Question 3

Why is plastic good for packaging

Answer 3

Thought so protects the product
Lightweight so the total weight isn’t too heavy
Clear so consumer can see inside
Economical, easy to make and readily available
Aesthetically useful, can be printed on and made to look god

Question 4

Properties and uses of bioplastics

Answer 4

Biodegradeable as based on plants, clear or coloured. Used for food packaging

Question 5

Properties and uses of cellulose acetate

Answer 5

Partially biodegradeable as made from plants and chemicals. Clear but not strong. Used for camera film

Question 6

Properties and uses of acrylic

Answer 6

Stiff but brittle. Can shape and polish to a nice shine, lots of colours. Pos display stands

Question 7

Properties and uses of PET polyethylene teraphthalate

Answer 7

Tough and doesn’t let gas through, fizzy drinks bottles

Question 8

Polystyrene

Answer 8

Weak, can be vacuum formed shell forms for packaging, cd jewel cases

Question 9

Properties and uses of expanded polystyrene styrofoam

Answer 9

Very light, impact absorbing. Used for packaging and block modelling

Question 10

Properties and uses of pvc, polyvinyl chloride

Answer 10

Tough and resists scratches. Used for blister packaging and game pieces

Question 11

Properties and uses of polypropylene

Answer 11

Flexible, seed for crisp packets

Question 12

How is vacuum forming done

Answer 12

Accurate mould is made with soft angles and suction holes.
Plastic is heated by heaters until it becomes soft and droops
Lever is pulled to push mould up into heated plastic.
Air is sucked from under the mould to form a vacuum so the outside pressure pushes the plastic into the mould.
Plastic is left to cool so it becomes rigid
Mould removed and excess material removed

Question 13

What are thermoplastics

Answer 13

Plastics that can be softened by heating and then become rigid once cool. This process can be done over and over again

Question 14

How is injection moulding done

Answer 14

Expensive steel mould made
Granules of thermoplastic are placed in hopper
Heaters let plastic into thick liquid while it’s pushed by an Archimedean screw
Hydraulic ram forces plastic into the mould using lots of pressure
Mould is cooled and object removed