Polymers (Plastics)

Question 1

What is a thermoplastic?

Answer 1

• can be heated + shaped many times
• soften when heated
• hardens when cooled
• no links between polymer chains

Question 2

ID code, properties + uses of PET (Polyethylene terephthalate)

Answer 2

ID: 1 PET
Properties
- barrier against atmoshperic gases
- doesn’t flavour contents
- clear appearence
- very tough
- lightweight (low density)
Uses
- fizzy drinks bottles
- food packaging
- food trains
e.g. coke bottle

Question 3

ID code, properties + uses of HDPE (High density polyethylene)

Answer 3

ID: 2 HDPE
Properties
- high chemical resistance
- good barrier to water
- tough + hard wearing
- can be coloured
- lightweight
- rigid
Uses
- unbreakable bottles
- very thin packaging sheets
e.g. bleach bottle

Question 4

ID code, properties + uses of PVC (Polyvinyl chloride)

Answer 4

ID: 3 PVC
Properties
- weather resistant
- chemical resistant
- gas impermeable
- strong - abrasion resistant
- rigid or flexible
Uses
- packaging for toiletries
- window frames
e.g. drain pipes

Question 5

ID code, properties + uses of LDPE (Low density polyethylene)

Answer 5

ID: 4 LDPE
Properties
- good resistance to chemicals
- good barrier to water but not chemicals
- tough + hard wearing
- can be coloured
- very light - floats on water
- very flexible
Uses
- milk carton coating
e.g. cling film
e.g. outer plastic of fizzy drink can multipack

Question 6

ID code, properties + uses of PP (Polypropylene)

Answer 6

ID: 5 PP
Properties
- lightweight
- rigid
- excellent cheimcal resistance
- stiff or flexible
- low moisture absorption
- good impact resistance
Uses
- food packaging
- yoghurt pots
- snack wrappers
e.g. fizzy drink caps

Question 7

Properties + uses of Acrylic

Answer 7

Properties
- stiff + hard
- scratches easily
- durable
- brittle in small sections
- good electrical insulator
- machines + ploses well
- cane be transparent
Uses
- signs
- aircraft canopies
- window covers
- wash basins
e.g. airplane windows

Question 8

Properties + uses of ABS (Acrylonitrile butadiene styrene)

Answer 8

Properties
- impact resistance + toughness
- pigments can be added
- resistant to acids + alkalis
- can be recycled
- lightweight
- can be injection moulded + extruded
Uses
- drain pipes
- musical instruments
- protective headgear
-e.g. lego bricks

Question 9

What is a thermosetting plastic?

Answer 9

• can only be heated + shapd once
• if reheated cannot soften as polymer chainsa re linked

Question 10

Properties + uses of Epoxy Resins (ER)

Answer 10

Properties
- good electrical insulator
- hard but briottle unless reinforced
- resists chemicals well
Uses
- used for casting
- adhesives
- bonding of other materials
e.g. fancy tabletops

Question 11

Properties + uses of Urea formaldehyde (UF)

Answer 11

Properties
- stiff, hard, strong but rittle
- good electrical insulator
Uses
- electrical fittings
- handles
- control knobs
e.g. toilet cover

Question 12

Properties + uses of Polyester resin (PR)

Answer 12

Properties
- stiff, hard but brittle unless laminated
- good electrical insulator
- resists chemicals well
Uses
- casting + encapsulation
- bonding of other materals
e.g. jacuzzi

Question 13

What is an elastomer?

Answer 13

• polymer with elasticity
• deforms under stress
• returns to orginal shape when stress is removed

Question 14

Properties + uses of Rubber

Answer 14

Properties
- occurs as milky suspension (latex) in sap of several plants
- can be produced synthetically
- good elasticity
- vulcanised rubber has very high tensile strength - harder + more abrasion resistance than reaw rubber
Uses
- car tyres
- toys
- paints
- shoe soles
e.g. rubber gloves