1. AS level Product Design Unit 2
Polymers
AS level Product Design
Unit 2

2. Synthetic Polymer Categories
Long chain polymers
Crosslinked polymers
Thermoplastics
Thermosetting
Plastics
Elastomers
Semi-crystalline
amorphous
Synthetic Polymer Categories

3. Properties Chemical resistance Transparent (see through)
Water absorption
UV resistance
Impact resistance
Tensile strength
Light weight
Rigid
Brittle (easy to shatter / break)
Opaque (solid colour)
Hard
Translucent (slightly see through)
Recyclable
Properties

4. Thermosetting Plastics
Thermosetting plastics (eg Araldite) are highly linked
One way process – cannot be reversed
Will not soften with heat
EPOXY RESIN
Araldite is a trade name for a resin based polymer
The resin is mixed with an activator to start curing
Urea formaldehyde
high heat distortion temperature, low water absorption, mould shrinkage, high surface hardness
Bonds MDF
Phenol formaldehyde
Used for light switches
Thermosetting Plastics

5. Thermoplastics Acrylic PVC (Polyvinyl chloride)
Paint, Point of sale displays
Food & pharmaceutical packaging
Baths, Car lights
HDPE (High Density Polyetherlene - PE)
Polypropelene (PP)
packaging and labeling
Bottles (biggest application)
Polystyrene (PS)
milk bottles (largest bottle sector)
Packaging trays, egg boxes, lids
LDPE (low Density PE)
Styrofoam
Supermarket carrier bags
Isulation, modelling
Packaging film (eg. cling film)
Washing up liquid bottles
PET (PE Terephthalate)
fizzy drinks bottles
(Carbonation makes HDPE unsuitable)
Thermoplastics

6. Material Properties: PET
Very light
Can stand high tensile stress
hard, stiff, strong
absorbs very little water
good chemical resistance (except to alkalis)
Medium resistance to UV
most commonly recycled plastic
drinks bottles are made from PET
Can degrade & become discoloured during heat treatment
Adds an unwanted flavour to food (can be compensated for at addition cost)
Min Temp: C
Max useful Temp: 1700C
Melting point: oC.
Material Properties: PET

7. Material Properties: HDPE
Excellent for any food related products
Not microwaveable
Machines extremely well (cut, bond, drill etc.)
Good chemical resistance
Good impact resistance
light weight
Poor UV tolerance
very low moisture absorption
high tensile strength
Not a good candidate for gluing.
Primarily used for blow moulding
Colours fade over time
Min Temp: C
Max temp: 1100C
Melting point: 1300C
Applications
Milk bottles
trays and tanks
pipe fittings, wear plates, hinges
cutting boards.
Material Properties: HDPE

8. Material Properties: PVC
Transparent
Is typically coloured to make opaque
Good UV resistance
Excellent chemical resistance
glueable and weldable
easily machine able & heat bends nicely
Stiff
Tough
Hard
Min temp can be reduced down to -400c by adding plasticizer
Makes PVC suitable for hose pipes etc
Max Temp: 600C
Min Temp: C
Material Properties: PVC

9. Material Properties: LDPE
Lower density & chemical resistance than HDPE
More transparent than HDPE
Less expensive than HDPE
Colours fade over time
Poor UV tolerance
Very soft & pliable
Max temp 700c
Min temp -50oc
Melting point 1200c
Material Properties: LDPE

10. Material Properties: Polypropelene (PP)
Poor UV resistance
Translucent
Rigid
Very light
Excellent chemical resistance
food storage applications
Medical applications (syringes)
Carpets
Microwaveable
Max temp C
Min temp 00C
Melting point: 1700C
Material Properties: Polypropelene (PP)

11. Polystyrene & EPS Flammable Excellent thermal insulation Solid:
Used in fridge linings
Solid:
Light, Hard, Stiff, Brittle
Expanded:
Light, Bouyant, Crumbles
Min temp: C
Max temp: c
Polystyrene & EPS

12. Material Properties: Acrylic
Trade names: perspex & plexiglass
Weather resistant (Can withstand sunlight for long durations)
Difficult to recycle
Can be done but is very expensive (not cost effective)
Stiff (Flexible compared to glass)
Less breakable than glass
Scratches easily
brittle
Resistant to most chemicals and industrial fumes
Can be cut by various methods
Corrosion resistant
Good electrical insulator
Min Temp: 50C
Max temp: 410C
Material Properties: Acrylic

13. Some acrylic Products

14. Styrofoam is a trademarked brand of closed-cell extruded polystyrene foam currently made for thermal insulation and craft applications.
Styrofoam is composed of ninety-eight percent air, making it light weight and buoyant
Styrofoam

15. Issues Safety Many chemical plastisizers contain oestrogen
Gender bending chemical
Some plastics (eg. PET) degrade & emit cancerous material over time
Life Cycle
Carbon based plastics take thousands of years to degrade
Biodegradeable plastics are being researched now
(covered in A2)
Sustainability
Today: a 500ML water bottle takes 100ml of crude oil to produce (+ energy to manufacture)
Recyclable by re-heating
Energy cost
Contamination is a big issue
Some are easier than others
Issues

16. Issues Energy for manufacture
All polymers (apart from elastomers) require heat to make them plastic
All plastics must be sorted and washed before being recycled
Where does this energy come from ?
Plastic is itself a fuel and can be incinerated
Toxic fumes are a consequence
Issues

17. Task Create a table with the following headings:
Polymer, Aesthetics, Properties, Products, Advantages, Disadvantages.
Task

18. Task HDPE LDPE PET PVC Acrylic PP PS Opacity etc
Polymer
Aesthetics
Properties
Products
Advantages
Disadvatages
HDPE
Opacity etc
Chemical resistance etc
LDPE
PET
PVC
Acrylic
Stryrofoam PP PS
Task