Thermoplastic Polymers Flashcards
Forms of polypropylene
- Moulded or extruded
- Spun into fibres
- Sheets
- Rods
What does PP stand for?
Polypropylene / polypropene
Properties of polypropene
- High tensile strength
- Tough
- Easily coloured
- Flexible
- Very low density
- Can be produced as a fibre
- High melting point
Uses of PP
- Ropes and slings
- Plastic chairs
- Kitchen utensils
- Items of medical equipment
- Electronic components
- Casings
Forms of supply of ABS
Sheets
Rods
Tubes
What does ABS stand for?
Acrylonitrile butadiene styrene
Properties of Acrylonitrile-butadiene-styrene
- Strong, high toughness and rigid
- Resistant to physical impacts
- Resistant to chemical damage, precipitation and solar radiation
- Stable
- Low melting point
- Easily shaped and sanded
Uses of ABS (Acrylonitrile butadiene styrene)
- Plastic children’s toys
- Plastic boxes and containers
- Kitchen utensils
- Pipe systems
- Golf club heads
- Automotive bumper bars
- Injection moulding
- 3D printing
Appearance of ABS
Glossy
- Originally white but pigments can add colour
Properties of HIPS High-impact polystyrene
- High-impact strength
- Food-safe but toxic when burned
- Tough and rigid with good dimensional stability
- Good machinability and mouldability (remoulded without weakening)
- -> cut and vacuum formed easily
- Easy to glue, print and paint
Appearance of HIPS
Available in many colours
What is high-impact polystyrene used for?
- Household appliance components eg toilet seats, bathroom cabinets
- Children’s toys
- Drinking cups
- Yoghurt pots
- CD cases
What is PMMA?
Acrylic, eg Perspex™
Properties of PMMA
- Strong, rigid, and very good impact resistance (better than glass)
- Tough and durable
- Easily heat-formed (to be pliable) without losing optical clarity
- Resistant to weather and sunlight
- Liable to attack by chemical solvents
- Can be cut, folded and polished well
- Subject to stress cracking
- does not shatter; breaks into large pieces
- Combustible
- Easily scratched
Appearance of PMMA/Acrylic
- High light transmittance
- -> comes translucent (eg smoked), transparent, or opaque
- Available in a variety of colours
- Shiny
Applications of acrylic
- Protective guards on workshop machinery
- Outdoor signs and corrugated roofing sheets
- Lenses
- General glass replacement eg aircraft windows and light fittings eg car lights
- Furniture
What does PVC stand for?
Polyvinyl chloride
Forms of supply of PVC
- Comes as either rigid or flexible
- Matt or high gloss
- Can be extruded or in flat sheets
Properties of polyvinyl chloride
- Very dense
- Good solvent resistance
- Brittle but durable
- Can be weled or bonded with an adhesive
Common uses of PVC polyvinyl chloride
- 3D printing and injection moulding When made in hard condition: - Building materials eg water piping, guttering, window frames - Medical devices When made in soft condition: - Insulative coating on electrical wires - Clothing eg raincoats - Upholstery
What does PTFE stand for?
Polytetrafluoroethylene
Properties of PTFE
- Highly flexible
- Tough
- High chemical solvent resistance (inert)
- Thermal resistance and stability
- Non-stick; low-friction surface
Where is polytetrefluoroethylene used?
- Non-stick coatings for cookware and kitchen utensils
- Bearings, seals and gaskets
- Containers and pipes
- Lubricant
- Cable insulation
Chemical name for nylon
Polyamide
Polyamide: alternative name
Nylon
Example forms of supply of polyamide
- Fibres
- Filaments
- Bristles
- Sheets and rods
Properties of polyamide
- Very strong, tough, durable and flexible
- Good solvent/corrosion resistance
- Resistant to extreme temperatures
- Deteriorates with exposure to outdoor conditions (poor sunlight resistance)
- Self-lubricates (oily nature) as it wears down, so good for moving parts
- Absorbs water (inc from air)
- Good insulator
Uses of nylon
- Gears and bearings that don’t need lubrication
- Screws
- Parachutes and life vests
- Clothing and textiles
- Ropes for docking boats
What does HDPE/LDPE stand for?
LD/HD Polyethylene
Properties of low-density polyethylene
- Very flexible
- Tough
Common properties of LDPE and HDPE
- Can be moulded into almost any form due to their excellent moulding qualities.
- -> ease of processing and forming
- Good solvent resistance
- Degrades if exposed to sunlight/UV radiation
Uses of LDPE
- Packaging eg grocery bags
- Cable and wire insulation
- Pipes and tubes
- Flexible squeeze containers
Properties of HDPE
- Lightweight
- Flexible
Similar to LDPE but - Harder, stiffer, stronger
- Withstands higher temperatures so can be sterilised
Uses of HDPE
- Food containers and tubs
- Items of medical equipment
- Washing baskets (resists weather)
- Furniture eg chairs
Example forms of supply of polycarbonates
Sheets
Tubes
General properties of polycarbonates
- Strong, tough and hard
- Good insulator; Thermal resistance; flame retardant
- High dimensional stability and impact resistance
- High compatibility with other polymers
- Limited chemical and scratch resistance
- Tends to yellow over time due to UV light
- Low weight
Manufacturing properties of polycarbonates
- Machines well
- Can be solvent bonded and welded tough to resist damage
Main transformation technique: extrusion - Good for manufacturing into other shapes
Secondary fabricating techniques: bending and drilling
Uses for polycarbonates
- Mobile phones (impact resistant if dropped)
- Electrical chargers and household appliances to insulate circuits
- Battery boxes
- Construction: eg glazing
- CDs, discs
- Bullet-proof windows (when thick)
