Polymers Flashcards
What is thermoforming?
Thermoforming can be heated and shaped many times in various ways
What is thermosetting?
Thermosetting can only be heated once
Types of thermoforming polymers?
High impact polystyrene (HIP)
High-density polythene (HDPE)
Polyethylene Terephthate (PET)
Acrylic(PMMA)
Polyproplyene (PP)
Polyvinyl chloride (PVC)
Types of Thermosetting polymers?
Urea Formaldehyde (UF)
Polyster resin
Phenol Formaldehyde (PF)
Melamine Formaldehyde (MF)
Exposy Resin
Properties of acrylic (PMMA)?
Hard
excellent optical quality
Good resistance to weathering
Scratches easily
Properties of High-impact polystyrene (HIPS)
Tough, hard and rigid
Good impact resistance
Lightwieght
Properties of High-density polythene (HDPE)
Hard and stiff
Excellent chemical resistance
Properties of polypropylene (PP)?
Tough
Good heat and chemical resistance
Lightweight
Fatigue resistant
Properties of Polyvinyl chloride (PVC)?
Hard and tough
Good chemical and weather resistance
Low cost
Can be rigid and felxible
Properties of polyethylene terephthate (PET)
Tough and durable
Lightweight
Food safe
Impearable to water
Low cost
Propertis of Exposy resin?
Electrical insulator
Good chemical and wear resistance
Properties of melamine formaldehyde (MF)?
Stiff, hard and strong
Excellent resistance to heat, scratching and staining
Properties of phenol formaldehyde (PF)?
Hard
Heat and chemical resistant
Good electrical insulator
Properties of polyester resin?
Brittle but becomes tough when laminated with glass fibre
Hard and resistant to UV
Properties of urea formaldehyde?
Stiff and hard
Heat resistant
Good electrical insulator
Common uses of acrylic (PMMA)?
Car light units, bath tubs, shop signage and displays
Common uses of high-impact polystyrene (HIPS)?
Children’s toys, yoghurt pots, refrigerator liners
Common uses of high density polythene (HDPE)?
Washing up bowls, buckets, milk crates bottles and pipes
Common uses of polypropylene (PP)?
Toys, DVD and blu-ray cases, food packaging film, bottle caps and medical equipment
Common uses of polyvinyl chloride (PVC)?
Pipes, gluttering, window frames
Common uses of polyethylene terephthate (PET)
Drinks bottles, food packaging
Common use of exposy resin?
Adhesives such as araldite, PCB component encapsulation
Common uses of Melamine formaldehyde (MF)?
Kitchen work-surface laminates, tableware
Common uses of phenol formaldehyde (PF)
Electrical fittings, saucepan, handles, bowling bowls
Common uses of polyster resin?
GRP boats, car body panels
What is Melamine
It is found in the manufacture of picnic crockery. It is hard so it resists scratching which enables it to maintain its aesthetics. It is more durable than ceramic alternatives
What are additives?
Where polymers can be further enhanced
Types of additives?
Plasticisers- Soft and flexible (often PVC)
Pigments- changes colour
Stabilisers- withstand UV light damage (outdoor products
Fillers
Types of polymer manufacture?
Injection moulding
Extrusion
Blow moulding
Line bending
Vacuum forming
Process of injection moulding?
Granules are fed into hopper
Screw in the chamber sends granules forward
Heated jackets melt the polymer
Screw winds back and ram comes forward into position
Mould is closed as ram forces melt into mould
Plastic is allowed to cool
