chapter 1 (polymers) Flashcards
what is a polymer made from?
made from monomers chemically bonded together to form long chain molecules (polymers)
thermoplastics - what happens when they’re heated and why?
- they become soft, allowing them to be bent, pressed or formed because:
- they’re made from long chains of molecules that are tangled together + have no fixed pattern. There’re few cross links between the long chains.
what happens when thermoplastics cool ?
•they cool and become stiff
thermoplastics - main advantage
- they can be reheated and reshape many times .
* they have a ‘memory’ and when they’re reheated they try to return to their original shape unless they’ve been damaged
THERMOPLASTICS- acrylic- properties (4)
- good impact strength (doesn’t shatter only breaks in large pieces)
- lightweight
- good electrical insulator
- durable
THERMOPLASTICS- acrylic- uses (3)
- ornamental fish tanks
- baths/bathroom furniture
- car indicator covers/ reflectors
THERMOPLASTICS -acrylic- pros (4)
- be recycled
- good environmental stability
- polishes&finishes well
- available in lots of colours
THERMOPLASTICS - acrylic- cons (3)
- relatively soft
- scratches easily
- poor chemical resistance
THERMOPLASTICS - polyethene - properties (4)
- tough
- resistant to materials
- soft&flexible
- good electrical insulator
THERMOPLASTICS - polyethene-uses (6)
- carrier bags
- toys
- washing up bowls
- bleach bottles
- buckets
- shampoo bottles
THERMOPLASTICS -polyethene- pros (2)
- be recycled (but not easily)
* good chemical resistance
THERMOPLASTICS -polyethene- cons (1)
•most waste ends up in land fill sites even though it can be recycled
THERMOPLASTICS -polyvinyl chloride (PVC)- properties (9)
- good chemical resistance
- weather resistant
- lightweight
- good electrical insulator
- stiff
- hard
- tough
- waterproof
- durable
THERMOPLASTICS -polyvinyl chloride (PVC)- uses (7)
- pipes (rainwater&guttering)
- bottles
- shoe soles
- window frames&fascias
- waterbeds
- swimming pool toys
- electrical cable insulation
THERMOPLASTICS -polyvinyl chloride (PVC)- pros (2)
- be recycled
* relatively cheap to manufacture
THERMOPLASTICS -polyvinyl chloride (PVC)- cons (2)
- expensive to recycle
* dangerous fumes given off when burnt
THERMOPLASTICS -high impact polystyrene (HIPS) - properties (4)
- tough
- high impact strength
- rigid
- good electrical insulator
THERMOPLASTICS -high impact polystyrene (HIPS) - uses (4)
- food appliances
- toys
- cutlery
- DVD/CD cases
THERMOPLASTICS -high impact polystyrene (HIPS) - pros (3)
- available in lots of colours
- can be machined & painted
- be recycled
THERMOPLASTICS - high impact polystyrene (HIPS) - cons (3)
- expensive
- limited flexibility
- won’t biodegrade
THERMOPLASTICS-acrylonitrile butadiene styrene(ABS)- properties (7)
- high impact strength
- tough
- scratch resistant
- lightweight
- durable
- good resistance to chemicals
- good electrical insulator
THERMOPLASTICS -acrylonitrile butadiene styrene(ABS)- uses(5)
- kitchenware
- camera cases
- toys
- car components
- telephone cases
THERMOPLASTICS -acrylonitrile butadiene styrene(ABS)- pros(1)
•available in numerous colours
THERMOPLASTICS -acrylonitrile butadiene styrene(ABS) -cons(1)
•expensive compared to polystyrene
thermosetting plastics ; what are they made up from?
•long chains of cross linked molecules that results in a rigid molecular structure
how are thermosetting plastics different to thermoplastics?
they can soften when heated buttt only for the first time so they cannot be reheated and reshaped, unlike thermoplastics
THERMOSETTING PLASTIC- polyester resin- properties(5)
- good electrical insulator
- hard
- brittle
- good hear and chemical resistance
- resists UV radiation
THERMOSETTING PLASTIC- polyester resin- uses(6)
- casting
- encapsulation for biological specimens
- boat hulls w/ fibreglass
- model figures
- adhesives
- filler materials
THERMOSETTING PLASTICS- polyester resin -pros (2)
- can be mixed with pigments to achieve a range of colours
* good resistance to water
THERMOSETTING PLASTICS- polyester resin -cons(2)
- contracts on curing
* can cause excess heat when too much catalyst used
THERMOSETTING PLASTICS- urea formaldehyde -properties (6)
- stiff
- hard
- brittle
- scratch resistant
- stain resistant
- high tensile strength
THERMOSETTING PLASTICS- urea formaldehyde - uses (4)
- table ware
- worktop laminates
- buttons
- electrical casings
THERMOSETTING PLASTICS- urea formaldehyde -pros (2)
- can be coloured
* high surface hardness
THERMOSETTING PLASTICS -urea formaldehyde -cons (1)
•toxic fumes given off when it cures
POLYMER PROPERTIES - plasticity ; definition, materials (2) & uses (1)
- the ability to change shape without cracking
- acrylic & ABS
- mounded products (e.g. garden chairs, shampoo bottles)
POLYMER PROPERTIES- durability; definition, materials (1) & uses(3)
- ability to withstand weathering deterioration/corrosion
- generally all plastics
- garden furniture, window/door frames & rainwater pipes/ guttering
