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