C1e - Designer polymers Flashcards
What bonds are atoms in polymers held together by?
strong covalent bonds
What are cross links
covalent bond that links two polymer molecules together
Describe the properties of weak plastics(3)
polymer molecules attracted to each other only by weak intermolecular forces between them
weak intermolecular forces need little energy to overcome, -melting point
molecules can easily slide past each other, stretchable
Describe the properties of strong plastics(3)
strong covalent bonds and cross links between polymer molecules
strong covalent bonds need lots of energy to overcome, +MP
rigid, cannot be stretched as molecules cannot slide over each other
Describe the properties of nylon(5)
waterproof
doesn’t let w vapour through it so sweat condenses(not breathable)
tough
lightweight
blocks UV light
Describe the properties of gore-tex(5)
waterproof
tough
lightweight
blocks UV light
breathable
Why is Gore-Tex useful
helps active outdoor people to cope with perspiration wetness as it is breathable and waterproof so they can hike without getting rained on or soaked in sweat
Why are Gore-Tex type materials waterproof and yet breathable(4)
nylon laminated with thin film of PTFE/polyurethane membrane
waterproof: tiny holes in membrane too small for big water droplets to pass through
breathable: holes big enough for water vapour (from sweat) to pass through
membrane is too fragile on its own, so laminated w/ nylon
Explain environmental and economic issues related to the disposal of polymers(6)
Disposal of non-biodegradable polymers means that landfill sites get filled quickly
- wasting land that could be used for other purposes
- takes years to decompose
Disposal by burning releases toxic gases
Disposal by burning or using landfill sites wastes the crude oil used to make the polymers
Difficult and expensive to sort out different polymers so recycling is difficult
What new types of polymers are scientists developing(2)
soluble polymers(dissolve in water)
biodegradable polymers
Why are chemists developing new types of soluble and biodegradable polymers(2)
soluble polymers: used to wrap around dishwater detergent tablets so that it dissolves once it gets wet in the dishwater
both: so that any plastic that is thrown away decomposes/dissolves rather than sitting there in landfill for ages
