describe the features of nylon (4)
nylon is tough, lightweight, keeps water out and does not let water vapour through.
what are the features of gore-Tex?
Gore-Tex has all the properties of nylon but is also breathable.
what is GORE-TEX made of?
it is made from a PTFE
describe what the holes do in PTFE
The holes in PTFE are too small for water to pass through but are big enough for water vapour to pass through.
what is good about the membrane from gore-Tex?
Water vapour from sweat can pass through the membrane but rainwater cannot.
what new types of polymers are scientists designing?
- polymers that dissolve
- biodegradable polymers
name 3 environmental or economic issues with the use of existing polymers?
- disposal means land fill sites get get filled quicker
- disposal by burning waste plastics release toxic gases
- landfill means wasting land that could be used for valuable purposes
what are atoms in a polymer held together by?
strong covalent bonds
plastics that have weak intermolecular forces between polymer molecules have what type of melting points?
low melting points
what does a low melting point of a polymer mean? and why?
it can be stretched easily as the polymer molecules can slide over one another
what type of melting points do strong polymer molecules have?
high
and what does this mean?
it can be stretched easily
how would you explain a polymer with strong covalent bonds?
rigid
what is another word for strong forces between polymer molecules?
covalent bonds or cross-linking bridges
name 3 types of polymers?
PVC, polyester and nylon
what is nylon used for and why?
clothing as it can make flexible fibres
what has the discovery of GORE-TEX helped?
outdoor people to cope with wetness and sweat.
what does non-biodegradable mean?
that they do not decay and are not decomposed by bacteria
name 3 ways polymers can be disposed of
- in landfill sites
- by burning
- by recycling
name 2 problems with disposing of polymers
- difficult to dispose of
- last a long time in land fill sites
