Polymers

Polymers

1. breathable polymers

   • nylon is:
     • tough
     • lightweight
     • keeps water and UV out
     • doesn't let water vapour back through
       • sweat condenses and makes the wearer wet and cold inside their jacket
   • GORE-TEX
     • al the properties of nylon but is breathable
       • water vapour from sweat can pass through the membrane but rain water can not
     • made from PTFE
       • polytetrafluoroethene
       • holes in PTFE are too small to allow water molecules to pass through but are big enough to let water vapour pass through
       • too fragile on its own
         • laminated onto nylon to produce a stronger fabric

2. disposing of polymers

   • scientists are developing new types of polymer that:
     • dissolve
     • are biodegradable
   • environmental and economical issues with use of existing polymers:
     • disposal of non-biodegradable polymers means that landfills get filled quickly
       • landfil wastes land that could be valuable for other purposes
       • wastes the crude oil that was used to make the polymers
     • burning polymers makes toxic gas
     • difficult to recycle becasue it's difficult to sort out different polymers

3. stretchy and rigid polymers

   • atoms in polymers are held together by string covalent bonds
   • plastics that have weak intermolecular forces between polymer molecules have low melting points and can be stretched easily as the polymer molecules can slide over each other
   • plastics that have strong intermolecular forces between polymer molecules have high melting points and cannot be stretched so are rigid