C1: Designer Polymers

C1: Designer Polymers

1. Breathable Polymers

   • Nylon- tough, lightweight, keeps water out and ultraviolet light.
     • Does not let water vapour through eg sweat.
       • Sweat condenses and makes the wearer wet and cold
   • GORE-TEX has all the properties of nylon but is breathable.
     • Sweat can pass through the membrane.
   • GORE- TEX-made from a PTFE membrane.
     • The holes in the PTFE membrane are too small for rainwater to pass through but are big enough for water vapour to pass throught.
     • PTFE is too fragile on its own so attached to Nylon.

2. Disposing of Polymers

   • New polymers- dissolvable & biodegradeable
   • Environmental & economic issues:
     • Landfill sited get filled quickly.
     • Landfill means wasting land that could be used for other purposes.
     • Disposal by burning plastics creates toxic gases.
     • Disposal by burning or using landfill sites wastes crude oil.
     • Recycling is difficult because polymers are difficult to sort.

3. Stretchy and Rigid Polymers

   • Atoms held together by strong covalent bonds.
   • Plastics that have weak intermolecular forces between molecules have low melting points- easily stretched as polymer molecules can slide over each other.
   • Plastics that have strong forces between molecules (covalent bonds or cross linking bridges) have high melting points- rigid.