desighning polymers

desighning polymers

1. Types of polymers

   • Nylon
     • Tough
       • Lightweight
     • Keeps water out
     • keeps ubv loght out
     • But
       • Does not let water vapour thru
         • Sweat condenses and so it becomes wet and cold inside jacket
   • Gortex
     • Porperties of nylon but is also breathable-worn in many activity things as water vapour from sweat can pass thru
       • Water vapour can pass through membrane but water cannot-diffusion
     • made from PTFE/poyurethene material
       • Holes in PTFE are too small for water to pass thru but are big enough for water vapour to pass through
         • PTFE is too fragile to be made by itself so is laminated onto tnylon to produce a stronger favric

2. Disposing polymers

   • Polymers that dissolve
     • Biodegradable polymers
   • Research into new polymers ar eimportant as there are envirmoental and economic properties to think about when cretaing a new one
     • Disposal of non degrabable olymers means landfill sites get filled quicker
     • landfill sites mean waste plastics make toxic gases
     • using landfill sites wastes the crude oil, which is finite resouirces, used ot make polymers
     • r hard to define what a polymer is so is difficult to sort out the different types

3. Stretchy polymers and rigid polymers

   • Atoms in polyners are held together by strong covalent bonds
   • The properties of plastics
     • through modals of their structures for example...
       • Plastics have weak intermolecular forces and so have low melting points as they need less energy to break
         • their for they can be stretched easily as the polymer molecules can break apart and slide over each other without becoming a new molecule
       • Plstics that have strong forces such as covalent bonds (=) have higher melting points and so cannot be stretched as tehy are too stiff and rigid
     • If teh intermoleculaar firces between two of the olymer molecules are wea, the pladstic can be stretched easily or "pulled apart" mroe without breaking off into a new molecule