Identifying plastic

Plastics can be difficult to identify.  Colours, hardness, transparency and density vary widely.  Thermo-sets tend to be stiff, hard and heat resistant. Thermo-plastics are often flexible.
Denser plastics sink, however with a foaming agent introduced during manufacture, they will float.
Chemical properties are best used to identify plastics.  Burning a test sample will indicate a number of properties -
  • ease of burning
  • colour of flame/smoke
  • presence of burning droplets
  • smell