Polymers

11.1 Addition polymerisation

  • Hydorcarbons are the main fuels for cars and the chemicals from hydrocarbons are most importantly used to make polymers
  • Plastics are made from very large, covalently bonded molecules called polymers
  • Monomers are the small molecules that bond together to make huge molecules called polymers
  • Ethene can be used to make polyethene which is a useful plastic as it's v. strong and easy to shape. It's transparent unless colours added to it. Eg.s = carrier bags, cling film, dustbins
  • ethene monomers --> poly(ethene)
  • Propene is an alkene used to make polypropene, which is a strong, tough plastic. E.g. ropes, carpets, milk crates
  • propene monomers --> poly(propene)

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  • When alkene molecules join, the double covalent bond between the carbon atoms 'opens up' and is replaced by a single carbon-carbon bond between the 2 carbon atoms. The polymer chains formed, make up the 'backbone' of 1000s of carbon atoms -- this reaction is addition polymerisation and the polymer made is called the addition polymer

Image result for ethene monomers into polyethene (http://www.bbc.co.uk/staticarchive/27d0683fa70c3e16981827d9a27c974f82625525.gif)

  • Polymers are made of repeating patterns of atoms

11.2 Condensation polymerisation 

  • Common polymers = nylon and polyester and nylon is strong, lightweight, easy to care for, non-absorbant, dry quickly, few wrinkles after being washed. Polyester and nylon are condensation polymers, not addition polymers
  • In addition polymerisation there's one product made but in condensation polymerisation there are 2 products made. Main product = polymer and there's also a small molecule given off - usually either water or hydrogen
  • addition polymerisation --> the addition polymer
  • condensation polymerisation --> the condensation polymer + a small molecule
  • Monomers in addition polymerisation are often the same alkene but in condensation polymerisation there are usually 2 different monomers used. One monomer will have a functional group at both ends of its molecule and the other will have a…

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