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Preview of Polymers

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A monomer is a single unit which can bond to another monomer to form a
polymer. Hence a polymer is lots of monomers bonded together.
Polymerisation is the process of turning lots of monomers into a long polymer
chain. Polymerisation is the process by which alkenes monomers form long
polymers, which are technically alkanes but are named with alkene names -
such as poly(ethene).
Drawing polymers from monomer units
Draw the polymers for the following monomers, using displayed formula:
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The process of making polymers:
The process for making a polymer is free radical addition. It is a homolytic
reaction, which means the electrons from the broken bonds are shared equally
between the atoms involved in the bond.
Initiation: An initiator reacts with an alkene, forming an alkane free radical.
Propagation: The alkane free radical reacts with another alkene.
Termination: The chain can now be n long - as it's length is unknown (it
depends on how long propagation lasts. Two free radical alkanes bond
together to make one long chain.
The discovery of polymers
ICI, a chemical company discovered polythene in 1933. The first polythene was
made by the polymerisation of ethene. This happened at 200oC and 1200 atm
pressure. It was a very useful material, as it still is today. It was commonly
used for packaging and forming various products. It was called low-density
polythene because of the branching molecules.

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Karl Ziegler was a Chemist who carried out work on polymers and developed a
different method for making polythene. He won the Nobel Prize in 1963 for his
work on polymers and plastics. He develop high-density polythene, which has
less branched chains so it was more rigid. This method used a catalyst and so
the temperature was 600oC but lower atmospheric pressures. The resulting
product melts at higher temperatures. Polypropene production also uses the
Ziegler process.
Polymers are very useful because it does not rot.…read more


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