... common inhibitor: Benzoyl Peroxide (Reference 4 ) The radical now combines with the spilt carbon-carbon double bond. The new radical continues to react with more alkenes and hence the chain grows. Eventually two free radicals collide producing a final molecule, as this has a random timing the chain lengths can vary from 2000 molecules to 20000. However, a chain can also combine with another growing chain if they were to rub together causing a bond to form between two carbons. E.g. (Reference 4 ) This shows The greater the temperature and pressure, the greater the degree of branching. This means that the chains are unable to get close together and form many intermolecular bonds with each other therefore it has a low density. Polyethene has a long chain structure with no cross-links to other chains. The chains forms bonds and join to one another to produce one large chain. For polythene a critical length of ...

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