The mechanism for addition polymerisation is another example of a radical reaction.
Teflon (PTFE), famously known for its non-stick properties, was formed in an accident at the Dupont chemical company in the late 1930s from the monomer tetrafluoroethene.
The reaction is initiated by the action of uv light on an organic peroxide molecule.
Propagation steps add the monomers to the polymer chain.
Since radicals are so reactive, in reality this is a difficult reaction to control as a radical may attack another chain at any point resulting in a mixture (mess?) of branched chain polymers of varying lengths.
Termination steps involve two radicals combining to form a non-radical.