The C=C double bond in ethene is involved in the polymerisation reaction. It allows ethene molecules to join, so it is an example of an addition reaction>. Poly(ethene) is an addition polymer.

Known as a thia-Michael addition, this reaction is reversible, meaning that the resulting polythioenones (PCTE) can be depolymerized back to the starting monomer. One of the synthesized polymers ...