monomer

In polymerization, small molecules (monomers) join together to make large molecules (polymers). In the polymerization of ethene to polyethene (polythene), electrons are transferred from the carbon-carbon double bond of the ethene molecule, allowing the molecules to join together as a long chain of carbon-carbon single bonds.

Chemical compound composed of simple molecules from which polymers can be made. Under certain conditions the simple molecules (of the monomer) join together (polymerize) to form a very long chain molecule (macromolecule) called a polymer. For example, the polymerization of ethene (ethylene) monomers produces the polymer polythene (polyethylene):

2nCH₂ CH₂→(CH₂CH₂ CH₂CH₂)_n