Oligomer

In chemistry, an oligomer is a molecule that consists of a few monomer units (ολιγος, or oligos, is Greek for "a few"), in contrast to a polymer that, at least in principle, consists of a nearly unlimited number of monomers. Dimers, trimers, and tetramers are oligomers. Many oils are oligomeric, such as liquid paraffin. Plasticizers are oligomeric esters widely used to soften thermoplastics such as PVC. They may be made from monomers by linking them together, or by separation from the higher fractions of crude oil. Polybutene is an oligomeric oil used to make putty. Greek prefixes are often used to designate the number of monomer units in the oligomer, for example a tetramer being composed of four units and a hexamer of six.