Degree of polymerisation

The degree of polymerisation (DP) describes the number of monomer units that on average combine to form a macromolecule during the polymerisation process. This quantity is decisive for the properties of the resulting polymer.

In a plastic, the molecular chains can be of different lengths, which means that not all macromolecules contain the same number of monomer units. To determine the degree of polymerisation precisely, it is calculated as a ratio. This quotient is derived from the average mass of a macromolecule (m_n) and the average mass of a monomer bonded in this molecular chain (m_0).