The physical properties and behaviour of polymers depend strongly on the properties of the polymer molecules themselves. Molecular weight and its distribution, as well as molecular size and structure all affect how the material will behave.

By understanding and controlling these properties, polymer manufacturers can control polymer production and quality.

Historically, accurate measurement of polymer molecular weight has been dependent on having standards of the same polymer but the introduction of advanced detection techniques such as light scattering and intrinsic viscosity have made absolute measurements possible.