Reaction that results in an exchange of atoms or groups between a polymer and low-molar-mass molecules, between polymer molecules, or between sites within the same macromolecule.
Note:
An interchange reaction that occurs with polyesters is called transesterification.
Source:
PAC, 2004, 76, 889. 'Definitions of terms relating to reactions of polymers and to functional polymeric materials (IUPAC Recommendations 2003)' on page 892 (https://doi.org/10.1351/pac200476040889)