chemical modification

Process by which at least one feature of the chemical constitution of a polymer is changed by chemical reaction(s).
Note:
A configurational change (e.g., cistransisomerization) is not usually referred to as a chemical modification.
Source:
PAC, 2004, 76, 889 (Definitions of terms relating to reactions of polymers and to functional polymeric materials (IUPAC Recommendations 2003)) on page 891