chemical functionality

Ability of functional groups present within a polymer or polymer network to participate in chemical reactions.
The chemical functionality of a network formed by a sol-gel process from a precursor such as (RO)3Si–CH=CH2 is that of the vinyl group.
PAC, 2007, 79, 1801 (Definitions of terms relating to the structure and processing of sols, gels, networks, and inorganic-organic hybrid materials (IUPAC Recommendations 2007)) on page 1804