constitutional heterogeneity

of polymers
https://doi.org/10.1351/goldbook.C01283
The variation in
constitution
from molecule to molecule in polymers with molecules uniform with respect to elemental composition. An example is a polymer composed of linear and branched molecules; another example is a
statistical copolymer
comprising two
isomeric
constitutional units.
Source:
Purple Book, 1st ed., p. 52 [Terms] [Book]