@P04742@ containing ionic or ionizable groups in a substantial fraction of its constitutional units.
- A @P04728@ @NT07562@ is sometimes called a crosslinked @P04728@. Use of the latter term is not recommended unless the @P04728@ @NT07562@ is formed by the @CT07136@ of existing @P04728@ macromolecules rather than by non-linear polymerisation.
- In contrast to a @P04728@, a @P04728@ @NT07562@ is always insoluble, although swelling or contraction can occur when it is immersed in a solvent.
- A @P04728@ @NT07562@ in contact with a solution of a @S05447@ is able to exchange @C01371@ (cations or anions) with ionic species in the solution and act as an @I03171@. Therefore, a @P04728@ @NT07562@ is frequently described as an @IT07155@.