3.2. Polyelectrolyte titration and nitrogen content
Polyelectrolyte titration was carried out in order to determine
the amount of charged amino groups immobilized on cotton surfaces.
Polyelectrolyte titration measurements on treated cotton
fabrics may be used to assess the availability of ionic charges on
the cotton fabrics which give information on the (statistical) sites
of crosslinker and on possible chain segment mobility of biopolymer
on-fibre. Chain mobility may determine any functionality envisaged [17]. The results represented in Table 1 show exemplarily
that the use of the anchor group butanetetracarboxylic acid,
BTCA almost only 1/3 of potential charge equivalents remain accessible
after fixation onto textile. It can be shown that by varying the
amount of anchor used, higher charge accessibility can be reached
with resulting in lower add-on. The charge accessibility related to
the amount of permanent add-on can be increased strikingly using
less anchor chemicals but with the risk of only low coverage and
thus lower total binding capacity of the treated cotton fabric. Table
1. also showed the nitrogen content for the treated cotton samples