TY - JOUR
T1 - Carboxyl groups in pre-treated regenerated cellulose fibres
AU - Fras Zemljič, Lidija
AU - Peršin, Zdenka
AU - Stenius, Peer
AU - Stana Kleinschek, Karin
PY - 2008/4/14
Y1 - 2008/4/14
N2 - The influence of peroxide bleaching and slack-mercerization on the amount of acidic groups in regenerated fibres (viscose, modal and lyocell) were studied. Conductometric titration was used to determine the total content of acidic carboxylic groups. Polyelectrolyte titration was used for surface and total charge determination, and to obtain information about the charge distribution and accessibilities of charged groups. Changes in fibre crystallinity to pre-treatment processes were characterized using iodine sorption (Schwertassek method) and correlated to treatments and the amount of carboxylic groups. For all three types of fibres the amount of accessible carboxyl groups was lowered by an increase in the degree of crystallinity. Bleaching with hydrogen peroxide causes some oxidative cellulose damage and, therefore, a larger amount of carboxyl groups (presumably formed at the end of cellulose chains). Slack-mercerization did not significantly change the total amount of acidic groups in the fibres, but their accessibility to cationic polyelectrolytes, in particular to polymers with high molecular weight was substantially lowered.
AB - The influence of peroxide bleaching and slack-mercerization on the amount of acidic groups in regenerated fibres (viscose, modal and lyocell) were studied. Conductometric titration was used to determine the total content of acidic carboxylic groups. Polyelectrolyte titration was used for surface and total charge determination, and to obtain information about the charge distribution and accessibilities of charged groups. Changes in fibre crystallinity to pre-treatment processes were characterized using iodine sorption (Schwertassek method) and correlated to treatments and the amount of carboxylic groups. For all three types of fibres the amount of accessible carboxyl groups was lowered by an increase in the degree of crystallinity. Bleaching with hydrogen peroxide causes some oxidative cellulose damage and, therefore, a larger amount of carboxyl groups (presumably formed at the end of cellulose chains). Slack-mercerization did not significantly change the total amount of acidic groups in the fibres, but their accessibility to cationic polyelectrolytes, in particular to polymers with high molecular weight was substantially lowered.
KW - Carboxylic groups
KW - Cellulose fibres
KW - Conductometric titration
KW - Crystallinity
KW - Polyelectrolyte titration
KW - Pre-treatment
KW - Regenerated fibres
UR - http://www.scopus.com/inward/record.url?scp=50649119480&partnerID=8YFLogxK
U2 - 10.1007/s10570-008-9216-6
DO - 10.1007/s10570-008-9216-6
M3 - Article
AN - SCOPUS:50649119480
SN - 0969-0239
VL - 15
SP - 681
EP - 690
JO - Cellulose
JF - Cellulose
IS - 5
ER -