TY - JOUR
T1 - Comparison study of TEMPO and phthalimide-N-oxyl (PINO) radicals on oxidation efficiency toward cellulose
AU - Biliuta, Gabriela
AU - Fras Zemljič, Lidija
AU - Drobota, Mioara
AU - Persin, Zdenka
AU - Kreze, Tatjana
AU - Stana-Kleinschek, Karin
AU - Ribitsch, Volker
AU - Harabagiu, Valeria
AU - Coseri, Sergiu
PY - 2013/1/16
Y1 - 2013/1/16
N2 - Regenerated cellulose fibers, type viscose, have been oxidized with sodium hypochlorite and catalytic amounts of sodium bromide by using two different protocols: first, involving the presence of 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) and second, employing N-hydroxyphthalimide (NHPI). The reactions were carried out at room temperature and pH = 10.5 for 2.5 h. Viscose oxidized samples were analyzed and compared in terms of the negative charged groups content, as determined by potentiometric titration and methylene blue adsorption, morphologies and crystallinities changes, as well as changes in the degree of polymerization. The highest content of the carboxylic groups and the best preservation of the morphology and molecular weight of the original material have been found in the case of using NHPI/anthraquinone as oxidation mediators. TEMPO-mediated oxidation leads to the highest depolymerization and cause significant degradation of the cellulosic material.
AB - Regenerated cellulose fibers, type viscose, have been oxidized with sodium hypochlorite and catalytic amounts of sodium bromide by using two different protocols: first, involving the presence of 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) and second, employing N-hydroxyphthalimide (NHPI). The reactions were carried out at room temperature and pH = 10.5 for 2.5 h. Viscose oxidized samples were analyzed and compared in terms of the negative charged groups content, as determined by potentiometric titration and methylene blue adsorption, morphologies and crystallinities changes, as well as changes in the degree of polymerization. The highest content of the carboxylic groups and the best preservation of the morphology and molecular weight of the original material have been found in the case of using NHPI/anthraquinone as oxidation mediators. TEMPO-mediated oxidation leads to the highest depolymerization and cause significant degradation of the cellulosic material.
KW - Cellulose fibers
KW - N-hydroxyphthalimide
KW - Nitroxyl radicals
KW - Oxidation
KW - Surface modification
KW - TEMPO
KW - Viscose fibers
UR - http://www.scopus.com/inward/record.url?scp=84868335995&partnerID=8YFLogxK
U2 - 10.1016/j.carbpol.2012.08.047
DO - 10.1016/j.carbpol.2012.08.047
M3 - Article
AN - SCOPUS:84868335995
SN - 0144-8617
VL - 91
SP - 502
EP - 507
JO - Carbohydrate Polymers
JF - Carbohydrate Polymers
IS - 2
ER -