Effect of urea on cellulose degradation under conditions of alkaline pulping

authors	Ershova, O; da Costa, EV; Fernandes, AJS; Domingues, MR; Evtuguin, DV; Sixta, H
nationality	International
journal	CELLULOSE
author keywords	Cellulose; Urea; Alkaline pulping; Peeling reactions; Carbamation; Maillard reaction
keywords	CARBONYL GROUPS; MASS-SPECTROMETRY; HOT ALKALI; KINETICS; OLIGOSACCHARIDES; POLYSACCHARIDES; HYDROCELLULOSE; ADDITIVES; PRODUCTS; WOOD
abstract	The effect of urea on the cellulose degradation under conditions of alkaline pulping has been studied using purified cellulose powder. The increased cellulose yield in the presence of urea was assigned essentially to the carbamation reactions which were confirmed by elemental analysis, UV-resonance Raman and solid-state C-13 nuclear magnetic resonance spectroscopy. The stabilizing effect of urea on the cellulose peeling reactions during heating up period of pulping process was suggested based on kinetic studies and additionally confirmed in model reactions using cellobiose. The reaction products formed in alkaline urea solutions were analysed by tandem electrospray ionization mass spectrometry and the occurrence of Maillard type reactions between reducing end groups of cellobiose and urea were evidenced. Both Maillard type reactions and carbamation of reducing end groups were proposed to be a part of cellulose protection mechanism against peeling under the conditions of alkaline pulping.
publisher	SPRINGER
issn	0969-0239
year published	2012
volume	19
issue	6
beginning page	2195
ending page	2204
digital object identifier (doi)	10.1007/s10570-012-9791-4
web of science category	Materials Science, Paper & Wood; Materials Science, Textiles; Polymer Science
subject category	Materials Science; Polymer Science
unique article identifier	WOS:000310538300031