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Licensed Unlicensed Requires Authentication Published by De Gruyter September 4, 2012

Behavior of xylans from the Eucalyptus species. Part 2. Characterization of 4-O-methylglucuronoxylans isolated from black liquors of kraft pulping of Eucalyptus grandis and E. urophylla

Andréia S. Magaton, Teresa Cristina F. Silva, Jorge Luiz Colodette, Dorila Piló-Veloso, Flaviana Reis Milagres and Janaína Oliveira Resende
From the journal Holzforschung

Abstract

4-O-methylglucuronoxylans isolated from Eucalyptus grandis and Eucalyptus urophylla kraft black liquors (KBLs) were chemically characterized by Fourier transform infrared spectroscopy (FT-IR), size exclusion chromatography (SEC), and nuclear magnetic resonance (NMR) spectroscopy. Doses of alkali charge, expressed as active alkali (AA), were 16, 17, and 18% while the sulfidity was kept at 25%. Kappa numbers of 19.1, 17.5, and 16.1 for E. grandis and 20.4, 16.8, and 15.4 for E. urophylla were obtained. At higher alkali charges, the recovery of xylans from the KBLs was lower and the degree of substitution of xylans with uronic acids decreased. The average molecular weight (Mw) of the recovered xylans was greater under conditions of mild pulping, i.e., in the case of pulps with higher kappa numbers. Mw of xylans ranged from 16.1 to 19.1 kDa for E. grandis and from 15.4 to 20.4 kDa for E. urophylla. The xylans from KBL may be useful as pulp modifying agents or as a raw material for advanced applications.


Corresponding author: Teresa Cristina F. Silva, Departamento de Engenharia Florestal, Laboratório de Celulose e Papel, Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil, Phone: +55 31 3899 2088

Received: 2012-2-27
Accepted: 2012-8-8
Published Online: 2012-09-04
Published in Print: 2013-02-01

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