title: Impact of pre-treatments on properties of lignocelluloses and their accessibility for a subsequent carboxymethylation.
abstract: In this issue, different chemical (alkaline and sulfite pulping, ozonolysis) and mechanical (vibratory ball milling) pre-treatments were utilized for activating wheat straw and beech sawdust prior to carboxymethylation. Detailed analysis by a range of methods, including Klason-lignin, cellulose and hemicellulose quantification, Powder-X-ray diffraction (PXRD) and attenuated total reflection (ATR) IR spectroscopy, enabled the investigation of material alterations. Subsequently, carboxymethylation was carried out with both untreated and activated materials, allowing the evaluation of activation steps by determining degrees of substitution with carboxymethyl groups (DSCM). Moreover, carboxymethylation conditions were optimized, realizing high DSCMof up to 1.05. Results further revealed that ball milling enhanced the subsequent conversion; whereas chemical pre-treatments did not effectively increase material accessibilities. Further studies on chemically untreated materials emphasized that a highly reactive surface was already generated in the course of the carboxymethylation, inter alia through the concomitant dissolution of matrix components.
authors.affiliation: Institute of Plant and Wood Chemistry, Technische Universität Dresden Pienner Straße 19, D-01737 Tharandt, Germany. Electronic address: katja.heise@forst.tu-dresden.de.
authors.forename: Katja
authors.initials: K
authors.lastname: Heise
authors.affiliation: Fraunhofer Center for Chemical-Biotechnological Processes CBP, Am Haupttor, D-06237 Leuna, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Rossberg
authors.affiliation: Institute of Plant and Wood Chemistry, Technische Universität Dresden Pienner Straße 19, D-01737 Tharandt, Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Strätz
authors.affiliation: Institute of Plant and Wood Chemistry, Technische Universität Dresden Pienner Straße 19, D-01737 Tharandt, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Bäurich
authors.affiliation: Institute of Analytical Chemistry, TU Bergakademie Freiberg, Leipziger Str. 29, D-09599 Freiberg, Germany.
authors.forename: Erica
authors.initials: E
authors.lastname: Brendler
authors.affiliation: BASF SE, Carl-Bosch-Straße 38, D-67056 Ludwigshafen, Germany.
authors.forename: Harald
authors.initials: H
authors.lastname: Keller
authors.affiliation: Institute of Plant and Wood Chemistry, Technische Universität Dresden Pienner Straße 19, D-01737 Tharandt, Germany.
authors.forename: Steffen
authors.initials: S
authors.lastname: Fischer
mesh_terms: D002482:Cellulose / Q000032:analysis; D008031:Lignin / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism*; D008745:Methylation; D014908:Triticum / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: C036909:lignocellulose; D002482:Cellulose; D008031:Lignin
keywords: Bio-based; Carboxymethyl cellulose; Crystallinity index; Lignocellulosic residue; Mercerization