Upgrading of paper grade pulps to dissolving pulps by nitren extraction: yields, molecular and supramolecular structures of nitren extracted pulps

• Published in: Cellulose (London) Vol. 15; no. 5; pp. 739 - 750
• Main Authors: Janzon, Ron, Puls, Jürgen, Bohn, Andreas, Potthast, Antje, Saake, Bodo
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01.10.2008; Springer Netherlands; Springer Nature B.V
• Subjects: Bioorganic Chemistry; Carbohydrates; Carbonyls; Carboxyl group; Cellulose; Ceramics; Chemistry; Chemistry and Materials Science; Composites; Fluorescence; Glass; Mass distribution; Molecular structure; Natural Materials; NMR; Nuclear magnetic resonance; Organic Chemistry; Oxidation; Physical Chemistry; Polymer Sciences; Sodium hydroxide; Sustainable Development; X-ray scattering; Carbonyl groups; HPSEC; Dissolving pulp; Carboxyl groups; Nitren extraction; C-CP/MAS-NMR; WAXS
• ISSN: 0969-0239; 1572-882X
• DOI: 10.1007/s10570-008-9224-6

Different paper grade pulps were extracted with nitren in order to produce dissolving pulps and polymeric xylan. The yield and molecular structure of the extracted pulps were investigated by carbohydrate analysis and HPSEC combined with fluorescence labelling in order to additionally monitor the carbonyl and carboxyl group profiles of the pulps. The supramolecular structure of selected pulps were further studied by solid state ¹³C-CP/MAS-NMR and wide-angle X-ray scattering (WAXS). These supramolecular data of nitren extracted pulps were compared to samples extracted with NaOH and a conventional dissolving pulp in order to classify the properties of nitren extracted pulps. Nitren extraction results in selective xylan removal without noticeable degradation or oxidation of the cellulose fraction. The resulting dissolving pulps have high molar masses, a narrow molar mass distribution and the typical contents of carbonyl and carboxyl groups. The supramolecular structure of cellulose is less affected by nitren compared to strong NaOH, and the resultant dissolving pulps still have the cellulose I structure.