Cellulose gelation in NaOH(aq) by CO2 absorption: Effects of holding time and concentration on biomaterial development

Guillermo Reyes; Rubina Ajdary; Esko Kankuri; Joice J Kaschuk; Harri Kosonen; Orlando J Rojas

doi:10.1016/j.carbpol.2022.120355

Cellulose gelation in NaOH_(aq) by CO₂ absorption: Effects of holding time and concentration on biomaterial development

Carbohydr Polym. 2023 Feb 15:302:120355. doi: 10.1016/j.carbpol.2022.120355. Epub 2022 Nov 23.

Authors

Guillermo Reyes¹, Rubina Ajdary², Esko Kankuri³, Joice J Kaschuk⁴, Harri Kosonen⁵, Orlando J Rojas⁶

Affiliations

¹ Biobased Colloids and Materials, Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Espoo, Finland. Electronic address: guillermo.reyes@aalto.fi.
² Biobased Colloids and Materials, Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Espoo, Finland; Bioproducts Institute, Department of Chemical & Biological Engineering, Department of Chemistry and Department of Wood Science, 2360 East Mall, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
³ Department of Pharmacology, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland. Electronic address: esko.kankuri@helsinki.fi.
⁴ Biobased Colloids and Materials, Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Espoo, Finland; Bioproducts Institute, Department of Chemical & Biological Engineering, Department of Chemistry and Department of Wood Science, 2360 East Mall, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada. Electronic address: joice.kaschuk@aalto.fi.
⁵ UPM Pulp Research and Innovations, UPM, Paloasemantie 19, FI-53200 Lappeenranta, Finland. Electronic address: harri.kosonen@upm.com.
⁶ Biobased Colloids and Materials, Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Espoo, Finland; Bioproducts Institute, Department of Chemical & Biological Engineering, Department of Chemistry and Department of Wood Science, 2360 East Mall, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada. Electronic address: orlando.rojas@ubc.ca.

PMID: 36604045
DOI: 10.1016/j.carbpol.2022.120355

Abstract

We address the limited solubility and early onset of gelation of aqueous sodium hydroxide to position it as a preferred green solvent for cellulose. For this purpose, we expand the concentration window (up to 12 wt%) by using a CO₂-depleted air and adjusting the time the dope remains in the given atmosphere, before further processing (holding time) and regeneration conditions. Cellulose solutions are extruded following characteristic (rheology and extrusion) parameters to yield aligned filaments reaching tenacities up to 2.3 cN·dtex^-1, similar to that of viscose. Further material demonstrations are achieved by direct ink writing of auxetic biomedical meshes (Poisson's ratio of -0.2, tensile strength of 115 kPa) and transparent films, which achieved a tensile strength and toughness of 47 MPa and 590 kJ·m^-3, respectively. The results suggest an excellent outlook for cellulose transformation into bioproducts. Key to this development is the control of the gelation ensuing solution flow and polymer alignment, which depend on CO₂ absorption, cellulose concentration, and holding time.

Keywords: Additive manufacturing; Alkali cellulose; CO(2) absorption; CO(2) capture; Cellulose rheology; Cellulose spinning; Cellulose textiles.

MeSH terms

Biocompatible Materials
Carbon Dioxide*
Cellulose*
Sodium Hydroxide
Solutions

Substances

Solutions
Sodium Hydroxide
Carbon Dioxide
Cellulose
Biocompatible Materials