Influence of DP and MMD of the pulps used in the Ioncell® process on processability and fiber properties

Thumbnail Image
Access rights
Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Degree programme
RSC Sustainability, Volume 1, issue 6
In this study, we have demonstrated for the first time the ability of the Ioncell fiber spinning process to produce high-quality regenerated cellulose fibers from dissolving pulps with a wide range of intrinsic viscosity from 140 to 1300 mL g−1 and different molecular mass distributions prepared by the applied acid, enzyme and sequential acid-enzyme pretreatments. To minimize the influence of the hemicellulose content, only dissolving pulps with a hemicellulose content of less than 4% were used. The rheological properties exhibited certain threshold values beyond which the spinnability of the prepared dope can be severely affected. A spinning dope with a dynamic modulus higher than 6000 Pa s or less than 1600 Pa s is not spinnable or results in an acceptable draw ratio. The best spinnability can be obtained at a crossover point for the dynamic moduli between 2800 and 3500 Pa and for the angular frequency between 0.4 and 1.2 rad s−1. In these ranges, the highest draw ratios of the spun filaments can be obtained for pulps with a viscosity of 420 to 500 mL g−1 and the lowest linear density (fiber titer) for pulps with viscosity from 500 to 730 mL g−1. The strength of the spun fibers is strongly DP dependent. The fiber tenacity gradually decreases with reducing pulp viscosity until non-spinnable dopes are prepared at a pulp viscosity below 300 mL g−1. Compared to acid-treated pulp, fibres made from enzyme-treated pulp generally have lower strength, which is due to a high polydispersity expressed in a high proportion of short-chain cellulose. At a suitable pulp viscosity between 360 and 820 mL g−1 and a cellulose concentration in the spinning dope of 11 to 15 wt%, Ioncell fibres with excellent tensile strength and toughness properties can be produced.
Funding Information: The author would like to acknowledge Sateri International, Singapore for the financial support of the project. We would also like to thank RYAM for providing the high viscosity softwood dissolving pulp and Bracell for providing the high purity hardwood dissolving pulp. Publisher Copyright: © 2023 RSC
Other note
Ma , Y , You , X , Nieminen , K , Sawada , D & Sixta , H 2023 , ' Influence of DP and MMD of the pulps used in the Ioncell® process on processability and fiber properties ' , RSC Sustainability , vol. 1 , no. 6 , pp. 1497-1510 .