Apparent specific surface area as an indicator of the degree of cellulose microfibrillation
Ämmälä, Ari; Sirviö, Juho Antti; Laitinen, Ossi; Liimatainen, Henrikki; Evikari, Ossi; Siljander, Sanna; Björkqvist, Tomas (2024-12-08)
Springer
08.12.2024
Ämmälä, A., Sirviö, J.A., Laitinen, O. et al. Apparent specific surface area as an indicator of the degree of cellulose microfibrillation. Cellulose 32, 797–809 (2025). https://doi.org/10.1007/s10570-024-06301-0
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© The Author(s) 2024. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
https://creativecommons.org/licenses/by/4.0/
© The Author(s) 2024. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:oulu-202412107141
https://urn.fi/URN:NBN:fi:oulu-202412107141
Tiivistelmä
Abstract
Tracking mechanical microfibrillation in nanocellulose production is time-consuming due to a lack of quick characterization methods. This study investigates optical monitoring of the mechanical microfibrillation process by determining the dimensions of microfibrillated cellulose (MFC) particles on micron scale. Bleached hardwood pulp was microfibrillated using three sets of grinding discs in a six-stage pilot process, analyzing MFC characteristics as a function of specific energy consumption via image analysis. A laboratory-scale ultrafine grinder was also used for comparison. The degree of microfibrillation was assessed over a broad energy range using the equivalent diameter derived from the MFC length and width through image processing. The microfibrillation process adhered to Rittinger’s law, i.e., changes in the apparent specific surface area (SSA) were linearly proportional to the applied grinding energy. SSA, being inversely proportional to equivalent diameter, predicted MFC quality in terms of nanofilm strength properties. The optical fiber image analyzer proved suitable for online monitoring and control of microfibrillation processes. Despite resolution limits in detecting sub-micron particles, their proportion interrelates to the size of optically visible particles, covering industrial needs for mechanical microfibrillation.
Tracking mechanical microfibrillation in nanocellulose production is time-consuming due to a lack of quick characterization methods. This study investigates optical monitoring of the mechanical microfibrillation process by determining the dimensions of microfibrillated cellulose (MFC) particles on micron scale. Bleached hardwood pulp was microfibrillated using three sets of grinding discs in a six-stage pilot process, analyzing MFC characteristics as a function of specific energy consumption via image analysis. A laboratory-scale ultrafine grinder was also used for comparison. The degree of microfibrillation was assessed over a broad energy range using the equivalent diameter derived from the MFC length and width through image processing. The microfibrillation process adhered to Rittinger’s law, i.e., changes in the apparent specific surface area (SSA) were linearly proportional to the applied grinding energy. SSA, being inversely proportional to equivalent diameter, predicted MFC quality in terms of nanofilm strength properties. The optical fiber image analyzer proved suitable for online monitoring and control of microfibrillation processes. Despite resolution limits in detecting sub-micron particles, their proportion interrelates to the size of optically visible particles, covering industrial needs for mechanical microfibrillation.
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