Flocculation of microfibrillated cellulose in shear flow

Anni Karppinen, Tapio Saarinen, Juha Salmela, Antti Laukkanen, Markus Nuopponen, Jukka Seppälä (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

99 Citations (Scopus)

Abstract

In this work, the rheological properties of microfibrillated cellulose suspensions under stepped flow and constant shear were studied using a combination of rotational dynamic rheometer and digital imaging. During each rheological measurement, the structure of the suspension was monitored through a transparent outer cylinder with a digital camera. This enabled simultaneous analysis of the suspension floc size distribution and traditional rheological characterization. In stepped flow conditions, a good correlation between suspension floc structure and flow curve measurement was found. At constant shear, the suspension structure was dependent on the shear rate and concentration of the suspension. A low shear rate resulted in heterogeneous floc structure, which was also detected by an increase in the ratio of the viscous component to elastic component in the rheological measurement. At low concentrations and 0.5 s−1 shear rate, flow induced a formation of floc cylinders between the rotating cylinder and stationary cup surface.
Original languageEnglish
Pages (from-to)1807-1819
Number of pages12
JournalCellulose
Volume19
Issue number6
DOIs
Publication statusPublished - 2012
MoE publication typeA1 Journal article-refereed

Keywords

  • Microfibrillated cellulose
  • rheology
  • floc structure
  • image analysis
  • flow curve

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    Karppinen, A., Saarinen, T., Salmela, J., Laukkanen, A., Nuopponen, M., & Seppälä, J. (2012). Flocculation of microfibrillated cellulose in shear flow. Cellulose, 19(6), 1807-1819. https://doi.org/10.1007/s10570-012-9766-5