Modifying the flocculation of microfibrillated cellulose suspensions by soluble polysaccharides under conditions unfavorable to adsorption

A Sorvari, T Saarinen, Sanna Haavisto, Juha Salmela, M Vuoriluoto, J Seppälä

Research output: Contribution to journalArticleScientificpeer-review

18 Citations (Scopus)

Abstract

Carboxymethylcellulose (CMC) and xanthan gum were studied as dispersants for microfibrillated cellulose (MFC) suspension using a rotational rheometer and imaging methods. The imaging was a combination of photography and optical coherence tomography (OCT). Both polymers dispersed MFC fibers, although CMC was more effective than xanthan gum. The negatively charged polymer chains increased the viscosity of the suspending medium and acted as buffers in between the negatively charged fibers. This behavior decreased the number and strength of contacts between the fibers and subsequently dispersed the flocs. The stronger separation of the fibers was reflected in the frequency sweep where the MFC/polymer suspensions had lower gel strength than pure MFC suspension. Dispersing effect was also observed in the flow measurements, where the floc size was more uniform with polymers in the decelerating flow and after long, slow constant shear, which normally induces a heterogeneous structure with large flocs into the MFC suspension
Original languageEnglish
Pages (from-to)283-292
Number of pages9
JournalCarbohydrate Polymers
Volume106
Issue number1
DOIs
Publication statusPublished - 2014
MoE publication typeA1 Journal article-refereed

Keywords

  • Carboxymethyl cellulose
  • dispersant
  • microfibrillated cellulose
  • optical coherence tomography
  • rotational rheometry
  • xanthan gum

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