Titrimetric methods for the determination of surface and total charge of functionalized nanofibrillated/microfibrillated cellulose (NFC/MFC)
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Total and surface charge of three different carboxymethylated nanofibrillated/microfibrillated cellulose (NFC/MFC) samples were investigated by using titrimetric methods (conductometric and polyelectrolyte (PE) titrations). Conductometric titration was found to be suitable method for the NFC total charge measurements when the back titration with HCl was applied. Surface charge measurements of NFC/MFC were conducted by using both indirect and direct PE titrations. The direct PE titration was found to be a more suitable method for the surface charge determination of NFC/MFC whereas the indirect PE titration produced too high surface charge values. This is presumably due to kinetically locked polyelectrolyte conformations on the NFC/MFC surfaces or entrapment of residual polymer after adsorption onto the NFC/MFC gel network. Finally, NFC was propargyl-functionalized and the changes in surface and total charge were successfully monitored and compared to those of propargyl-functionalized pulp. A good correlation between the titrimetric methods and elemental analysis was observed.
KeywordsNanofibrillated cellulose Charge density Surface charge Total charge Propargyl-NFC
This work was funded by Naseva2 project. Graduate School for Biomass Refining (BIOREGS) and Refining Lignocellulosics to Advanced Polymers and Fibers (PolyRefNorth) network are thanked for personal financial support (KJ). Ms. Gunborg Glad-Nordmark, Ms. Åsa Blademo, Ms. Ritva Kivelä, Ms. Anu Anttila, Ms. Marja Kärkkäinen and Ms. Johanna Mareta are thanked for laboratory assistance. KJ acknowledges fruitful discussions with Ali Naderi and Jonas Sundström (Innventia AB).
- Herrick FW, Casebier RL, Hamilton JK, Sandberg KR (1983) Microfibrillated cellulose: morphology and accessibility. J Appl Polym Sci Appl Polym Symp 37:797–813Google Scholar
- Katz S, Beatson RP, Scallan AM (1984) The determination of strong and weak acidic groups in sulfite pulps. Sven Papperstidn 87:R48–R53Google Scholar
- Pääkkö M, Ankerfors M, Kosonen H, Nykänen A, Ahola S, Österberg M, Ruokolainen J, Laine J, Larsson PT, Ikkala O, Lindström T (2007) Enzymatic hydrolysis combined with mechanical shearing and high-pressure homogenisation for nanoscale cellulose fibrils and strong gels. Biomacromolecules 8:1934–1941CrossRefGoogle Scholar
- Solala I, Volperts A, Andersone A, Dizhbite T, Mironova-Ulmane N, Vehniäinen A, Pere J, Vuorinen T (2011) Mechanoradical formation and its effects on birch kraft pulp during the preparation of nanofibrillated cellulose with Masuko refining. Holzforschung 66:477–483Google Scholar
- Taniguchi T (1996) Microfibrillation of natural fibrous materials. J Soc Mater Sci Jpn 45:472–473Google Scholar
- Turbak AF, Snyder FW, Sandberg KR (1983) Microfibrillated cellulose, a new cellulose product: properties, uses and commercial potential. J Appl Polym Sci Appl Polym Symp 37:815–827Google Scholar
- Wågberg L, Winter L, Ödberg L, Lindström T (1987) On the charge stoichiometry upon adsorption of a cationic polyelectrolyte on cellulosic materials. Colloids Surf 27:163–173Google Scholar
- Walecka JA (1956) An investigation of low degree of substitution carboxymethylcelluloses. Tappi J 39:458–463Google Scholar