Optimization of carboxymethylation reaction as a pretreatment for production of cellulose nanofibrils
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We investigated the optimal reaction conditions for carboxymethylation as a pretreatment method for the production of cellulose nanofibrils (CNF). The influence of the reaction sequence, solvent composition, and presence of water in the reaction medium on the carboxymethylation of pulp was studied. We also investigated the effects of water in the reaction medium on CNF properties. The most effective carboxymethylation of pulp was achieved with non-solvent exchanged pulp and isopropanol. An increase in pulp consistency increased the carboxyl group content. The optimum reaction condition used only one-third the amounts of monochloroacetic acid and sodium hydroxide for the same level of carboxymethylation. The number of passes required for mechanical fibrillation of the pulp, the morphology and dispersion instability of CNF were all strongly influenced by the carboxyl content introduced during the carboxymethylation reaction. The number of mechanical treatment steps required to produce CNF decreased as the carboxyl content increased. Pulp with a high carboxyl content resulted in a more stable suspension due to the increased electrostatic repulsion between the fibrils.
KeywordsCellulose nanofibrils Carboxymethylation Carboxyl content Chemical cost saving
This work was supported by the Technological Innovation Program funded by the Ministry of Trade, Industry & Energy (10062717).
- Ambjörnsson HA, Schenzel K, Germgård U (2013) Carboxymethyl cellulose produced at different mercerization conditions and characterized by NIR FT Raman spectroscopy in combination with multivariate analytical methods. BioResources 8(2):1918–1932Google Scholar
- Mohkami M, Talaeipour M (2011) Investigation of the chemical structure of carboxylated and carboxymethylated fibers from waste paper via XRD and FTIR analysis. BioResources 6(2):1988–2003Google Scholar
- Qi H, Liebert T, Meister F, Heinze T (2009) Homogenous carboxymethylation of cellulose in the NaOH/urea aqueous solution. React Funct Polym 69:779–784. https://doi.org/10.1016/j.reactfunctpolym.2009.06.007 CrossRefGoogle Scholar
- Qiu H, He L (1999) Synthesis and properties study of carboxymethyl cassava starch. Polym Adv Technol 10:468–472. https://doi.org/10.1002/(SICI)1099-1581(199907)10:7 CrossRefGoogle Scholar
- Ren JL, Sun RC, Peng F (2008) Carboxymethylation of hemicelluloses isolated from sugarcane bagasse. Polym Degrad Stab 93:786–793. https://doi.org/10.1016/j.polymdegradstab.2008.01.011 CrossRefGoogle Scholar
- Suflet DM, Chitanu GC, Popa VI (2006) Phosphorylation of polysaccharides: new results on synthesis and characterization of phosphorylated cellulose. React Funct Polym 66:1240–1249. https://doi.org/10.1016/j.reactfunctpolym.2006.03.006 CrossRefGoogle Scholar
- Wang M, Olszewska A, Walther A, Malho JM, Schacher FH, Ruokolainen J, Ankerfors M, Laine J, Berglund LA, Österberg M, Ikkala O (2011) Colloidal ionic assembly between anionic native cellulose nanofibrils and cationic block copolymer micelles into biomimetic nanocomposites. Biomacromolecules 12:2074–2081. https://doi.org/10.1021/bm101561m CrossRefGoogle Scholar