1. Insights into the EDC-mediated PEGylation of cellulose nanofibrils and their colloidal stability.
- Author
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Kaldéus, Tahani, Nordenström, Malin, Carlmark, Anna, Wågberg, Lars, and Malmström, Eva
- Subjects
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CELLULOSE nanocrystals , *AMALGAMATION , *COUPLING reactions (Chemistry) , *CHEMICAL yield , *DISPERSION (Chemistry) , *PHASE transitions - Abstract
EDC-mediated coupling has frequently been utilized to poly(ethylene glycol) functionalize (PEGylate) cellulose-based materials, but no work has previously been reported on the direct N -(3-dimethylaminopropyl)- N -ethylcarbodiimide (EDC)-mediated PEGylation of cellulose nanofibrils (CNF). Herein, we report the first study where CNF has been directly sterically stabilized with amine-terminated PEG employing N -hydroxysuccinimide (NHS)-assisted EDC-coupling. This work has shown that this coupling reaction is highly sensitive to the reaction conditions and purification procedures, and hence an optimized coupling protocol was developed in order to achieve a reaction yield. Elemental analysis of the nitrogen content also showed the successful PEGylation. It was also shown that a surprisingly low PEGylation (1%) is sufficient to significantly improve the colloidal stability of the PEGylated samples, which reached dispersion-arrested-state-transitions at higher concentrations than neat CNF. The colloidal stability was preserved with increasing ionic strength, when comparably long polymer chains were grafted, targeting only 1% PEGylation. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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