Dry, hydrophobic microfibrillated cellulose powder obtained in a simple procedure using alkyl ketene dimer

Yutao Yan, Hassan Amer, Thoma Rosenau, C. Zollfrank, Jörg Dörrstein, Cornelia Jobst, Tanja Zimmermann, Jozef Keckes, Stefan Veigel, Wolfgang Gindl-Altmutter, Jianzhang Li

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In order to produce dry and hydrophobic microfibrillated cellulose (MFC) in a simple procedure, its modification with alkyl ketene dimer (AKD) was performed. For this purpose, MFC was solvent-exchanged to ethyl acetate and mixed with AKD dissolved in the same solvent. Curing at 130 °C for 20 h under the catalysis of 1-methylimidazole yielded a dry powder. Scanning electron microscopy of the powder indicated loss in nanofibrillar structure due to aggregation, but discrete microfibrillar structures were still present. Water contact angle measurements of films produced from modified and unmodified MFC showed high hydrophobicity after AKD treatment, which persisted even after extraction with THF for 8 h. The hydrophobized MFC was characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance and X-ray analysis. In summary, strong indications for the presence of AKD on the surface of MFC before and after extraction with solvent were found, but only a very small amount of covalent β-ketoester linkages between the modification agent and cellulose was revealed.
Original languageUndefined/Unknown
Pages (from-to)1189-1197
Number of pages9
Issue number2
Publication statusPublished - 2016

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