University of Oulu

Ludovici, F., Hartmann, R. & Liimatainen, H. Aqueous bifunctionalization of cellulose nanocrystals through amino and alkyl silylation: functionalization, characterization, and performance of nanocrystals in quartz microflotation. Cellulose 30, 775–787 (2023).

Aqueous bifunctionalization of cellulose nanocrystals through amino and alkyl silylation : functionalization, characterization, and performance of nanocrystals in quartz microflotation

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Author: Ludovici, Feliciana1; Hartmann, Robert2,3; Liimatainen, Henrikki1
Organizations: 1Fiber and Particle Engineering Research Unit, University of Oulu, P. O. Box 4300, 90014, Oulu, Finland
2Department of Chemical and Metallurgical Engineering, School of Chemical Engineering, Aalto University, P.O. Box 12200, 00076, Espoo, Finland
3Fraunhofer Center for Chemical-Biotechnological Processes, 06237, Leuna, Germany
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.6 MB)
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Language: English
Published: Springer Nature, 2022
Publish Date: 2022-12-05


Surface modifications of cellulose nanomaterials can be used to tailor their surface charge and hydrophilicity-hydrophobicity characteristics. Additionally, it can facilitate the selective interaction of nanocelluloses with other solid particles to further expand their applicability in different fields. For instance, cellulose nanocrystals (CNC) with amphiphilic features are potential green alternatives in mineral processing such as particle flotation. In the present study, aqueous, one- and two-step silylation of CNCs with amino and alkyl silanes was considered to create a novel bifunctionalized CNCs that contained both positively charged amino silane moieties and hydrophobic alkyl chains. Especially, the effects of reaction conditions and different reaction routes on the silylation were investigated, and the electric surface potential and hydrophobicity of CNCs were determined. The bifunctionalization conducted by the simultaneous addition of an amino silane and alkyl silane led to a high reaction efficiency, and the grafting amount was notably higher than that obtained with the sequential reactions with individual reagents. After the functionalization, the hydrophobicity of the CNCs was strongly altered, leading to water contact angles of up to 135° on CNC films. However, the silylation with amino silanes slightly affected the ζ-potential of the functionalized CNCs. Due to the relatively low ζ-potential, the interaction and orthokinetic attachment of CNCs onto quartz surfaces were insufficient, resulting in a limited flotation recovery in microflotation using a Hallimond tube.

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Series: Cellulose
ISSN: 0969-0239
ISSN-E: 1572-882X
ISSN-L: 0969-0239
Volume: 30
Issue: 2
Pages: 775 - 787
DOI: 10.1007/s10570-022-04961-4
Type of Publication: A1 Journal article – refereed
Field of Science: 116 Chemical sciences
216 Materials engineering
218 Environmental engineering
221 Nanotechnology
222 Other engineering and technologies
Funding: © The Author(s) 2022. Open Access funding provided by University of Oulu including Oulu University Hospital. The research leading to these results received funding from the Horizon 2020 Program of the European Community under Grant Agreement no. 812580 (MSCA-ETN SULTAN) and Academy of Finland project “ACNF” (325276). R.H would like to thank the Academy of Finland for their financial support with the “BioMInt” (13324592) Postdoctoral Research Project.
EU Grant Number: (812580) SULTAN - European Training Network for the remediation and reprocessing of sulfidic mining waste sites
Academy of Finland Grant Number: 325276
Detailed Information: 325276 (Academy of Finland Funding decision)
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