Cellulose nanocrystals prepared via formic acid hydrolysis followed by TEMPO-mediated oxidation.
Cellulose nanocrystals (CNCs) as a renewable and biodegradable nanomaterial have wide application value. In this work, CNCs were extracted from bleached chemical pulp using two stages of isolation (i.e. formic acid (FA) hydrolysis and 2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO) mediated oxidation) under mild conditions. In the first stage, FA was used to remove hemicellulose, swell cellulose fibers, and release CNCs. The FA could be readily recovered and reused. In the second stage, the CNCs isolated by FA were further modified by TEMPO-mediated oxidation to increase the surface charge of CNCs. It was found that the modified CNCs with more ordered crystal structure and higher surface charge had better redispersibility and higher viscosity in aqueous phase. Therefore, the modified CNCs could be more effective when used as rheology modifier in the fields of water based coating, paint, food etc.
CAS Kay Laboratory of Bio-Based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; Johan Gadolin Process Centre, C/O Laboratory of Wood and Paper Chemistry, Åbo Akademi University, Turku FI-20500, Finland.
Bin
B
Li
Johan Gadolin Process Centre, C/O Laboratory of Wood and Paper Chemistry, Åbo Akademi University, Turku FI-20500, Finland.
Wenyang
W
Xu
Laboratory of Physical Chemistry, Åbo Akademi University, Turku FI-20500, Finland.
Dennis
D
Kronlund
Laboratory of Physical Chemistry, Åbo Akademi University, Turku FI-20500, Finland.
Anni
A
Määttänen
Johan Gadolin Process Centre, C/O Laboratory of Wood and Paper Chemistry, Åbo Akademi University, Turku FI-20500, Finland.
Jun
J
Liu
Laboratory of Physical Chemistry, Åbo Akademi University, Turku FI-20500, Finland.
Jan-Henrik
JH
Smått
Laboratory of Physical Chemistry, Åbo Akademi University, Turku FI-20500, Finland.
Jouko
J
Peltonen
Johan Gadolin Process Centre, C/O Laboratory of Wood and Paper Chemistry, Åbo Akademi University, Turku FI-20500, Finland.
Stefan
S
Willför
CAS Kay Laboratory of Bio-Based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China. Electronic address: muxd@qibebt.ac.cn.
Xindong
X
Mu
Johan Gadolin Process Centre, C/O Laboratory of Wood and Paper Chemistry, Åbo Akademi University, Turku FI-20500, Finland. Electronic address: cxu@abo.fi.
Chunlin
C
Xu
Cellulose nanocrystals; Characterization; Formic acid; Rheology; TEMPO oxidation