One-pot functionalization of cellulose nanocrystals with various cationic groups

Jasmani, Latifah; Eyley, Samuel; Schütz, Christina; Gorp, Hans Van; Feyter, Steven De; Thielemans, Wim

doi:10.1007/s10570-016-1052-5

Cited by 27 publications

(16 citation statements)

References 27 publications

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“…The one-pot reaction for the modification of CNCs with a pyridinium salt was described earlier by Jasmani et al 33 The modification was performed five times, under different reaction conditions as described in Table 1 to achieve different degrees of substitution in line with work by Lombardo et al 34 Compared to Lombardo et al's report, one additional reaction at 25 o C was performed in this work. The procedure for the synthesis of N-benzylmethylimidazolium grafted CNCs is a modified procedure reported by Jasmani et al 35 Similar to the benzylpyridinium grafted CNCs, the reaction was carried out five times under different reaction conditions to obtain different degrees of substitution as reported in Table 1. The conditions were the same as for the pyridinium reaction, except that pyridine was replaced with methyl imidazole.…”

Section: Synthesis Of Benzylpyridinium Grafted Cncs ([Br][bnpy]-g-cncs)mentioning

confidence: 99%

Cationic Cellulose Nanocrystals for Flocculation of Microalgae: Effect of Degree of Substitution and Crystallinity

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Verfaillie

Eyley

et al. 2019

ACS Appl. Nano Mater.

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Flocculation could offer a low-cost and straightforward solution to harvest microalgae in an economic and energy-efficient way. Cationically modified cellulose nanocrystals (CNCs) have been proposed as an alternative to biopolymer-based flocculants such as chitosan. The aim of this study was to fine-tune the cationic modification of CNCs for use as flocculants for harvesting the freshwater microalgae Chlorella vulgaris. CNCs were functionalized with two cationic groups: pyridinium (PYR) or methylimidazolium (MIM) and the degree of substitution (DS) was varied by controlling reaction conditions (stoichiometry, reaction time, and temperature). The DS ranged from 0.08 to 0.34 for PYR modifications and from 0.10 to 0.29 for MIM modifications. All cationic CNCs achieved flocculation efficiencies of > 95 % at optimal dosage. The required dose to induce flocculation decreased with increasing DS and did not differ between the PYR and MIM modified CNCs. The relation between DS and the flocculant dose points to the importance of electrostatic interactions in the flocculation mechanism. To check the advantages of a rigid flocculant compared to a flexible flocculant, we compared flocculation between rigid cationic CNCs and the flexible molecular polymer chitosan. While CNCs required a slightly higher dose by weight compared to chitosan, CNCs required a lower dose than chitosan when expressed per number of cationic charges added. Moreover, overdosing resulted in dispersion restabilisation when chitosan was used, but not when cationic CNCs were used, pointing to a different mechanism of flocculation between rigid cationic CNCs and the molecular polymer chitosan. 2 Opposed to flexible flocculants, CNCs cannot reorient all their charges towards the microalgal cell. This results in patches of positive charges onto the surface. Because of the rigidity of CNCs, we propose an electrostatic patch mechanism as the mechanism of flocculation for CNC-based flocculants.

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Section: Synthesis Of Benzylpyridinium Grafted Cncs ([Br][bnpy]-g-cncs)mentioning

confidence: 99%

Cationic Cellulose Nanocrystals for Flocculation of Microalgae: Effect of Degree of Substitution and Crystallinity

Blockx

Verfaillie

Eyley

et al. 2019

ACS Appl. Nano Mater.

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“…The degree of substitution (DS) was determined by combining the results of elemental analysis (EA) corrected by the water content obtained with thermogravimetric analysis (TGA) as described by Eyley and Thielemans. 25,42 Briey, a Thermo Scientic FLASH 2000 elemental analyser was used to Fig. 1 Modification of cellulose nanocrystals with glycine betaine, reaction scheme.…”

Section: Characterisation Of the Cncsmentioning

confidence: 99%

“…40 Examples of reported synthetic cationic gras are poly(4vinylpyridine), polyacrylamide derivatives, polyethylenimine, and pyridinium-and imidazolium-derived groups. 16,[33][34][35][41][42][43] With this study, we wanted to create cationic CNC-based occulants where the gra is a bio-based molecule. N,N,N-trimethylglycine, oen referred to as glycine betaine or historically even simply as betaine, was chosen for this purpose.…”

Section: Introductionmentioning

confidence: 99%

Glycine betaine grafted nanocellulose as an effective and bio-based cationic nanocellulose flocculant for wastewater treatment and microalgal harvesting

et al. 2021

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“…The resulting highly charged cationic CNCs were found to be excellent flocculants for freshwater microalgae harvesting. Recently, the same group exploited this one-pot synthetic method given the high grafting density to expand on the design of cationic CNCs with varying properties [65] ( Figure 2). Two different structural amines, 1-methylimidazole and 4-dimethylaminopyridine, were employed in this study, which also acted as the catalytic base for the esterification step as well as the nucleophile to attack the electrophilic carbon of the C-Br and generate the cationic charge.…”

Section: Cationic Imidazolium and Pyridinium Grafted Cncsmentioning

confidence: 99%

Synthetic Strategies for the Fabrication of Cationic Surface-Modified Cellulose Nanocrystals

Sunasee

Hemraz

2018

Fibers

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Cellulose nanocrystals (CNCs) are renewable nanosized materials with exceptional physicochemical properties that continue to garner a high level of attention in both industry and academia for their potential high-end material applications. These rod-shaped CNCs are appealing due to their non-toxic, carbohydrate-based chemical structure, large surface area, and the presence of ample surface hydroxyl groups for chemical surface modifications. CNCs, generally prepared from sulfuric acid-mediated hydrolysis of native cellulose, display an anionic surface that has been exploited for a number of applications. However, several recent studies showed the importance of CNCs' surface charge reversal towards the design of functional cationic CNCs. Cationization of CNCs could further open up other innovative applications, in particular, bioapplications such as gene and drug delivery, vaccine adjuvants, and tissue engineering. This mini-review focuses mainly on the recent covalent synthetic methods for the design and fabrication of cationic CNCs as well as their potential bioapplications.

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One-pot functionalization of cellulose nanocrystals with various cationic groups

Cited by 27 publications

References 27 publications

Cationic Cellulose Nanocrystals for Flocculation of Microalgae: Effect of Degree of Substitution and Crystallinity

Cationic Cellulose Nanocrystals for Flocculation of Microalgae: Effect of Degree of Substitution and Crystallinity

Glycine betaine grafted nanocellulose as an effective and bio-based cationic nanocellulose flocculant for wastewater treatment and microalgal harvesting

Synthetic Strategies for the Fabrication of Cationic Surface-Modified Cellulose Nanocrystals

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