Recyclable deep eutectic solvent for the production of cationic nanocelluloses

Area of Science:

• Green Chemistry
• Materials Science
• Nanotechnology

Background:

• Deep eutectic solvents (DESs) offer sustainable alternatives as reaction media and reagents.
• Cellulose modification is crucial for advanced material applications.
• Developing eco-friendly methods for producing functionalized nanomaterials is a key research area.

Purpose of the Study:

• To synthesize cationic nanocelluloses using a recyclable deep eutectic solvent (DES).
• To investigate the efficiency and recyclability of the DES system for cellulose cationization.
• To tailor the morphology of cationic nanocelluloses (CNFs and CNCs) through controlled reaction conditions.

Main Methods:

• Preparation of a recyclable DES from aminoguanidine hydrochloride and glycerol (AhG).
• Cationization of dialdehyde celluloses (DACs) using the AhG DES under mild conditions.
• Mechanical disintegration of cationized celluloses to produce cationic nanocelluloses.
• Characterization of nanocellulose morphology and charge density using techniques like transmission electron microscopy.

Main Results:

• Successfully produced cationic dialdehyde celluloses (CDACs) with high charge densities (up to 2.48 mmol g⁻¹).
• Demonstrated the excellent recyclability of the AhG DES over five cycles without loss of efficiency.
• Tailored nanocellulose morphology to yield cationic cellulose nanofibrils (CNFs) and cellulose nanocrystals (CNCs) with controlled dimensions.
• Confirmed the formation of individual CNFs (4.6 ± 1.1 nm width) and CNCs (5.7 ± 1.3 nm width).

Conclusions:

• The AhG DES provides a promising, green, and recyclable route for producing high-charge-density cationic nanocelluloses.
• The method allows for the controlled production of CNFs and CNCs with tunable morphologies.
• This approach minimizes chemical waste and enhances the sustainability of nanocellulose production.