Aqueous-Cellulose-Solvent-Derived Changes in Cellulose Nanocrystal Structure and Reinforcing Effects

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Cellulose nanocrystals (CNCs) are promising reinforcing agents, but their dimensions depend on the source.
• Modulating CNC morphology is key to optimizing their reinforcing capacity.

Purpose of the Study:

• To manually alter cellulose nanocrystal (CNC) morphology using different cellulose solvents.
• To investigate the reinforcing effects of CNCs with varied morphologies.

Main Methods:

• Waste cotton fabric was treated with sulfuric acid and NaOH/urea aqueous solutions.
• Regenerated cellulose was hydrolyzed to produce CNCs (RCNC-H and RCNC-N).
• CNCs were incorporated into polyvinyl alcohol (PVA) films to evaluate reinforcing effects.

Main Results:

• Sulfuric acid treatment yielded needle-like RCNC-H (aspect ratio ~15.2) with a hybrid crystalline structure.
• NaOH/urea treatment dissolved cotton, producing rod-like RCNC-N (aspect ratio ~6.3) with cellulose II structure and higher crystallinity.
• PVA/RCNC-H films showed improved tensile strength and oxygen barrier.
• PVA/RCNC-N films exhibited lower water vapor permeability.

Conclusions:

• This study presents a method to tailor CNC nanostructures using solvent treatment.
• Modified CNCs offer tunable properties for diverse material applications.
• Altering CNC morphology provides a new avenue for advanced material design.