Single-step method for the isolation and surface functionalization of cellulosic nanowhiskers

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Cellulosic nanowhiskers (CNW) are promising polymer reinforcements.
• Surface modification typically requires multiple reaction steps.
• Improving CNW compatibility with hydrophobic polymers is crucial.

Purpose of the Study:

• To develop a single-step method for surface-functionalizing CNW.
• To achieve simultaneous hydrolysis and esterification of cellulose.
• To enhance CNW dispersibility in organic solvents.

Main Methods:

• Utilized a mixed acid system (hydrochloric and organic acid) for cellulose treatment.
• Verified CNW dimensions using multiangle laser-light scattering and transmission electron microscopy.
• Quantified surface hydroxyl group substitution via Fourier-transform infrared spectroscopy.

Main Results:

• Achieved simultaneous hydrolysis and esterification in one step.
• Produced CNW with similar dimensions but narrower diameter polydispersity compared to traditional methods.
• Demonstrated over 50% substitution of surface hydroxyl groups.
• Obtained CNW dispersible in ethyl acetate and toluene, indicating increased hydrophobicity.

Conclusions:

• The single-step method efficiently produces surface-functionalized CNW.
• Surface modification enhances CNW individualization and dispersibility.
• These modified CNW show improved compatibility for use as reinforcing agents in hydrophobic polymers.