Eco-Friendly Cellulose Nanofibrils Designed by Nature: Effects from Preserving Native State

Area of Science:

• Materials Science
• Nanotechnology
• Biomaterials

Background:

• Cellulose nanofibrils (CNFs) possess excellent mechanical properties, surpassing other nanocomposite reinforcements.
• Current methods for producing small-diameter, stable CNFs often require costly and less eco-friendly chemical modifications.
• Achieving high performance in CNF-based materials typically necessitates chemically modified CNFs.

Purpose of the Study:

• To develop an unmodified, small-diameter cellulose nanofibril (Holo-CNF) with enhanced properties.
• To investigate the potential of using native CNFs with preserved hemicellulose for advanced applications.
• To evaluate the mechanical properties, optical transmittance, and recyclability of Holo-CNF based nanopaper.

Main Methods:

• Mild peracetic acid delignification of wood fibers to obtain holocellulose.
• Low-energy defibrillation using a kitchen blender to produce Holo-CNF.
• Characterization of Holo-CNF structure, including diameter, length, crystallinity, and charge.
• Fabrication and testing of CNF nanopaper to assess mechanical properties and optical transmittance.

Main Results:

• Successfully produced unmodified Holo-CNF with small diameter (<5 nm) and preserved native fibril structure.
• Holo-CNF nanopaper exhibited superior mechanical properties: Young's modulus of 21 GPa and ultimate strength of 320 MPa.
• The preserved hemicellulose coating contributed to high optical transmittance and enabled recyclability of the dried nanopaper.

Conclusions:

• Native, unmodified Holo-CNF offers a cost-effective and eco-friendly alternative to chemically modified CNFs.
• The hemicellulose coating plays a crucial role in enhancing mechanical performance and enabling recyclability.
• This native CNF is suitable for large-scale applications in nanopaper and other nanomaterials.