Deaggregation of cellulose macrofibrils and its effect on bound water

Area of Science:

• Materials Science
• Colloid and Surface Chemistry
• Biomaterials Engineering

Background:

• Pulp fiber swelling is crucial for material properties.
• Understanding hierarchical swelling is key to optimizing fiber-based products.
• Electrostatic interactions and osmotic pressure are potential control mechanisms.

Purpose of the Study:

• To control and measure hierarchical swelling in pulp fibers.
• To investigate the role of electrostatic interactions and localized osmotic pressure.
• To explore the impact of increased phosphate groups on fiber properties.

Main Methods:

• Utilized a eutectic solvent system to modify cell wall chemistry.
• Systematically increased phosphate groups and fiber charge.
• Employed X-ray scattering, solute exclusion, and a novel thermoporosimetry method.

Main Results:

• Increased fiber charge enhanced swelling properties.
• Macrofibril deaggregation occurred at 180-200 μmol/g charge, increasing swelling (0.9 to 2.5 mL/g) and surface area (400 to 1000 m²/g).
• Hydrated surface area ranged from 1200-1400 m²/g, aligning with simulations.

Conclusions:

• Hierarchical control of fiber swelling via electrostatic interactions is feasible.
• Macrofibril deaggregation is a key event influencing swelling and surface area.
• This approach holds potential for improving strength/density in packaging and other fiber products.