Processing-Structure-Property Correlation Understanding of Microfibrillated Cellulose Based Dimensional Structures...

Area of Science:

• Materials Science
• Biomaterials Engineering
• Nanotechnology

Background:

• Microfibrillated cellulose (MFC) is a renewable biomaterial with potential applications in various fields.
• Controlling the network structure of MFC is crucial for tailoring its properties.
• Understanding the relationship between processing methods and MFC network characteristics is essential for material design.

Purpose of the Study:

• To investigate the impact of different processing routes on the network formation and properties of wood-based MFC.
• To evaluate the water flux, porosity, pore size distribution, and tensile strength of MFC structures fabricated via freeze-drying, pressing, vacuum filtration, and casting.
• To assess the efficiency of surface-functionalized MFC in removing ferric ions and identify key factors influencing adsorption.

Main Methods:

• Fabrication of MFC networks using freeze-drying (FD), pressing (PFD), vacuum filtration (VF), and casting (CS) methods.
• Characterization of network porosity, pore size distribution (Hg porosimetry), and surface area.
• Measurement of water flux using a dedicated device and tensile strength.
• Upscaling of VF structures using an Experimental Paper Machine (XPM).
• Surface functionalization of MFC with hexokinase for ferric ion removal and evaluation of adsorption efficiency.

Main Results:

• Freeze-drying (FD) produced highly porous (98%) networks, while casting (CS) resulted in dense, low-porosity (17%) structures.
• Water flux varied significantly, with pressed freeze-dried (PFD) followed by vacuum-filtered (VF) showing 11.4 L/m²h and CS showing 0.7 L/m²h.
• CS structures exhibited the highest tensile strength (87 MPa), indicating a compacted network, whereas PFD had the lowest (1.6 MPa).
• XPM-based structures showed improved tensile strength (73 MPa) compared to CS structures, attributed to fiber alignment.
• Surface functionalization and network properties, including charge densities and zeta potential, influenced ferric ion removal efficiency.

Conclusions:

• Processing routes significantly control the porosity, pore size, water flux, and mechanical properties of MFC networks.
• Casting (CS) and vacuum filtration (VF) methods yield denser networks with higher tensile strength, suitable for structural applications.
• Freeze-drying (FD) creates highly porous structures with high water flux, potentially useful for filtration.
• Surface functionalization of MFC is effective for ferric ion removal, with adsorption influenced by material properties.
• The study demonstrates the versatility of MFC and the importance of processing control for targeted applications.