Lignocellulose, found in wood and many plants, can be collected and chemically modified to improve its properties. Using these chemical changes allows the researchers to create advanced materials and new ways to build sustainably. Collaborators include the University of Miami and Oak Ridge National Laboratory. The team proved that adding extremely hard minerals at the nanoscale could make the walls of wood cells stronger – without making the wood heavy, expensive, or bad for the environment.
Ring-Porous Wood: Focus on Oak, Maple, and Walnut Trees
The team focused on a type of hardwood known as ring-porous wood, which comes from oak, maple, and walnut trees. Researchers used red oak and introduced an iron compound into the wood through a simple chemical reaction. By mixing ferric nitrate with potassium hydroxide, they created ferrihydrite, an iron oxide mineral commonly found in soil and water.
Enhancing Wood Durability Without Increasing Weight
Although the internal structure became more durable, the wood’s overall behaviour – such as how it bends or breaks – remained largely unchanged. This is likely because the treatment weakened the connections between individual wood cells, affecting how the material holds together on a larger scale.
Strengthening Plant-Based Materials Without Environmental Harm
The researchers found that it is possible to enhance the strength of wood and other plant-based materials without increasing their weight or harming the environment. “Wood, like many natural materials, has a complex structure with different layers and features at varying scales. To truly understand how wood bears loads and eventually fails, it’s essential to examine it across these different levels,” said Vivian Merk, senior author and an assistant professor in the FAU Department of Ocean and Mechanical Engineering, the FAU Department of Biomedical Engineering, and the FAU Department of Chemistry and Biochemistry within the Charles E. Schmidt College of Science. “To test our hypothesis – that adding tiny mineral crystals to the cell walls would strengthen them – we employed several types of mechanical testing at both the nanoscale and the macroscopic scale.”
Using Advanced Tools for Nanoscale Testing
Researchers used advanced tools like atomic force microscopy (AFM) to examine the wood at a very small scale, allowing them to measure properties such as stiffness and elasticity. They used AM-FM (Amplitude Modulation – Frequency Modulation), which vibrates the AFM tip at two different frequencies. One frequency generates detailed surface images, while the other measures the material’s elasticity and stickiness. This method gave them a precise view of how the wood’s cell walls were altered after being treated with minerals.
Additionally, the team conducted nanoindentation tests within a scanning electron microscope (SEM), where tiny probes were pressed into the wood to measure its response to force in different areas. To round out their analysis, they performed standard mechanical tests – such as bending both untreated and treated wood samples – to evaluate their overall strength and how they broke under stress.
Impact of Research on Sustainable Building Materials
“This research marks a significant advancement in sustainable materials science and a meaningful stride toward eco-friendly construction and design,” said Stella Batalama, the dean of the College of Engineering and Computer Science. “By reinforcing natural wood through environmentally conscious and cost-effective methods, our researchers are laying the groundwork for a new generation of bio-based materials that have the potential to replace traditional materials like steel and concrete in structural applications. The impact of this work reaches far beyond the field of engineering – it contributes to global efforts to reduce carbon emissions, cut down on waste, and embrace sustainable, nature-inspired solutions for everything from buildings to large-scale infrastructure.”
