Can a naturally occurring clay mineral improve the strength and heat resistance of plant-based foam materials?
This study investigates how different concentrations of kaolin filler affect the mechanical, thermal, and structural properties of rigid furanโlignin bio-based foams.
The foams were produced using furfuryl alcohol and a lignin-based polyol derived from coconut shell, with kaolin added at concentrations ranging from 0 to 2.5 g. Six formulations, identified as KF1โKF6, were evaluated.
The researchers used density measurements, compression testing, Fourier-transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and derivative thermogravimetry to assess the foams.
The results showed that foam performance did not increase continuously with kaolin content. Instead, an optimum filler concentration was observed.
KF4, containing 1.5 g of kaolin, achieved the best overall performance. It recorded the highest density of 0.256 g/cmยณ and the greatest compressive stress of 26.63 MPa, substantially outperforming the other formulations.
The same formulation also displayed the strongest thermal resistance, with degradation delayed to approximately 588.39 ยฐC during the final decomposition stage. It retained 19.48% residue at 863 ยฐC, indicating strong char-forming and heat-barrier properties.
Microscopic analysis showed that KF4 had a more uniform and refined open-cell structure, with cell sizes ranging from 40 to 90 ยตm. Its well-dispersed kaolin particles strengthened the foam walls, improved stress transfer, and limited heat and volatile movement through the material.
Lower kaolin concentrations did not provide sufficient reinforcement, while higher concentrations caused particle clustering, structural irregularities, and reduced mechanical performance.
The findings demonstrate that carefully controlled kaolin loading can significantly improve the strength and thermal stability of renewable furanโlignin foams.
These bio-based materials may be suitable for applications requiring rigid, heat-resistant, and load-bearing foams, including protective packaging, automotive components, impact-energy absorption, and thermal insulation.
๐ Read the full article here:
https://doi.org/10.46481/jnsps.2026.3355
Published in: Journal of the Nigerian Society of Physical Sciences