Freeze drying-driven fabrication of sustainable bio-based foam from bio-polymer

With the increasing need for sustainable materials, the development of biodegradable alternatives to synthetic foams has gained significant attention. Conventional thermal insulation materials such as expanded polystyrene (EPS) and polyurethane foams, though widely used, contribute to environmental pollution due to their non-biodegradability and reliance on petroleum-based resources. In response to these concerns, bio-polymer-based foams have emerged as a promising alternative, offering both thermal insulation efficiency and environmental sustainability. This study presents the successful fabrication and characterization of novel bio-polymer foam using cellulose microcrystalline (CMC) as a renewable and eco-friendly solution. The fabrication process involved a three-stage method: dissolution of CMC, formation of a foamy solution and stabilization of the porous architecture via freeze-drying. The resulting material was comprehensively characterized to evaluate its potential for thermal insulation applications. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) assessed the foam’s thermal stability and energy properties, while scanning electron microscopy (SEM) revealed its microstructural morphology. Fourier transform infrared (FTIR) spectroscopy confirmed the chemical bonding within the foam matrix. Brunauer–Emmett–Teller (BET) surface area and Barrett–Joyner–Halenda (BJH) pore size analyses were performed to investigate the specific surface area, pore volume, and pore size distribution, providing insight into the foam’s highly porous architecture. Furthermore, compression and flexural tests were conducted to evaluate the mechanical integrity of the bio-foam, confirming its ability to withstand compressive and bending loads while maintaining its lightweight porous structure. Thermal conductivity analysis revealed that the CMC bio-foam exhibited a thermal conductivity of 0.15 W/m·K, demonstrating its ability to provide effective thermal resistance while allowing controlled heat transfer. Rather than functioning as a complete thermal barrier, this moderate thermal conductivity makes the bio-foam suitable for applications where a balance between thermal insulation and heat dissipation is desirable. The combined thermal, structural, and mechanical properties indicate that the lightweight and biodegradable CMC bio-foam has significant potential for further material optimization, enabling its use in advanced thermal management systems and sustainable insulation applications that require tailored thermal performance.