In a circular economy-driven innovation, researchers are transforming spent coffee grounds (SCGs) into biochar, providing a novel solution to enhance the fire retardancy of epoxy nanocomposites. This approach not only repurposes waste but also delivers superior mechanical and thermal performance in industrial applications.

Coffee biochar (CB) is produced through pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More and integrated with a silicon-modified epoxy resin. The study demonstrates that CB, combined with ammonium polyphosphate (APP) and a ternary metal oxide (Si-Ti-Mg), significantly improves the flame retardant properties of the epoxy resin. The hybrid material containing 20% CB and 1% phosphorus achieves a UL 94-V-0 classification, meaning it is self-extinguishing and does not drip when exposed to flames. This formulation also reduces the peak heat release rate (pHRR) by 65%, alongside a 15% improvement in flexural modulus, indicating enhanced stiffness.

Key to the material’s success is the formation of a protective, graphitic ceramic char during combustion, which acts as a thermal shield, slowing the release of heat and limiting smoke production. This method leverages the acidic and basic characteristics of the fillers, promoting carbonization and further enhancing fire resistance.

This sustainable approach highlights the potential of biowaste-derived materials in developing eco-friendly, high-performance flame retardants for epoxy resins, offering both environmental and industrial benefits.