An FR-PCM composite was produced for the development of an efficient material for thermal energy storage and fire protection through the incorporation of paraffin wax into a cassava starch-oil palm empty fruit bunch lignin-nano-bentonite-boric acid-based biopolymer-mineral matrix. Characterization of the material was done through FTIR, TGA/DTG, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), XRD, Brunauer–Emmett–Teller (BET) analysis, leakage test, thermal cycling, cone calorimetry, smoke-toxicity screening, mechanical properties assessment, and water uptake analysis. FTIR analysis revealed the presence of the C–H bands associated with paraffin wax as well as hydrogen bonding and borate interactions within the biopolymer-mineral matrix. TGA/DTG revealed the increase in the onset of decomposition from about 180 \(^\circ\)C for pure paraffin to about 245 \(^\circ\)C and the increase in residue at 600 \(^\circ\)C from about 15% for pure paraffin to about 30%. Cone-calorimetry smoke/toxicity screening test demonstrated the enhancement in fire performance attributes, such as the increase in time to ignition from 35 s for pure paraffin to 85 s, decrease in peak heat release rate from 900 to 380 kW m\(^{-2}\) and decrease in fire growth index from 2600 to 900 W s\(^{-1}\). Laboratory flame-spread testing revealed reduction in flame spread rate from 3.50 to 1.36 cm min\(^{-1}\) and increase in ignition delay to 97 s. SEM, EDS, XRD and BET analysis revealed the successful incorporation of biopolymer and mineral materials, maintenance of paraffin crystalline nature, control of mesoporosity and formation of cohesive protective char layer. Leakage and thermal cycling revealed the ability of the matrix to preserve 92% shape retention at 70 \(^\circ\)C and more than 90% latent heat retention after 100 thermal cycles. Mechanical and water-uptake properties assessment revealed improvement in the material structural characteristics together with introduction of mild moisture sensitivity. Overall, the FR-PCM composite provides a practical balance between latent heat storage, thermal transport, shape stability, and fire safety for energy-efficient building applications.
