Characterization and experimental modeling of rockwool, hot-sprayed polyurea, and casted polyurea as thermal insulation for heat mitigation in landfill liner

• Rockwool, HSP, and CP show potential as thermal insulation in MSW landfills. • Rockwool excels in thermal properties even under elevated temperatures. • HSP and CP offer superior durability with minimal defects and high resistance. • Rockwool has highest thermal stability, reducing the highest ET on the CCL surface. • HSP achieves the lowest final temperatures in deeper CCL of landfill model. The growing amount of municipal solid waste (MSW) calls for the development of sustainable landfill systems, including thermally efficient liners to mitigate the negative effects of elevated temperatures. While rockwool is a well-established thermal insulation material, its applicability in landfill liners requires further investigation. Novel insulation materials, hot-sprayed polyurea (HSP) and casted polyurea (CP), remain underexplored despite their potential. These materials align with circular economy principles, with rockwool derived from recycled industrial by-products, while both HSP and CP are prepared as coating films using reprocessed plastics, with HSP produced via hot spraying and CP through casting techniques. This study evaluates the thermal performance, durability, and structural properties of these materials through comprehensive thermal, physical, chemical, and mechanical characterizations. Thermal stability was analyzed using thermogravimetric analysis (TGA), and structural integrity was examined with scanning electron microscopy (SEM), while chemical composition was assessed via Fourier transform infrared spectroscopy (FTIR). A laboratory-scale landfill liner model simulated real-world conditions under elevated temperatures. Results show rockwool excels in thermal properties, reducing landfill temperatures from 40 °C to 28.5 °C and demonstrates stable thermal properties under elevated temperatures. However, HSP provides superior water and chemical resistance, with more effective insulation and heat dispersion in deeper layer of the landfill model. Meanwhile CP exhibiting moderate insulating performance but most resistant to puncture force. This research contributes to sustainable thermal management in MSW landfill systems for enhanced environmental resilience.