Recycled brick red-based boards for thermal insulation: filler to polyurethane composite

This study reported the effects of adding red ceramic waste in the production of composites with PU as a thermal insulator. The composites were characterized for chemical structure by FTIR, morphology by SEM and OM, thermal stability with TGA, and the mechanical properties, water absorption, and thermal conductivity were verified. For this purpose, composites were prepared to contain 10-30% red ceramic residue powder (brick) in the PU matrix and PU without residue. The composites presented similar thermal stability to the PU, and the FTIR bands of the urethane chemical bonds were verified. The microstructure analysis revealed the formation of a porous structure characteristic of the PU system. However, the increase in the residue concentration led to the formation of heterogeneous and open pores in the structure. This characteristic directly influenced the material properties, reducing compressive strength, Yong modulus, and thermal conductivity values and increasing the water absorption value. The thermal conductivity of all composites was lower than for PU, the best thermal insulation result obtained for the PUCER-10 composition. It is suggested that composite boards be prepared to be used as insulators with the incorporation of a certain amount of waste when seeking the environmental sustainability of the construction industry.