Development of composite polyurethane foam with waste stone wool

In this study, the effects of incorporating waste stone wool into polyurethane-based rigid foam systems used in sandwich panel applications were experimentally investigated with respect to mechanical and thermal properties. The aim of the study was to evaluate the potential use of waste stone wool in polyurethane foams in order to enhance environmental sustainability and to contribute to the development of alternative composite core materials. For this purpose, composite polyurethane foam specimens containing different amounts of waste stone wool (0.5%, 1%, 2%, 4%, and 6%) were prepared and compared with a reference polyurethane foam system. Compressive strength, tensile strength, and thermal conductivity tests were conducted in accordance with relevant standards. In addition, the effects of stone wool addition on the cellular structure of the foams were qualitatively examined using optical microscopy. The experimental results indicated that the mechanical and thermal performance of the polyurethane foams was strongly dependent on the waste stone wool content. At low and moderate addition levels (0.5 - 2%), the cellular structure of the foams was largely preserved, and the mechanical properties remained balanced when compared to the reference foam. In contrast, higher stone wool contents (4% and 6%) led to noticeable deterioration in the cellular structure, resulting in reduced mechanical strength and increased thermal conductivity. Overall, the findings demonstrate that waste stone wool can be effectively incorporated into polyurethane foam systems up to a certain content, with stone wool additions in the range of 1 - 2% providing an optimal balance between mechanical performance and thermal insulation properties. These results highlight the potential of waste stone wool as a sustainable filler material for polyurethane-based composite foam applications.