Studies of ReCrete: A polyurethane foam
Polyurethane foam is often molded directly in place as a thermal or vibration insulator, energy absorbing material, or core material for a sandwich structure. A smooth thin skin forms between the mold and the interior cellular structure of the foam. A non-uniform microstructure is often visible when foam cross-sections are examined, resulting in density variations throughout the foam and the resulting mechanical property variations. This study investigates the effect of mold temperature and mold size on the average density and some of the resulting mechanical and thermal properties for a polyurethane foam system molded in aluminum cylinders and boxes. Resulting properties are also compared to more uniform foam samples cored out from larger molds. It is shown that the molding process, temperature, and size have a significant effect on the foam density. The density, in turn, affects the quasi-static and dynamic mechanical properties, as well as thermal and chemical properties.