Abstract
Nanocomposite flexible polyurethane foams (nFPUfs) were obtained by modifying the polyurethane formulation by adding a halloysite nano-filler in the amount of one to five parts by weight per hundred parts of used polyol (php). Flexible polyurethane (PU) foams with an open-cell structure and with a beneficial SAG factor were obtained. Premixes with nano-filler had a lower reactivity than the reference PU system. This favored the production of smaller cells, but with a more rounded shape in comparison with the REF foam without the nano-filler. During the study, the morphology and physical and mechanical properties were characterized, including apparent density, compressive stress, rebound flexibility, SAG factor, closed-cell content, and thermal stability, and compared with the properties of the unmodified reference foam. Scanning electron microscopy (SEM) showed that the cell structures of all prepared foams were open, and the cell size decreased with increasing nano-filler content. Apparent densities, SAG factors and rebound flexibilities of the foams increased with the increase of nano-filler content, while the resistance to permanent deformation showed the opposite trend. The proper selection of raw materials and optimally developed polyurethane formulations allow for obtaining environmentally friendly foams with favorable functional properties, taking into account price and the needs of sustainable development in the synthesis of flexible foams dedicated to the upholstery industry.