Influence of filler surface characteristics on morphological, physical, acoustic properties of polyurethane composite foams filled with inorganic fillers

In modern automobiles, noise pollution is a critical issue, and polyurethane foam is commonly used due to its high sound absorption and ease of production. In this study, polyurethane composite foams were fabricated using inorganic fillers (Talc, Zinc Borate, and Aluminum Hydroxide), and the morphological and physical properties were assessed. The cavity and pore sizes of composite foams with hydrophobic fillers were smaller than those of foams with hydrophilic fillers due to differences in the cell collapsing phenomena. This difference in the surface properties of the filler also significantly affects the physical strength of the composite materials, and it is further related to the sound absorption efficiency of the foams. This sound absorption coefficient revealed the same trend with the loss modulus reflecting a measure of the dissipated energy between the polymer chains and fillers through microstructural deformations.