Structure–property correlation of polyurethane nanocomposites: Influence of loading and nature of nanosilica and microstructure of hyperbranched polyol



New generation polyurethane nanocomposites based on toluene diisocyanate, poly(propylene glycol), hyperbranched polymers (HBPs), and nanosilica were synthesized with the aim of determining the effect of the loading and nature of nanosilica and the functionality of HBP on the structure and properties of polyurethane nanocomposites. Good dispersion of nanosilica at 4 wt % loading in the polymer was confirmed from atomic force microscopy. The properties of the polyurethane nanocomposites were a function of content and nature of the nanosilica in the matrix. The optimum silica loading was 4 wt %. At this loading, tensile strength and storage modulus at 25°C of the nanocomposites increased by 52 and 40%, respectively over the pristine polyurethane. Organo-treated nanosilica exhibited higher physico-mechanical properties than the untreated one. With the increase of functionality in the hyperbranched polyol, the tensile strength, thermal stability, and dynamic mechanical properties of the nanocomposites improved. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013