Positional assembly of hybrid polyurethane nanocomposites via incorporation of inorganic building blocks into organic polymer

Polyurethane (PU)/silica nanocomposites (PSNs) were synthesized using the "grafting from" technique by incorporation of inorganic nano-sized silica building blocks into a polyurethane matrix. Structurally well-dispersed and stable hybrids were obtained via a two-step functionalized reaction. Firstly, 3-aminopropyltriethoxysilane (APTS) was employed to encapsulate silica as the core surface. Secondly, the PU shell was tethered to the silica core surface via surface functionalization. In order to obtain complete encapsulation of silica with APTS, different ratios of APTS to silica were investigated. The mechanism of the incorporation process was also revealed. PSNs hybrids were characterized by attenuated total reflectance and Fourier transform infrared spectroscopies, differential scanning calorimetry, thermogravimetric analysis, and transmission electron microscopy.