A novel polyhedral oligomeric octa(propargylaminophenyl)silsesquioxane (OPAPS, (SiO1.5C6H4NHCH2C?CH)8) was prepared from octa(aminophenyl)silsesquioxane and propargyl bromide. The chemical structure of OPAPS was characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance, X-ray diffraction (XRD), high-performance liquid chromatography, gel permeation chromatography, differential scanning calorimetry, and thermal gravimetric analysis (TGA). The structure of the thermally cured polymer of OPAPS was characterized by FTIR, XRD, and TGA. It had good thermal stability. TGA demonstrated that the thermal decomposition temperatures (Td5) of the cured OPAPS polymer in nitrogen and air were 455.6 and 458.8 degrees C, respectively. The thermal curing reaction kinetics of OPAPS were studied and some kinetic parameters were obtained. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012