The new nanocomposites, by means of an in situ sol-gel process consisting of metallocene polyethylene-octene elastomer (POE) and titanium tetraisopropylate (TTIP), were investigated. In addition, the acrylic acid grafted POE (POE-g-AA) was studied as an alternative to POE. Fourier transform infrared (FTIR) spectroscopy, a dynamic mechanical analyzer (DMA) spectrometer, an X-ray diffractometer (XRD), differential scanning calorimetry (DSC), a thermogravimetric analyzer (TGA), an Instron mechanical tester, and a scanning electron microscope (SEM) were used to characterize and examine the samples. The results indicate that the POE-g-AA/TiO2 hybrid could have a positive effect on the properties of the POE/TiO2 hybrid because the carboxylic acid groups of acrylic acid should act as coordination sites for the titania phase to form a Ti-O-C chemical bond. The strength of interfacial bonding between the polymer chains and the ceramic phase depended on the amount of TiO2, as shown by the change in glass-transition temperature (T-g) with TiO2 content. The result of mechanical and thermal tests showed that both the tensile strength and the T-g increased to a maximum value and then decreased with an increasing of TiO2 because excess particles (e.g., greater than 10 wt % TiO2) might cause separation or segregation between the organic and inorganic phases. (C) 2004 Wiley Periodicals, Inc.