Modification of polyethylene-octene elastomer by silica through a sol-gel process

In this study, tetraethoxysilane (TEOS) and a metallocene polyethylene-octene elastomer (POE) were chosen as the ceramic precursor and the continuous phase, respectively, for the preparation of new hybrids by an in situ sol-gel process. To obtain a better hybrid, a maleic anhydride-grafted polyethylene-octene elastomer (POE-g-MAH), used as the continuous phase, was also investigated. Characterizations of POE-g-MAH/SiO2 and POE/SiO2 hybrids were performed by Fourier transform infrared (FTIR) and Si-29 solid-state nuclear magnetic resonance (NMR) spectrometers, a differential scanning calorimeter (DSC), a thermogravimetry analyzer, and an Instron mechanical tester. The results showed that the POE-g-MAH/SiO2 hybrid could improve the properties of the POE/SiO2 hybrid because the interfacial force between the polymer matrix and the silica network was changed from hydrogen bonds into covalent Si-O-C bonds through dehydration of hydroxy groups in POE-g-MAH with residual silanol groups in the silica network. The existence of covalent Si-O-C bonds was proved by FTIR spectra. For the POE/SiO2 and POE-g-MAH/SiO2 hybrids, maximum values of the tensile strength and the glass transition temperature were found at 9 wt % SiO2 since a limited content of silica might be linked with the polymer chains through the covalent bond. (C) 2003 Wiley Periodicals, Inc.