Polyethylene-octene elastomer/silica hybrids prepared by a sol-gel process using tetraethoxysiliane

Abstract

In this study, new organic-inorganic hybrid composites were prepared by means of an in situ sol-gel process. The polymer used as the continuous phase was the metallocene polyethylene-octene elastomer (POE) or the acrylic acid grafted polyethylene-octene elastomer (POE-g-AA). The silica forming the inorganic phase was produced by the hydrolysis and condensation of tetraethoxysilane (TEOS) in polymers. Characterizations of POE-g-AA/SiO2 and POE/SiO2 hybrids were performed by Fourier transform infrared (FT-IR) spectroscopy, 29Si solid-state nuclear magnetic resonance (NMR) spectrometry, X-ray diffraction (XRD) spectroscopy, differential scanning calorimetry (DSC), thermogravimetry analysis and Instron mechanical tester. We found that the POE-g-AA/SiO2 hybrid could enhance the properties of the POE/SiO2 hybrid, since the interfacial forces of the former are the covalent Si-O-C and hetero-associated hydrogen bonds but the latter only has weaker hydrogen bonds. The result of 29Si solid-state NMR spectra showed that Si atom coordination around SiO4 units is predominantly Q3 and Q4. It was also found that the POE-g-AA/SiO2 hybrid with 9 wt% SiO2 gave the maximum value of tensile strength since excess particles might cause the separation between the organic and inorganic phases when the silica content was beyond this point.