Cr/SBA-15 catalysts were prepared by the grafting of chromium nitrate nonahydrate [Cr(NO3)(3)center dot 9H(2)O] complexes onto SBA-15 mesoporous materials. Shish-kebab and nanofiber polyethylenes (PEs) were prepared under different temperatures via ethylene extrusion polymerization with the Cr(NO3)(3)center dot 9H(2)O catalytic system. The diameter of a single nanofiber was 100-250 nm. Scanning electron microscopy images showed that the polymer obtained from the SBA-15-supported catalyst under different polymerization temperatures produced nanofiber and/or shish-kebab morphologies. X-ray diffraction and differential scanning calorimetry were used to characterize microstructures of the materials. Polymers obtained with all of the catalysts showed a melting temperature, bulk density, and high load melt index; this indicated the formation of linear high-density PE. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 3658-3665, 2010