Rod-like mesoporous SBA-15 silica particles were surface modified by different silane coupling agents firstly, then polymethyl methacrylate (PMMA) was prepared in the confined nanopores of the SBA-15 via activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP). The PMMA/SBA-15 nanocomposites and PMMAs inside the nanopores were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption measurements, gel permeation chromatography (GPC), fourier transform infrared spectroscopy (FT-IR), thermogravimetry analysis (TGA), proton magnetic resonance (H-1 NMR), and differential scanning calorimetry (DSC), respectively. The results demonstrated that the nanopores of SBA-15 could serve as nanoreactors and had great confinement effects on the MMA polymerization. The morphology of PMMAs obtained in the channels was similar to that of intrinsic structure of SBA-15. The thermal stability, molecular weights, isotacticity of PMMAs inside the pores were all increased significantly compared to the conventional PMMA by ARGET ATRP, while broadened the polydispersity index (PDI) values and reduced the syndiotacticity. (C) 2017 Elsevier Ltd. All rights reserved.