Multiwalled carbon nanotubes (MWNTs) grafted with poly(methyl methacrylate) (PMMA) were synthesized by emulsion reactions and used as a reinforcement for commercial PMMA. Both scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that the applied tensile load on the Composites was transferred to the PMMA-grafted MWNTs, leading to a strain failure of the MWNTs rather than an adhesive failure between the MWNTs and the matrix. Dynamic mechanical analysis (DMA) data showed that the storage modulus at 20degreesC of the PMMA composite containing 20 wt.-% of the PMMA-grafted MWNTs was significantly enhanced by similar to29 GPa (or by similar to1100%) as compared with commercial PMMA.