A coreshell polyacrylate elastomer containing ultraviolet (UV) stabilizer was synthesized via semicontinuous seeded emulsion polymerization from butyl acrylate (BA), methyl methacrylate (MMA), and a polymerizable UV stabilizer 2-hydroxy-4-(3-methacryloxy-2-hydroxylproroxy)benzophenone (BPMA). The coreshell poly(MMA-BA-BPMA) was investigated by Fourier transform infrared spectroscopy, gel permeation chromatography UVvisible (UVvis) absorption spectroscopy, and transmission electron microscope. Furthermore, the obtained coreshell poly(MMA-BA-BPMA) elastomer was used as a modifier to enhance the UV resistance and impact resistance of polyoxymethylene (POM). As studied by scanning electron microscope, the coreshell poly(BA-MMA-BPMA) elastomer could be well dispersed in POM matrix, indicating that the elastomer had good compatibility with POM. In addition, the POM/poly(MMA-BA-BPMA) blend was examined by differential scanning calorimetry before and after UV irradiation. The results showed that the melting point decreased as the irradiation time increased; however, the crystallinity culminated at 500-h UV irradiation slightly decreased and at last leveled off. The mechanical properties of POM/poly(BA-MMA-BPMA) before and after UV irradiation were also studied. It revealed that the photostabilizing fragments in the elastomer could provide long-term UV resistance to POM. Besides, the impact strength was also improved when compared with pure POM. POLYM. ENG. SCI., 2012.(C) 2012 Society of Plastics Engineers