Coreshell nanoparticles chemically functionalized by hindered amine stabilizer (HAS), poly(BA-MMA-co-PMPA) (PBMP), were prepared by two-stage emulsion polymerization from butyl acrylate, methyl methacrylate, and 1,2,2,6,6-pentamethylpiperidin-4-yl acrylate. The incorporation of HAS into the particles was confirmed by nuclear magnetic resonance (1H-NMR) and the coreshell microstructure of PBMP particles was revealed by transmission electron microscopy. Furthermore, PBMP capable of one-step toughening and photostabilizing, was melt-blended with polyoxymethylene (POM), and its dispersion in POM was investigated by scanning electron microscope. The results showed that the coreshell nanoparticles could be well dispersed in POM matrix, indicating its good compatibility with POM. The UV resistance and impact resistance of POM were obviously improved by the HAS-functional coreshell nanoparticles simultaneously. In addition, the coreshell nanoparticles could confer excellent protection to the surface of POM from UV-light damage, regardless of the adverse effects on the thermal-oxidative stability of POM, as investigated by thermogravimetry analysis under aerobic condition. (c) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012