The present contribution reports a novel strategy to prepare polypropylene (PP)-based nanocomposites with highly dispersed noble metal nanoparticles (NPs), which includes the impregnation of a metal salt inside the porosity of PP reactor granule and subsequent in-situ generation of the NPs therein. Thus formed nanoparticles were confined and retained in the porosity, thus minimizing the sintering and leaching of the NPs during melt processing. The so-called reactor granule technology was applied to successfully prepare PP-based nanocomposites with Ag and Au NPs, and unique nonlinear optical properties and the antibacterial ability of the PP/Ag nanocomposites were demonstrated. (C) 2017 Elsevier Ltd. All rights reserved.