Hybrid polymer composites incorporating preformed ZnO alone or its mixture with Ag nanoparticles created during UV irradiation of some urethane acrylic monomers including trietoxysilylpropyl carbamoyloxyethyl methacrylate were synthesized and characterized by spectroscopic (H-1(C-13) NMR, FTIR, UV-vis, fluorescence, X-ray diffraction) and microscopic (AFM, ESEM/EDX, TEM) techniques. The results confirmed that the double bond conversion measured through FTIR spectroscopy varied in the range of 57-90% (after 60s of irradiation), exhibiting formulation composition dependence. In the crosslinked polymer networks the existence of individual nanoparticles with primarily spherical shape and sizes between 5 and 15 nm for ZnO, and around 3 nm for in situ photogenerated silver nanoparticles was evidenced. Additionally, the photocatalytic effect of the photopolymerized hybrid films was investigated by determining the decomposition rate of the methylene blue (MB) in ethanol (over 90%) under UV (2.7 x 10(-2) s(-1)) and visible irradiation (2.9 x 10(-2) min(-1)). It was found that the composite films containing a higher amount of ZnO-Ag nanoparticles placed in water induced the photodecomposition of MB (similar to 87% after 100 min of visible irradiation; k = 2.1 x 10(-2) min(-1)). The good efficiency of the NPs from these polymer films make them attractive for applications in photocatalysis of organic dye molecules. (C) 2016 Elsevier B.V. All rights reserved.