We have synthesized a polyhedral oligomeric silisesquioxane (POSS) derivative containing eight acetoxystyryl functional groups [octa(acetoxystyryl)octasilsesquioxane (AS-POSS)] and then blended it with phenolic resin to form nanocomposites stabilized through hydrogen bonding interactions between the phenolic resin's hydroxyl group and the AS-POSS derivative's carbonyl and siloxane groups. One-and two-dimensional infrared spectroscopy analyses provided positive evidence for these types of hydrogen bonding interactions. In addition, we calculated the interassociation equilibrium constant, based on the Painter-Coleman association model (PCAM), between phenolic resin and POSS indirectly from the fraction of hydrogen-bonded carbonyl groups; quantitative analyses indicate that the hydroxyl-siloxane interassociation from the PCAM is entirely consistent with the classical Coggesthall and Saier (C and S) methodology. From a thermal analysis, we observed that the miscibility between phenolic and AS-POSS occurs at a relatively low AS-POSS content, which characterizes this mixture as a polymer nanocomposite system. (c) 2006 Wiley Periodicals, Inc.