POSS (polyhedral oligomeric silsesquioxanes) are hybrid caged molecules closely related to silicones, with a chemical structure (RSiO1.5) consisting of an inorganic core (SiO1.5) and organic side groups (R). As a result of this structure, POSS can be incorporated into polymer systems in a number of ways including blending, grafting and copolymerization. When blended into and confined within multilayered polymer films, which can contain up to thousands of individual layers, significant deviations from bulk behavior occurs. This study investigates the structure-property relationships of two POSS-polymer systems within such multilayered film structures. A series of isotactic polypropylene and nylon 6 blends with POSS additives were produced, and then layered to nanometer thicknesses to test the effects of confinement upon polymer property modification. Under a high degree of layered confinement, limited enhancements to the film’s mechanical properties have been observed for a precise concentration of POSS within the system. It has been shown, however, that outside of this critical concentration, POSS is a structurally ineffective filler, lacking solubility and favorable interaction with the polymer matrices, and resulting in the formation of large, phase separated aggregates, in order to minimize interactions with the matrix. The following work investigates this critical POSS concentration in highly confined 2D film layers, and aims to reveal how POSS interacts under such conditions. By utilizing and comparing systems in which the POSS molecules are able to directly and indirectly interact with the polymer matrix, we can reach general conclusions into the behaviors of POSS within these systems.