The pressure-volume-temperature (PVT) dependencies of commercial polypropylene melt (PP) and its nanocomposites containing X wt% of organoclay (Cloisite-15A, or C15) and 2X wt% of a compatibilizer were determined at T = 450-530 K and P = 0.1-190 MPa. C15 was used at concentrations: X = 0, 2, and 4 wt%. Three functionalized PP's were used as compatibilizers: two maleated and one grafted with glycidyl methacrylate. Incorporation of X = 2 wt% C 15 into PP resulted in reduction of specific volume by DeltaV approximate to 1%, but that of free volume (hole) fraction by Deltah approximate to 5%. The latter quantity was computed from the Simha-Somcynsky lattice-hole equation of state. Furthermore, at constant T and P the hole fraction was found to be linearly related to the bulk-average energetic interaction parameter and to be a sensitive indicator of structural changes. In binary (polymer + organoclay) systems Deltah is linearly related to the interlayer spacing, d(001). So, where statements from the previous paper are repeated or there are similarities, this is done for purposes of comparison. In three-component systems (with a compatibilizer) the proportionality has been preserved, but large changes of Deltah result in relatively small changes of d(001). Mechanical properties hardly correlate with either Deltah or d(001), as polymer/compatibilizer morphology and crystallinity complicate the behavior.