Using the Inverse Gas Chromatography Method (IGC), the morphology, surface energy, degree of crystallinity and the thermodynamics of 27 solutes with blends of amylopectin (AP) and poly (3-hydroxybutyric acid) (PHBA) were investigated at a range of 80-120 °C. The strength of the interactions of three compositions of AP-PHBA blends was investigated. The effect of the chemical nature of solutes on the thermodynamic quantities was eliminated. The effect of various compositions of the blend on these quantities was also explored. Retention diagrams of semi-crystalline AP blended with amorphous PHBA enabled the estimation of the melting temperature, T_m, of AP in the blend. IGC showed a modest affinity of AP, as a host, to PHBA as a diluent polymer. This observation was complemented by the degree of crystallinity and the dispersive component of surface energy. The degree of crystallinity was significantly reduced when AP was blended with three weight fractions of PHBA, which led to a depression in AP’s T_m values. This was complemented by the dispersive component of the surface energy of AP, it was reduced by the blending process.