Polypropylene solutions were prepared using three solvents: paraffin oil, decalin, and a novel solvent-camphene. The effects of these solvents were evaluated based on the activation energy of flow and on their melting-point depression. Experimental results indicate that the values of the viscosity of the resulting solutions were close to Newtonian behavior in the shear rates below 34 s(-1). The Arrhenius-Frenkel-Eyring equation was used to describe the dependence of the viscosity on the temperature. In addition, the viscosity increased with the polymer concentration, which can be described by a power-law correlation. The activation energy of the flow of the polypropylene/camphene solution was the lowest and that of the paraffin oil solution was the highest. Correspondingly, the melting-point depression of polypropylene solutions in camphene and decalin were substantially lower than that in paraffin oil (71, 61, and 33 degrees C, respectively). These results indicate that lower activation energies of flow correspond to higher values of melting-point depression. Moreover, analysis of variance indicated that the primary factor affecting the viscous behavior is the concentration, followed by the solvent and the temperature.