THERMODYNAMICS OF POLYMER DILUENT SYSTEMS FOR THERMALLY INDUCED PHASE-SEPARATION .3. LIQUID LIQUID-PHASE SEPARATION SYSTEMS

Thermodynamic analysis of the system isotactic polypropylene/n,n-bis(2-hydroxyethyl) tallowamine was performed using Flory's equation of state theory adapted to the polymer/oligomer system using parameters determined in the first paper in this series. The estimated results were in good agreement with those from melting temperature depression and cloud point measurements. The equilibrium phase diagram was estimated even in the experimentally unavailable region. When the estimated phase diagram could be compared with the experimental data, the agreement was good. The interaction parameter for this system increased greatly with temperature resulting in upper critical solution temperature behaviour. The increased end group polarity of n,n-bis(2-hydroxyethyl) tallowamine resulted in much greater enthalpic interactions than the n-alkane and n-fatty acid systems covered in the second paper in this series.