Calorimetric/PVT Investigations of the Interactions in Polymer/Gas Systems under High Pressures

Materials selection is usually made according to their thermophysical and structural properties. To provide a useful guide to the utilization of materials in a given set of conditions (temperature T, pressure P and pressurizing conditions), PVT-Controlled scanning calorimetry named scanning transitiometry permits to well document phase diagrams. The type and extent of {polymer/gas} interactions as well as thermophysical properties are obtained from thermal and mechanical measurements resulting from the methodology controlling precisely the temperature and pressure. Scanning transitiometry permits to scan one of the independent variables (P, V, or T) while the other independent variable is kept constant. Simultaneous change of the dependent variable is recorded together with the associated thermal effect. The effect of pressure on the thermophysical properties, especially using carbon dioxide as a pressurizing fluid, is investigated along two types of runs. Pressure-Controlled Scanning Calorimetry (PCSC) run is employed to determine the global cubic thermal expansion coefficients ‡ of semicrystalline polymers in interaction with a fluid. Temperature-Controlled Scanning Calorimetry (TCSC) run is employed to investigate the isotropic transitions of amphiphilic liquid crystalline di-block copolymers under a pressurizing fluid. These polymers play an essential role as regards the safety of transport of petroleum products and are promising candidates as templates for microelectronics and biotechnology.