Solubility of pressurised carbon dioxide in three different polydimethylsiloxanes

Abstract We present an experimental investigation into the binary phase behaviour of carbon dioxide and three different linear polydimethylsiloxanes (PDMS) with molecular weights of 4800 g/mol, 11000 g/mol and 18000 g/mol. Experiments were carried out at 25 °C, 40 °C and 60 °C and at pressures of up to 30 MPa. Solubilities were measured with the help of a high pressure view cell using two different techniques, the observation of cloud points, and a static analytic method based on sampling under phase equilibrium conditions. Rather low molecular weight polydimethylsiloxanes were chosen to close the existing data gap regarding the behaviour of these compounds with carbon dioxide. All experiments in the present work were carried out under isothermal conditions. Hence, diagrams of the p- x type are used for displaying the measured data at constant temperatures.