Abstract
It is well-known that liquid ethanol at ambient conditions is a nonsolvent for polystyrene (PS). Surprisingly, the supercritical (SC) CO 2 /ethanol mixture is able to solvate PS, allowing the use of such media to perform fractionation of PS. 1 The first part of this work is devoted to the determination of the solubility of PS in the SC CO 2 /ethanol solution and to assess the selectivity of the mixture using UV spectroscopy. The second part concerns an infrared absorption and Raman scattering study aimed at the understanding of the microscopic interactions involved in this system. We have performed measurements on CO 2 /ethanol mixtures at various compositions (weight % of ethanol = 10, 30, and 42) in the temperature range 333-423 K and at pressures ranging from P = 15 up to 35 MPa. Several species were found to coexist, namely, ethanol aggregates and monomers. In addition, evidence of a weak interaction between CO 2 and ethanol was found. Finally, monomeric ethanol is likely to be responsible for the PS solvation in the SC CO 2 /ethanol mixture.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
