Infrared cell for supercritical fluid–polymer interactions

Abstract

A novel high pressure cell for Fourier transform infrared studies of extraction, impregnation, partitioning, and interactions between supercritical fluids and polymers is presented. Two parallel optical paths through the cell permit the measurement of IR spectra of the supercritical fluid and the polymer sample under the same conditions without essential overlapping of the absorption bands studied. This cell has been applied to study the supercritical CO2 drying of poly(methyl methacrylate) using deuterated water to eliminate the overlap of the IR absorption bands of the stretching modes of water with the bands due to combination modes of CO2. The technique for attaining quantitative measurements of the partitioning of the solute between the supercritical fluid and polymer phases is described.