HIGH-PRESSURE FTIR STUDIES OF GAS POLYMER INTERACTIONS

FTIR spectra of cellulose acetate (CA) and poly(methyl methacrylate) (PMMA) at 35°C have been obtained as a function of carbon dioxide pressure at pressures up to 55 atm in a specially designed FTIR cell. Results indicate that the carbonyl stretching vibrations for CA (1752 cm−1) and PMMA (1731 cm−1) shift to slightly higher wave numbers with increasing pressure. The small shifts suggest dipole–dipole interactions between CO2 and the carbonyl group. In both cases, the shift appears to be linear with pressure. This linearity is interpreted in the framework of the dualmode theory to suggest that gas–polymer interactions occur in the Henry's law dissolution mode. Copyright © 1990 John Wiley & Sons, Inc.