Polymer Solvent Diffusion and Equilibrium Parameters by Capillary Column Inverse Gas Chromatography
Inverse Gas Chromatography (IGC) is used to measure the polymer solvent diffusion and equilibrium parameters under conditions of infinitely dilute solvent. A capillary column with a five micron thick uniform annular coating of polymer was used instead of the conventional packed column. A pulse of the volatile compound was injected into a column which was at constant temperature. Measurements of toluene in poly(vinyl acetate) were taken at temperatures of 80°C and 40°C. The elution profiles were then analyzed using the CCIGC model to determine the diffusion coefficient and the equilibrium constant. The data at finite dilution were compared to data taken by other methods of finite concentrations using predictive models. A prototype poly(vinyl alcohol) column was prepared by an outside company. Calculations using the CCIGC model were not possible because of varying polymer thickness. Peaks were recorded for water in poly(vinyl alcohol) at 100°C, 80°C, 60°C. 42°C as well as methanol and methyl acetate at 100°C. These peaks were compared to support the belief that PVOH was in the column.