A study of the solubility and diffusion kinetics of CO2 in a polyimide film at various temperatures



A small piece of the film was directly loaded into the IGA-001
system. It was outgassed to high vacuum (<10-6mb) at a
temperature of 60 °C.
The sample was then studied isothermally at 20 °C, 35 °C and
60°C by stepping up the pressure to measure the adsorption
branch then stepping down the pressure to measure the
desorption branch using CO2 as the sorbate.
The IGA method described in Figure 1 was utilised to fit to the
weight relaxation resulting from each of the pressure steps.
The F1 model was utilised during this experiment.
The IGA method predicts the point of equilibrium uptake from
the fit and determines the rate constant of the adsorption k (k=1
/ time constant), it also ensures that each point on the isotherm