Carbon dioxide plasticization of thin glassy polymer films

Abstract We have demonstrated in previous studies that thin glassy polymer films exhibit complex responses to highly sorbing penetrants, such as CO 2 , relative to their thick film counterparts. In this paper, we apply similar experiments to two new polymers, including a polysulfone made from bisphenol A (PSF), and poly(2,6-dimethyl-1,4-phenylene oxide) (PPO), and compare their responses to Matrimid ® to understand better CO 2 plasticization behavior of these materials when in thin film form. As expected, the extent of plasticization response tracks with CO 2 solubility; CO 2 diffusivity may also be an important factor at shorter exposure times. Experiments at longer CO 2 exposure times revealed that each polymer experiences the permeability maximum observed in our previous work as well. However, polymers that are not as highly sorbing to CO 2 , like polysulfone, may not at some conditions exhibit a distinct permeability maximum but will still decrease in permeability after a long period of CO 2 exposure owing to physical aging.