Gas sorption and transport in poly(alkyl (meth)acrylate)s. I. Permeation properties

The gas permeability of poly(alkyl acrylate)s was measured as a function of temperature in both the amorphous and crystalline states. Penetrant permea bility in the amorphous state increases as the side-chain length becomes lo nger but shows mixed trends in the crystalline state. A decrease in permeab ility was observed in the amorphous state when the backbone was stiffened, i.e. polymethacrylate versus polyacrylate. The influence of side-chain leng th and backbone stiffness on the magnitude of the change in permeability up on traversing the melting point, or permeability switch, is discussed. The effect of main versus side-chain crystallinity on the permeation switch is analyzed. The influence of a compositional change in the amorphous phase up on melting on the gas permeability of side-chain crystalline polymers is ad dressed. (C) 2001 Elsevier Science Ltd. All rights reserved.