ISOMERIC POLY(ETHER IMIDE)S - SYNTHESIS, THERMAL-PROPERTIES AND PERMEABILITIES

This paper describes the synthesis of a novel series of poly(ether imide)s formed as isomeric pairs of polymers by interchanging the diol and diamine derived units. The polymers contained units having flexible and stiff hinges and groups to hinder segmental rotation. Most Polymers were soluble in a variety of solvents, which allowed them to be characterized and cast into membranes. Permeabilities to carbon dioxide and methane and glass transition temperatures were determined. Consideration of structure-property relations showed the properties of the polymers to be sensitive to the position of the structural units within the polymer. The polymers showed a linear relationship between permeabilities to the two gases. There was a strong trend between high permeability and high glass transition temperature, suggesting that rigid polymers incapable of inefficient packing lead to highly permeable membranes and that such factors were enhanced by the presence of bulky substituents.