Application of poly(phthalazinone ether sulfone ketone)s to gas membrane separation

A series of poly(phthalazinone ether sulfone ketone) (PPESK) copolymers containing different component ratios of bis(4-fluorodiphenyl) ketone and bis(4-chlorodiphenyl)sulfone with respect to a certain amount of 4-(4-hydroxyphenyl)-2,3-phthalazin-1-one were synthesized by polycondensation. Glass transition temperatures of these polymers were adjusted from 263°C to 305°C by changing the ratios of reactants. Gas permeability and selectivity of the dense membranes of the polymers for three kinds of gases (CO2, O2, and N2) were determined at different temperatures. The result indicated that the membrane of PPESK (S/K = 1/1, mol ratio) had an excellent gas separation property. Permeability of the polymer membranes for CO2, O2, and N2 was P = 4.121 barrier, P = 0.674 barrier, and P = 0.0891 barrier, respectively. Separation factors of α and α were 7.6 and 46, respectively. New material was made into a composite membrane with silicone rubber for blocking up leaks and defects on the surface of its nonsymmetrical membrane. As a result of the test, permeability of the composite membrane was J = 7.2 × 10−6 cm3 (STP) cm−2 S−1 cm−1 Hg and J = 0.99 × 10−6 cm3 (STP) cm−2 S−1 cm−1 Hg, whereas the α was still higher than 7. These showed that PPESKs had a bright prospect as the potential membrane material for high-temperature gas separation. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2385–2390, 1999