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Homogeneous membranes based on fullerene‐polyphenylene oxide compositions containing up to 2 wt% fullerene C60 were prepared. The effect of fullerene addition on PPO transport properties was studied in gas separation and pervaporation processes. Permeability coefficients of H2, O2, N2, CH4, and CO2 were measured; a correlation between gas transport properties and membrane free volume was established. Pervaporation properties were studied for the system with ethyl acetate synthesis reaction: quaternary system ethanol—acetic acid—water—ethyl acetate and some constituent binary and ternary mixtures. Pervaporation in binary systems, ethanol–water and ethyl acetate–water was considered with the use of the data on sorption capacities and interaction parameters. In pervaporation of a quaternary reacting mixture, the permeate containing essentially ethyl acetate was obtained. Results show that membranes with fullerene additives exhibit improved transport properties.

Three types of imide-containing polyamic acids (polybenzoxazinoneimide prepolymers), namely, a homopolymer, a copolymer, and a polymer–metal complex were synthesized and used for homogeneous membranes preparation. These membranes exhibited good physico-mechanical properties and also chemical and hydrolytical stability. Their gas separation properties were measured and analyzed by correlation with macromolecular packing density. Polybenzoxazinoneimide membranes were prepared by heating prepolymer membranes to 220 °C. Difference between gas separation properties of membranes based on polybenzoxazinoneimides and those of their prepolymers was estimated. Gas transport properties of all novel membranes were compared with those of known membranes by using Robeson's diagram. It was established that a polybenzoxazinoneimide membrane including a polymer–metal complex is the most effective among membranes studied here.

Poly(1,4-phenylene sulfide) was sulfonated with chlorosulfonic acid in 1,2-dichloroethane. The product (IEC = 2.38 mequiv./g) was ground and sieved (mesh size 63 μm) to obtain small particles. The particles and linear polyethylene were mixed in various ratios and the resulting blends were press-molded at 150 °C to obtain the membranes. Membranes containing up to 66 wt.% of sulfonated particles could be prepared without any problem in mechanical strength. The membranes were characterized by their stability in oxidative environment, ionic conductivity, and diffusive permeability to methanol. The membrane containing 66 wt.% of sulfonated particles was almost as conductive as Nafion 117; it exhibited, however, much lower diffusive permeability to methanol. In a strongly oxidative environment (3% aqueous H2O2 at 70 °C), the prepared membranes were less stable than Nafion 117, but much more stable than membranes with sulfonated poly(styrene-co-divinylbenzene) particles. In preliminary laboratory tests with H2/O2 and direct methanol fuel cells, the prepared membranes with high concentrations of sulfonated particles performed similarly to Nafion 117.

Fullerene–polyphenylene oxide (C60–PPO) compositions containing up to 2 wt% C60 were obtained and used for homogeneous membranes formation. Gas separation properties were estimated by measuring the permeability of individual gases H2, O2, N2, CH4, and CO2. A correlation between gas permeability and free volume was established. The pervaporation of water/ethanol mixtures through fullerene‐containing membranes showed that C60–PPO membranes exhibit dehydration properties. The degree of equilibrium sorption for PPO and C60–PPO membranes in a water/ethanol system was estimated in the liquid phase. Gas separation and pervaporation properties were treated as a reflection of molecular interactions between PPO and C60 molecules in compositions.

Molecular motion and thermal stability in two series of nanophase-separated polyimide–silica (PI–SiO2) hybrid materials with chemically bound components were studied. The hybrids were synthesized from p-aminophenyltrimethoxysilane-terminated poly(amic acid)s as PI precursors and tetramethoxysilane as a silica precursor via a sol–gel process. The hybrids differed in their PI chemical structure and chain length (number-average molecular weight = 5.000, 7.500, or 10.000) and in their SiO2 content, which ranged from 0 to 50 wt %. Differential scanning calorimetry, laser-interferometric creep rate spectroscopy, and thermally stimulated depolarization current techniques were used for studying the dynamics from 100 to 650 K and from 10−3 to 10−2 Hz. Comparative thermogravimetric measurements were also carried out from 300 to 900 K. Silica nano- or submicrodomains that formed affected PI dynamics in two opposite directions. Because of the loosening of the molecular packing of PI chains confined to nanometer-scale spaces between silica constraints, an enhancement of small-scale motion, mostly at temperatures below the β-relaxation region, occurred. However, a partial or total suppression of segmental motion could be observed above the β-relaxation temperature, drastically so for the shortest PI chains at elevated silica contents and within or close to the glass-transition range, because of the covalent anchoring of chain ends to silica domains. Large changes in thermal stability, including a 2.5-fold increase in the apparent activation energy of degradation, were observed in the hybrids studied. A greater than 100 °C rise in long-term thermal stability could be predicted for some hybrids with respect to pure PI. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1056–1069, 2002

Gas separation membranes composed of sulfonated poly(phenylene oxide) as a support and polypyrrole were prepared by two alternative ways: (1) the support films were saturated by oxidant and then treated with pyrrole vapor; (2) the support films were saturated with pyrrole vapor and then treated with the oxidant. Study of the polymerization conditions has shown that the second method of membrane preparation results in formation of a dense polypyrrole layer on the support surface. The membranes were characterized by Fourier transform infrared spectroscopy, ultraviolet spectroscopy, optical microscopy and atomic force microscopy. Measurements of gas transport properties demonstrated that the O 2 vs. N 2 selectivity coefficient of this polypyrrole layer was 15, which is one of the highest values described in the literature.