Using one-step high-temperature polycyclocondensation organosoluble homo- and copolyimides containing various side groups, such as CF₃‒, СOOН‒, Cl‒, and fluorene, and their certain combinations, are synthesized, and their effect on O₂, N₂, CO₂, He, and CH₄ permeability coefficients of films is studied. The synthesized polymers with a inherent viscosity of 0.41–0.76 dL/g are characterized by a high heat resistance (230°C ≤ Т_g ≤ 380°C) and form strong films (60 MPa ≤ σ ≤ 140 MPa; 0.9 GPa ≤ E ≤ 1.6 GPa). It is shown that depending on the nature of side groups the polyimides under consideration demonstrate different gas-transport behavior. For example, for one of the polymers the selectivity factor for He/CH₄ separation is 315 (a He permeability coefficient of 9.5 Barrer), while for another polymer the selectivity factor for CO₂/CH₄ separation is 34 (at a CO₂ permeability coefficient of 37.3 Barrer). For crosslinked polyimide films the selectivity factor for He/CH₄ separation attains 125 (at a He permeability coefficient of 19.7 Barrer) and the selectivity factor for CO₂/CH₄ separation is 43 (at a CO₂ permeability coefficient of 7.0 Barrer).

The radical homopolymerization of methyl methacrylate and styrene in the presence of polyimide that contains aliphatic moieties and is dissolved in the monomer is studied. The viscosity characteristic

The development of photocurable compositions is in high demand for the manufacture of functional materials for electronics, optics, medicine, energy, etc. The properties of the final photo-cured material are primarily determined by the initial mixture, which needs to be tuned for each application. In this study we propose to use simple systems based on di(meth)acrylate, polyimide and photoinitiator for the preparation of new photo-curable compositions. It was established that a fluorinated cardo copolyimide (FCPI) based on 2,2-bis-(3,4-dicarboxydiphenyl)hexafluoropropane dianhydride, 9,9-bis-(4-aminophenyl)fluorene and 2,2-bis-(4-aminophenyl)hexafluoropropane (1.00:0.75:0.25 mol) has excellent solubility in di(met)acrylates. This made it possible to prepare solutions of FCPI in such monomers, to study the effect of FCPI on the kinetics of their photopolymerization in situ and the properties of the resulting polymers. According to the obtained data, the solutions of FCPI (23 wt.%) in 1,4-butanediol diacrylate (BDDA) and FCPI (15 wt.%) in tetraethylene glycol diacrylate were tested for the formation of the primary protective coatings of the silica optical fibers. It was found that the new coating of poly(BDDA–FCPI_23%) can withstand prolonged annealing at 200 °C (72 h), which is comparable or superior to the known most thermally stable photo-curable coatings. The proposed approach can be applied to obtain other functional materials.

Nanocomposites based on polymethylmethacrylate and silica were synthesized by means of bulk polymerization. The morphology of the obtained polymer composites was studied by scanning electron microscopy. It was established that silica influences the mechanical and tribological properties of nanocomposites.