V. M. Svetlichnyi

Effect of the structure and shape of filler nanoparticles on the physical properties of polyimide composites

Model nanocomposites on the basis of specially synthesized amorphous and semicrystalline polyimide matrices, silicate (natural and synthetic) and carbon nanoparticles with different morphology (tubes, platelets, discs, and spheres) have been developed. The influence of nanoparticle morphology on the rheological behavior of nanocomposite melts at the stage of their processing has been investigated.

Modification of films of heat-resistant polyimides by adding hydrosilicate and carbon nanoparticles of various geometries

The possibility of modifying the properties of poly(4,4′-oxydiphenylene)pyromellitimide films by introducing into prepolymer solutions nanoparticles of various compositions and structures [hydrosilicate nanoparticles in the form of layered structures (montmorillonite) and nanotubes; carbon nanofibers] was examined. New intercalating agents, tetranuclear aromatic diamines, were suggested for pretreatment of montmorillonite prior to introduction into heat-resistant polymers. The mechanical characteristics of the nanocomposites with hydrosilicate nanotubes can be optimized by chemical pretreatment of the nanotubes prior to introduction into the polymer matrix. Introduction of the above-named nanoparticles into the polymer matrix appreciably increases the elastic modulus of the material. The largest increase in the elastic modulus is observed with hydrosilicate nanotubes of the chrysotile structure, coated with an aromatic modifier.

Nanocomposite based on polyamidoimide with hydrosilicate nanoparticles of varied morphology

Polymeric nanocomposites based on aromatic polyamidoimide and nanotubes of magnesium hydrosilicate Mg3Si2O5(OH)4 with a chrysotile structure were obtained and studied for the first time. The morphology and mechanical and transport properties of the composites formed were analyzed, which enabled optimization of their synthesis conditions.

Effect of single-walled carbon nanotubes and carbon nanofibers on the structure and mechanical properties of thermoplastic polyimide matrix films

The effects of additives of single-walled carbon nanotubes prepared via electric-arc synthesis and carbon nanofibers produced via gas-phase synthesis on the crystallization capacities and mechanical and electric properties of composite films of a thermoplastic polyimide (PI) matrix based on 1,3-bis-(3,3′, 4,4′-dicarboxyphenoxy)benzene and 4,4′-bis-(4-aminophenoxy)biphenyl after their uniaxial drawing and additional annealing are studied. The use of these fillers induces the heterogeneous nucleation of a crystalline phase of PI on the nanoparticle surface. A higher specific interface area in the case of addition of carbon nanotubes relative to that of carbon nanofibers leads to the formation of the crystalline structure of PI with a small crystallite size and high imperfection. Uniaxial drawing leads to the formation of a supermolecular structure that is optimum for crystallization during additional annealing and removes the kinetic hindrances to crystal growth. The properties of these fillers have a significant effect on the orientation of the nanoparticles and the matrix macromolecules during the uniaxial drawing of the films, which is accompanied by an increase in the elastic modulus with an increase in the draw ratio and the ability of the composite films to undergo orientational crystallization during additional annealing.

Aromatic polysulfone imides and membranes based on them

Aromatic polyimides containing diphenyl sulfone fragments in the backbone were prepared. Asymmetric microporous films of the synthesized polymers were prepared by wet forming under the conditions of a phase-inversion process. The morphologies and the mechanical and transport properties of nonporous and phase-inversion films as materials for pervaporation membranes were studied. Multilayer composite membranes with diffusion layers of an aromatic polyether imide were prepared on the basis of microporous polyamido imide films. These membranes showed high performance in pervaporation separation of ethanol-cyclohexane mixtures of various compositions.

Conducting film-forming composites based on polyaniline-polyimide blends

A procedure is developed for preparing conducting films by their casting from polymer solutions containing polyaniline in the form of a protonated emeraldin base and polyimides in two cosolvents, N-methylpyrrolidone or m-cresol. Self-supporting films cast from composites based on polyimides and camphorsulfonic acid-protonated polyaniline combine a conductivity of 10−1−10−2S/cm with good mechanical properties: elastic modulus E = 2.0−2.4 GPa, breaking strength σb = 55−60 MPa, and elongation at break ɛb = 8−10%. It has been shown that, when m-cresol and N-methylpyrrolidone are used as cosolvents, the maximum film conductivity is achieved at polyaniline amounts in the composites of 20 and 3%, respectively. In the latter case, films with good strength parameters are formed.

Pervaporation Membranes for Separating Mixtures of Methanol and Methyl tert-Butyl Ether

Transport characteristics of new types of bi- and multilayer composite polymer pervaporation membranes and asymmetrical membranes in separating mixtures of methanol and methyl tert-butyl ether were studied. The principles of design of the membranes and their mass-exchange characteristics are treated in terms of the Henis-Tripodi resistance model.

Structure, morphology, and thermal properties of nanocomposites based on polyamido imide and hydrosilicate nanotubes

New nanocomposites based on heat-resistant poly[(diphenyl oxide)amido-N-phenylphthalimide] with Mg3Si2O5(OH)4 hydrosilicate nanoparticles of tubular structure were prepared. The structure, morphology, and thermal properties of the nanocomposites were studied in relation to the content of hydrosilicate nanotubes.

Composites of multiblock (segmented) aliphatic poly(ester imide) with zirconia nanoparticles: Synthesis, mechanical properties, and pervaporation behavior

On the basis of pyromellitic dianhydride, p-phenylenediamine, and poly(butylene adipate) diol (M n = 1 × 103) and poly(ethylene adipate) diol (M n = 1 × 104) taken at a molar ratio of 10 : 1, initial samples of multiblock poly(ester imide) and its composites with nanoparticles of two types—zirconia ZrO2 surface-treated with γ-aminopropyltriethoxysilane and zirconia doped with yttria (Y0.03Zr0.97O1.985)—are synthesized. Nanoparticles are introduced into the polymer matrix at the stage of synthesis of the poly(ester imide) prepolymer. The mechanical properties of films of poly(ester imide) and its nanocomposites are determined under static and dynamic testing conditions, and the permeabilities and separation selectivities of corresponding solid films for mixtures of aromatic and aliphatic hydrocarbons (toluene-n-octane and benzenecyclohexane) of various compositions are measured under pervaporation testing conditions. It is shown that the different mechanical and pervaporation properties of film samples are due to the presence of zirconiabased nanoparticles.

Optically active polyamidoimides based on amino acids containing cyclohexane fragment

New amino carboxylic acids containing a cyclohexane fragment and an L-leucine or L-valine fragment were synthesized. The reactions of the synthesized amino acids with 4,4′-oxydiphthalic anhydride gave in quantitative yields the dicarboxylic acids, which were converted to the corresponding dichlorides. Low-temperature polycondensation of the synthesized dichlorides with 4,4′-diaminodiphenyl ether yielded optically active polyamidoimides, which are soluble in various organic solvents and exhibit enhanced heat resistance. The structures of the synthesized monomeric compounds and polymers were confirmed by elemental analysis, IR and 1H NMR spectroscopy, and high-resolution mass spectrometry. Specific rotation angles of the synthesized amino carboxylic acids and polyamidoimides were determined.