In this study, oriented nanocomposite gel-spun fibers and solid-state-processed tapes were manufactured and analyzed. The fibers and tapes were produced using a specific type of nascent disentangled ultra-high molecular weight polyethylene (UHMWPE) reactor powder. As the filler, commercially available electrically conductive carbon black (CB) was used. The ultra-high filler content values up to 75 wt.% were achieved for the UHMWPE/CB gel-spun fibers, while the degree of filling was limited (up to 30 wt.%) in the case of the solid-state processing approach. This was attributed to the type of the filler distribution achieved with both processing methods. The influence of the filler distribution on the composite characteristics in case of the homogeneous filler distribution in the gel- spun fibers and extremely segregated filler distribution in the solid-state tapes was studied. To this end, the resulting composite UHMWPE/CB gel- spun fibers and solid-state processed tapes were characterized using a combination of research techniques, including X-ray diffraction, scanning electron microscopy, mechanical testing, and conductivity measurements. A comparative study of the electrical conductivity of the gel-spun and solidstate-processed UHMWPE/CB composites was conducted for both the unoriented and oriented states of the composite materials. The obtained solid-state processed UHMWPE/CB tapes were characterized by a low filler percolation threshold value of 2.5 wt.%, while the percolation threshold for the composite gel-spun fibers exceeded 15 wt.%. Regardless of the filler distribution type, a notable reduction in electrical conductivity was observed following the orientation drawing of the composites. At the same time, while a notable reduction in the maximum achievable orientation deformation ratio and subsequent tensile strength decline was observed in the case of gel-spun fibers, no impact of the filling on orientation strengthening was detected in the case of solid-state processed tapes.

The results of a comprehensive investigation into the structure and properties of nanodiamond soot (NDS), obtained from the detonation of various explosive precursors (trinitrotoluene, a trinitrotoluene/hexogen mixture, and tetryl), are presented. The colloidal behavior of the NDS particles in different liquid media was studied. The results of the scanning electron microscopy, dynamic light scattering, zeta potential measurements, and laser diffraction analysis suggested a similarity in the morphology of the NDS particle aggregates and agglomerates. The phase composition of the NDS nanoparticles was studied using X-ray diffraction, Raman spectroscopy, electron diffraction, transmission electron microscopy, atomic force microscopy, and scanning tunneling microscopy. The NDS particles were found to comprise both diamond and graphite phases. The ratio of diamond to graphite phase content varied depending on the NDS explosive precursor, while the graphite phase content had a significant impact on the electrical conductivity of NDS. The study of the mechanical and tribological characteristics of polymer nanocomposites, modified with the selected NDS particles, indicated that NDS of various types can serve as a viable set of model nanofillers.

Organic semiconductor materials with a unique set of properties are very attractive for interfacing biological objects and can be used for noninvasive therapy or detection of biological signals. Here, we describe the synthesis and investigation of a novel series of organic push-pull conjugated molecules with the star-shaped architecture, consisting of triphenylamine as a branching electron donor core linked through the thiophene π-spacer to electron-withdrawing alkyl-dicyanovinyl groups. The molecules could form stable aqueous dispersions of nanoparticles (NPs) without the addition of any surfactants or amphiphilic polymer matrixes with the average size distribution varying from 40 to 120 nm and absorption spectra very similar to those of human eye retina pigments such as rods and green cones. Variation of the terminal alkyl chain length of the molecules forming NPs from 1 to 12 carbon atoms was found to be an efficient tool to modulate their lipophilic and biological properties. Possibilities of using the NPs as light nanoactuators in biological systems or as artificial pigments for therapy of degenerative retinal diseases were studied both on the model planar bilayer lipid membranes and on the rat cortical neurons. In the planar bilayer system, the photodynamic activity of these NPs led to photoinactivation of ion channels formed by pentadecapeptide gramicidin A. Treatment of rat cortical neurons with the NPs caused depolarization of cell membranes upon light irradiation, which could also be due to the photodynamic activity of the NPs. The results of the work gave more insight into the mechanisms of light-controlled stimulation of neuronal activity and for the first time showed that fine-tuning of the lipophilic affinity of NPs based on organic conjugated molecules is of high importance for creating a bioelectronic interface for biomedical applications.

Aspects of solid-state processing of nascent disentangled ultra-high-molecular-weight polyethylene (UHMWPE) powders of different syntheses mixed with electrically conductive carbon nanoparticles (NPs) of various types are studied. Effect of multiple parameters of the processing procedures on the electrophysical characteristics of the composite samples is investigated. Such parameters include time of preliminary ultrasonication (US) of NPs, time of US of UHMWPE/NPs mixtures, molding time, temperature, and pressure, deformation degree, etc. It is observed that by selecting optimal values of such parameters it is possible to obtain samples of composites with an extremely segregated structure made of the NPs, with NPs distributed evenly on the surfaces of the compacted UHMWPE powder particles. This ensures high levels of conductivity at very low values of NPs content. The segregated structure is retained when the composites are strengthened using the solid-state uniaxial shear deformation process. While conductivity of most of the composites filled with various types of NPs monotonously decreases with the deformation ratio, conductivity of the composites filled with exceptionally long double-walled carbon nanotubes is maintained. The processed oriented composites are also characterized by high EMR shielding properties, as well as interesting temperature dependencies of the electrical conductivity.

The stages of solid-state processing of nanocomposites, based on nascent disentangled ultra-high-molecular-weight polyethylene (d-UHMWPE) reactor powders (RPs) and carbon nanoparticles (NPs) of various types, were meticulously investigated. The potential for optimizing the filler distribution through variation of the processing parameters, and the impact of the d-UHMWPE RP and nanofiller type on the electrical conductivity of the resulting composites were discussed. The specifics of the dependences of conductivity and tensile strength on the deformation ratio for the composites, oriented under homogeneous shear conditions, were investigated. The obtained results and the results on piezoresistivity and temperature dependency of conductivity in the oriented and compacted composites demonstrated the independence of the UHMWPE matrix orientational strengthening on the filling. The interchangeability of high-temperature uniaxial deformation and deformation under homogeneous conditions for orientational strengthening and electrical conductivity changes in the preliminary oriented composite samples was confirmed. The potential for simultaneously achieving high strength and conductivity in composite tapes and the possibility of directly processing d-UHMWPE RP and NPs mixtures into oriented composite tapes were demonstrated. The overall results suggest that the studied composites may serve as a viable model system for investigating the deformational behavior of conductive networks comprising NPs of varying types and contents.

Structural studies were carried out and physicomechanical characteristics of samples of ultrahigh molecular weight polyethylene (UHMWPE) were determined for successive stages (compacting/monolithization—orientational stretching) of the continuous solid-state processing of nascent reactor powders of UHMWPE (RP UHMWPE) into high-strength tapes. The use of nascent RP UHMWPE with the morphology, molecular weight, and bulk density optimal for solid-state processing makes it possible to obtain high-strength (∼3 GPa) and high-modulus (120–130 GPa) tapes. The conditions for both compacting/monolithization and the orientational stretching have a significant effect on the structure and properties of highly oriented tapes and can be optimized in order to prepare materials with a complex of the highest elastic-strength characteristics.

The influence of different types of deformation of the metal matrix on mechanical behavior of the amorphous PET film upon its transverse compression in the ductile metal matrix has been investigated. Three deformation modes have been probed. In the first case, a disc-shaped polymer specimen has been put between two 5 mm thick discs of the lead–tin alloy and squeezed in the press. In the second and the third cases, planar elongation has been performed in the so called “dead channel”, i.e., the channel with fixed side walls, the film being elongated due to decrease in the width or thickness, respectively. The plots of true yield stress at different draw ratios have formed a common master curve. At high total draw ratio Λ, the true yield stresses have been close for the considered three types of drawing in the metal. At the draw ratio Λ > 2.6, the neck has not appeared, and the specimen has been deformed uniformly. When the film in the channel is elongated due to the decrease in thickness at constant width, the specimen width has been mainly decreased during subsequent elongation in the testing machine. When the film in the channel is elongated due to the decrease in width at constant thickness, further elongation has mainly led to the decrease in the specimen thickness. The true stress Σ has been expressed as Σ = Σ 0 + K Λ 3 , with K being a constant. Deformation of the polymer in the channel occurred with the formation of shear bands . At the preliminary draw ratio Λ = 1.82, the bands have been oriented at the angle 21.5° with respect to the stretching axis. The planar elongation has led to abnormally strong deformation softening of the polymer. The drawing has been accompanied by an increase in the elasticity modulus of the polymer. The obtained results have suggested that the macromolecules orientation is the main reason for strain hardening of the polymer.

Thermal stability of macrocyclic complexes with alkaline earth metal salts is of crucial importance for their applicability as the components of new electrolytes, ionic liquids and precursors in chemical vapor deposition processes. The complexes of 18-crown-6 and stereoisomeric dicyclohexano-18-crown-6 with alkaline earth metal halides were synthesized and studied by the combination of simultaneous DSC/TGA and FTIR-spectroscopy. The stability of these compounds depended on the size of the cation and anion as follows: Ba 2+ < Sr 2+ < Ca 2+ and Cl − < Br − ≈ I − . The two-stage mechanism of destruction was found for the complexes with CaCl 2 , SrBr 2 , SrI 2 . This implies, most probably, the coexistence of two conformationally nonequivalent forms of the macrocycles with different thermal stability rather than the destruction of the macrocycle at high temperatures. The revealed trends, in our opinion, were caused by changes in the interaction energy between macrocycle and metal cation.

In this work, a multi-scale and multi-physics model taking into account structure-property relationships that are interconnected across the length scales is developed to predict electrical conductance deformational behavior for glass fiber reinforced electroconductive nanocomposites (GFRNCs). To verify numerical model predictions, composites with polypropylene (PP) matrix filled with nanoparticles and reinforced with woven glass fibers were manufactured. As nanosized electroconductive fillers multi-walled carbon nanotubes and carbon black particles were used. Uniaxial deformation of the obtained GFRNCs with simultaneous continuous electrical conductance measurements was performed. Results of the numerical modeling were compared with experimental data obtained for modified PP and for GFRNCs. It was concluded that introduction of woven glass fiber in the electrically conductive matrix noticeably affects electrical conductivity changes with deformation for the material, which can be adequately predicted numerically using proposed multi-scale modeling approach for correct composite structure representation.

A series of aromatic polyimides based on the asymmetrical diamine 3,4ʹ-oxydianiline and various tetracarboxylic acid dianhydrides, both “rigid” and “flexible” structure, have been synthesized using the original method of one-pot high-temperature catalytic polycondensation in molten benzoic acid. The synthesized polyimides were investigated using fourier-transform infrared (FTIR) and 1H NMR spectroscopy, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), thermomechanical analysis (TMA) and wide-angle X-ray scattering (WAXS). It was found that the synthesized polyimides, depending on the used dianhydride, are characterized by different solubility in organic solvent and molten benzoic acid, molecular weight, glass transition temperature (Tg) from 198 to 270 °C, an amorphous or semi crystalline structure with the degree of crystallinity from 41 to 52%. The influence of the method of synthesis on the formation of the crystalline phase of polyimides was studied, and the obtained results were compared with the literature data. The effect of dianhydride chemical structure on the performance of polyimide in pervaporation more specifically, dehydratation of azeotropic isopropanol solution was investigated and compared with the commercially available polyetherimide Ultem 1000™. Membrane structure was studied using scanning electron microscopy. It was found that polyimide PI-DA is the most effective for separation of 88 wt.% isopropanol/12 wt.% water mixture compared to the polyimide PI-6FDA and commercial polyetherimide Ultem 1000™ demonstrating normalized permeation flux of 2.77 kg µm m−2 h−1 and separation factor of 264 (water content in permeate 97 wt.%).

A correlation was established between, on the one hand, the values of the molecular weight of UHMWPE synthesized using postmetallocene bis-phenoxyimine catalysts and the bulk density of synthesized nascent reactor powders of UHMWPE, and, on the other hand, the values of the elastic modulus, breaking strength and breaking elongation of oriented tapes obtained from reactor powders of UHMWPE by the method of solid-state processing below the melting temperature of the polymer without the use of solvents. It has been established that the application of UHMWPE reactor powders with a bulk density of no higher than 0.09 g/cm3 and, at the same time, a polymer molecular weight of not less than 4.5 × 106 g/mol allows one to obtain on their basis by a solid-state method, simultaneously, high-strength (breaking strength up to 3.6 GPa) and high-modulus (modulus of elasticity up to 150 GPa) materials, that is, having the maximum value of the deformation energy to break, which is important for practical applications. Reactor powders of UHMWPE with optimal for solid-state processing values of MM and bulk density, at the level of structural subunits of the nanometer size range had a morphology of the “stack of lamellas” type.

In this work, the results of a complex investigation of structure and properties of nanodiamond soot (NDS) of detonation synthesis are presented. Size distribution of NDS particles, dispersed in different liquid media, was investigated using dynamic light scattering and laser diffraction analysis methods. The results of the investigation, as well as the results of zeta-potential measurements, allowed us to characterize the agglomeration process of the NDS particles as independent of the medium, making NDS a good model filler for research of composite-modified nanosized particles. Additional data obtained using scanning electron microscopy, scanning tunneling microscopy, atomic force microscopy, X-ray diffraction, and Raman spectroscopy, demonstrated that in NDS the spherical nanodiamond (ND) particles with diameter ~5 nm are densely packed into strong-coupled aggregates with diameter ~300 nm, surrounded by graphite nanoribbons. X-ray diffraction analysis estimated the volume fraction of NDs in NDS as ~45 vol.%, simultaneously showing that the graphite is not defective, which was confirmed with the electron diffraction method. It was demonstrated that this structure of NDS allows to efficiently use NDS as a filler for polymer composites to increase polymer characteristics such as electrical conductivity or tribological characteristics, similarly to conventionally applied fillers such as carbon black.

Process of nanoscale carbon filler migration in polymer composite melts is studied. Monotonous decrease of electrical resistance is observed for composite materials during their stay in a melted state. This is especially pronounced for composites with concentration of filler much lower than percolation threshold determined for a specific matrix/filler/mixing method combination. This phenomenon can be observed for composites based on different polymer matrices. Also, it is demonstrated that the type and geometry of the electrically conductive filler does not affect presence of the phenomena. A setup for measurement of conductance for volume and surface layer components is used. The results of electrical conductance measurements of the polymer composite melt using this setup allows to attribute the increase of composite material conductance to formation of filler enriched surface layer. To obtain information on the processes occurring at the microscopic level, molecular dynamics simulations are conducted. Variation of several simulation parameters with comparison of the results to experimental data allows to understand the macroscopic composite material conductance behavior.

Conditions were determined for the formation of a ternary complex of polyethylenimine with copper and cobalt ions, ensuring the predominant binding of the metal ions with the macromolecule of the polyethylenimine stabilizer. Metal particles were prepared under the conditions of different binding of metal ions with the stabilizer. The reduction of cobalt and copper ions in the presence of polyethylenimine yields Cu and Co metal nanoparticles irrespective of the mode of metal ion binding with the stabilizer. The metal particles obtained using the preliminarily prepared ternary complex of polyethylenimine with Cu2+ and Co2+ ions have approximately spherical shape and smaller characteristic size compared to the particles prepared without this complex. In the latter case, the particles are anisometric aggregates elongated in one direction.

A method developed for producing composites based on polylactic acid (PLA) and elemental boron nanoparticles by the method of solid-state polycondensation is presented. The synthesis parameters (time, temperature, and residual pressure) were optimized to obtain PLA with desired properties. The influence of the nanosized boron filler was evaluated. When boron nanoparticles are added in an amount of 0.03 wt.%, the properties of PLA change: the degree of crystallinity increases by 20% compared to the polymer without additives and an increase in the molecular weight of the polymer up to 60 kDa is observed. The properties of the solid-state polycondensation products were studied by NMR spectroscopy, X-ray phase analysis, gel-permeation chromatography, and differential scanning calorimetry.

A method for producing elemental boron nanoparticles with a size of less than 100 nm by ultrasonic dispersion in a liquid medium and subsequent cascade fractionation is described. The resulting boron nanoparticles were used as a target for boron neutron capture therapy (BNCT). According to the results of an experimental preclinical study of BNCT with the synthesized boron nanoparticles, neutron irradiation for 1 h of T98G human glioma cells pre-incubated in a medium with boron nanoparticles (10, 20, and 40 ppm in terms of boron-10 isotope) leads to a significant suppression of cell viability.

Graft copolymers of chitosan with cellulose ether have been obtained by the solid-state reactive mixing of chitin, sodium hydroxide and hydroxyethyl cellulose under shear deformation in a pilot twin-screw extruder. The structure and composition of the products were determined by elemental analysis and IR spectroscopy. The physicochemical properties of aqueous solutions of copolymers were studied as a function of the composition, and were correlated to the mechanical characteristics of the resulting films to assess the performance of new copolymers as coating materials, non-woven fibrous materials or emulsifiers for interface stabilization during the microparticle fabrication process.

Graft-copolymers of chitosan with hydroxyethylcellulose and polyvinyl alcohol were synthesized through solid-state reactive blending under shear deformation in twin-screw co-rotated extruder. Structure of the obtained products was studied by elemental analysis and FTIR spectroscopy. Effect of the copolymer composition on the ability to electroform was evaluated in terms of casting solutions viscosity, conductivity and surface tension. Mechanical properties of the copolymeric films were investigated.