The regularities of formation of silver nanoparticles with a shell of coordinatively bound monocarboxylate ligands in a one-step synthesis by the reaction of low-temperature reduction of precursors, that is, silver alkyl- and oligostyrylmonocarboxylates, with triethylamine, diepoxy oligomer ED-20, and polyurethane prepolymer, were studied. A single mechanism of formation of silver nanoparticles through the dissolution of precursors in reducing agents by the reaction of formation of diphilic complexes between silver monocarboxylate molecules organized in micelles and electron-donor groups of reducing agents with a subsequent reduction reaction and self-assembly of nanoparticles was determined, which ensures the preservation of the spherical shape, small sizes (d ≈ 2–8 nm), and narrow dispersions: Ag+ → Ag0 → (Ag0)n. Based on the determined mechanism, we propose a strategy for the preparation of polymer nanocomposites by curing with amines a pre-prepared modified binder consisting of epoxy resin ED-20 or polyurethane prepolymer, silver nanoparticles, and unreacted silver oligostyrylmonocarboxylate. The limiting concentration of the precursor in the modified binder, at which a uniform distribution of silver nanoparticles within the bulk of the nanocomposites is achieved, was determined. It is shown that silver nanoparticles slightly reduce the glass transition temperature and do not affect the mechanical properties of epoxy nanocomposites. The termophysical properties of the nanocomposites depend on the topology of the epoxy matrix.

The regularities of the formation, as well as the structure and properties of the epoxy nanocomposites synthesized via curing with 4,4′-diaminodiphenylmethane and triethylamine of the ED-20 epoxy binders modified by spherical small ( r ~ 2 nm) narrowly dispersed silver nanoparticles with oligostyrylmono-carboxylate ligands were studied by SEM, UV–Vis spectroscopy, and DSC methods. The limiting initial concentration of silver oligostyrylmonocarboxylate in the modified binder, which affords uniform distribution of the silver nanoparticles ( r ~ 8–20 nm) in the nanocomposites, was estimated at 2.5 wt %. The silver nanoparticles cause a slight decrease in the glass transition temperature and do not affect the mechanical characteristics of the epoxy nanocomposites. The thermophysical characteristics of the nanocomposites depend on the topology of the epoxy matrix.

Using transmission electron microscopy and UV–Vis spectroscopy, the effect of the concentration of the silver oligostyrylmonocarboxylate precursor in the range of 0.3–3.2 wt % in the reaction with the ED-20 epoxy resin on the formation of silver nanoparticles at a temperature of 75°C is studied. At the initial carboxylate concentration ≤0.3 wt %, silver nanoparticles with oligostyrylmonocarboxylate ligands having a spherical shape, small size, and narrow dispersion are produced. With an increase in the initial concentration of silver oligostyrylcarboxylate ≥0.3 wt %, the accumulation of nanoparticles is accompanied by the appearance of aggregates of arbitrary shape due to the van der Waals interaction of carboxylate ligands. The presence of aggregates leads to the broadening, splitting, and redshift of surface plasmon resonance peaks. Silver nanoparticles in aggregates are separated by ligand shells that reduce the probability of coalescence.

Regularities of the formation of silver nanoparticles with oligostyrylcarboxylate ligands during the one-step reduction of silver oligostyrylcarboxylates with triethylamine are studied via UV–Vis and IR spectroscopy. It is shown that the synthesis of silver nanoparticles occurs in a system with micellar organized molecules of the oligomeric precursor–ionomer. The formation of silver nanoparticles occurs through the successive formation of a diphilic silver oligostyrylcarboxylate/triethylamine complex, reduction of Ag + in the cores of reverse micelles with the formation of (Ag 0 ) n nuclei, and their subsequent growth through self-assembly.

The kinetic features of thermal degradation of polycarbonate films containing 0.02–0.13 wt % silver are investigated. The analysis of surface plasmon resonance spectra shows that the composite films contain silver nanoparticles with sizes from 10 to 200 nm. The shapes and sizes of particles are determined via scanning electron microscopy. It is shown that the rates of thermal degradation of the nanocomposites are much higher than the rate of degradation of the initial polycarbonate; the highest catalytic activity is exhibited by spherical silver nanoparticles with sizes below than 40 nm, while particles shaped as bipyramids and having sizes of 100–200 nm are less active catalytically.

The mechanical and thermomechanical properties of metal-containing epoxy composite films based on silver nanoparticles synthesized in situ are investigated. There is a nonmonotonic dependence of the mechanical properties on the concentration of silver myristate used as a precursor. It is found for the first time that the breaking strength and elastic modulus increase by a factor of 1.8–1.5 relative to those of the unmodified matrix at a small concentration of precursor nanoparticles (on the order of 0.1 wt %). DSC and thermomechanical studies reveal that the glass-transition temperature decreases slightly (by 5–6°C) as the precursor concentration is increased to 0.5 wt %, thereby suggesting a weak plasticization of the modified epoxy matrix. On the basis of the spectrophotometry data measured in the region of surface plasmon resonance of silver nanoparticles (420–425 nm) and SEM data, it is inferred that the in situ strengthening of an epoxy nanocomposite based on epoxy resin ED-20, triethylamine, and silver myristate is attained because silver nanoparticles smaller than 20 nm in size and having a narrow particle-size distribution are formed during curing.

Исследованы механические и термомеханические свойства пленок металлосодержащих эпоксидных композитов на основе наночастиц серебра, синтезированных in situ. Установлена немонотонная зависимость механических свойств от концентрации прекурсора – миристата серебра. Впервые обнаружено увеличение прочности при разрыве и модуля упругости в 1.8–1.5 раз по сравнению с немодифицированной матрицей при малой концентрации прекурсора наночастиц (порядка 0.1 мас. %). Методами ДСК и термомеханики показано незначительное снижение температуры стеклования на 5–6°С с повышением концентрации прекурсора до 0.5 мас. %, свидетельствующее о слабой пластификации модифицированной эпоксидной матрицы. На основании данных спектрофотометрии в области поверхностного плазмонного резонанса наночастиц серебра (420–425 нм) и данных СЭМ сделан вывод о том, что упрочнение эпоксидного нанокомпозита in situ на основе эпоксидной смолы ЭД-20, триэтиламина и миристата серебра достигается за счет формирования в процессе отверждения наночастиц серебра, меньших 20 нм, с узким распределением по размеру.

Silver nanoparticles stabilized by polystyrylmonocaboxylate ligands with varied chain lengths are synthesized via the low-temperature reduction of silver polystyrylmonocaboxylate with triethylamine. Silver nanoparticles have small dimensions, narrow size distributions, high stability, and ability to redisperse in nonpolar solvents. The kinetic features of the reaction are studied via high-performance liquid chromatography; UV, visible and IR spectroscopy; and transmission electron microscopy. It is shown that the reduction of silver occurs in the cores of reverse micelle species organized by diphilic macromolecules of silver polystyrylmonocarboxylates.

Sols of silver nanoparticles in toluene were studied by broadband dielectric spectroscopy (10−3–105 Hz). The frequency dependences of the specific alternating current (ac) conductivity and the complex electric modulus were used to estimate the temperature/frequency intervals of long- and short-range charge transfer occurs, respectively. A considerable increase (by more than 30 °C) in the Vogel temperature T 0 and the glass transition temperature T g in sols compared with the pure solvent was found. It can be hypothesized that these cooperative effects reflect the initial stage of the superlattice formation. Although the dielectric characteristics of sols are generally controlled by the conductivity relaxation, the dielectric response was observed in the high-frequency range (1–103 Hz) at low temperatures (from −50 to +10 °C). This response results from the presence of nanoparticles in solution. It is supposed that the relaxation is caused by the motion of ion impurities on the Ag nanoparticle surface within the carboxylate ligands shell. The dielectric properties of films strongly depend on both the characteristics of nanoparticles and the conditions of the film preparation. Like in sols, the direct current (dc) conductivity and the dielectric response of Ag nanoparticles in films are due to ion impurities.

The process of nonisothermal radical polymerization of styrene in an ideal well-mixed batch reactor was considered. Kinetic constants for the elementary polymerization reactions were selected on the basis of published data. By phase-plane analysis of the set of differential equations describing the nonisothermal process, sufficient conditions (initial temperature and heat removal rate) for the steady-state proceeding of the process to ensure a safe temperature regime were established. The influence of the initial temperature and heat withdrawal conditions on the conversion, the character of temperature change, and the molecular-mass distribution of the polymer during nonisothermal polymerization was studied.

The physical meaning of the effective relaxation time as a quantity characterizing the relaxation spectra of polymers is discussed. For monodisperse polymers and their mixtures, some theoretical models and the plots of the relaxational elastic modulus versus frequency are analyzed. A qualitative relationship between the weight-average and number-average relaxation times and their ratio, on the one hand, and the structural and dynamic characteristics of polymer systems, on the other hand, is shown.

The relaxation properties of the Rouse chain with inhomogeneous links have been investigated. The problem has been solved by direct integration of systems of differential‐difference equations which describe the relaxations of the chain length and stress. It has been shown that these two processes are different in both the set of relaxation modes and the characteristic of the spectrum. The influence of the chain structure on these parameters has been demonstrated. The effect of “packing” of the relaxation modes has been revealed; it appears on introduction of links with an increased coefficient of friction into the chain and manifests itself in the fact that the high‐frequency modes come closer together and even merge, so that their total number becomes substantially smaller than that in the case of the Rouse model.

An algorithm of finding the relaxation parameters of oligomeric chains within the framework of the Kargin-Slonimskii-Rouse model is developed. This algorithm makes it possible to analyze chains whose structure is nonuniform in terms of its relaxation characteristics. ne maximum relaxation times are shown to be different under strain and stress relaxation regimes. The presence of elements with significantly different relaxation characteristics in the chain reduces the number of relaxation modes because of the packet formation effect, wherein high-frequency relaxation modes approach each other and even merge.

A phase separation in an epoxy resin–oligomeric additive system induced by curing proceeded by a mechanism of anionic polymerization was studied by the optical microscopy. Changes in the morphological structure of the reaction system in the course of its curing were in situregistered. It was shown that the intensity of particle coalescence in a segregating phase at the late stage of phase separation and, consequently, morphology of a two-phase polymer thus formed depend on the chemical mechanism and conditions of curing; i.e., on the initial mixture composition and reaction temperature.