Alla N. Pivkina's research while affiliated with Russian Academy of Sciences and other places

Publications (111)

Article
To solve actual tasks for the implementation of the modern space program, it is necessary to search for new high-energy components of rocket propellants. For this purpose, we designed a...
Article
There is an urgent demand for novel energetic materials with improved performance to serve as oxygen suppliers (oxidizers) and high-energy additives. Synthesis and characterization of compound that combines both of the above roles, bis-(2-difluoroamino-2,2-dinitroethyl)nitramine (1), is reported. 1 was synthesized by difluor-oamination of bis(2,2-d...
Article
A regioselective approach toward the synthesis of a set of new (2‐vinyltetrazolyl)furoxans as potential energetic monomers has been realized. All target energetic materials were thoroughly characterized by spectral and analytical methods. Moreover, crystal structures of two representative heterocyclic systems were studied by single‐crystal X‐ray di...
Article
Novel 7-azidofurazano[3,4-d ][1-3]triazine 5-oxide was synthesized from 3-amino-4-(tetrazol-5-yl)furazan and nitronium salt. Its characterization including energetic properties is described.
Article
Impact sensitivity of energetic material is considered to be not an intrinsic property of the compound, but to depend on multiple variables, including, in addition to chemical nature of the substance, both the powder and the instrument-depending factors. Therefore, the comparison of the sensitivity data obtained using different impact machines and...
Article
Six novel energetic furazans containing tetrazol-5-yl-NNO-azoxy moiety were synthesized using (cyano-NNO-azoxy)-furazans as starting compounds. The obtained compounds exhibit high enthalpies of formation (531–792 kcal kg–1), acceptable densities (1.70–1.76 g cm–3), good thermal stability (Tonset = 146–199 °C), and, as a result, excellent detonation...
Article
Novel energetic furazans 3a–3c and 4a–4c containing isomeric (3,4-dinitro-1H-pyrazol-1-yl)-NNO-azoxy and (3,5-dinitro-1H-pyrazol-1-yl)-NNO-azoxy moieties have been obtained. A synthetic approach to aminofurazans 3a and 4a involves the reaction of 1-amino-3,4-dinitro-1H-pyrazole or 1-amino-3,5-dinitro-1H-pyrazole with 2,2,2-trifluoro-N-(4-nitrosofur...
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A strategy for the synthesis of 5-((2-cyanoethyl)-X-amino)-[1,2,3]triazolo[4,5-c][1,2,5]oxadiazol-5-ium-4-ides (X = H; CH2CH2CN; NO2 (4a); CN (4b); CO2Et (4c)) starting from 3-amino-4-azido-1,2,5-oxadiazole was developed. The key step in this strategy is the intramolecular thermolytic cyclization of the azido group and the bis(2-cyanoethyl)triazene...
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Nitrogen-rich energetic materials comprised of a combination of several heterocyclic subunits retain their leading position in the field of materials science. In this regard, a preparation of novel high-energy materials with balanced set of physicochemical properties is highly desired. Herein, we report the synthesis of a new series of energetic sa...
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Energetic materials constitute one of the most important subtypes of functional materials used for various applications. A promising approach for the construction of novel thermally stable high-energy materials is based on an assembly of polynitrogen biheterocyclic scaffolds. Herein, we report on the design and synthesis of a new series of high-nit...
Article
Understanding the thermal stability of energetic materials is of great importance for storage and safety issues. In the present work, we report on the thermolysis kinetics and mechanism of the two fused energetic heterocycles, viz., 6,8-dinitrotriazolo[1,5-a]pyridine (1) and 2-amino-6,8-dinitro[1,2,4]triazolo[1,5-a]pyridine (2). The experimental ki...
Article
Nitrogen-oxygen organic materials constitute an important family of multipurpose high-energy materials. However, the preparation of energetic boosters and oxidizers for various civil and space technologies remains a challenging task and such materials usually require special precautions and fine tunability of their functional properties. To find a...
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A reliable kinetic description of the thermal stability of energetic materials (EM) is very important for safety and storage-related problems. Among other related issues, autocatalysis very often complicates the decomposition kinetics of EM. In the present study, the kinetics and decomposition mechanism of a promising energetic compound, 5-amino-3,...
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Modern trends in the development of energetic materials include the various methods of particle surface modification and the widespread use of nanosized powders. Atomic force micros-copy (AFM) is a useful, but often overlooked advanced tool for the investigation of surface, subsurface, and interface properties of energetic compounds. This review hi...
Article
Methods for the synthesis of 1,2-bis(3,4-dinitropyrazol-1-yl)diazene (1), 1,2-bis(3,5-dinitropyrazol-1-yl)diazene (2), and 1,2-bis(3-nitro-1,2,4-triazol-1-yl)diazene (3) were improved. The standard enthalpies of formation of these compounds were determined experimentally using combustion calorimetry. The density of compound 1 was refined. The possi...
Article
For the first time, complex geometry combustible structures of an ammonium perchlorate–polylactic acid composite have been successfully printed using fused deposition modeling (FDM). The structural and energetic capabilities of the printed structures are demonstrated. Combined with the ability to be produced by FDM printing, these combustible eleme...
Article
The continuous need for energetic materials with increased performance and improved safety characteristics stimulates synthetic efforts as well as physical modification of existing compounds. The present study reports the fabrication of 1,3,5,7-tetranitro-1,3,5,7-tetrazoctane (HMX)-based composites with common commercial polymers , polymethyl acryl...
Article
A series of novel, structurally diverse 1,2,4- and 1,2,5-oxadi- azole assemblies was synthesized from readily available furoxanyl precursors. Experimentally determined physico-chemical properties and calculated detonation parameters showed an application potential of the prepared nitrogen-oxygen molecular systems as promising energetic materials.
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Novel energetic azoxy- and azofurazans bearing nitro-NNO- azoxy and amino groups were synthesized using the ammonolysis of some known (nitro-NNO-azoxy)furazans. 3-Amino-4-{[4′-(nitro-NNO-azoxy)f urazan-3′-yl]-NNO- azoxy}furazan displays the highest melting point (114 °C, decomp.) among the known (nitro-NNO-azoxy)furazans, optimal density (1.80 g cm...
Article
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Three novel energetic furazans with a cyano-NNO-azoxy group were synthesized using cyanamide and 2,2,2-tri- fluoro-N-(4-nitrosofurazan-3-yl)acetamide as the starting compounds. (Cyano-NNO-azoxy)furazans obtained display high experimental enthalpies of formation (+742 to +1073 kcal kg⁻¹), good thermal stability (Tonset = 193–222 °C) and moderate mec...
Article
Energetic compounds containing a new explosophoric fragment, (3,4-dinitro-1H-pyrazol-1-yl)-NNO-azoxy group, and furazan rings linked by azo and azoxy bridges were synthesized. Furazans obtained combine a high calculated enthalpy of formation and acceptable thermal stability and are of interest as potential components of energy-rich materials.
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The effect of polymer binders on the thermal behavior, combustion, and composition of condensed gasification products of model boron-containing compositions was studied to determine the optimal fuel composition for the gas generator of a ducted rocket engine. The physicochemical transformations of boron particles during combustion wave propagation...
Article
Mechanical and thermal hazards are critical for chemical compounds. Foremost, the design of novel energetic materials that are stable, insensitive, but have a detonation performance superior to in-service materials is of great interest. However, a single source of safety data for hazardous materials with explosophoric functionalities is still missi...
Article
A method was developed for the synthesis of 3(5)-aryl-5(3)-pyrazolyl-1,2,4-oxadiazoles by acylation of amidoximes with acyl chlorides, followed by cyclization of pyrazolyl-O-acylamidoximes into the respective oxadiazoles. Nitration of these products was studied, in combination with nucleophilic substitution reactions in the obtained nitro derivativ...
Article
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A series of highly energetic nitrogen-rich salts comprised of a 5-(trinitromethyl)tetrazolate anion and high-nitrogen cations was synthesized by simple and efficient chemical routes from readily available commercial reagents. These energetic materials were fully characterized by IR and multinuclear NMR (1H, 13C, 14N) spectroscopy, elemental analysi...
Article
Progress in the rocket industry is only possible on the basis of new, higher performance and more environmentally friendly materials compared to up-to-date propellant ingredients for liquid, solid, gelled and hybrid propellant systems. In this work, synthetic methods have been developed for the preparation of new energetic azofurazans bearing nitro...
Article
The reaction of 3-amino-4-[(3-nitro-1H-1,2,4-triazol-1-yl)-NNO-azoxy]furazan (4a) with 2,2,2-trifluoro-N-(4-nitrosofurazan-3-yl)acetamide (6) in the presence of dibromoisocyanuric acid (DBI) followed by removal of the protective trifluoroacetyl group gives 3-amino-4-({4-[(3-nitro-1H-1,2,4-triazol-1-yl)-NNO-azoxy]furazan-3-yl}-NNO-azoxy)furazan (5a)...
Article
A series of novel energetic materials comprising of azo‐bridged furoxanylazoles enriched with energetic functionalities was designed and synthesized. These high‐energy materials were thoroughly characterized by IR and multinuclear NMR ( 1 H, 13 C, 14 N) spectroscopy, high‐resolution mass spectrometry, elemental analysis, and differential scanning c...
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The standard state enthalpy of formation and the enthalpy of sublimation are essential thermochemical parameters determining the performance and application prospects of energetic materials. Direct experimental measurements of these properties are complicated by low volatility and high heat release in bomb calorimetry experiments. As a result, the...
Article
There is a need for dense energetic oxidizers whose composition is restricted to carbon, hydrogen, nitrogen and oxygen atoms as chlorine-free alternative to current oxidizers of energetic materials such as explosives, propellants and pyrotechnics. High nitrogen heterocyclic frameworks containing trinitromethyl units are an attractive and increasing...
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Thermal decomposition of solids is often accompanied by autocatalysis, one of the possible causes of which is the formation of a liquid phase. The kinetic model considering the liquefaction of solid reactant under isothermal conditions was proposed by Bawn in the 1950s. Present study reports the application of the Bawn model to the thermolysis of 3...
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Professor Yurii V. Frolov passed away from coronavirus related complications in Moscow on 30 January 2021. His research concerned propellants, pyrotechnic formulations, and combustion. He is particularly renowned for his insights into the enhancing performance of compositions including aluminum and other metals. Prof. Frolov served as a head of lab...
Article
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Thermal decomposition of cis-1,3,4,6-tetranitrooctahydroimidazo-[4,5-d]imidazole (Bicyclo-HMX) both in solid state and in solution has been studied with a set of thermal analysis methods. Differential scanning calorimetry data obtained at several heating rates were analyzed using the model-fitting kinetic technique using the free open-source THINKS...
Article
High energy andmoderate sensitivity are the twomost important demands formodern energetic materials. The powerful CL-20 and its previously obtained derivatives do not meet safety requirements. To reach the desired goal of high-performance polycyclic cage multi-nitramine structures with reduced sensitivity, a novel family of energetic compounds was...
Article
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In the present work, we studied in detail the thermochemistry, thermal stability, mechanical sensitivity, and detonation performance for 20 nitro-, cyano-, and methyl derivatives of 1,2,5-oxadiazole-2-oxide (furoxan), along with their bis-derivatives. For all species studied, we also determined the reliable values of the gas-phase formation enthalp...
Article
A smooth synthesis of 4H-[1,2,3]triazolo[4,5-c][1,2,5]oxadiazole 5-oxide 1 and its energetic salts (ammonium, hydroxylammonium, guanidinium, triaminoguanidinium) is reported. The compounds synthesized were characterized by multinuclear nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy, mass spectrometry, elemental analysis, differenti...
Article
Nitronium borates of NO2[B(OX)4] type with X = CF3CO and NO2 as ligands were synthesized, and their structures were determined by powder X-ray diffraction. Crystalline NO2[B(ONO2)4] is relatively stable at room temperature and undergoes transformation to B2O3 upon heating. The [B(CF3COO)4]⁻ anion was obtained for the first time and characterized as...
Article
The problem of the space debris is an important aspect of the on-ground casualty risk reduction. Some articles, like fuel tanks made of titanium alloy, survive during the atmospheric post-mission re-entry and impact the Earth's surface, thus posing a serious hazard. A pyrotechnic device is proposed to bring an additional heating of space debris at...
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Physicochemical changes occurring in an oxide shell of boron particles during heating are extremely important for the oxidation and combustion of boron, including those in solid propellant compositions. The Al2O3, MgO, MgF2, Al, and Mg impurities were experimentally discovered in an oxide layer on boron particles obtained by various methods. The go...
Article
The kinetics of thermal transformations of the energetic compound 2,4,6-tris(2,2,2- trinitroethylnitramino)-1,3,5-triazine (1) and products of this reaction were studied by differential scanning calorimetry, thermogravimetry, IR spectroscopy, single-crystal X-ray diffraction, and powder X-ray diffraction. The kinetic and activation parameters of th...
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A supercritical antisolvent process has been applied to obtain the nitrocellulose nanoparticles with an average size of 190 nm from the nitrocellulose fibers of 20 μm in diameter. Compared to the micron-sized powder, nano-nitrocellulose is characterized with a slightly lower decomposition onset, however, the friction sensitivity has been improved s...
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The kinetic parameters of thermal decomposition of furazano-1,2,3,4-tetrazine-1,3-dioxide (FTDO) and the (75/25) FTDO/dinitrazapentane (DNP) system were experimentally investigated by differential scanning calorimetry. Kissinger kinetic analysis was performed using differential scanning calorimetry data obtained at heating rates of 0.1–5.0 K/min. T...
Article
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Several thermite systems (Al/Fe2O3 and Mg/Fe2O3) with promising applications in sealed pyrotechnic heat sources under space conditions have been reported earlier. Experiments have found excellent propagation of the combustion reaction of these thermites inside sealed steel tubes. Outer tube surfaces have been heated up to 700–1000°C. This article f...
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Thermal decomposition of solids often includes simultaneous occurrence of the overlapping processes with unequal contributions in a specific physical quantity variation during the overall reaction (e.g., the opposite effects of decomposition and evaporation on the caloric signal). Kinetic analysis for such reactions is not a straightforward, while...
Article
A series of highly energetic organic salts comprising of a tetrazolylfuroxan anion, explosophoric azido or azo functionalities and nitrogen‐rich cations was synthesized by simple, efficient and scalable chemical routes. These energetic materials were fully characterized by IR and multinuclear NMR (1H, 13C, 14N, 15N) spectroscopy, elemental analysis...
Article
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Combustion of thermite composition Mg/Fe2O3 with micron-and nano-sized components was studied in pyrotechnic heater setup. Pressed charges were burned out in hermetic steel tubes with simultaneous pressure and temperature registration. Advanced system of thermocouples connections allows drawing thermal maps of the steel case heating with high spati...
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Thermal stability of energetic materials, being of the utmost importance for safety issues, is often considered in terms of kinetics, e.g., the Arrhenius parameters of the decomposition rate constant. The latter, in turn, are commonly determined using conventional thermoanalytical procedures with the use of simple Kissinger or Ozawa methods for kin...
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This paper describes a study of boron powders and powder compounds, obtained by various methods, including metallothermal, electrolytic, and borane cracking methods. The crystal state, particle size and microstructure, presence and composition of impurities, and chemical composition of the oxide layer of boron particles are profoundly investigated....
Article
Oxidation of nanosized titanium (nano-Ti), a promising component of energetic compounds, was studied using thermogravimetry and differential scanning calorimetry. To obtain more comprehensive insight into the kinetics and mechanism of oxidation, a variety of complementary non-isothermal and isothermal thermoanalytical experiments were performed. In...
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A conceptual approach to improve the safety of rocket-space activity is presented, including minimization of space debris returning from space. The main idea is to eliminate hazards of uncontrolled re-entry of detachable rocket design elements after finishing their mission with the use of the energy of pyrotechnic thermite reaction to disrupt these...
Article
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The key steps of the synthesis of two high energy compounds, namely, 4-(2,2,2-trinitroethyl)-2,6,8,10,12-pentanitrohexaazaisowurtzitane and 4,10-bis(2,2,2-trinitroethyl)-2,6,8,12-tetranitrohexaazaisowurtzitane, were optimized. Their enthalpy of formation, density, impact and friction sensitivity, and thermal stability were experimentally determined...
Article
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Thermal behavior of two principally different wax materials (viz., paraffin Russian grade P-2 and microcrystalline Sasol 0907) has been investigated using thermogravimetry and differential scanning calorimetry at atmospheric and elevated pressure. The variation of experimental conditions during thermoanalytical studies highly affects the kinetics a...
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This study focused on kinetic modeling of a specific type of multistep heterogeneous reaction comprising exothermic and endothermic reaction steps, as exemplified by the practical kinetic analysis of the experimental kinetic curves for the thermal decomposition of molten ammonium dinitramide (ADN). It is known that the thermal decomposition of ADN...
Article
[Figure not available: see fulltext.] Regioselective introduction of nitro groups was studied in the case of pyrazoles containing a 1- or 5-tetrazole substituent at position 3(5). All the possible isomeric C-mononitropyrazoles were synthesized. The reduction of these compounds gave the respective 3(5)-amino-5(3)-tetrazolylpyrazoles, which were nitr...
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FOX-7, first synthesized two decades ago, is a promising insensitive energetic compound. Enthalpy of formation is among the most important parameters that influence, e.g., the detonation velocity, a crucial performance indicator of an energetic material. Very surprisingly, despite the fact that FOX-7 has been known for almost 20 years, its accurate...
Article
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Thermal decomposition of a novel promising high-performance explosive dihydroxylammonium 5,5’-bistetrazole-1,1’-diolate (TKX-50) was studied using a number of thermal analysis techniques (thermogravimetry, differential scanning calorimetry, and accelerating rate calorimetry, ARC). To obtain more comprehensive insight into kinetics and mechanism of...
Chapter
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The thermal decomposition and combustion of binary mixture of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and ammonium perchlorate (AP) are investigated at various concentrations. Thermal stability was investigated by thermal analysis techniques, i.e., DSC/TGA, combined with FTIR spectrometry, and accelerating rate calorimetry (ARC). Two...
Article
Continuing advances in energetic pyrazole construction foster further its rational use. This work establishes an approach for the first synthesis of nitropyrazole that bear both furazan and trinitromethyl moieties. The approach to the installation of the C(NO2)3 group exploits the destructive nitration of N-acetonyl group. The target 3-(3,4-dinitro...
Article
Analytical and experimental studies conducted at Semenov Institute of Chemical Physics for investigating the use of pyrotechnic compositions, i.e., thermites, to reduce the risk of the fall of thermally stable parts of deorbiting end-of-life LEO satellites on the Earth are described. The main idea was the use of passive heating during uncontrolled...
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The nitrogen-rich energetic compound 5-amino-3,4-dinitropyrazole (5-ADP) was investigated using complementary experimental techniques. X-ray diffraction indicates the strong intermolecular hydrogen bonding in 5-ADP crystals. Compound exhibits low impact sensitivity (23 J) and insensitivity to friction. The activation energy of thermolysis determine...
Article
Inspired by the recent victory of the computer program Alpha Go [D.Silver et al, Nature, 2016] over the world strongest human Go player and by the ability of this program based on artificial neural networks(ANN) for self-learning, we present the attempt to perform the thermokinetic analysis using ANN models. Various virtual combinations of kinetic...
Article
High pressure differential scanning calorimetry (HP-DSC) has been used to study thermal decomposition of energetic materials, i.e., trinitrotoluene, cyclotrimethylenetrinitramine, and ammonium dinitramide. HP-DSC runs have been performed in the range of 0.1–14 MPa both in inert and oxidative environments to determine the effect of pressure on vapor...
Chapter
The influence of nanosized oxides of Ti, Al, Fe, and Si on the HMX thermolysis and combustion is reported. The following order of their catalytic efficiency in HMX thermolysis was obtained: TiO2 > Fe2O3zAl2O3 > SiO2. The catalytic performance was analyzed and the key factors were shown to be specific surface area, content, and the acid/base propert...
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Fully nitrated five-membered heterocycles (pyrazoles), polynitropyrazoles in particular, have been actively studied as promising high-energy materials. Polynitropyrazoles have high density and high enthalpy of formation combined with reduced sensitivity to external stimuli. We have studied non-equilibrium processes of thermal decomposition of the f...
Article
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Non-equilibrium process of combustion-wave propagation of thermite compositions (Mg/Fe2O3) inside the sealed steel tube have been investigated to study the burning rate at elevating pressure. Under confinement the hot gas-phase products, formed during thermite combustion result in considerable overpressure inside the tube that reverses the gas flow...
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Aluminum particles with a diameter of ≈50 nm were synthesized by means of the Gen-Miller flow-levitation method with alumina or trimethylsiloxane coatings formed on the surface of these particles. Aluminum/HMX nanocomposites manufactured by suspension atomization drying or dry mechanical mixing were investigated by x-ray diffraction analysis, scann...
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The influence of nanosized oxides of titanium, aluminum, iron, and silicon on HMX thermolysis is reported. The catalytic performance was analyzed and the key factors were shown to be specific surface area, content, and the acid/base properties of the metal oxide surface. The acidity of the surface of nanosized titania was varied to evaluate the sub...
Conference Paper
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The search for environment-friendly high-energy materials with effective performance to replace traditional energetic materials has led to discovery of polynitropyrazoles, which comprise a fivemembered heterocyclic ring with two neighboring nitrogen atoms substituting the carbon atoms and at least two nitro groups. This class of energetic compounds...
Article
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Thin film titanium/poly-para-xylylene nanocomposites with controlled Ti content are prepared by vacuum coevaporation and cocondensation of Ti and paracyclophane. The structure and chemical composition of as-deposited samples and the changes of electrical resistivity, which they undergo upon heating, are studied by atomic force microscopy, optical a...