No abstract

No abstract

No abstract

complex formation of K 2 [Pdcl 4 ] with 1-phenyl-1-hydroxymethylene bisphosphonic acid (PhhMBP, h 4 K e y w o r d s: palladium(II) complexes, bisphosphonic acid, cytotoxic activity, toxicity.C isplatin is still one of the most famous and efficient anticancer drugs used in the clinical practice [1]. Nevertheless, searching for new compounds with antineoplastic action continues to eliminate the serious side effects, to improve the clinical efficacy and to broaden the antitumor spectrum. In particular, palladium(II) bisphosphonates are promising species for the treatment of bone cancer and metastases: complexes include a cytotoxic metal (palladium) and a bisphosphonic acid, which possesses affinity for bone tissue and can ensure targeted delivery of the cytotoxic metal to the lesion site [2][3][4][5][6][7][8][9]. The P-C-P moiety present in bisphospho nic acids provides their active link to the bone matrix, and two side substituents determine their physicochemical and pharmacologic properties. To study the effect of the structure of complex and chemical nature of the substituents bonded to the carbon atom of bisphosphonate moiety on the biological activity, the formation of palladium(II) complexes with 1-phenyl-1-hydroxymethylene bisphosphoniс acid was investigated, which, besides two phosphonic groups, contain a hydroxy group and a phenyl moiety.

The purpose of the work was to determine the properties of the developed material (bitumen). In this study, the technological process was improved by modifying low-molecular weight butadiene and chloroprene rubbers structured with carbon nanotubes (CNTs) to obtain a material with the necessary set of desired properties. The article shows the possibility of modifying the bituminous binder of asphalt concrete with elastomeric rubbers structured with CNTs. The article also considers the use of promising polymer composite materials and the increase in their reliability and service life. Improvements in the properties of the composite and in the technology due to direct reinforcement with nanomaterials are described. The article defines the areas of application and recommended improvement of composite materials, as well as existing limitations.

In accordance with the principles of sustainable development, improving the quality and durability of structural elements and coatings, the construction industry requires the development and the implementation of resource- and energy-efficient building materials, as well as innovative technologies for their production. The use of complex modifiers for no-slump concrete mixtures and concrete is becoming increasingly widespread in modern materials science. The article presents the studies of influence of polymer additive structured carbon nanomaterials on physical and mechanical characteristics of no-slump concrete mixtures. The methods of infrared spectroscopy and thermogravimetric analysis showed that the use of carbon nanomaterials alters the structure of no-slump concrete mixtures significantly. As a result of the fact that the high-strength nanomaterial is the centre of crystallization of cement stone neo-formation, a denser reinforced microstructure is formed, which increases significantly the strength properties of no-slump concrete mixtures. The inclusion of a complex polymer additive in no-slump concrete mixtures leads to higher and longer plasticizing, which plays an important role in the production of monolithic products. It was determined that, in the presence of a complex modifier (a polymer additive structured by carbon nanotubes), the crystalline structure of calcium silicate hydrate is compacted, which determines high physical and mechanical characteristics of modified no-slump concrete mixtures. It was experimentally shown that the additive acted as an accelerator of a setting and hardening cement test and also increases its strength characteristics. In general, in this study, there is a water-reducing effect from the application of the additive for all no-slump concrete mixtures. Water consumption is reduced by 5% of the mass, while the strength is increased by 19%. No-slump concrete mixtures recipes modified by polymer additives, structured by carbon nanotubes, with high performance were developed.

The use of complex modifiers for cement-concrete mixtures and concretes is becoming increasingly popular in modern materials science. The paper presents studies of the effect of a polymer additive structured with carbon nanomaterial on the physical and mechanical characteristics of cement-concrete mixtures. IR spectroscopy and thermogravimetry revealed that the use of carbon nanomaterial significantly changes the structure of cement-concrete mixtures. As a result of the fact that high-strength nanomaterial is the center of crystallization of cement stone formations, a denser reinforced microstructure is formed, which significantly increases the strength characteristics of cement-concrete mixtures. Inclusion in the composition of cement-concrete mixtures of polymer complex additives leads to higher and longer plasticization, which plays an important role in the production of monolithic products. It is established that in the presence of a complex modifier (polymer additive structured with carbon nanotubes) the crystal structure of calcium hydrosilicates is compacted, which causes high physical and mechanical characteristics of modified cement-concrete mixtures. It is experimentally shown that the additive acts as an accelerator of hardening and hardening of cement paste, as well as increases its strength characteristics. In general, for all cement-concrete mixtures in this study there is a water-reducing effect of the additive. Water consumption decreases by 5 wt. %, while the strength increases by 19%. Formulations of cement-concrete mixtures modified with polymer additives, structured carbon nanotubes, with high performance characteristics have been developed.

The review is devoted to the analysis of modern research in the development of formulations and technology for the manufacture of composites based on bituminous binders for the creation of improved asphalt concrete. Methods for modification of bitumen by polymer additives, chemical stabilizers, industrial wastes (recycled polymers, ground tire rubber, fly ash, etc.), nanodispersed additives and carbon nanomaterials to obtain the necessary predetermined properties are considered. The positive and negative aspects of using various modifiers are analyzed. The efficiency of modification of bituminous binders with recycled polymers and nano(ultra)dispersed fillers is shown, which makes it possible to create composites based on bituminous binders for asphalt concrete pavements with high performance characteristics. The optimal content of additives to the bitumen binder has been analyzed: the amount of thermoplastic polymers and thermoplastic elastomers in the range of 3-10 wt.%, thermosetting polymers − over 10 wt.%, elastomers − up to 15 wt.%, and nano-sized additives: nano-oxides ≥ 5 wt.%, nanoclay ~ 3 wt. %, carbon nanotubes, graphene < 1.2 wt.%. Modification of bitumen with recycled polymers and partial replacement of expensive polymer modifiers with cheaper polymer waste, composite modifiers, namely recycled polymer mixed with ground tire rubber and / or fly ash are considered. This allows solving the environmental problems (waste utilization and secondary use) and reduce the cost of asphalt concrete. From the analysis of the experimental results, it becomes clear that for prediction of the properties of modified asphalt concrete, the basic characteristics of the original bitumen, which can differ significantly, are important, as well as the type of modifier (combination of modifiers), its chemical nature, and the efficiency of its dispersing in bitumen. The different chemical composition of the initial bitumen and its physicochemical properties probably play a primary role in imparting high and low temperature properties to asphalt concrete. Modification of a bituminous binder with waste polymers and nanofillers, first of all, makes it possible to improve such important performance characteristics of bitumen and asphalt concrete, such as softening temperature, penetration, penetration index, ductility, viscosity, moisture resistance, complex shear modulus, rutting parameter, resistance to cracking, etc.