Reinforced Epoxy Composites Modified with Functionalized Graphene Oxide

The possibility of using graphene oxide as a modifying additive for polymer fiber-reinforced composites based on epoxy resin and basalt roving has been studied. The content of graphene oxide in the system has been experimentally selected, which has the best effect on the physico-mechanical properties of the obtained polymer composite material. The efficiency of the modification of the graphene oxide surface with APTES finishing additives and aminoacetic acid, which provides chemical interaction at the polymer matrix–filler interface, has been considered. The influence of graphene oxide and functionalizing additives on the polymer curing process was investigated using the thermometric method and differential scanning calorimetry.

Rheological characteristics of the binder for foam concrete with a complex of mineral modifiers

The paper considers the effect of mineral additives on the rheological characteristics of a binder for foam concrete. The compositions in the study were divided into two groups: based on nanostructured binder (NB) and based on cement. For the compositions of the first group portland cement is proposed as a modifying additive,for the compositions of the second group NB and anhydrite were used as modifying additives. It has been shown that the introduction of cement into NB increases the viscosity due to an increase in the concentration of large-sized particles, while the combined use of nanostructured binder and anhydrite as modifiers of the cement system helps to reduce the viscosity of the cement mortar and increase its mobility, which reduces the amount of mixing water. From a technological point of view, this will make it possible to obtain materials with a rational pore structure by optimizing porosity processes.

Nanomodification of Lightweight Fiber Reinforced Concrete with Micro Silica and Its Influence on the Constructive Quality Coefficient

A hypothesis was put forward that a nano-modifying additive of micro silica, which had a beneficial effect on achieving a perfect structure of heavy concrete, can also be effectively used in lightweight fiber-reinforced concrete. The nano-modifying additives of micro silica application in manufacturing lightweight fiber reinforced concrete products and structures can significantly enchain their strength characteristics without increasing their mass and consequently improve their design characteristics. The purpose of the work was to increase the structural quality coefficients for all types of strengths of lightweight fiber-reinforced concrete due to its modification with micro silica. The effect of nano-modifying additives of micro silica on the strength characteristics of lightweight fiber reinforced concrete was studied. The optimal amount of micro silica addition was experimentally confirmed and established of 10% of the cement mass. The coefficients of constructive quality for all experimentally determined strength characteristics of lightweight fiber-reinforced concrete modified with micro silica additives were calculated. The coefficient of constructive quality for tensile strength in bending of lightweight fiber reinforced concrete with additives was two and a half times higher than that of heavy concrete without additives and up to 37% higher than that of lightweight fiber-reinforced concrete without additives.

Influence of titanium and zirconium on structure and heat-resistance of low-carbon iron-aluminium alloys

The paper considers the effect of introducing ferroalloys containing titanium and zirconium on the structure and heat-resistance of low-carbon ferroalloys. Theoretically and experimentally, it has been proven that addition of 1.0 mass. % of titanium and 0.1 mass. % of zirconium to a low-carbon iron-aluminum melt containing 12 – 14 mass. % of aluminum, grinds its structure increasing temporary resistance and heat-melting. Titanium and zirconium are strong carbide-forming elements. When introduced into a low-carbon iron-aluminium alloy, they form a large number of crystallization centers, thus affecting its microstructure, allowing to get shredded and more equal grain compared to an alloy without additive. This in turn increases the strength limit of processed alloy. In addition, the use of titanium as a modifying additive in a low-carbon ferroalloy allows increasing its heatresistance, which exceeds several times the heat-resistance of famous chrome-nickel steel of 20Kh23N18 grade. As a result, a new technology for obtaining titanium and zirconium was developed based on research of the effect of their modifying additives on the structure and heat-resistance of low-carbon iron-aluminum alloys.

MODIFIED CARBON-CONTAINING ALUMINUM CHLORIDE CATALYSTS

Catalytic systems based on metallic aluminum Al and carbon tetrachloride CCl4, modified by Mg, CuCl2, NiCl2, MgCl2, have been developed. EPR and IR spectroskopiya studies of synthesized samples of catalysts were carried out. Based on the EPR spectrum, the presence of a Cu-C -bond was revealed in the Al + CCl4 catalyst with the modifying additive CuCl2. Using IR spectra, it was determined that catalysts without modifiers and with modifiers are a mixture of two complexes based on Corbin-type structures. In this case, the catalysts differ in the ratio of the main structures with double C=C and triple C≡C bonds. Catalysts with modifying additives NiCl2 and Mg have significantly fewer of these structures than a catalyst without modifiers, and a catalyst with Mg is characterized by the smallest number of structures containing C=C bonds. It is shown that the catalysts obtained on the basis of Al and CCl4 and its various modifications are complexes, the carbon-containing part of which is represented by polycumulene and polyine structures containing ethylene and acetylene bonds.

Improving the Quality and Durability of Restorative Coatings by Arc Deposition and Modification with Natural Additive Bentonite Clay

The study considers the possibility of improving the quality and service life of reducing coatings by arc deposition and modifying with natural additive bentonite clay. It has been established that when the modifier is introduced into the fluid bath during arc deposition, the phases and their interactions change. Introduction of the modifying additive bentonite clay significantly changes the crystalline lattice of the carbidephases. The optical-mathematical method revealed the absence of austenite and the pair interaction of ferrite-carbide during modification. The maximum proportion of phases corresponds to ferrite (33.8% -2 times decrease) and ferrite-austenite-carbide interaction (48.62% -2 times increase). The ferrite-austenite interaction increases almost 8 times during modification. The wear coefficient in this case is 2.2 times lower in comparison with the original steel 65Gand 1.4 times lower in relation to arc deposition with only T-620 electrode.

STRUCTURE AND PROPERTIES OF THE АК12М2МгН (AlSi12Cu2MgNi) PISTON ALLOY FORMED UNDER THE INFLUENCE OF A COMPLEX MODIFYING ADDITIVE OF FULLERENE-CONTAINING SOOT AND COPPER

The article presents the study results of the complex modification of eutectic silumin АК12М2МгН (AlSi12Cu2MgNi) with additives of fullerene-containing soot (FCS) and copper. It is shown that the effect on the alloy structure is caused by the introduction of carbon nanoparticles into the melt and is manifested in the dispersion of the structural phases and their uniform distribution in the casting volume. At the same time, the use of dispersed copper powder provides wetting of aluminum carbon particles with the melt and additional alloying of the melt. The formation of a dispersed structure leads to an increase in the mechanical and tribotechnical characteristics of the alloy: an increase in the ultimate strength (by 1.3–1.6 times) with a simultaneous increase in the relative elongation by up to 3 times, a significant decrease in the coefficient of friction (by 1.1–1.7 times) and the intensity of wear. The lowest coefficient of friction and high wear resistance are achieved at small fractions of FCS (0.05–0.1 wt.%) and the copper content in the modifier is not more than 0.5 wt.%.

Improvement of Environmental Safety in the Processing and Use of Elastomeric Waste

The possibilities of use of combined modifying additive in the production of polymeric materials from general-purpose rubber production wastes are considered. Such additives facilitate reduce of the exhaust of pollutants into the environment at the stage of waste processing. Inorganic salts, including sodium phosphate and ammonium sulfate in a certain ratio can be used as a combined modifying additive the results of the study confirm the advantages of using of this complex modifier in polymeric materials from rubber production waste to increase their resistance to thermal decomposition, fire and aggressive media in comparison with an unmodified product. It was demonstrated that the complex modifying additive is more compatible with ISK rubbers and less washed out from it than with SKS rubbers.

Modification of polyvinylchloride by the silicates on the base of rice husk

As a modifying additive in PVC-compositions, silicates produced by means of rice husk processing are of practical interest. Rice husk ash obtained by burning at 350°C, along with synthetic and naturally occurring wollastonite, significantly reduce plasticizer’s migration from the PVC-composition due to their porosity. This is due to the fact that the part of hydroxyl components of the plasticizer EDOS has adsorbed on the surface or retained by the silicates pores. Along with that, Miwoll 10-97 ensures a greater decrease in plasticizer’s migration than synthetic calcium silicate on the base of rice husk ash. When all the researched silicates are modified by the rice husk and naturally occurring wollastonite, heat stability of PVC-compositions grows. This is preconditioned by the alkaline origin of the surface of filling compounds that allows their possible reaction with chlorine hydride released from PVC during thermal decomposition. Synthetic and naturally occurring wollastonite enhance strain-strength properties of PVC-compositions whereas silicates on the case of rice husk reduce these parameters.