Hydration of Cement in the Presence of Biocidal Modifiers Based on Metal Hydrosilicates

This article presents the results of a study of the characteristics of hydration and properties of a composite biocidal cement binder containing hydrosilicates of barium, copper or zinc. It was found that copper hydrosilicates block hydration processes, and when zinc hydrosilicates are used, the rate of hydration is determined by the content of silicic acid. The limiting concentrations of biocidal modifiers have been established: zinc hydrosilicates—no more than 4% and copper hydrosilicates—no more than 0.5%, which are advisable to use for the manufacture of a biocidal composite binder. It is shown that modifying additives slow down the setting time, the amount of tricalcium silicate in cement stones increases, and their strength for some compositions decreases. Active binding of portlandite with the formation of calcium hydrosilicates occurs when the content of zinc hydrosilicates is 2%, which leads to an increase in the strength of the materials.

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.

Ceramic Mass Modifiers for the Production of Wall Ceramic Products

Modern methods of improving the characteristics of ceramic products by introducing modifying additives based on various industrial wastes into the composition of the ceramic mass are considered. The compositions of ceramic masses and some features of the technology of manufacturing ceramic products using industrial waste are described. A diagram for the distribution of wastes from various industries (modifiers of the ceramic mass) according to the main type of action and predominant oxides is proposed.

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.

Investigation of the Fluxing Additives Effect on the Foaming of Different Silicate Raw Materials

The main trends in the use of silicate raw materials for the production of heat-insulating materials are considered. It is shown that the introduction of modifying additives-fluxes is promising to reduce the energy intensity of the technology. The substances that play the role of fluxes in the silicate industry are selected. The most active fluxes were chosen - sodium tetraborate Na2B4O7 (borax) and sodium fluoride NaF. The mechanism of their melting effect on the silicate mass is investigated. It is shown that both borax and sodium fluoride are active fluxes, intensifying the melting of silicate raw materials of all types. The use of fluoride is hampered by a narrow temperature range, in which the formation of a stable porous structure is possible.

Analysis of Phase Composition and Properties of Composite Nickel-Phosphoric Coatings Using Wear-Resistant and Antifriction Modifying Agents

The possibility of introduction of antifriction and wear-resistant modifying agents into the matrix of a composite nickel-phosphorus coating to obtain effective composite coatings, is considered. The analysis of the possible influence of modifying additives in the form of ultrafine powders on the tribological properties of the developed coatings, is carried out.

EFFICIENCY OF MODIFYING ADDITIVES IN POWDER COATING MATERIALS

Rapid rates of development in production of powder coatings are, in comparison to liquid paint-and-lacquer materials, evidence of their importance, high effectiveness and prospectivity. The increase in popularity of powder coatings can be explained by their environmental adequacy and attractiveness from the perspective of the environmental protection as well as high effectiveness related to the possibility of obtaining high quality protective and decorative coatings during the one-layer application. At the same time, it is obvious that during modern powder coating-and-lacquer materials have not exhausted all possibilities of improving pharmaceutical compositions and expanding the assortment as well as modernizing their production technology the relatively short period of their development. The composition of the thermosetting powder coating contains five key components: polymer resin, hardener, pigments, fillers and functional additives. In general, the polymer resin and hardener play a key role in ensuring necessary mechanical characteristics and lifespan of the powder coating. In this case, the role of functional (modifying) additives is extremely important to obtain characteristics that are often fundamentally required to meet predetermined technical specifications of the products and needs of end users. Additives play an important role in forming properties of powder coatings and coatings based on them as they have become their integral part for several main reasons: because of control of rheological properties, surface defects as well as light and temperature stabilization of coatings. The study deals influence of modifying additives on properties of the powder coating. The authors using rheological and degassing modifying additives with different nature of the main active substance. It was found that the additives based on the acrylate polymer adsorbed on the silicon dioxide in the form of Byk-3900P and on the polyoxyethylene derivative of the castor oil in the form of Luvotix R400 decreasing the surface tension in the coating film, which, in its turn, contributes to the increase in the wettability of base during the melting of the powder coating, decrease the ‘orange peel’ effect during the cross-linking, reduction in pinholes on the obtained surface and improvement of mechanical characteristics of the coating. At the same time, rheological additives based on the bentonite in the form of Luvogel 4B and on the hydrophilic silicon dioxide in the form of Cab-o-sil M5 cause the increase in the surface tension in the coating film, which, in its turn, leads to the worsening of flow, appearance and mechanical characteristics of the powder coating.