Nanotechnologies in Construction: A Scientific Internet-Journal

97–109

Authors: Samchenko S.V., Kozlova I.V, Zemskova O.V, Dudareva M.O.

ABSTRACT: Introduction. The current stage of the construction industry and building materials science development involves the introduction and widespread application of nano- and fine particles capable of improving the properties of traditional materials. However, it is necessary to provide stabilization of nano- and fine-dispersed components in the cement system. Plasticizing additives can be used as stabilizers. It is important to set their concentration. Therefore, the purpose of this study is outlined, which lays in the methodological substantiation the stabilizing effect of various types of plasticizers on the suspension of fine synthetic bismuth titanate used in the modification of cement systems, and the establishment of the limits of their optimal concentrations. Materials and methods. The research is aimed at establishing the limits of optimal concentrations of polycarboxylate and sulfonaphthalene formaldehyde plasticizers. The limits of plasticizers optimal concentrationsis determined withdye solubilization method, surface tension and conductometric methods, and studies on establishing the stabilizing effect of plasticizers on a bismuth titanate fine particles suspension. Results and discussion. To establish the limits of the optimal concentration capable of stabilizing fine particles of bismuth titanate in suspension, CMC is determined by the dye solubilization method, surface tension and conductometric methods. It is found that a polycarboxylate plasticizer is characterized by one CMC point, and a sulfonaphthalinformaldehyde plasticizer is characterized by two CMC points: CMC1 and CMC2. At CMC1 point unstable spherical micelles are formed, which turn into stable ones at the CMC2 point. At concentrations exceeding the CMC2 value, polymorphic transformations of spherical micelles into nonspherical asymmetric micelles occur. The same can be traced for the polycarboxylate plasticizer CMC only in one stage. It can also be concluded that it is not reasonable to increase the plasticizer concentration above CMC for polycarboxylate plasticizer and above CMC2 for sulfonaphthalinformaldehyde plasticizer, which is due to structural changes in the micelles of plasticizers. It is assumed that in order to stabilize bismuth titanate fine particles, it is necessary to choose the plasticizers concentration within the limits not exceeding the values of CMC for polycarboxylate plasticizer and CMC2 for sulfonaphthalinformaldehyde plasticizer. Conclusion. Concluding results demonstrate the limits of optimal plasticizers concentrations for the stabilization of bismuth titanate fine particles suspension. For polycarboxylate plasticizer this range of concentrations is 1.1 – 1.5 g/l; for sulfonaphthalinformaldehyde plasticizer its 2.2 – 4.0 g/l.

117–123

Authors: Nazarov V.G., Ivanov L.A., Dedov A.V., Bokova E.S., Statnik E.S.

ABSTRACT: Introduction. The aim of the work is to determine the influence of the structure of the filter materials formed as a result of modification of the surface layer on their water permeability and the size of trapped solid particles. Materials and methods. The non-woven fabrics from a mixture of polyethylene-terephthalate (PET) (70 wt.%) and bicomponent fibers (BCF) of the coreshell structure were used as objects of the study. The non-woven fabrics were obtained by mechanically forming the canvas with its subsequent hardening by needle punching. The resulting materials were modified by heat treatment. The water transfer in the modified materials was determined by the permeability coefficient. The filtration efficiency was determined by the number of trapped particles of a certain size. Results and discussion. The needle-punched non-woven fabrics without additional heat treatment are not suitable for water filtration. The proposed method of thermal and deformation-thermal modification provides the production of gradient materials with a controlled thickness of the nanoscale surface layer. Although a decrease in water permeability is observed, the modified material traps solid particles with a smaller (compared to unmodified ~ 20 µm) equivalent diameter of 2–4 µm, which is sufficient to prepare water for use in steam generators and in the production of building materials. Conclusion. The optimal parameters of deformation-heat treatment for obtaining the high-effective filtration non-woven materials were established: the temperature – 180оC, the processing speed – 3.5 m/min.

139–151

Authors: Yudaev P.A., Tamboura B., Chistyakov E.M.

ABSTRACT: Introduction. In connection with the growing demand for living and working conditions in civil and industrial construction, there is an increasing need for high-quality building materials with the required set of performance properties. Polymer reinforced composite materials are promising materials in the construction industry due to their high strength, durability, reliability and economy. Polymers such as polyvinyl chloride, polyurethanes, polyacrylates, epoxy resins, polypropylene are used in construction for the manufacture of decorative elements, self-leveling floors, coatings for appliances and equipment. However, the use of polymeric materials creates risks of electric shock due to the generation of static charge. The use of electrically conductive nanomaterials as fillers makes it possible to reduce the resistivity of polymeric materials and slow down the flow of electric charges. Main part. This review article presents the benefits and drawbacks of antistatic additives for polymer materials used in industry and in the construction industry. Conclusion. An analysis of the literature has shown that over the past seven years, the largest number of relevant papers has been devoted to carbon materials as antistatic additives (8 articles), metal and metal oxide nanoparticles (7 articles), ionic liquids (7 articles), and polyaniline (7 articles). The most studied characteristics of antistatic polymer materials are the specific surface RS and volume RV resistances. According to the reviewed articles, metal and metal oxide nanoparticles are the most suitable antistatic additives to polymeric materials, since they are well dispersed in the polymer matrix. However, further research is needed to eliminate the negative effect of nanoparticles on the mechanical properties of polymeric materials

164–170

Authors: Mazitova A.K., Sukhareva I.A., Sidorov G.M., Talipov R.A., Aminova A.F.

ABSTRACT: Introduction. Phenols and petroleum products are common wastewater contaminants in many industries. Due to their persistence and toxicity in the natural environment, an efficient waste disposal technology is needed. Ozonation in the presence of heterogeneous catalysts is one of the advanced methods for treating wastewater from these toxicants. Since most catalysts are expensive, they are being sought on the basis of transition metals and their oxides, which have high activity and relatively low cost. In this regard, the Scientific and Educational Center for Innovative Technologies (SECIT) of USPTU carried out work on the search for an effective and affordable catalyst for the deep oxidation of phenol and petroleum products in wastewater under the influence of ozone. Methods and materials. To study catalytic ozonation, we used model waste water containing phenol and oil products at concentrations of 8 and 30 mg/dm3, respectively. Ozonation was carried out in the presence of fresh (1) and spent (2) NiO–MoO3 catalyst deposited in the form of a film on cylindrical Al2O3 granules weighing 0.5 – 2 g. Results. Optimal conditions of ozonation have been found (1), within 10 min of the decomposition process in its presence, COD decreased by 25% compared to the oxidation process with a catalyst (2), and by 40% compared to classical ozonolysis. It was found that the optimal loading of catalyst (1) is 1 g, duration is 35 min, pH = 8.5, temperature – 22 – 30оC, ozone dose – 5 g/dm3. Discussion. At catalyst dosages of less than 1 g/dm3, the low efficiency of removing phenol and hydrocarbons is probably due to a lack of the adsorption surface of the catalyst. Conclusion. The studied method of purification allows to reduce the content of phenol and oil products to the standard indicator of drinking water quality (0.001 and 0.05 mg/dm3, respectively), COD by 96% and solve the problem of the harmful effects of these toxicants on ecosystems.