Nanotechnologies in Construction: A Scientific Internet-Journal

Number 6, 2019

623-639
Properties of porous heat-resistant composition materials. Part I.

Authors: Kudryavtsev P.G.

Abstract

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This article is a continuation of a series of articles on the production of porous composite nanomaterials. This paper presents an overview of the properties of porous, heat-resistant inorganic composite materials. The physicochemical and mechanical characteristics of various porous refractory materials produced industrially are presented. A separate class of materials with a regular and quasi-regular porous structure is considered. Such materials include the so-called cellular or «lattice» materials, that are becoming widely applied in modern industry. An example of such materials is ceramic foam – a sintered ceramic material with a foamy cellular structure. A special group of materials with opal pore structure has been also focused. Synthetic opals have received intensive development in recent years because they are model objects for the development and research of new spatial-periodic structures with nonlinear optical properties. Such structures include composites based on classical and inverted opals, in which the pores are filled with various dielectric, semiconductor, or metallic substances. The optical properties of these systems are determined by the size of the close-packed particles, as well as the dielectric constant of the components.

650-666
«Intellectual» system of ventilation and air conditioning in apartments in high-rise buildings

Authors: Belozerov V.V.

Abstract

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Number of views: 263

One of the global problems in the world is the protection of humanity from fires, 70% of which occur in high-rise residential buildings and individual houses. The article presents the application of the methodology of «intellectualization» of household electrical appliances for split systems to control dangerous factors of fire and explosion (DFFE) from household gas leaks in apartment buildings and individual houses. The principal difference of the proposed modification is that, firstly, a multisplit-system with two or three internal blocks is used, one of which is to be installed in the kitchen and is connected to the gas meter with an electromagnetic valve to block the supply of household gas. Secondly, the «kitchen block» disconnects the power supply in the apartment/individual house, in the apartment/individual house, when detecting DFFE with help of powerful triac or magnetic starter, which is mounted in the electrical panel of the apartment/individual house. And thirdly, a battery and converter are integrated in each indoor unit to ensure their operation when power is turned off, and to charge the unit when power is supplied. Fourthly, in addition to smoke, heat and gas sensors, a thermomagnetic air separator is built into each indoor unit, which is turned on when detects dangerous fire and explosion factors from the pumped air, separates and removes oxygen to the outside,returning only inert gas to the room and thereby preventing explosion or fire spread. The controller, including the thermomagnetic air separator, generates an audible alarm for residents and an SMS call to the corresponding emergency service. The results prove the effectiveness of nanotechnology of gas separation and detection of DFFE in multi-split-systems, not only for ventilation and air conditioning of apartments in high-rise buildings and individual houses, but also for their fire protection.

671-685
Modeling flexibility of nanocomposite pipelines.

Authors: Baikov I.R., Smorodova O.V., Baibakov V.R.

Abstract

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Number of views: 245

Pipes for oil and gas pipelines made of nanocomposite materials are increasingly used. The most common manufacture of composite piping is by winding fiberglass onto a rotating mandrel. With continuous winding, it is possible to choose the angle of laying the threads – the so-called angle of reinforcement. Depending on its value, as well as on the angle of curvature of the pipeline when its axis deviates from the straight direction, the strength indicators of the pipe change. The article discusses the modeling of the flexibility behavior of a composite pipeline of a curved shape. It is curved pipelines that are in the most difficult operating conditions, accompanied by the manifestation of the Karman effect in the pipe turning angles. As a modeling parameter, a coefficient of increase in the flexibility of the pipe is adopted. Influencing factors are the angle of reinforcement of the composite and the angle of curvature of the axis of the pipeline. An analysis of the results of the calculation performed earlier showed that in the range of reinforcement angles from 0о to 85о the dynamics of the coefficient of increase in pipe flexibility is different. Mathematical models have been developed for two ranges of values for the coefficient of increase in the flexibility of a composite pipe. Modeling error averages no more than 2%.

686-695
Nanomodification of epoxy binders

Authors: Abdrakhmanova L.A., Khozin V.G., Nizamov R.K.

Abstract

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Number of views: 259

In this work, we studied the effect on the properties of epoxy polymers of domestic nanoproduction – carbon nanotubes produced by NanoTechCenter LLC (RF, Tambov). It has been determined that the modification of functionalized CNTs is the most effective in the composition of epoxy resins, for example, in terms of increasing the adhesive properties of binders, and they can be recommended in the formulations of epoxy adhesives. Modification of CNTs leads to a change in the microstructure of the polymer, depending on the curing conditions.

696-705
Development of a new PVC composition with reduced flammability

Authors: Mazitova A.K., Vikhareva I.N., Zaripov I.I., Mazitov R.M., Kanarekin V.I.

Abstract

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Number of views: 283

Polyvinyl chloride (PVC) is one of the mostly plasticized polymers. The plasticizers used in this case are esters of aromatic or aliphatic acids with linear or branched aliphatic alcohols with a moderate chain length. Among them, phthalates (orthophthalic acid esters with fatty alcohols) have the widest range of applications among aromatic acid esters. They are characterized by excellent compatibility not only with PVC, but also with a number of other polymers, possess good physical and mechanical properties,but are toxic compounds. Therefore, their use is gradually being replaced by low-toxic and non-toxic plasticizers. Adipic acid esters which are widely used are environmentally safe. However, their use in plastic compounds for cable products requires the introduction of special additives – flame retardants. The results of the development of a low combustible PVC formulation are described herein. The dibutoxyethyl adipate developed by us was used as a plasticizer, and industrial di-(2-ethylhexyl) phenyl phosphate – as a flame retardant. First of all, we obtained an ester of adipic acid and ethoxylated butanol with a degree of ethoxylation of 5. Conditions of its production with maximum yield are selected. The physical and chemical properties of the synthesized compound were studied. Formulations of PVC compositions based on the obtained adipate with various amounts of di-(2-ethylhexyl) phenyl phosphate were compiled. Flammability tests of PVC compounds are presented. The combustible characteristics of the cable plastic samples using the developed plasticizers comply with state standard 5960-72 with changes 3-9. The best results were obtained by using phosphorus-containing additive in an amount of 3 wt%. It is shown that small amounts of di-(2-ethylhexyl) phenyl phosphate provide fire-fighting properties.

719-729
The inventions in nanotechnologies as practical solutions. Part V.

Authors: Ivanov LA., Razumeev K.E., Bokova E.S., Muminova S.R.

Abstract

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Number of views: 264

A brief review of patents is given. The research performed by scientists, engineers and specialists in the area of nanotechnologies and nanomaterials resulted in increased efficiency of construction, housing sector and adjacent fields of economy.For example, the invention «A method to produce fireproof wood-polymer composites on the basis of secondary polyolefine» can be used in construction, car industry, shipbuilding, machine manufacturing, furniture trade and other industries. The method includes following stages: drying of composite components, mixing and heat forming of them by means of extrusion in extrusion Co- Kneader plant under treatment temperature120оС–150оС and conveyor screw rotation speed 350–450 RPM with further granulation. The obtained fire-resistant wood-polymer composite possesses high performance characteristics. The specialists can also be interested in the following inventions in the area of nanotechnologies: a method to produce strengthened nanocomposite with additional properties, anodic material for lithium-ion battery and a method to produce it, a method to rise breaking strength of composite material by preliminary impregnation of carbon fibers with carbon nanotubes, a method to produce carbon metal-containing nanostructures, a method to produce volume microscale structures from nanoparticles and a device to perform it, antistatic floor coating with carbon nanotubes and other.

730-742
Self-healing cements – the key to maintaining the integrity of cement sheath. Part 2.

Authors: Agzamov F.A., Ismagilova E.R.

Abstract

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Number of views: 253

To control water production, it is necessary to seal the channels of 20–25 mm thickness in the cement sheath at a depth of hundreds and thousands of meters. The most promising solution is the use of self-healing cements. The concept of self-healing materials has been known since the 1980s due to the studies of Donald Jud. The most fundamental works are by Sybrand van der Zwaag, Sheba D. Bergman and Fred Wudl, Richard P. Wool, D.Y Wu, N.R. Sottos, Erin B. Murphy, Henk Jonkers, who substantiated the concept, suggested technologies and additives to restore the integrity of polymer and cement materials. Despite active research in this area, Schlumberger is the only service company which elaborated and successfully applied the «self-healing» well cement called Futur. The authors of the article set the task of well cement modification that could enable autonomous «healing» of water-conducting channels through which formation water migrates. The following materials were used in the study: polyacrylamide (PAA), water-swellable polymer (VNP V-615), sodium polyacrylate (SP), cross-linked PAA copolymers, active waterproofing mineral additives and swelling elastomers. Most of the additives have a degree of swelling of more than 150%, they effectively reduce a permeability of the cement stone, however multi-layer coating is required to control the speed of their swelling. A significant drawback of the analyzed materials was the complexity of the coating. A cross-linked AA copolymer based on anionic polycrylamide was the most effective reagent that was easily covered with a water-soluble shell. The cement stone with integrated agent of AA copolymer demonstrated a permeability of 0.0018 μm2 with the strength of the samples for bending at the age of 2 days equal to 8.0 MPa.