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Project titleResearch of thermal and surface effects in complex nanomodifiers for the production of new functional materials for road construction

AffiliationFederal State Budget Educational Institution of Higher Education "Moscow State University of Civil Engineering (National Research University)",

Research area 09 - ENGINEERING SCIENCES, 09-205 - Development of new structural materials and coatings

Keywordscarbon primary nanomaterials, hydrocarbon plasticizers, new functional material, ultrasonic dispersion, thermal effects, adsorption, thermodynamics, functional efficiency criterion, stability, bitumen, asphalt concrete, efficiency, reliability, durability

Annotation
In accordance with the national priority project of the Russian Federation "Safe and high-quality roads", the priority direction is the creation of new functional materials ensuring the durability of road construction materials, in particular asphalt concrete and new materials which the improvement of synthesis methodology and research methods. The development of modern technologies in the field of building materials, including in road construction relies on the use and creation of objects on the principle of multicomponent composite materials with a given set of properties. The formation and assembly of component parts, key components of a multifunctional system should be based and carried out on the principles of building synergistic relationships and the functioning of the entire complex as a whole. Currently, the use of nanoscale systems is of particular interest. The dependence of some properties of a substance on the size of the object of which it consists allows in the field of materials science to actively influence the processes of structure formation and to obtain materials with properties that substantially exceed the properties of analogs. The study of thermal effects and the sorption capacity of carbon primary nanomaterials (CPN) in the process of ultrasonic dispersion in a plasticizing hydrocarbon medium is a source of fundamental knowledge about surface phenomena that take place. However, despite the promising use of carbon nanostructures, in the scientific literature there are isolated studies on the patterns of interaction between metal-containing nanostructures and carbon primary nanomaterials with hydrocarbon liquids (acetone and propanol, respectively). The attempts made to quantitatively describe the influence of various factors on the dispersion of carbon primary nanomaterials and the proposed mathematical expressions are not universal, which make it possible to correctly describe the experimental data, and also have a low predictive ability. In the open scientific literature, the interaction of carbon primary native nanomaterials with hydrocarbon plasticizers is not covered. In accordance with the basic principle of continuity put forward by N.S. Kurnakov, continuous change of parameters expresses the state of the system and the properties of its individual phases change continuously, while the properties of the system, taken as a whole, also change continuously, but under the condition that no new phases arise and the old ones do not disappear. Previously, an experiment to study the temperature change from ultrasonic impact on dispersed (plasticizing) hydrocarbon systems containing primary carbon native nanomaterials, ceteris paribus, showed the presence of deviations in the kinetics of temperature changes for the dispersed system from the similar kinetics of the dispersion medium. It is obvious that the system undergoes structural changes affecting the level of kinetic energy of the molecules of the dispersion medium. This project is aimed at the study of thermal effects and surface phenomena in the interaction of carbon primary native nanomaterials with hydrocarbon plasticizers and the development of new functional materials. The proposed study will allow to establish the intensity of the proceeding structural intermolecular interactions, to establish scientifically based methods for selecting the carrier medium (hydrocarbon plasticizer) for carbon primary native nanomaterials according to the criteria of energy efficiency, sustainability and functional efficiency. Establishing the relationship between the parameters of a dispersive hydrocarbon system containing nanoclusters with the studied responses will allow us to formulate the mechanism of molecular interaction of carbon primary native nanomaterials with hydrocarbon plasticizers. This in turn will allow to control the process of their deagglomeration in the environment and to obtain stable nanoscale dispersions with specified parameters, which will provide the possibility of directional structure formation of a new functional material and the formation of synergistic bonds ensuring the durability of the composite material. As a practical application of the developed new functional materials (hydrocarbon dispersion system including PCN) a promising direction is the use of asphalt concrete in structural road construction material. Its main structural component is bitumen, which in the initial state in the composition of the composite is not able to continuously resist the impacting mechanical and climatic loads on the roadway. A common method of modifying bitumen is the use of polymers, but the limiting factor of this method is a number of drawbacks, such the stratification of a multicomponent system, low adhesive adhesion to the stone material and premature thermo-oxidative aging of bitumen. According to the state of the art, the introduction of a plasticizer into bitumen, in the preparation of polymer-modified binders, increases the dissolving ability of the dispersion medium of the bitumen binder, which makes it possible to prevent a decrease in the thickness of the solvation shell in asphalt-resinous complexes (in the bitumen structure) and increase the manufacturability of the product, which is not always observed with the introduction of polymer in the bitumen and the absence of a plasticizer. The developed new functional material is well compatible with bitumen binder and polymer, its additional nanocluster structuring will allow for multiple local interaction with asphalt-resin complexes (the main structure-forming elements of bitumen binder), which will contribute to the formation of hierarchically-related structures that form synergistic relationships and the functioning of the entire complex. Scientific novelty of the project: 1. The mechanism and parameters of the molecular interaction of carbon primary nanomaterials with hydrocarbon plasticizers, explaining the nonlinear nature of the deviations in the temperature of a dispersed system in the process of ultrasonic treatment as compared with changes in the temperature of the dispersion medium. 2. The dependence of the influence of prescription-technological factors of new functional materials on the parameters of the structure and properties of polymer-bitumen binders and asphalt concrete based on them, which ensures the management of the structure formation of road composites with enhanced performance indicators.

Expected results
The expected results of the project are: - new theoretical scientific knowledge about the conditions for the formation of thermodynamically stable dispersed systems containing nanoclusters; - new scientific knowledge about the optimal technological parameters for the preparation of dispersed hydrocarbon systems with carbon primary native nanomaterials for ultrasonic dispersion; - new scientific knowledge about the influence of the molecular weight of hydrocarbon plasticizers and the concentration of carbon primary nanomaterials in solution on the dispersing ability and stabilizing effect of the medium; - new scientific knowledge about the influence of ultrasonic exposure on the thermal effects occurring in hydrocarbon plasticizers and dispersed systems based on them containing nanoclusters; - new scientific knowledge about the influence of the molecular structure and physico-chemical properties of hydrocarbon plasticizers on the interfacial interaction; - the mechanism and parameters of the molecular interaction of carbon primary nanomaterials with hydrocarbon plasticizers, which explains the nonlinear nature of the temperature deviation of the dispersed system during ultrasonic processing in comparison with the temperature change of the dispersion medium; - criteria for energy efficiency, sustainability and functional efficiency of the new functional material being developed; - compounding, technological and methodological bases for the use of the developed new functional material to ensure the possibility of implementing a given vector in structure formation, that is, a directed change in the properties of bituminous binders; - dependences of the influence of the new functional material on the parameters of the physical, mechanical and operational properties of the nanomodified composite binder, including: heat resistance, crack resistance, elasticity, resistance to delamination, aging, adhesive adhesion, rheological properties; - dependences of the influence of a new functional material in the composition of a nanomodified complex binder on the physical and mechanical, strength and deformative properties of asphalt concrete, including resistance to rutting and fatigue failure; - feasibility study of the use of effective asphalt concrete based on nanomodified composite binders containing a new functional material for the road construction industry. Scientific and public significance of the expected results of the project: Conditions of existence (parameters) of a dispersed system containing nanoclusters ("hydrocarbon plasticizer-carbon primary nanomaterials») at which a homogeneous, thermodynamically stable system is formed. The features of the adsorption processes will allow us to determine the intensity of the interaction of the contacting substances at the interface of the phases in the dispersed system, which affect the bulk properties of the composite material. The criteria of energy efficiency, stability and functional efficiency will allow us to determine the intensity of the structural intermolecular interactions and to develop scientifically based methods for selecting a carrier medium (a hydrocarbon plasticizer) for carbon primary nanomaterials. Features of the molecular interaction of the primary carbon nanomaterials with hydrocarbon plasticizers, explaining the non-linear nature of temperature deviation of a disperse system in the process of ultrasonic treatment compared to the temperature change of the dispersion medium will allow you to control the process of disagglomeration in the environment and have a stable nanoscale dispersion with the specified parameters, allowing the directed formation of a new functional material and ensure synergies and operation of the whole composite material as a whole. Designed and scientifically sound criteria in the study, and also installed the control factors in the form of technology and materials that will allow the scientific community to use the new knowledge in assessing the applicability of regional plasticizing hydrocarbon raw materials as media-media carbon nanostructures. The possibility of practical use of the expected results of the project: The use of the established features of interaction in the system of hydrocarbon nanodispersions will help to scale the implementation of the principles of nanotechnology for controlling the initial structure and final properties of polymer-bitumen binders and asphalt concretes based on them, which will ensure the production of road composites with increased performance indicators. The use of a new functional material as part of a complex nanomodified binder in asphalt concrete technology for the construction of highways will increase the durability of the operational condition of the coating without additional repair costs and the need to stop traffic; The new scientific knowledge gained in the framework of the project can be used in the training of highly qualified innovation-oriented specialists, ensuring the further development of the direction and its integration into related areas.

Annotation of the results obtained in 2022
The research work carried out made it possible to establish optimal technological parameters for the preparation of polymer-bitumen binders with the developed nanomodified dispersed systems, providing statistically significant results: 1) at the first stage, a nanomodified dispersed system "hydrocarbon plasticizer – carbon nanotubes" is pre-prepared using an immersion ultrasonic dispersant until a homogeneous state is reached (https://www.mdpi.com/2311-5629/9/1/18 ). Next, the bitumen is heated in a container with a sealed lid to an operating temperature of 160-170 ° C. Then a mixer and a sensor for monitoring the heat supply are immersed in the container. The mixer is switched on at a speed of 100-300 rpm and the dispersed system "hydrocarbon plasticizer-carbon nanotubes" is slowly introduced for 2-3 minutes. Next, the system is mixed for 5-10 minutes; 2) at the second stage, after the time has elapsed, the polymer is slowly introduced into the bitumen containing the nanomodified dispersed system for 3-10 minutes at a mixing speed of 100 rpm; 3) at the third stage, after the time has elapsed, the mixer speed is increased to 300 rpm, the container with a modified polymer-bitumen binder (MPBB 60) is hermetically sealed with a temperature sensor to control the heat supply and mixing is carried out until the polymer homogenization is achieved in the volume of bitumen. Then the modified polymer-bitumen binder is placed in a drying cabinet at a temperature of 135 oC for "ripening", which will ensure the stabilization of the binder structure. "ripening" is carried out within 1-2 hours (https://www.e3s-conferences.org/articles/e3sconf/abs/2023/20/e3sconf_tt21c2023_04095/e3sconf_tt21c2023_04095.html). A more intensive inhibition of the aging processes in the developed formulations of MPBB has been established. Thus, the introduction of 0.001% carbon nanotube Taunit into the binder with an extract of selective oil purification allows structuring of the binder, which slows down the aging process by 8 times in terms of changes in brittleness temperature and 3 times in terms of changes in softening temperature after aging TFOT. The introduction of 0.005% Taunit into the binder with the III vacuum pogon makes it possible to slow down the aging process by 3 times by changing the brittleness temperature and by 2 times by changing the softening temperature after aging. Whereas the introduction of 0.005% Taunit into the binder with industrial oil also makes it possible to slow down the aging process, but not so intensively – by 78% and 60%, respectively (https://www.sciencedirect.com/science/article/abs/pii/S0950061821023461). When studying the conditions that slow down the aging process using Infrared Spectroscopy before and after aging, it was found that the absorption intensity of peak 1600 cm-1 occurs in the basic PBB compositions, which indicates the ongoing processes of destructive thermo-oxidative aging, that is, in this case, the transition of resins to asphaltenes occurs, the absorption intensity of peak 1370 cm-1 indicates the growth of aldehydes and esters, which occurs as a result of thermal oxidation processes in unsaturated compounds. According to the data obtained, the compositions of MPMB 60 are characterized by a slight change in these peaks, which indicates a slowdown in the thermo-oxidative aging processes and obtaining a more stable structure of the material. During the study of adhesive adhesion, it was found that the introduction of a carbon nanotubes allows for the formation of more stable bonds at the interface of the phases "surface of mineral material-binder film", which characterizes such materials as more resistant to the aggressive effects of water. The establishment of the optimal ratio of components in the modified polymer-bitumen binders being developed to ensure the best quality indicators was carried out by means of a complete factor experiment. Particular quality criteria have been developed for each studied parameter of the IPBV, and a generalized efficiency criterion that takes into account the characteristics of the analyzed object (each composition of the MPBB). The analysis of the obtained generalized criteria for the effectiveness of the developed MPBB compositions, taking into account all the properties, allows us to conclude that the introduction of carbon nanotubes with compatible hydrocarbon plasticizers reduces the content of an expensive polymer component by 25% with simultaneous improvement of properties. According to the results of the shear viscosity of the studied compositions, it was found that the use of stable dispersed systems containing nanoclusters makes it possible to increase the maximum possible critical operating temperatures of the studied binders to 76 oC. When studying the effect of MPBB on the properties of crushed-mastic asphalt concrete SMA-16, it was found that the water saturation characterizing the ability of the formed film of MPBB 60 on the surface of the stone material to resist the penetration of water, which will subsequently destroy the composite from the inside, with the introduction of compatible and stable dispersed systems with nanoclusters as part of a polymer-bitumen binder decreased by 27%. It was found that with prolonged exposure to aggressive conditions, the strength characteristics of crushed-mastic asphalt concrete samples without the introduction of a binder nanomodifier in the composition deteriorate by 30-41%. Whereas the additional multiple local structuring of the binder, containing a stable dispersed system with nanoclusters, allows additional structuring and strengthening of the binder films on the stone material, all this provides a reduction in strength by only 10-14%. It has been established that the introduction of a nanomodifier makes a significant contribution to the improvement of adhesion during shear, an increase of this indicator to 240% is observed. Which in turn indicates a significant increase in the elastic component in the road composite for effective shear resistance and the formation of plastic shifts and surges in the road surface (https://engstroy.spbstu.ru/en/article/2021.106.7 /). Thus, it can be concluded that the use of an extract of selective oil purification and III vacuum shoulder strap in combination with a nanomodifier as part of a polymer-bitumen binder allows for the formation of a strong and structured system at the contact "binder-surface of mineral material", which will significantly reduce the depth of the plastic track and reduce the rate of track formation after the stage of compaction, which is a positive way it will affect the durability of the uninterrupted operation of the road surface made with their use. During the feasibility study, net discounted income (NDI) was calculated, which is an integral discounted cost for the options of net benefits from the use of new and best technologies in the implementation of transport infrastructure facilities, reduced to the current time, which for 25 years amounted to 9.25 million rubles. The yield index (YI) is calculated, which is an index of the profitability of discounted investments and is 1.65, which indicates the high efficiency of the implementation of the use of MPB 60 (the calculation was made on the example of the addition of the "selective purification extract -Taunit" system to the MPBB).

Publications

1. Obukhova Svetlana, Korolev Evgenii Physical Processes Occurring in Dispersed Media with Carbon Nanomaterials under the Influence of Ultrasonification C – Journal of Carbon Research, 9(1), 18 (year - 2023) https://doi.org/10.3390/c9010018

2. Obukhova Svetlana, Korolev Evgenii Features of interaction of carbon primary nanoscale materials with hydrocarbon plasticizers for quality management of polymer modified binders E3S Web of Conferences, Vol. 383, 04095 (year - 2023) https://doi.org/10.1051/e3sconf/202338304095

Annotation of the results obtained in 2021
Performed research study aimed at establishing the influence of the molecular structure and physico-chemical properties of hydrocarbon plasticizers on interfacial interaction in dispersed systems (such as: established conditions for the formation of thermodynamically stable dispersed systems; established optimal technological parameters for the preparation of dispersed hydrocarbon systems with carbon primary nanomaterials (СPNM) for ultrasonic dispersion; the established conditions for achieving the maximum dispersing ability and stabilizing effect of hydrocarbon media; the established dependences of the influence of ultrasonic exposure on thermal effects occurring in hydrocarbon plasticizers and dispersed systems based on them containing nanoclusters of nanomaterials; the established dependences of the influence of the molecular structure and physico-chemical properties of hydrocarbon plasticizers on the interfacial interaction in dispersed systems with СPNM) allowed us to formulate the mechanism of molecular interaction of carbon primary nanomaterials with hydrocarbon plasticizers, the course of which is possible only in hydrocarbon plasticizers containing asphaltene-resinous complexes. Some of these molecules are redistributed ("migrates") from the surface layer to the surface of the solid phase under the action of ultrasonic action, that is, they are adsorbed on the particles of multi-walled carbon nanotubes of Taunit, blocking their double electrical layers, while simultaneously forming their own diffuse layer, less mobile compared to the original one. In this case, a decrease in the specific free surface energy at the medium-particle interface and the presence of adsorption also causes "almost spontaneous" dispersion without external mechanical influences, but with the participation of internal stresses in the aggregates of nanoparticles. This "almost spontaneous" dispersion, which is called "peptization" leads to a significant increase in the number of free particles per unit volume, which can be combined into a spatial structure if not the entire surface of the particles is stabilized, that is, protected from coagulation. The peptization process is initiated after ultrasonic dispersion due to the fact that the adsorption layers of asphalt-resin complexes migrate along the inner surface to the areas of point contacts of the CMWNT Taunit particles, overcoming adhesion at the point of contact of the particles. Thus, it was found that the complete stabilization of nanoparticles in a hydrocarbon plasticizing medium can be provided by hydrocarbon substances containing asphalt-resinous complexes in their composition. Adsorption, especially of high-molecular substances forming a diffuse layer on the surface, less mobile than the initial one, lyophilizing the surface of particles and having increased viscosity leads to the formation of a structural and mechanical barrier that prevents aggregation and contributes to ensuring the stability of the colloidal system with primary carbon nanomaterials. Based on the information obtained during the study of the effect of ultrasonic dispersion on the rate of change in temperature heating of systems based on the studied hydrocarbon plasticizers and on the average reduced diameter of multi-walled carbon nanotubes Taunit, a mechanism was formulated to explain the nonlinear nature of the temperature deviation of the dispersed system during ultrasonic treatment compared with changes in the temperature of the dispersed medium: when nanomaterials are introduced into hydrocarbon plasticizers during the initial period of ultrasonic dispersion, a less intense change in the heating rate is observed, which indicates that energy absorption occurs in the system. This energy is necessary for the destruction of the aggregate, to overcome the forces of adhesion between the particles, and also includes the energy costs of wetting the formed particles, smaller size and overcoming the resistance forces of the hydrocarbon medium to move the particles. It is established that at the time when the minimum average reduced diameter of carbon nanoparticles is fixed in the system, a sharp jump in the rate of change in the temperature heating of the dispersed system is observed. Which may indicate that there is an energy release that overcomes the forces of adhesion between particles and ensures the destruction of aggregates of nanomaterial particles, after which there is a gradual equalization of temperatures in the studied systems "CMWNT Taunit – hydrocarbon plasticizer", may indicate that multi-walled carbon nanotubes are completely dispersed and evenly distributed over the volume. A direct correlation of the rate of change of temperature heating in the studied systems with the achieved dimension of multi-walled carbon nanotubes Taunit was established. The more intense the temperature jump under the influence of ultrasonic dispersion, the smaller the CMWNT dimension is characterized by the system.

Publications

1. Shekhovtsova S.Yu., Korolev E.V. Formation of polymer modified binder structure in the presence of carbon nanomaterials Construction and Building Materials, 303 (2021) 124591 (year - 2021) https://doi.org/10.1016/j.conbuildmat.2021.124591