Polyfunctional Modifier Research Articles

EPOXY COMPOSITES REINFORCED WITH FIRE-RESISTANT DIORITE

As a result of the work, the influence of the polyfunctional modifier oligo (resorcinol phenyl phosphate) and the dispersed mineral filler diorite with terminal phenyl groups on the physicochemical and deformation -strength properties of epoxy composites was studied. The effectiveness of using diorite epoxide as an active polymer filler has been proven. The effectiveness of using diorite as an active filler in epoxy polymers, which increases strength and changes the physicochemical properties of epoxy composites, has been proven. The optimal composition of diorite was selected as a structural additive and filler in the composition of an epoxy composite (0.1 and 50 parts by weight), which strengthens the epoxy diorite composite. It has been established that the addition of diorite to the epoxy composition leads to an increase in the heat resistance of Vicat from 132ºС to 140-188ºС and increases the thermal stability of the epoxy composite, which is expressed in a shift in the initial degradation. In addition, the thermal decomposition of the composite increases the yield of carbon structures (from 54 to 70-77% by weight), prevents the pyrolysis products from entering the gas phase, which leads to a decrease in its flammability. The effectiveness of diorite surface functionalization has been proven using APTES, which provides chemical interaction at the polymer matrix/filler interface and also prevents aggregation of diorite particles.

Adhesive Strength of Modified Cement–Ash Mortars

The main aim of this article, carried out in relation to ash–cement mortars, is to determine the effect of complex additives of polyfunctional modifiers, including, in addition to superplasticizers, air-entraining and water-retaining additives, at different values of water–cement ratios. With the use of experimental–statistical models, the complex effect on the adhesive strength of cement–ash mortars of water–cement and ash–cement ratios, as well as complex additives of polyfunctional modifiers, including air-entraining and water-retaining additives, is considered. The extreme nature of the water–cement and ash–cement ratios on the adhesive strength of ash–cement mortars are established. Their optimal values are in the ranges of 0.7–0.75 and 0.35–0.4, respectively. The addition of a naphthalene-formaldehyde superplasticizer makes it possible to increase the adhesive strength of mortars by up to 40%. A positive effect is achieved along with the addition of a superplasticizer by introducing optimal amounts of air-entraining and water-retaining additives into the mortar mixtures. Quantitative parameters of mortar compositions that positively affect adhesive strength are established. The influence on the adhesive strength of the fly ash was also investigated, as well as on the binder–sand ratio. In addition, a positive effect on the adhesive strength of modified cement–ash mortars was experimentally shown by increasing the specific surface area of fly ash by regrinding it and increasing the cement–sand ratio.

Development and Analysis of the Physicochemical and Mechanical Properties of Diorite-Reinforced Epoxy Composites.

The aim of this paper is to study the effect of a polyfunctional modifier oligo (resorcinol phenyl phosphate) with terminal phenyl groups and a dispersed mineral filler, diorite, on the physicochemical and deformation-strength properties of epoxy-based composites. The efficiency of using diorite as an active filler of an epoxy polymer, ensuring an increase in strength and a change in the physicochemical properties of epoxy composites, has been proven. We selected the optimal content of diorite both as a structuring additive and as a filler in the composition of the epoxy composite (0.1 and 50 parts by mass), at which diorite reinforces the epoxy composite. It has been found that the addition of diorite into the epoxy composite results in an increase in the Vicat heat resistance from 132 to 140–188 °C and increases the thermal stability of the epoxy composite, which is observed in a shift of the initial destruction temperature to higher temperatures. Furthermore, during the thermal destruction of the composite, the yield of carbonized structures increases (from 54 to 70–77% of the mass), preventing the release of volatile pyrolysis products into the gas phase, which leads to a decrease in the flammability of the epoxy composite. The efficiency of the functionalization of the diorite surface with APTES has been proven, which ensures chemical interaction at the polymer matrix/filler interface and also prevents the aggregation of diorite particles, which, in general, provides an increase in the strength characteristics of epoxy-based composite materials by 10–48%.

The Role of Surface Phenomena in Modified Cement Dispersions at Studying Poly-Functional Modifiers' Mechanism of Action

The research findings of colloid and chemical properties of poly-functional modifiers (PFM) with various chemical compositions and qualitative and quantitative proportions of polar organic substances with various molecular weights have been presented. The possibility of regulating the properties of PFM and concrete mixes, modified by them by means of not only changing the chemical composition of modifiers, but combining the types and quantity of active admixtures of polar organic substances with various molecular weights has been shown. It has been demonstrated that the modifiers under study possess the surface activity at solid-solution phase boundary, reducing the surface tension σsolid-liquid (σs-l) At the same time the surface tension at the solution-air phase boundary can remain the same or reduce to a certain extent depending on the modifier’s chemical composition. PFM and superplasticizer (SP) SB-3, which have, unlike SP S-3, the certain surface activity at solid-solution boundary, increase the air entrainment into concrete mix by 0.5÷1.5%, additionally increasing the freeze-thaw resistance of concretes of both fluid and equal-workable compositions without affecting their strength. The adsorption of modifiers on the disperse phase of suspension is conditioned by dispersion forces and, independently of its kind, is of monomolecular nature. For the localization of PFM molecules on the surface of a particle, its molecule should have a system of bonded aromatic rings or conjugated double bonds. The adsorbed modifier’s molecules should make the disperse phase surface hydrophilic and for this purpose they should contain hydrophilic groups along the full length. All this predetermines the role of adsorption-solvation factor in modifiers’ mechanism of action.

Improving the Bio-Resistance of Cement Concretes by Means of Fungicidal Poly-Functional Modifiers

The research findings of physical and chemical properties of heavy and light concretes, contaminated with water suspension of mold fungi spores, are presented. It is noted that the concretes’ funginertness (resistance to fungi) is significantly influenced by their age, porosity and the alkalinity of medium. In the course of time the strength of concrete decreases, which is conditioned by the activation of mold fungi growth processes, as a result of de-alkalization of concrete, due to carbonization of cement stone and release of organic acids into the material. To improve the concrete’s resistance in biologically aggressive media, it is suggested to modify concrete with a new poly-functional fungicidal modifier, obtained on the basis of resorcine production waste. It has been demonstrated that the addition of resorcinol-formaldehyde oligomers to concrete mix completely inhibits mold fungi growth and allows obtaining concretes with the increased density and strength, which can be used in conditions of biologically aggressive media. The strength characteristics of the cement stone with the researched modifiers are not reduced at mold fungi spores’ contamination, but, on the contrary, slightly increase, due to the increase of cement paste fluidity, decrease of W/C ratio, reduction of micro-cracks in concrete and compaction of its structure, due to the peptizing action of the modifier.

ADDITIVES TO BITUMENS

Objectives.Improving the quality of road bitumen is currently particularly relevant, since allows you to extend the life of road asphalt coatings with the ever-increasing fleet of cars. The main task of research was to study the effect of used oils on the process of structure formation of oxidized bitumen.Method.The introduction of additives of different nature, i.e. its modification, both itself and raw materials, is one of the main ways to improve the physicomechanical properties of bitumens. Introduction to bitumen of small additives containing carboxyl groups, hydroxy acids and resin acids allows one to control not only the adhesion properties of bitumens, but also to ensure the stability of the asphalt concrete mixture at high temperatures. As components of a polyfunctional modifier, to improve the physicochemical and physicomechanical properties of bitumen and their asphalt concrete, the following distilled talovoe oil TU 13-00281074-26-95, petaerythritol GOST 9286-76 and ethylene-vinyl acetate copolymer are proposed. -97.Result.A technology has been developed to draw used oils into tars in order to obtain high-quality road bitumen grades BND 60/90 and to investigate the qualitative characteristics of bitumen raw materials, used synthetic and mineral oils and bitumen. Waste oils with deter-gent - dispersant additive CPD (colloidal dispersion of calcium carbonate in oil M-14 stabilized with calcium sulfonate, used in the preparation of motor fuels) can be used in the composition of the residual raw materials of refining processes as an activating additive.Conclusion.Improvement of the physicomechanical properties of high-quality bitumen is possible by complex modification with various additives, which allows creating conditions for the long-term operation of pavements under the influence of modern traffic loads and adverse weather conditions. In order to obtain modified bitumen of improved quality, selection of modifying additives and the technology for their preparation are required.

The Modified Composite Binder For Cement-Concrete Road Surfaces**The article has been prepared within the framework of the Flagship University Development Program on the basis of BSTU named after V.G. Shukhov.

The comparative analysis of motor road surfaces made of cement concrete and asphalt concrete has been carried out. The advantages of cement-concrete road surfaces as compared to the traditionally used asphalt concrete have been shown. The necessity of using cement-concrete road surfaces has been substantiated, with the purpose of meeting the up-to-date requirements of transport safety, service reliability, comfort and environmental compatibility. The factors, which influence the strength and frost resistance of road surfaces, have been noted. A factory-fabricated modified binder based on a new polyfunctional modifier has been suggested, which would allow considerably increasing the strength of cement-concrete road surfaces, and especially their frost-resistance. The experimental data of studying the colloid-chemical properties of the obtained modifier and the technological and performance properties of the binder and the cement concrete based on this modifier have been presented. It has been shown that the presence of individual components with various hydrophilic groups results in the combined plasticizing and air-entraining effects. The resulting modified binder allows obtaining concrete with frost-resistance 800-1000 cycles, which would significantly increase the durability of cement-concrete road surfaces.

The Research of the Influence of Ferruginous Aggregates’ Surface and Polyfunctional Modifiers on Interfacial Phenomena and Strength Formation of the Contact Area in Concretes

The findings of the research concerning the strengthening of the contact area between the cement stone and aggregate, the influence of its surface’s mineral composition and of the interfacial phenomena on the contact area strength formation and the properties of the concrete matrix volume have been summarized. The opportunity of regulating interfacial phenomena and, consequently, the properties of the concrete itself and the strength of its contact area by means of polyfunctional chemical admixtures have been demonstrated. The findings of studying the new efficient polyfunctional modifiers’ influence on the strength formation of the contact area between the cement stone and ferriferrous aggregates and their influence on interfacial processes, occurring at its formation, are presented.

A Mechanism of Action of a Polyfunctional Modifier Made of Hydrocarbons Production Waste in Mineral Suspensions Based on Fine-Ground Cements

The findings of the research of colloid and chemical properties of mineral suspensions, based on fine-ground cements and modified with the new polyfunctional modifier, obtained from hydrocarbons production waste, have been presented. It has been demonstrated that the introduction of modifier allows influencing the adsorption processes, electrokinetic potential, rheological parameters, aggregative and sedimentation stability of minerals suspensions, as well as purposefully regulating their properties and considerably cutting the consumption of Portland cement clinker by replacing it with mineral admixtures. The comparative analysis of the obtained modifier with the known analogues has been carried out. On the basis of the carried-out experimental research and the literature data the key points concerning the required properties of modifiers have been formulated. This allows determining their mechanism of action and demonstrates that it is conditioned by the combined action of adsorption-solvation and electrostatic factors. The exclusion of one of these factors results in the loss of the modifier’s activity.

Polyfunctional Modifiers for Bitumen and Bituminous Materials with High Performance

Over the last decade increase in capacity and the intensity of vehicular traffic has increased manifoldly, including heavy trucks, super singles, and higher tire pressures, resulting in significant increase of dynamic loads on the road surface which in turn lead to high quality requirements for bitumen in order to avoid premature wear and failure of asphalt concrete pavements. One of the possibilities to increase the quality of bitumen is to use special additives and modifiers that can provide a high adhesion to mineral filler and inhibit the aging and degradation processes in the asphalt coating. To achieve this, in the present study composite modifiers based on bisimidazolines derivatives were synthesized. The developed polyfunctional modifier (PFM) of complex action provides enhanced thermal stability, significantly improves the adhesion between bitumen binder and aggregates, and also improves the physical‐mechanical properties of the asphalt concrete. Based on the test results it is recommended to use the synthesized samples of the PFM additive with complex action in asphalt mixtures for road paving.

ТЕОРЕТИЧЕСКИЕ И МЕТОДОЛОГИЧЕСКИЕ ОСНОВЫ СОЗДАНИЯ ПОЛИФУНКЦИОНАЛЬНЫХ МОДИФИКАТОРОВ МОНОЛИТНЫХ БЕТОНОВ ДЛЯ ПРОВЕДЕНИЯ РЕКОНСТРУКЦИОННЫХ РАБОТ

The findings of the known research in the sphere of concretes and concrete mixes chemical modification have been generalized and systematized; the theoretical statements and methodological recommendations in creating high-performance polyfunctional modifiers have been presented. It was demonstrated that the leading role in concrete modification is played nowadays by this class of additives, as their application provides concretes and concrete mixes with a set of prescribed properties for their operation in various conditions. It was pointed out that this sector is especially relevant in mass concreting, as the most widely used in conducting building and repair works and more demanding to the quality of concretes and concrete mixes. The modifiers were classified and the requirements to modifiers with account of their workability and functional use were listed. A high-performance fungicidal polyfunctional modifier for mass concretes, containing a plasticizing agent and hydration and hardening accelerator has been synthesized. The colloid-chemical properties of the obtained modifier and the properties of concretes and concrete mixes with this modifier have been researched.

Effect of Bicyclic Polyfunctional Modifier (BPM) on the Characteristics of Wood Composite Materials Based on Urea Formaldehyde Oligomers

The paper represents the results of research related to the application of urea and glyoxal condensation product to modify the urea-formaldehyde resins (UF resins) aiming to obtain low-toxicity wood plates on the basis thereof. It was stated that the bicyclic polyfunctional compound is an effective modifier which not only does allow reducing the toxicity of wood-composite materials based on UF resins, but also increasing their physical-mechanical characteristics.

THE COMPLEX POLYFUNCTIONAL MODIFIERS INFLUENCE ON THE CORROSION OF THE REINFORCEMENT IN THE CONCRETE

In the article the mechanism of metal corrosion and the influence of complex polyfunctional modifiers on corrosion resistance of steel framework in the concrete is examined.

Polyfunctional modifier for compounds based on ethylene–propylene and chloroprene rubbers

Polyfunctional modifier for compounds based on ethylene–propylene and chloroprene rubbers

Adhesive and anticorrosive polymeric coatings obtained from modified industrial waste oligostyrenes

In this study, as a continuation of our previous studies on the chemical modification of different molecular weight polystyrenes (PS) with polyfunctionalized modifiers by using cationic catalyst, industrial waste oligostyrenes (IWOS) were used as raw material. These oligostyrenes are formed as waste material in the rectification of styrene, used for the production of PS in industry, and they cause environmental pollution. Chemical modification of these waste oligomers (IWOS) without waste residence was carried out with polyfunctional modifiers such as maleic (MA) and acetic anhydrides (AA) by using BF 3·O(C 2H 5) 2 catalyst in a single stage. Upon modification, it was determined that a maximum amount of functional groups ( COOH group 130 mg KOH/g polymer and 18 mol% CH 3CO group) was bonded to the structure of the oligostyrenes. Adhesion properties, corrosion resistance and impact of the polymeric coatings on metal surface changed as a result of the amount and structure of the polyfunctional groups bound to the polymer structure. It was determined that the modified IWOS had higher adhesion properties; and it was more resistant to corrosion and impact. Therefore, more economical resistant polymeric coatings were obtained; and their application areas were located by using this waste as raw material in polymeric reactions.