Adhesive Binder Research Articles

Optimization of honeycomb sandwich floor panels made of polymer-matrix low-combustible composite materials based on high-strength carbon and glass fibers and adhesive binder

The article deals with the task of designing aircraft honeycomb sandwich floor panels considering experimental data on the mechanical properties of new high-strength low-combustible composite materials. The developed experimental and analytical design procedure and optimization algorithm are described. The design task is formulated in terms of nonlinear mathematical programming in which the mass per square meter of the construction is the objective function. The thickness of the base layers, the height of honeycomb core and some other parameters are considered as the design variables. The proposed visual interpretation of the optimal design task allows reducing possible design solutions based on the experimental data to an enumeration of a limited number of design alternates. The article presents a demo task and the results of designing floor panes for an advanced passenger aircraft in the aisle area using a new low-combustible composite material. The floor panel is regarded as a continuous multiply supported plate loaded with distributed load. The proposed grapho-analytical method makes it possible to form the area of rational designs that differ from the optimal one in terms of mass by a specified allowable value. The performed computational and experimental analysis shows that with the use of the new material, a floor panel can be designed with base layers made of carbon or fiberglass and lightweight honeycomb filler with the mass of a square meter from 2,9 to 3,4 kg, which is the state-of-the-art.

Effects of Aniline Tetramer-Co-Acrylic Monomer Grafted to Polysaccharide Backbone As a Conductive and Adhesive Binder for High Capacity Si/C Composite Anodes

Conducting polymers such as polyaniline and polypyrrole have been sometimes described as a potential candidate binder for high silicon anode materials due to its low price, high conductivity, and simple synthesis. The manufacturing process of conducing polymerbased electrodes requires environmental-unfriendly organic solvents such as n-methylpyrrolidone. Due to the drawback, natural polysaccharides blended with the conductive polymers have been often investigated as water-soluble, electronically conductive, and adhesive binder to improve the electrochemical performance of the high-capacity Si anodes. However, the polymer blends are still needed to modify their properties through functionalization with some additional groups, for example, grafting with adhesive monomers and crosslinking for high adhesion strength.In this study, we first prepared aniline tetramer-co-acrylic monomer (AT-Am) by two step polymerization using 4-aminodiphenylamine in acidic solution at ~ 0°C, and then AT was reacted with acryloyl chloride monomer at room temperature for 3 hours to produce AT-Am monomer. Finally, AT-Am and pure acrylamide (AAm) monomers with various weight ratios are grafted and polymerized to the backbone of sodium alginate (Alg). Here AT and AAm have roles of electronic conduction and strong adhesion, respectively. This water-treatable alginate-graft-poly(acrylamide-aniline tetramer) (Alg-g-PAAT) was used as a conductive and adhesive binder for Si/C composite anodes to improve electronic conduction and adhesion ability when compared to natural Alg and Alg-g-PAAm. As a result, the Si/C anode containing Alg-g-PAAT yielded 800 mAh g-1 after 200 cycles with maintaining high columbic efficiency when compared to Alg-g-PAAm and physical blend between Alg-g-PAAm and AT.

Biopolymers as sustainable metal bio‐adhesives

AbstractWe describe the use of biopolymers, such as sodium alginate, as an sustainable adhesive binder for several metals and high‐density polyethylene. A standard pull test and peel test was performed with disks, made of different material and size. Adhesive failure was investigated by varying the amount of applied alginate solution, drying time, drying temperature, effect of surface area, and the nature of the adherend. Alginate adhesion was remarkably strong, relatively general, and sensitive to the presence of water. A brief comparison with other biopolymers is also provided.

Predictive model of modified asphalt mixtures with nano hydrated lime to increase resistance to moisture and fatigue damages by the use of deicing agents

Deicing agents are used to dissolving the frost on road surfaces in winter and cold areas. Researchers have evaluated the impact of different deicing agents on the moisture susceptibility performance of asphalt mixtures, but they have not investigated the effect of these agents on fatigue failure and thermodynamic parameters of asphalt mixtures. Therefore, in this research, by investigating the effect of two new deicing agents of calcium magnesium acetate (CMA) and potassium acetate (PA) as well as sodium chloride (NaCl) traditional agent on moisture and fatigue performances of asphalt mixtures, predictive model of the tensile strength ratio (TSR) and the fatigue life ratio (NFR) using genetic programming (GP) based on the surface free energy (SFE) components and other properties of asphalt mixtures were presented. Nano hydrated lime (NHL) was applied as an asphalt binder modifier and an anti-stripping agent to improve the strength of asphalt mixtures. The results indicated that the saturated mixtures in CMA had the highest indirect tensile strength (ITS) and fatigue life in lower freeze-thaw cycles, while the NaCl-saturated samples had more ITS and fatigue life in higher cycles. The CMA-saturated samples had the greatest TSR and NFR. Using NHL in all saturated samples resulted in increasing TSR and NFR values. Results of SFE method showed that using NHL increased the polar, non-polar and basic components of asphalt binders and decreased their acidic components. Also, using NHL increased the total SFE amount of asphalt binder, enhancing the adhesion of aggregate and asphalt binder and cohesion in asphalt binder membrane, and as a result, improving the moisture resistance in asphalt mixtures. Using 1.5% NHL had the greatest effect on improving adhesion free energy (AFE), cohesion free energy (CFE) and detachment energy (DE). Among deicing solutions, CMA had the highest CFE, in general, and NaCl had the best DE values. PA-saturated samples had the greatest permeability of asphalt mixture (PAM) values. GP model had a high R2 96.4% and 98.3% for TSR and NFR, respectively. Using GP model to achieve the maximum TSR and NFR, the Pareto curve showed that 1.32% NHL was the optimum value for simultaneously increasing moisture resistance and fatigue life.

Research of changes of strength indicators of semi-rigid covers glued by modified adhesive compositions

The object of research is the processes for producing modified adhesive compositions based on PVA (polyvinyl acetate) dispersions for use in technological processes for the manufacture of semi-rigid book and magazine covers. The conducted experimental studies are based on the application of a comparative method for determining the tensile strength of glued, without bias, samples of binding materials using modified adhesive compositions and identical compositions without modification. The main assumption of the study is that the use of polymer thickeners and emulsifiers compatible with latex PVA, which are actively used in the technological processes of the paper and printing industries, contribute to the formation of additional strength of semi-rigid covers. This can be achieved without analysis and the selection of possible components, taking into account the mechanical properties that arise after the use of such modifiers that substantially depend on the adhesive strength between the material of the outer part of the cover and the adhesive binder. It is proposed for an experimental study of the use of substances with high adhesive properties to thick coated papers and thin binding boards, from which semi-rigid book and magazine covers are made. The structural features of adhesive films obtained from polyvinyl acetate latex were determined, which have improved flexibility, elasticity, high adhesion and water resistance when water-soluble modifiers are added to them. An experimental determination was made of the possibilities of increasing the structural strength of semi-rigid book and magazine covers after gluing with modified binding adhesives, which did not significantly increase the thickness of the adhesive layer and did not change the contour geometry of the manufactured covers. It was proved that the adhesive mixtures used to modify the PVA dispersion did not affect the structural homogeneity of the glued spatial structure of the semi-rigid covers, and did not affect the appearance of external defects in the form of plane inhomogeneity, or point thickenings of the surface of the covers. The results of studies on the gluing of structural parts of reamers of semi-rigid covers with modified adhesive compositions create additional opportunities in planning the use of consumables in the manufacture of covers for strength indicators, predefined dimensional conditions for the use of modifier substances. Experimental studies have shown discreteness – growth, decrease in dimensional indicators of the strength of semi-rigid covers glued with modified adhesive compositions, contributes to the practical application of the results, both in the planning of technological processes and in the calculation of the cost of book production.

Understanding the role of water-soluble guar gum binder in reducing capacity fading and voltage decay of Li-rich cathode for Li-ion batteries

The practical application of high-capacity Li-rich cathode materials is hindered by capacity fading and voltage decay. The capacity fading and voltage decay could be effectively overcome by using water-soluble guar gum (GG) binder instead of traditional polyvinylidene fluoride (PVDF). However, the specific role of the GG binder is not clear yet, though the GG binder can significantly improve the electrochemical performance of Li-rich cathode. To understand the effect of GG binder on the morphology, microstructure of electrode and electrode/electrolyte interfaces, ex-situ scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray adsorption near edge spectroscopy (XANES), in-situ electrochemical impedance spectroscopy (EIS) were applied to comparatively study the charge-discharge processes of Li-rich Li1.2Ni0.2Mn0.6O2 cathode when using GG and PVDF as binders. The results indicate that the GG binder can prevent electrode crack and active material loss, ascribing to the strong mechanical adhesion of GG binder with active material particles and current collector. It has found that the GG binder can also induce the formation of a uniform layer on Li1.2Ni0.2Mn0.6O2 particles’ surface. As a consequence, both the electrolyte decomposition and the electrode corrosion were significantly inhibited. The strong chelation between Mn2+ and polar OH group restrain Mn ion dissolution, which contributes to surface structural transformation mitigation. The present study reveals the role of water-soluble GG binder in reducing capacity fading and voltage decay of Li-rich material and is of great importance in design functional binders for high-performance Li-rich electrodes.

Modern Polymer Composites Based on Adhesive Preforms

Basic information on the physicomechanical and stress-strain properties of polymer composites based on a wide assortment of adhesive preforms and glass and carbon reinforcing fillers is presented. The main advantages of composites with adhesive binders over those with melted binders are discussed. Information about the technological specifics for fabricating construction elements of adhesive binder polymer composites is included. Data from promising research on the design of new polymer composites based on adhesive binders and glass and carbon reinforcing fillers are given.

Improving the Energy Efficiency of Autoclave Equipment by Optimizing the Technology of Manufacturing Parts from Polymer Composite Materials

Autoclaves used for the manufacture of parts from polymer composite materials (PCM) for structural purposes are equipment that consumes a significant amount of energy. In the manufacture of parts of a monolithic design from PCM in 2 transitions in order to reduce energy consumption, it was proposed: during the first molding, reduce the main exposure time, which reduced the operating time of the autoclave tens. In the workpiece, the complete polymerization of the adhesive binder occurs during the second molding transition. Also, it was proposed to manufacture parts of a honeycomb structure from adhesive prepregs for one molding with an autoclave under-molding at an elevated temperature instead of the first molding. The formation of a monolithic zone of honeycomb parts in one cycle eliminated the formation of unacceptable defects: "delamination" and "increased attenuation of the ultrasonic signal." A change in the technology of molding PCM parts has reduced manufacturing time, labor and energy consumption compared to the previously used mode in 2 transitions. The quality of gluing parts according to this advanced technology is confirmed by the results of acoustic control and mechanical tests.

Synthesis of silicon anode binders with ultra-high content of catechol groups and the effect of molecular weight on battery performance

Highly adhesive binders are developed to prolong the cycle life of silicon anodes and accelerate their practical application. A series of poly(N-methacryloyl-3,4-dihydroxy-l-phenylalanine) (PMDOPA) binders, containing ultra-high content of catechol groups, are synthesized through radical polymerization and applied to silicon anodes. The ultra-high content of catechol groups endows the PMDOPA binder superior adhesive strength compared to the carboxyl groups of the polyacrylic acid (PAA) binder. As the molecular weight increases, the flexibility, solvent resistance and adhesive strength of the PMDOPA binders are all enhanced, which effectively alleviates the electrode pulverization during long-term cycling and prolongs the cycle life of batteries. Especially, the PMDOPA-20 binder, which possesses the highest molecular weight of 208 kDa among all the PMDOPA samples, exhibits the longest cycle life of 665 cycles at the current density of 840 mA g−1, even though its molecular weight is lower than PAA. This work demonstrates that both the functional adhesive group and molecular weight are crucial for binder performance, which provides a valuable reference for the future development of high-performance binders.

Adhesion of Mineral Binders with Organic Aggregates

The article presents the results of studies of the adhesion properties of organic aggregates such as rice husks, cotton stalks, kenaf core and pine shavings with mineral binders Portland cement, gypsum and alkaline activated binder. It was shown that adhesion between the organic aggregate and mineral binders depends not only on the type of binder, but also on the type of organic aggregate and its surface structure

Improved adhesion of cross-linked binder and SiO2-coating enhances structural and cyclic stability of silicon electrodes for lithium-ion batteries

Silicon (Si) has been considered as a promising alternative anode material for high energy density lithium-ion batteries because of high theoretical capacity, low cost, environmentally benign, and abundant source. But the huge volume change during cycles greatly hinders the application of Si anodes. Constructing robust electrode structures via effective binders are still a challenge. Herein, a cross-linked polyacrylic acid and glycerol (PAA-GL) binder is synthesized in situ and a surface coating of silicon dioxide is obtained on silicon nanoparticles (Si@SiO2), both of which together construct a strong electrode. The Cross-linked binder with massive hydroxyl and carboxyl groups possesses luxuriant contact sites to Si@SiO2, meanwhile, the free carboxyl groups of binder and hydroxyl of Si@SiO2 offer an enhanced interaction, leading to robust electrode with strong mechanical properties. Except for binder, the SiO2-modified coat acts as a protective layer to buffer volume change of Si. Therefore, the remarkable structural stability is obtained. In addition, the Si@SiO2-PAA-GL electrode exhibits excellent electrochemical performance, a high capacity of 1192.7 mA h g−1 at 2 C after 500 cycles with a teeny capacity decay rate of 0.0337% per cycle.

Improving the Energy Efficiency of Autoclave Equipment by Optimizing the Technology of Manufacturing Parts from Polymer Composite Materials

Autoclaves used for the manufacture of parts from polymer composite materials (PCM) for structural purposes are equipment that consumes a significant amount of energy.In the manufacture of parts of a monolithic design from PCM in 2 transitions in order to reduce energy consumption, it was proposed: during the first molding, reduce the main exposure time, which reduced the operating time of the autoclave tens. In the workpiece, the complete polymerization of the adhesive binder occurs during the second molding transition. Also, it was proposed to manufacture parts of a honeycomb structure from adhesive prepregs for one molding with an autoclave under-molding at an elevated temperature instead of the first molding. The formation of a monolithic zone of honeycomb parts in one cycle eliminated the formation of unacceptable defects: “delamination” and “increased attenuation of the ultrasonic signal.” A change in the technology of molding PCM parts has reduced manufacturing time, labor and energy consumption compared to the previously used mode in 2 transitions. The quality of gluing parts according to this advanced technology is confirmed by the results of acoustic control and mechanical tests.

Comparative evaluation of the bitumen binders adhesion by the methods normalized by national standards of Ukraine

Problem. Bitumen binders as a component of the asphalt pavement must be characterized by a certain list of qualities. It includes high cohesion values, good adhesion to the surface of all mineral materials, low temperature susceptibility and high stability of properties during technological proceeding and durability pavement period. The high rate of a new adhesives and adhesion assessment methods invention points on the topicality of the problem of improving binder adhesion and it’s validate assessment both in Ukraine, and abroad. Goal. There are a few national standards (GOST 11508-74, DSTU B V.2.7-81-98, DSTU 8787:2018, DSTU EN 12697-11:2018) that regulate the adhesion assessment of bitumen in Ukraine. The comparative analysis of adhesion values, founded by these methods, is a purpose of this research work. Methodology. Three mineral materials (quartzite, grey and red granite) of different grading are chosen for the tests. Bitumen modified by polymer, warm mix additive and a surfactant additive are used to evaluate the susceptibility of the test methods to the presence of these additives in bitumen due to the purpose of this research work. Results. The advantages and disadvantages of the analyzed methods are set due to the results of this research. It is found that difference in temperature ranks and mineral grading, set by test conditions, leads to the significant difference in adhesion values. Originality. The comparative analysis of test methods that regulates bitumen adhesion quality in Ukraine, and finding their advantages and disadvantages make the scientific originality of the presented research. Practical value. Due the research results, the advantage of adhesion value quantitative evaluation and its validity is set as a feature of adhesion test by the DSTU B V.2.7-98 method in comparison with other test methods. The improvement of the DSTU B V.2.7-98 method enables it to the modified bitumen adhesion assessment and makes the test results compatible with the European Rolling Bottle Test (DSTU EN 12697-11:2018) results.

Efficiency and durability of g-C3N4-based coatings applied on mortar under peeling and washing trials

Durability of photocatalytic coatings is a major concern in engineering practice. Here, two types of novel visible light-responsive coatings, both consisting of vinyl chloride/vinyl ester/ethylene copolymer (as a binder) and graphitic carbon nitride (g-C3N4) but different in fabrication, are proposed and applied on the mortar surface. The first type is mono-layer coating (MC), where the g-C3N4 suspension containing the binder is directly sprayed on the mortar. The second type is double-layer coating (DC), where the binder layer is applied on mortar surface before spraying the g-C3N4 layer. Results show that the binder addition leads to a good anchorage of the coatings on both MC and DC mortar substrates, along with desirable resistance to peeling and washing, compared to the g-C3N4 coated mortar without the binder. The well-distributed binder in g-C3N4-based coating inevitably decreases the photocatalytic efficiency of the MC mortar due to masking effect of the binder on the coating surface. The DC mortar, on the contrary, takes full advantage of the binder adhesion by inserting a binder layer and therefore holds strong resistance to peeling and washing without compromising its photocatalytic efficiency. The proposed DC technique provides a promising strategy to fabricate highly cost-effective and durable photocatalytic coatings applied on cementitious materials.

Effect of liquid anti-stripping agents on moisture sensitivity of crumb rubber modified asphalt binders and mixtures

Influence of three liquid anti-stripping agents (ASAs) (named as M1, T9 and LOF-6500) with three dosages (0.25%, 0.50%, and 0.75%) on laboratory performance of crumb rubber modified asphalt (CRMA) mixture was investigated. The performance included aggregate–CRMA binder adhesion bond, water stability, high-temperature stability and low-temperature anti-cracking property, which were evaluated by surface free energy (SFE), freeze-thaw indirect tensile strength (ITS), Marshall stability and low-temperature ITS tests, respectively. The results manifest that the addition of ASAs can improve effectively the adhesion bond between aggregate and CRMA binder under dry or wet condition. Compared with three ASAs, the CRMA containing LOF-6500 has the highest wet adhesion energy. With regard to M1 and LOF-6500, the CRMA incorporating 0.75% dosage shows the highest dry and wet adhesion energy. Additionally, the water resistance and high-temperature stability of CRMA mixture are improved obviously by incorporating ASAs despite of the types and dosages. However, the ASAs can lower the low-temperature anti-cracking property of CRMA mixture in certain degree, and the influence of T9 is less than that of M1 or LOF-6500.

Mesoscale observations of the thermal decomposition of energetic composites under ultrasonic excitation

Polymer bonded explosives (PBXs) have exhibited localized heating and, in some cases, subsequent reactions in response to ultrasonic excitation. The objectives of this work are to investigate the conditions for, and locations of, hot spot initiation of energetic crystals embedded within a polymer binder subjected to periodic mechanical excitation from a contacting transducer operating at 210.5 kHz. Crystal and binder interactions and events such as delamination, solid-solid phase change, and gas production were observed in real time via optical microscopy. We conclude that there are two main pathways of heat generation which are capable of driving an explosive to decomposition in the systems of interest: frictional heating from a delaminated and moving binder interface and viscoelastic heating in the binder near an embedded crystal. Formulations that address the vibration initiation sensitivity of PBX composites require knowledge of the key internal heat generation mechanisms. The results included here indicate that improving binder adhesion to energetic crystals or improving crystal morphology to reduce heating during cyclic loading may only address one of the available pathways of energy dissipation and that binder and crystal selection should be done concurrently. Furthermore, the results presented herein appear to indicate that rounded particles, in contrast to faceted crystals, with strong adhesion to the binder are expected to result in decreased heating rates under ultrasonic excitation.

Production of Ceiling Board from Piliostigma thonningii using Styrofoam Adhesive as Binder

The use of synthetic fibres resulted in environmental degradation and the growing interests towards the utilisation of readily available agricultural fibres as a potential replacement for synthetic fibres. This research aims to produce a ceiling board composite from piliostigma thonningii particulate using styrofoam adhesive binder. The board was produced from the readily available materials leading to the low cost of production. The composition has a formulation of fibre/binder mixing ratios (2:1, 1:1, 1:2 w:w), pressures of (100, 300, 500 kg/m 2 ) and temperatures of (30, 65, 100 °C) respectively. The process was successfully modelled and optimized using a Box–Behnken design method. The optimal conditions for the piliostigma thonningii board were found to be fibre/binder mixing ratio of 1:1 w:w, pressure of 500 kg/m 2 and temperature of 92 °C yielded response values of density (151.5 kg/m 3 ), water absorption (9.04 %), tensile strength (16.9 N/m 2 ), thermal conductivity (0.11 W/mK). Hence the board has greater insulating properties and good potential to be used as a ceiling board.

ASSESSMENT OF ADHESION BETWEEN BITUMINOUS BINDER AND MINERAL AGGREGATE USING DIGITAL IMAGE ANALYSIS

Asphalt mixtures often fail due to a low adhesion of bituminous binder to mineral aggregate, which leads to surface coarse damages like potholes and fatigue cracking. To avoid this phenomenon, different types of adhesion promoters may be admixed into bituminous binder but a new question about their effectiveness arises. This paper presents two semi-automatic methods, which reliably replace the subjective assessment. Both of them use a digital image of asphalt mixtures as an input. The first is based on a gray level thresholding, while the second one on an entropy-based image segmentation. Asphalt mixtures composed from Zbraslav aggregate (fraction 8–16 mm), paving grade bitumen 50/70 and several types of adhesion promoters were made and subjected to the adhesion assessment. It was shown that aggregate grains coated by binder was equal to ca. 83–88% in the case of reference binder, while that was increased by ca. 10–13% if whatever adhesion promoters were used.

Molecular Dynamics Simulation to Investigate the Adhesion and Diffusion of Asphalt Binder on Aggregate Surfaces

Asphalt-aggregate interface properties are considered to play a crucial role in asphalt mixture. To better understand the detailed binding mechanism, the present study analyzed the adhesion and diffusion of asphalt binder on mineral surfaces at a nanoscale based on molecular dynamics simulation. A 12-component AAA-1 asphalt model and five oxide models were generated to represent asphalt binder and mineral aggregates, respectively. The effectiveness of these models was validated by comparing the physical properties of the model with the values reported in the literature. The binding energy and diffusion coefficient obtained were examined to characterize the adhesion and diffusion of asphalt on different mineral surfaces. The results indicated that van der Waals energy played the main role in forming the strong physisorption of asphalt on the mineral surface. Among all four fractions of asphalt, asphaltene made a great contribution to the adhesion of asphalt on the mineral surface. It was also found that the work of adhesion between asphalt and five oxides ranked MgO > CaO > Al2O3 > Fe2O3 > SiO2. The content of MgO and CaO in mineral aggregates can be further adopted as an index to evaluate and classify mineral aggregates during asphalt mixture design. Meanwhile, asphalt mobility does not entirely rely on the molecular mass but also depends strongly on the medium it adsorbed into and interaction energy. This work provides a fundamental understanding of the adhesion and diffusion of asphalt binder on the mineral aggregate surface at the atomistic scale.

Compactability and Mechanical Properties of LNA-Modified Asphalt Concrete

Effective compaction is essential for achieving the desired density and better mechanical behavior of asphalt paving mixtures. The higher the mixture compactability, the lesser is the compaction effort required to attain the desired density. Addition of nanomaterial to asphalt binder improves the adhesion of binder to aggregate, compactability, resistance to moisture susceptibility, and permanent deformation. This paper investigates the effects of liquid nanoadditive (LNA) on the asphalt binder properties, compactability, and mechanical properties of asphalt concrete through laboratory investigations. Compactability, which describes the ease with which asphalt mixture can be compacted, is examined through volumetric properties. Binder viscosity is found to decrease with the increase of LNA content at a given temperature. Addition of LNA provided better binder–aggregate adhesion, improved compactability of the mixture, and increased moisture resistance and resilient modulus.