Foaming Agent Content Research Articles

The study of foaming agent concentration choice in EPB shield soil conditioning

The study of foaming agent concentration choice in EPB shield soil conditioning

Optimizing Glass Foam Production from Recycled Sources: Influence of Variation in Cullet Color and Spent Alkaline Battery Components

Glass foams present a compelling opportunity for upcycling glass waste, offering a favorable combination of low weight, thermal insulation, and mechanical strength. Prior works demonstrated the feasibility of producing glass foams from glass waste and foaming agents sourced from synthetic textile waste, manganese oxides, and spent alkaline battery cathodes. This work explores the optimization of the process, investigating the impact of glass composition of differently colored glasses on final properties and incorporating entire alkaline batteries, encompassing both cathode and anode components. By carefully adjusting the composition, foaming agent content, and process temperature, customizable properties are achieved. Increasing foaming agent content or utilizing transparent glass improves insulation but lowers density and mechanical properties. Lowering foaming agent content or using brown/green glass enhances density and strength at the expense of insulation. Temperatures beyond 900 °C increase crystalline content, boosting mechanical performance without affecting density. This innovative approach not only offers a pathway to sustainable insulation materials but also underscores the potential for minimizing environmental impact through the efficient upcycling of glass waste.

Research on mechanism of controlling water and stabilizing production in heavy oil reservoirs with edge-bottom water

The development of edge-bottom water heavy oil reservoirs typically involves short water-free production period and a rapid increase in water cut, leading to generally low oil recovery factors. Combining the advantages of foam and viscosity reducers for composite development can effectively address the challenges in edge-bottom water reservoirs; however, the mechanism of action remains unclear. In this study, the concentrations of foaming agent and viscosity reducer were initially determined using a foam evaluator and an Anton Paar rheometer. Subsequently, a 2D large flat plate model was employed to conduct a composite group production experiment after water flooding, and then the change in oil saturation during flooding was analyzed by measuring electrical resistance. Finally, the dynamic curves of flooding were compared to analyze the mechanism of water control and oil stabilization (WCOS). The results indicate that the 2D large flat plate model and the method of inverting saturation field maps can effectively simulate the oil-water flow behavior during the composite flooding process after water flooding. The synergistic mechanism of N2 foam controlling bottom water coning and CO2 enhanced viscosity reducer to reduce viscosity in deep areas was revealed, increasing the overall recovery factor by 10.3% compared to water flooding. The mechanism of the combined oil recovery is clarified, which providing a reference for formulating WCOS plans following water flooding.

Developing sustainable steel slag-based aerated concrete: Effects of accelerated carbonation on performance and carbon emissions

This research undertakes an in-depth examination of the properties of carbonated steel-slag aerated concrete (CSSAC), the mineral composition and microstructure were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), life cycle assessment (LCA) also employed for evaluating its environmental impacts. Results revealed that a strength of 6.6 MPa and a dry density of 958 kg/m3 for CSSAC was achieved through carbonation curing, utilizing a 30 vol% CO2 concentration at ambient pressure for a duration of 24 h. Nonetheless, elements such as high water-solid ratio, cement content, and foaming agent content were found to negatively affect the strength development. Furthermore, the overuse of lime as a cement substitute formed a dense pore structure on the surface layer, consequently lowering CO2 sequestration efficiency. It was found that compressive strength was enhanced and water absorption was reduced by 66 % with calcium stearate, through effective pore structure optimization. Significantly, the carbon footprint of CSSAC stood at a minimal 0.0673 kg∙CO2∙eq/kg, achieving a substantial 73.36 % reduction when compared with its original carbon footprint. This adoption of carbonation curing effectively mitigated the carbon footprint of the product, offering actionable insights for the manufacturing of zero-carbon and even negative-carbon building materials.

Operando visualization of porous metal additive manufacturing with foaming agents through high-speed x-ray imaging

Porous metals find extensive applications in soundproofing, filtration, catalysis, and energy-absorbing structures, thanks to their unique internal pore structure and high specific strength. In recent years, there has been an increasing interest in fabricating porous metals using additive manufacturing (AM), leveraging its unique advantages, including improved design freedom, spatial material control, and cost-effective small-batch production. In this study, we conducted pioneering operando visualization of AM porous metal using a laser powder bed fusion (L-PBF) setup combined with a high-speed synchrotron x-ray imaging system. Single track printing experiments using Ti6Al4V (Ti64) combined with titanium hydride (TiH2) and sodium carbonate (Na2CO3) as foaming agents, with varying mixing ratios were performed under different processing conditions. The results elucidate the dynamic development of porosity formation. The average pore size is significantly influenced by the particle size of foaming agents when pore coalescence is absent. For all foaming agent content tested in the current study, the number of pores is found to be more sensitive to changes in laser power than in laser scanning speed. Increasing linear energy density (increasing laser power or reducing laser scanning speed) promotes the foaming agent activation thereby porosity formation. However, high linear energy density skews pore distribution towards the surface despite forming deeper melt pools. In addition, the impact of additional factors including foaming agent’s laser absorptivity and decomposition kinetics with respect to AM time scales should be carefully considered to avoid ineffective activation of foaming agents during the AM of porous metals.

Optimizing foaming agent concentration and recycled fine aggregate content to enhance mechanical and durable properties of foam concrete mixes

This research explores the impact of using recycled fine aggregates from construction and demolition wastes (CD-RFA) through the replacement of natural sand in proportion of 0 %, 10 %, 30 %, 50 %, 70 %, and 100 % for making foam concrete mixes. Protein based foaming agent was diluted with water in ratios of 1:20, 1:40 and 1:60. It was found that with the increase in the proportion of recycled fines, the porosity, sorptivity and water absorption of foam concrete mixes increases significantly. At the same time, a downward trend in the mechanical characteristics was noted. However, the obtained values of compressive strength, flexural strength, and split tensile strength of 22.35, 5.68 and 2.27 MPa were found to be well within the ACI 523 R 2014 recommended ranges of 8–22, 3–6.4 and 1–2.2 MPa, respectively. Hardened density, abrasion resistance, and resistance to sulphates and chlorides attack showed perceptible decline. The present study recommends the replacement of natural sand up to 50 % with CD-RFA. The foam concrete mix prepared using recycled fines will help clearance of a large quantities of CD wastes, thereby benefiting the environment and ecology.

The novel inorganic solidified foam prepared by direct foaming and its characteristics for preventing spontaneous combustion of coal

ABSTRACT To mitigate coal spontaneous combustion disasters caused due to air leakage in coal mines, inorganic solidified foam is widely employed to seal these areas. This study proposes a simplified method for preparing such foam by directly foaming a mixture of water, cement, fly ash, and foaming agent. This new inorganic solidified foam plugging material aims to enhance sealing effectiveness. The research investigates the foaming ability and stability characteristics of different types of surfactants, analyzing their compatibility with cement and fly ash. It identifies that lauramidopropyl surfactant (LX) exhibits the lowest viscosity in the cement-fly ash slurry mix, resulting in superior foaming performance. By studying effects of water-cement ratio and foaming agent concentration on the foaming performance of cement-fly ash slurry mix, it is found that when the water-cement ratio is 0.6 and the foaming agent concentration is 0.5%, the foaming performance of inorganic solidified foam is optimal, yield the highest foaming efficiency with a multiple of 4.33 times and compressive strength of 0.13 MPa, effectively bonding and reinforcing fractured coal bodies to sealing air leakage cracks efficiently. This study contributes to simplifying the preparation equipment and the application processes of inorganic solidified foam, making it more suitable for widespread application in the confined spaces of coal mines, providing a new technical approach for preventing and controlling coal spontaneous combustion in mines.

Research on compound amidohydroxysulfobetaine foamer for high-temperature and high-salinity clastic reservoirs

A high-quality foaming agent should exhibit excellent solubility in formation water and strong foaming ability, while also meeting the requirements of stability under high-temperature and high-salinity conditions, as well as low adsorption capacity. This study explores the potential of amidohydroxysulfobetaine surfactant as a foaming agent in sandstone reservoirs under specific reservoir conditions of 110 ℃ and 25.0×104 mg/L salinity. The findings indicate that compounding EHSB with a small amount of LHSB to form LA13 significantly reduces the Krafft point of EHSB. Furthermore, LA13 demonstrates outstanding solubility in 25.0×104 mg/L brine and exhibits an overall adsorption capacity on quartz sand surfaces lower than 0.6 mg/g when its concentration is below 1.0 wt%. Performance evaluation of bulk foam for LA31 at concentrations ranging from 0.05 wt% to 0.4 wt% suggests that using a foaming agent concentration of 0.05 wt% results in relatively low foaming volume and foam decay half-life; however, consistent foaming performance is observed across other concentrations, leading to highly stable foam due to the compound system's higher surface dilational modulus being the primary factor contributing to foam stability. Flow experiments reveal that the foam generated in cores with permeabilities of 46.5 mD, 185.5 mD, 632.0 mD, and 2005.3 mD exhibits a high resistance factor when the concentration of LA13 exceeds 0.1 wt%, while also demonstrating commendable gas-channeling regulation capability. Therefore, it is recommended to use LA13 as a foaming agent for field applications when its concentration surpasses 0.1 wt%. Additionally, comparing the mobility of foam formed by concentrations of 0.1 wt% and 0.2 wt% LA13 in cores with varying permeabilities shows that LA13 exhibits selective mobility regulation specifically in cores with permeabilities lower than 632.0 mD.

Effect of concentration of foaming agent and wipping time on foam mat drying of sapota pulp

Effect of concentration of foaming agent and wipping time on foam mat drying of sapota pulp

Heat of hydration in ultralight cementitious foams incorporating metakaolin and microencapsulated phase change material

The paper presents the results of a study on the hydration heat of ultralight cementitious foams envisaged as insulation materials for building envelopes. The examined porous foam-cement material was additionally enhanced by embedded microencapsulated phase change material (PCM) to improve the desired thermal properties of the material. The heat emission and heat flow were measured at 20 °C and 30 °C for 168 h using the isothermal calorimeter. The experimental study comprised composites with dry densities of 240 kg m−3 and 480 kg m−3, two concentrations of protein-based foaming agent (2% and 4%) and two dosages of the embedded PCM material (10% and 20%). The reference composite without PCM was also tested. The effect of the necessary admixtures used to achieve the stability of ultralight cementitious foams was also examined. The results showed that hydration in ultralight foam-cement composites is retarded, and the values of heat released are lower than those of the paste used to produce the composites. In this regard, the main factors contributing to the lower heat released and its lower rate are the excess water from the foam, the dosage of the foaming agent and the admixtures introduced to achieve the stability of the ultralight composite. The stabiliser was found to be the most retarding admixture. Considering PCM, which was added at 10% and 20% of the paste volume, a rather low influence on the course of the hydration process was observed due to the overall composition of ultralight cementitious foams specially modified for each assumed content of PCM.

Additive manufacturing of functional corundum-mullite refractory with acid-corrosion resistance and heat insulating by direct ink writing

The low thermal conductivity and high chemical stability of corundum-mullite refractories have garnered attention for high-temperature insulation and acid-corrosion-resistant applications. A 3D extrusion-based method (direct ink writing) utilizing clay-alumina-silica fume foaming inks was employed to create corundum-mullite refractories with controllable structures (non-porous surface, porous interior). The rheology and printing ability of the inks were modified by adjusting the additives (dispersant and foaming agent) content. Printing parameters, specifically pressure and nozzle moving speed, were adjusted to enhance the precision of the printed construction. The impact of extrusion pressure in the ink on the surface structure of printed products was also investigated. The properties of the corundum-mullite refractory were evaluated by heating it from 1200 °C to 1500 °C, resulting in improvements in acid corrosion rate (from 1.9 % to 14.7 %), thermal conductivity (from 0.35 to 1.65 W/m·K), and compressive strength (from 20.1 to 45.5 MPa), respectively. The Ashby-Glicksman model (closed pore) was employed to forecast the thermal conductivity of the porous refractory with complex pore structures, proving to be a beneficial choice. After acid corrosion for 12 h, there were minimal microcracks and pores on the surface of the refractory prepared at 1500 °C, and the acid corrosion rates were less than 3.4 %. This study illustrates the effectiveness of optimizing printing parameters to adjust pore structure and enhance refractory properties.

Optimization of foam mat drying using Central Composite Design to produce mixed juice powder: A process and characterization study

This study aimed to optimize the mixed juice powder through foam mat drying to achieve a high solubility index. The process variables were optimized using a central composite design, assessing the influence of foaming agent concentration (5, 10, and 15) (% w/w), drying temperature (50, 60, and 70) °C, and foam thickness (2, 4, and 6) mm on powder solubility. The optimized juice was evaluated for the physical, chemical, technological characteristics and bioactive compounds. The optimal conditions were determined as a drying temperature (60.27 °C), foam thickness (2.82 mm), and 8.56 (% w/w) maltodextrin. The final product characterization revealed notable properties, including a soluble solids content of 8.75 °Brix, pH of 4.48 ± 0.01, and water activity of 0.44 ± 0.04. The analysis covered aspects related to color, porosity, sedimentation index, and solubility, highlighting a browning index of 0.81 ± 0.03. The powder microstructure exhibited a variety of shapes, reflecting the stability of the foam. The results confirmed the stability of the mixed juice powder, indicating that it maintained a consistent total carotenoid concentration of 10.65 μg/g and preserved its physicochemical characteristics. The cubic response surface model was the most suitable for solubility response with maximum value desirability (1.00).

Study on the performance of porous polyimide bearing cage material modified with molybdenum disulfide and glass fiber

This study explores material modification utilizing molybdenum disulfide and glass fiber as lubricating and reinforcing modified materials respectively. The specimens underwent tests for mechanical-physical properties, oil storage capacity and frictional characteristics. The differential analysis identified the optimal mechanical-physical properties of the porous composite PI material at a molding pressure of 192 MPa, molding temperature of 330°C, 9% of AC foaming agent content, 8% of molybdenum disulfide content, and 20% of glass fiber content. The wear coefficient increased with load and decreased with rotational speed, indicating the suitability of this porous composite oil-retaining PI material for medium-high-speed and low-load frictional conditions.

Experimental and simulation study on the expansion mechanism of polyurethane grout

Understanding the expansion mechanism of polyurethane polymer grout can supply guidance for accurate grouting. However, most of the polymer grout expansion calculations were defined simplistically by the polymer density-expansion pressure empirical relationship expression, which failed to meet the time history of the expansion pressure during the polymer reaction process. The objective of this paper was to investigate the expansion mechanism of polyurethane foam in various constraint conditions during the whole polymer reaction process. A model describing the expansion mechanism of polyurethane foam was established based on the energy conservation principle, the chemical reaction kinetic equation solved by the Runge-Kutta method, and the ideal gas state equation. The model was proved applicable compared to the experiments under fixed volume and fixed confining pressure boundaries. In addition, the effects of grouting quantity, confining pressure, initial temperature, and physical foaming agent content on the grout expansion pressure, density, and components conversions were discussed. The results showed that the expansion pressure of polymer grout gradually increased with time under the fixed volume conditions, and the grout expansion pressure increased as the density increased. The final grout expansion pressure will increase with the increase of initial temperature or the content of physical blowing agent. Under the fixed confining pressure condition, the polymer grout density gradually decreased with time, the grout density increased as the confining pressure increased while the conversions of the two components alcohol and isocyanate increased. The final density decreases with the increase of initial temperature or the content of physical blowing agent.

Preparation of thermal expandable epoxy resin and properties of foam sandwich composites formed by thermal expansion molding process

AbstractThermal expansion molding process (TEMP) is a sophisticated molding technique for creating complex sandwich composites. The core key of TEMP is a high‐performance, thermally expandable resin film. In this study, the epoxy resin is used to create a specific crosslinking network that can provide the support force required for the stable molding of the vesicles during the expansion process of the foaming agent. The curing process of the resin was determined by analyzing the change in the exothermic amount of the epoxy resin during the curing process and the flow behavior of the resin. The pore size distribution of the epoxy foam was investigated, and the expansion force of the thermally expandable resin was tested. The TEMP molding process was compared with the vacuum bag press molding (VBPM) process. The TEMP molding technique increased tensile and compressive strength by about 25%, flexural strength by 34.5%, and shear strength by 54.5%. Finally, the section on microanalysis of the comparative materials and the short beam bending experiments of the sandwich structure provides a theoretical foundation for developing complicated sandwich structures.Highlights Preparation of thermally expandable epoxy prepregs with stabilized foaming by means of pre‐curing. The effects of curing temperature, foaming agent content and expansion multiplicity on the thermal expansion force of epoxy prepreg adhesives were investigated. Thermally expandable epoxy prepreg molding composites with different expansion multiplicities and analysis of the mechanical properties of the composites. Preparation of foam core sandwich composites by thermal expansion in‐mold monolithic molding process and their verification by bending experiments.

Optimization of natural rubber foams: Effect of foaming agent content and processing conditions on the cellular structure and mechanical properties

In the past decades, natural rubber (NR) foams became popular in the automotive, construction and aerospace industries because of their lightweight, flexibility and shock-absorbing properties. The selection of optimal formulation and processing parameters is critical to produce foam with specific properties depending on the application. In this study, the effect of foaming agent concentration, foaming temperature and time on the morphological and mechanical properties of NR foams was investigated. First, increasing the foaming agent content from 5 to 9 phr (parts per hundred rubber) increased the cell size (16%), while decreasing the compression modulus (28%). In the second part, increasing the foaming temperature (145 to 155°C) resulted in larger cell size (163%); while decreasing the cell density (28%), compression modulus (2%), and hardness (1%). In the third part, increasing the foaming time (25 to 45 min) led to smaller cell size (63%) combined with higher cell density (100%), compression modulus (16%), and hardness (3%). Based on all the results obtained, the best NR foam was obtained with 7 phr of foaming agent and produced at 150°C for 35 min leading to superior morphological and mechanical performance: the smallest cell size (25 µm) and the most uniform cell size distribution ( Đ = 1.03) generating the highest compression modulus (3.36 MPa). Finally, the experimental compression results were combined to build a nonlinear regression model to optimize the formulation and processing conditions leading to 6.5 phr of OBSH molded at 150°C for 36 min. The model showed good agreement with a validation test with less than 2% deviation observed for both compression modulus and strength.

Effects of process conditions and nano-fillers on the cell structure and mechanical properties of co-injection molded polypropylene-polyethylene composites

Compared with traditional injection foaming, co-injection foaming serves as a method to prepare products with high-quality surfaces and enhanced mechanical properties, demonstrating excellent technical advantages and economic benefits. The effects of high-density polyethylene (HDPE) content, foaming agent content, melting temperature of core material, and nano-organic montmorillonite (OMMT) content on the cell structure, mechanical properties, and crystallization behavior of isotactic polypropylene (iPP)/HDPE composite foam prepared by co-injection foaming were systematically studied. At a foaming agent content of 2 wt.%, HDPE content of 30 wt.%, OMMT content of 3 wt.%, and the melting temperature of core material of 190 °C, the composite foam exhibited a cell size measuring 85 μm, a cell density of 2.5 × 105 cells/cm3, a tensile strength of 25.8 MPa, and an impact strength of 12.5 kJ/m2. The addition of HDPE reduced the crystallinity of iPP matrix, while enhancing the solubility of carbon dioxide within the matrix. The non-miscible interface between HDPE and iPP helped reduce the energy barrier for cell nucleation. Furthermore, the introduction of OMMT as a nucleating agent in iPP/HDPE composite material dramatically decreased the energy barrier for cell nucleation. These synergistic effects result in foam with the smaller cell size and the higher cell density, exhibiting excellent comprehensive mechanical properties. This work provides a feasible method for preparing composite foam with excellent comprehensive performance.

Experimental investigation of flow patterns and rheological characteristics of compressed air foam in horizontal tube

The use of compressed air foam (CAF) for fire suppression has undergone rapid development in recent years. It has been successfully applied in fire incidents in the petroleum and chemical industries. The increasing need to fighting fires at high elevations necessitates an understanding of the rheological characteristics, pressure gradient changes, flow characteristics, and regularities of CAF within long firehoses. Therefore, this paper focuses on an investigation of the flow characteristics of CAF at foaming agent concentrations ranging from 0.1% to 1.2% and gas–liquid ratios ranging from 5 to 25. Specifically, it explores foam characteristics, pressure loss, and the relationship between flow rate and foaming agent concentration. The findings reveal that CAF exhibits four flow patterns: wave flow, elastic flow, ring flow, and dispersion flow. For most CAF firefighting applications, a foaming agent concentration of 0.3%–0.5% and a gas–liquid ratio of approximately 10 are suitable. However, for fire isolation purposes, a foaming agent concentration of 0.7%–1.0% and a gas–liquid ratio of over 15 should be employed. By utilizing a power-law rheological model and an experimental regression method, a prediction model is obtained for the flow characteristics and pressure loss of CAF in pipelines. The predictions of the model exhibit an error of less than 10% when compared with experimental results, validating the model. The results of this study provide a theoretical basis and technical support for understanding liquid supply resistance loss, which is crucial for maximizing firefighting effectiveness.

The Effect of Foaming Agent and Whipping Time on Albedo Characteristics of Watermelon Flour

The fruit's rind is one of the natural waste products that can support nutrients like carbohydrates, proteins, and lipids. Reused rind contributes significantly to the effective handling of this fruit's byproduct. Processing watermelon rind into powder by lowering water content and activity is an alternative to extending its shelf life. The flour form is easier and more suitable for application in multiple processing food products such as snacks, beverages, bread, and pasta. The focus of this study was to verify the optimal state for foam mat drying using concentrations of foaming agent in the form of egg albumin (10, 15, 20), foam stabilizer in the form of CMC with concentrations of 1 %, and whipping time (5, 7, and 9 minutes) on for bulk density, WSI, hygroscopicity, L* value, a* value, b* value of total phenol and antioxidants activity, and the maximum antioxidant content of watermelon albedo flour using Completely Randomized design with 2 factorial resulting in nine treatments with three replications. Based on the outcome, the bulk density of the resulting watermelon albedo flour ranges from 0.25-0.50 gr/cm-3 and 0.11-0.26%. of WSI; 22.63-28.18g/100g-1 of hygroscopicity; 1.92-4.67% of total phenol; 47.48-66.59% of L*value; 3.74-6.11% of a*value; 5.47-16.08% of b*values and 6.80- 25.26% RSa of antioxidants activity. The best treatment for antioxidant activity was 25.26% RSA using 10% of the foaming agent and whipping time in 9 minutes. These findings have implications for the food industry because they suggest that treatments can influence the properties of watermelon albedo flour.

On recycling earth pressure balance shield muck with residual foaming agent: defoaming and antifoaming investigations.

Earth pressure balance (EPB) shield is increasingly employed in metro tunnel construction, and causes a series of environmental, safety, and resource waste problems due to the disposal of a considerable amount of muck. In situ recycling of EPB shield muck is an effective solution, whereas the foam is generated by residual foaming agents used as the muck conditioning material during tunnelling, which often adsorbs clay particles and overflows the flocculation tank. To achieve defoaming and antifoaming during the reuse of muck, this study prepared novel eco-friendly silicone oil-polyether defoamers by condensation, compounding, and shear emulsification. Defoaming and antifoaming performances of different defoamers were tested using a modified Ross-Miles method and a scale model of field flocculation systems. The results indicated that a high efficiency in defoam and antifoam was characterized by chemical grafting of nano-SiO2 from silicone oils, uniform distribution and large size of grains, low viscosity, and surface tension. The defoamer dosage of 0.002-0.004 wt% near critical micelle concentration (CMC) for each defoamer is reasonable. Overall, the prepared hydroxyl silicone oil-glycerol polyoxypropylene ether (H-G) defoamer compared with other silicone oil-polyether defoamers and commercial defoamers presents the highest defoaming and antifoaming efficiency. Considering the effects of EPB shield muck, the H-G defoamer is least affected by the compound materials and increasing concentration of the commercial foaming agent. Nevertheless, the stability of the H-G emulsion system is weaker than that of the dimethyl silicone oil-glycerol polyoxypropylene ether (D-G) emulsion system after 1 month of sealed storage.