Foaming Characteristics Research Articles

GRAPHITE FOAM STRUCTURES AS AN EFFECTIVE MEANS TO COOL HIGH-PERFORMANCE ELECTRONICS

Due to their unique heat transfer features, graphite foams are used in the current analysis to form heat sinks effective enough to dissipate extreme heat generated within high-performance electronics. The heat sinks proposed are formed from foamed-baffles arranged either in parallel or perpendicular to the coolant paths through the staggered slots in between to alleviate the penalty of pressure drop while maintaining high heat dissipation capability. Two different sorts of dielectric coolants namely, air and the FC-3283 electronic liquid developed by 3MTM, have been utilized to directly dissipate the heat generated. The feasibility of the currently proposed heat sinks has been examined numerically based on the volume averaging concept of porous media employing the local thermal non-equilibrium model to account for interstitial heat exchange between the foam solid matrix and the fluid particles flowing across. A wide range of design parameters has been tested including the heat sink configuration along with structural characteristics of the graphite foam used. It has been found that foam baffles oriented perpendicular to the path of coolant flow can dissipate heat by about 50% better than those parallel to it, but with higher pressure losses. It has also been found that heat dissipation capability, for a certain orientation of baffles, can be improved by up to 100% when the foam pore size is doubled with outstanding saving in pressure losses by up to 300%. The impact of operating conditions, including the coolant flowrate and the heat flux applied, has also been inspected. The currently proposed heat sinks have been found efficient to meet the thermal demands of high-performance electronics and sweep away the extreme heat generated there with reasonable cost of pressure drop, where the proper selection of design parameters in light of the operating conditions applied can prevent the emergence of hot spots entirely. Extreme operating conditions, i.e. with heat density of up to 10W/cm2 for air-cooled heat sinks and 100W/cm2 for those cooled with FC-3283, can be well managed when a heat sink is configured from baffles that are oriented perpendicularly to the coolant flow path and formed of graphite foam having low porosity (∅=0.8) and larger pore size

Effects of sodium oleate surface properties on the characteristics of two-phase foam in froth flotation

Aiming at the problem that the active agent foam is too stable during the flotation process, the experiments of the surface tension, surface viscoelasticity and gas-liquid two-phase foam performance of sodium oleate were carried out under the conditions of different concentrations, pH and temperature. The aim is to explain the changes in macroscopic blistering phenomena by changes in microscopic surface properties. The results show that concentration, pH and temperature all affected the foam properties of sodium oleate. When the sodium oleate solution is 10−3 mol/L (cmc), the foam stability is the best. The foam is most stable at pH of around 8.5. Temperature has a significant effect on the foaming property of sodium oleate, the foaming ability of sodium oleate is weak at a low temperature, while sodium oleate is unstable at high or low temperature. The lower the surface tension of the sodium oleate solution, the stronger the foaming performance; and the higher the expansion modulus, the more stable the foam. This study serves as a guide to control the parameters of sodium oleate flotation system and the optimal stabilisation of foam.

Current status and recent advances in magnesium-matrix syntactic foams: Preparation, mechanical properties, and corrosion behavior

Over the last ten years, magnesium (Mg)-based syntactic foams (SFs) have gained significant attention and their popularity continues to grow. This is because they possess unique properties such as high mechanical strength and are lightweight, making them potential candidates for applications in various industries, including aerospace, automotive, and biomedical (especially in orthopedics). This article reviews and discusses different fabrication techniques used in producing magnesium-matrix syntactic foams (Mg-MSFs). These techniques include stir casting, disintegrated melt deposition, powder metallurgy, and melt infiltration. The review comprehensively analyzes microstructure specifications, mechanical properties, and corrosion behavior exhibited by Mg-MSFs fabricated to date. The findings suggest that the properties of these foams, including microstructural characteristics, mechanical properties, and corrosion behavior, are significantly influenced by factors such as filler particle amounts and properties, Mg alloy-matrix specifications, fabrication techniques, process parameters, and post-processing treatments (such as annealing and sintering). These factors play a crucial role in determining the final characteristics of the syntactic foams. While Mg-MSFs hold substantial importance and potential, a limited body of research exists in this area. Therefore, more research is necessary to comprehensively understand these structures, which will facilitate their effective utilization in both industrial and biomedical applications.

Study on the thermal characteristics and heat-insulation ability of gel-stabilized foam used for preventing the spontaneous combustion of coal

Gel-stabilized foam serves a critical role in preventing spontaneous combustion of coal by impeding heat transfer from the coal-fire area to adjacent safe areas. To elucidate the thermal characteristics of gel-stabilized foam, the microstructure and heat-transfer characteristics were investigated. The results revealed that gel-stabilized foam was an accumulation system of many stable and closed bubbles, and there was a layer of gel structure on the bubble surface. This gel layer endows the bubbles with exceptional heat-insulation capability by effectively encapsulating air. To further analyze the relationship of heat-transfer characteristics and foam structure parameters, a theoretical thermal-conductivity model was established to revel the thermal characteristics of gel-stabilized foam. Moreover, the experimental tests were conducted to verify the accuracy of theoretical model, and found that the fitting errors were around 8 %, affirming the model's suitability for gel-stabilized foam. Notably, the theoretical model demonstrated that foam's thermal-conductivity was only monotonically related to foam expansion ratios in theory. In addition, the heat-insulation experiments indicated that the heat-transfer rate of foam depended not only on the thermal-conductivity but also on the foam's stability, both of which were affected by the expansion ratio. Hence, the effective heat-insulation time (EHT) was proposed to assess gel-stabilized foam's heat-insulation characteristics. The heat-insulation ability tests results showed that EHT values initially increased and then decreased with rising foam expansion ratios, primarily influenced by the volume of air encapsulated within the foam. Particularly noteworthy were the test results indicating that gel-stabilized foam with an expansion ratio of 10 times and a stacking thickness of at least 15 cm exhibited excellent heat-insulation capability against heat transfer from the spontaneous combustion zones. The research may provide a theoretical foundation and offer guidance for the prospective utilization of gel-stabilized foam in coal mines.

Numerical analysis of radiative transfer and prediction of spectral properties for combined material composed of nickel foam and TiO2 nanofluid

Accurate spectral radiative transfer simulation and property prediction are basic for improving the performance of combined collecting material in the field of solar photothermal utilization. In this work, the combined material composed of open-cell nickel foam and TiO2 nanofluid is proposed, and the various multi-scale structures are modeled. The realistic structures of nickel foams with different porosities and PPI are reconstructed with the μ-CT technique, meanwhile, the spherical nanoparticles with different radii are considered separately for modeling the structures of nanofluids with different particle sizes and volume fractions. A numerical simulation process is introduced for achieving the across-scale analysis, with the FDTD method and the MCRT method applied jointly. The numerical analysis integrating micro/nano-scale and macroscale radiative transfer processes is conducted for predicting the spectral radiative properties of nanofluid and combined material, with the complex size characteristics of nanoparticle, nanofluid and porous metal foam considered. Then, in the discussed waveband from 300 nm to 1000 nm, the absorption portions of different components are compared by changing the structural parameters at different scales. The effects of macro-scale and micro/nano-scale structural parameters on the spectral properties are analyzed. It can be observed that the extinction process inside nanofluid can be regulated by changing the particle size and volume fraction. Besides, in the discussed waveband, when the combined material with thickness exceeding 10 mm is applied, almost all the incident solar radiation can be absorbed. At last, the absorption performance is contributed by both nanofluid and solid foam, and the occupied portions of different components change with increasing wavelength. The absorption portions are affected by porosity, PPI, ligament surface morphology, nanoparticle size and volume fraction together.

Preparation and fire extinguishing characteristics of inorganic solidified foam with large amount of slag

ABSTRACT Aiming at the problems of conventional cement-based foam plugging and filling materials, such as large amount of cement, low utilization rate of solid waste, unclear bonding, and plugging mechanism, it was proposed that a kind of plugging and preventing fire material named inorganic solidified foam was prepared from industrial slag, cement, and water-based foam as the main raw materials. Based on the fluidity, expansion ratio and mechanical strength of solidified foam, it was determined that S105 slag powder with high content of 60%~65% and the optimal content of the chemical activator 6%. The dry density of solidified foam was about 410~450 kg/m3, and the compressive strength reached 0.5~0.55 MPa. The formation process, the bonding-reinforcement mechanism, and the fire prevention characteristic fire of solidified foam were explored. The results showed that solidified foam could significantly improve the pozzolanic activity of solid waste under the effect of physical and chemical synergy, promoted the hydration reaction of the material, increased the structural compactness of the hydration product of the material, further improving the strength. Fire-fighting experiments and field application exhibited that solidified foam could rapidly diffuse and accumulate to high places through crack channels, quickly extinguish and cool down, and coat loose high-temperature coal piles, showing excellent effect of preventing coal spontaneous combustion. Moreover, the field test results showed that the solidified foam could quickly plug the air leakage, and reduce the CO concentration in the air leakage are. Specifically, the CO concentration of high falling area decreased from 315 ppm to 22 ppm in 3 days, eventually stabilizing below 10 ppm, thereby timely inhibiting the development of spontaneous combustion fire.

Pyrolysis characteristics, kinetics and products of flexible polyurethane foam in luxury cruise ship via TG, FTIR, GC-MS and Shuffled Complex Evolution

Flexible polyurethane foam is widely used in furniture upholstery, car seats, and other products. Its safety has attracted increasing attention, especially fire safety in luxury cruise ship. Thermogravimetry-Fourier Transform Infrared Spectroscopy-Gas Chromatography-Mass Spectrometry (TG-FTIR-GC-MS) is used to explore the pyrolysis characteristics of flexible polyurethane foam. The experimental results show that three weight loss peaks can be observed in the pyrolysis of flexible polyurethane foam under nitrogen atmosphere, which implies that the pyrolysis behaviors of isocyanate, polyol and catalyst are responsible for the peaks. The pyrolysis process of flexible polyurethane foam can be divided into two regions: the fifth-order reaction (F5) model and the one-dimensional diffusion (D1) model corresponding to regions I and II, respectively. The main pyrolysis intermediate function groups includes CO2, gaseous H2O, C-O, CO, C-H and other functional group stretching products. The amount of intermediate function groups generated in order of most to least is C-O > C-H > CO2 > CO > H2O. Six main products are generated under the N2 atmosphere, including Ethane, 2-Octen-1-ol, 3,7-dimethyl-isobutyrate, Diisopropyl ether, 1-Propoxypropan-2-yl acetate, Z-8-Methyl-9-tetradecenoic acid, Methyl 7,9-tridecadienyl ether and N-(2-Methylbutyl) undeca-(2E,4E)-diene-8,10-diynamide. The Shuffled Complex Evolution (SCE) algorithm is used to optimize the experimental pyrolysis kinetic parameters, and the optimized data show good agreement with the experimental data.

The Role of Fatty Acid Synthase in the Vascular Smooth Muscle Cell to Foam Cell Transition.

Vascular smooth muscle cells (VSMCs), in their contractile and differentiated state, are fundamental for maintaining vascular function. Upon exposure to cholesterol (CHO), VSMCs undergo dedifferentiation, adopting characteristics of foam cells-lipid-laden, macrophage-like cells pivotal in atherosclerotic plaque formation. CHO uptake by VSMCs leads to two primary pathways: ABCA1-mediated efflux or storage in lipid droplets as cholesterol esters (CEs). CE formation, involving the condensation of free CHO and fatty acids, is catalyzed by sterol O-acyltransferase 1 (SOAT1). The necessary fatty acids are synthesized by the lipogenic enzyme fatty acid synthase (FASN), which we found to be upregulated in atherosclerotic human coronary arteries. This observation led us to hypothesize that FASN-mediated fatty acid biosynthesis is crucial in the transformation of VSMCs into foam cells. Our study reveals that CHO treatment upregulates FASN in human aortic SMCs, concurrent with increased expression of CD68 and upregulation of KLF4, markers associated with the foam cell transition. Crucially, downregulation of FASN inhibits the CHO-induced upregulation of CD68 and KLF4 in VSMCs. Additionally, FASN-deficient VSMCs exhibit hindered lipid accumulation and an impaired transition to the foam cell phenotype following CHO exposure, while the addition of the fatty acid palmitate, the main FASN product, exacerbates this transition. FASN-deficient cells also show decreased SOAT1 expression and elevated ABCA1. Notably, similar effects are observed in KLF4-deficient cells. Our findings demonstrate that FASN plays an essential role in the CHO-induced upregulation of KLF4 and the VSMC to foam cell transition and suggest that targeting FASN could be a novel therapeutic strategy to regulate VSMC phenotypic modulation.

Thermo-rheological improvement of magnetorheological foam with the addition of silica nanoparticles

Magnetorheological (MR) foam has become a potential soft robotic gripper-based material that can provide a better grasping force and handling objects due to its ability in varying stiffness in correspond to applied magnetic fields. However, MR foams are facing degradation issue that may reduce the storage modulus when often exposed to thermal exposure from the operating system of a device. Therefore, this study focuses on improving the storage modulus and simultaneously enhancing the thermal properties of MR foam. Hence, silica nanoparticles were introduced as an additive to achieve the improvement target. MR foams were embedded with different concentrations of silica nanoparticles from 0 to 5 wt.%, and the corresponding rheological properties was examined under different temperature conditions from 25 °C to 65 °C. The results revealed that increasing temperatures have reduced the storage modulus of MR foams, however, the embedded silica has countered the drawbacks by strengthening the interfacial interactions between CIP-polyurethane foam matrix. In addition, the morphological characteristics of MR foams also showed less debris or peel-off PU foam with silica nanoparticles. Besides, the silica nanoparticles have delayed the thermal degradation of MR foam for approximately 30 °C.

Anisotropic compression response of functionally gradient syntactic foam comprising of fly ash cenosphere and polyurethane

A novel functionally gradient (FG) syntactic foam with hierarchical cell structure was prepared by incorporating fly ash cenosphere of different size distribution into rigid polyurethane foam (PUR). The mechanical anisotropic behavior was experimentally studied by axial and traverse compression, and the influence of density gradient on failure mechanism was discussed through digital image correlation (DIC) technique. Results shown that the density graded (GD) syntactic foam produced stepwise stress strain response under axial compression, but failed by global shear pattern under traverse compression. The plateau stress of layered density (LD) syntactic foam gradually increased under both compression modes. The mechanical anisotropic property of FG syntactic foam was much smaller than that of functionally gradient aluminum foam. Failure mechanism of FG syntactic foam under axial compression was mainly controlled by the compression strain band generated in low density layers, and the deformation band successively extended to high density region. Under traverse compression, the material interfaces in LD foam significantly affected the propagation of shear deformation bands generated in high density layers, producing more short-range interpenetrating shear bands. The layered density gradation shown great potential in decreasing the anisotropic characteristics of syntactic foams. These findings can provide a valuable guide for designing and optimizing the impact resistance of functionally gradient foams.

Potential health and environmental benefits of the identified phytochemicals screening of (Azadirachta indica) neem leaves in Bauchi Metropolis, Bauchi State, Nigeria

The phytochemical screening of (Azadirachta indica) Neem leaf extract was conducted to identify and quantify the presence of bioactive compounds. The study conducted various tests to assess the phytochemical components. About 1kg of matured fresh leaves of (Azadirachta indica) neem was collected from five (5) different location in Bauchi metropolis, these locations are; Kobi Street, Gida Dubu, Yelwan Tudu, Wuntin dada and Federal Low-cost areas in Bauchi metropolis, Bauchi State, Nigeria. The leaves of the plant, which were ground into a fine powder using a mortar and pestle. An ethylacetate solvent was used to derive the A. indica leaf extract. The results of the research shows that the presence of alkaloids, saponins, phenols, and cardiac glycosides in the neem leaf extract is significant, and flavonoids, terpenoids, and steroids were not detected in the neem leaf extract. The presence of alkaloids, saponins, phenols, and cardiac glycosides suggests that neem leaves may hold promise in traditional and contemporary medicinal practices. Alkaloids, known for their pharmacological significance, may contribute to the plant's therapeutic properties. Saponins, with their frothing and foaming characteristics, have been associated with immunomodulatory effects and their potential in agrochemical applications. Phenolic compounds, as evidenced by the positive response to the Ferric chloride test, indicate the antioxidant potential of neem leaves, which can combat oxidative stress. Conversely, the absence of flavonoids, terpenoids, and steroids suggests that these specific phytochemical classes may be limited in neem leaves. These findings open avenues for further research and utilization of neem as a valuable natural resource.

In-depth investigation of how carbon nanofiller dispersion affects microcellular foaming behavior in poly(butylene succinate) nanocomposites

This study explores the impact of carbon nanotubes (CNTs) dispersion on the microcellular foaming characteristics of poly(butylene succinate) (PBS) matrices. Two distinct dispersion methods, primary (PD) and secondary (SD), were employed to fabricate PBS/CNT nanocomposites, resulting in different filler dispersion states. The PD technique involves the conventional method of direct melt blending PBS with CNTs, while the SD technique adopts a more advanced strategy by integrating the Pickering emulsion template with melt blending, achieving finer CNTs distribution within the PBS matrix. The results reveal that the SD technique leads to significantly more uniform distribution of CNTs, which in turn enhances the melt strength and crystallization of the polymer matrix, thereby broadening the window for microcellular foaming. Notably, foams developed through the SD method exhibited a decrease in cell size to 10.4 μm and an increase in cell density to 1.8×1010 cells·cm‐3. Moreover, this uniform distribution of CNTs contributed to superior cell stability and an increase in compressive strength to 14.0 MPa. These findings highlight the pivotal role of nanofiller dispersion in determining foam properties and establish foundational knowledge for designing PBS foams with consistent and uniform cell structures. Such advancements are crucial for enhancing the applicability and performance of PBS-based materials across a spectrum of industries.

Effect of benzoic acid-based and cinnamic acid-based polyphenols on foaming properties of ovalbumin at acidic, neutral and alkaline pH conditions

To broaden the application of ovalbumin (OVA) in food formulations, it is meaningful to improve its foaming characteristics. This study aimed to investigate the effect of benzoic acid-based (3,4-dihydroxybenzoic acid, DA) and cinnamic acid-based polyphenols (trans-2-hydroxycinnamic acid, T2A) on the foaming properties of OVA at acidic (pH 3.0), neutral (pH 7.4) and alkaline (pH 9.0) pH conditions. Both the addition of polyphenols and acid treatment enhanced the foaming properties of OVA. Surface hydrophobicity, circular dichroism, free sulfhydryl groups, and Fourier transform infrared spectroscopy results indicated that after acidic workup, the presence of stronger hydrophobic interactions in OVA-polyphenol aggregates induced more disordered protein conformation and conversion or breakage of disulfide bonds. Particle size and zeta potential indicated that acidic treatment neutralized protein surface charges, further inducing self-aggregation and swelling of OVA, ultimately enhancing foaming properties. Comparatively, T2A exhibited better foam-inducing capacity due to its stronger interaction with OVA, leading to the unfolding of the OVA structure and the exposure of more hydrophobic groups. The intrinsic and 3-D fluorescence spectra experiments also confirmed that OVA-T2A aggregates at pH 3.0 had greater altered non-covalent interaction forces and protein secondary and tertiary structures compared to other complexes. This study provides a theoretical basis for designing protein formulations with excellent foaming properties.

Dynamic Interfacial Properties and Foamability of DoTAB/SiO2 Mixtures

The interaction between nanoparticles and cationic surfactants is an exciting and emerging field in interfacial science. This area of research holds significant promise, linking fundamental principles to practical applications in a variety of industries, including chemical processes, biomedical applications and the petroleum industry. This study explores the interaction between dodecyltrimethylammonium bromide (DoTAB) and silica (SiO2) nanoparticles, investigating their influence on dynamic interfacial properties and foam characteristics. Through equilibrium and dynamic surface tension measurements, along with examining the dilational visco-elasticity behavior, this research reveals the complex surface behavior of DoTAB/SiO2 mixtures compared to individual surfactant solutions. The foamability and stability experiments indicate that the addition of SiO2 significantly improves the foam stability. Notably, stable foams are achieved at low SiO2 concentrations, suggesting a cost-effective approach to enhancing the foam stability. This study identifies the optimal stability conditions for 12 mM DoTAB solutions, emphasizing the crucial role of the critical aggregation concentration region. These findings offer valuable insights for designing surfactant-nanoparticle formulations to enhance foam performance in various industrial applications.

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.

Effect of electrolytic gases on characteristics of two-phase foam

Effect of electrolytic gases on characteristics of two-phase foam

Experimental study of thermal stability and spread characteristics of gel-protein foam for liquid tank fires

Gel foams have been increasingly used for extinguishing coal fires due to its high thermal stability. However, their applications in liquid fuel fires are very limited because of its high viscosity. In this work, the thermal stability and spread performance of -gel-protein foams were examined for tanks fires against a commercial fluorinated foam (FF). Fourier transform infrared spectra (FTIR) and scanning electron microscopy (SEM) of the gel-protein foams were analyzed to unravel its gelling mechanism. The extinguishing mechanism of the foams was also investigated. The results showed that the gel-protein foam attached by a dense gel film layer, formed by –COO- and Ca2+, can efficiently improve its foam stability. The gel-protein foam also showed good thermal stability with a collapse time of more than 1800 s, a 50% increase over FF. and a water loss temperature of 156 °C, 15 °C higher than that of FF. The gel-protein foam also demonstrated excellent firefighting efficiency in the gasoline tank fire extinguishing tests with a faster spreading rate compared with FF due to the formation of the ‘egg-box’ gel structure by calcium alginate.

Relationship between viscosity, foaming, and structure of CaO–SiO2–Al2O3–MgO–FeO slag with the addition of SiO2 and Al2O3

Optimizing the foaming characteristics of slag in electric arc furnaces (EAF) presents a challenging task, affecting electrode heating efficiency and increasing smelting cost. This study explores the impact of adding silicon dioxide (15–35 wt%) and a small quantity of alumina (5–10 wt%) on the viscosity and foaming properties of CaO–SiO2–Al2O3–MgO–FeO slag. Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) were employed to investigate structural changes in the slag melt. The findings reveal that higher levels of silica or a slight increase in alumina content enhance slag polymerization and foaming efficiency. Specifically, a 10 wt% alumina content, in contrast to 5 wt%, leads to high silica content, leading to faster polymerization but relatively lower viscosity. Structural analysis confirms that increasing alumina content, particularly when silica content is high, results in a less stable Al–O–Si structure, causing a shift from Q0 and Q1 units to Q2 and Q3 units, which ultimately reduces viscosity. When the alumina content remains at 5 wt% and silica content increases from 15 wt% to 35 wt%, foaming efficiency improves from 13.06 cm min to 94.97 cm min, a remarkable 627% rise. Moreover, when silica content is 30 wt% and alumina is slightly increased by 5 wt%, there is a notable enhancement in foaming efficiency, rising from 47.11 cm min to 89.16 cm min, while the effect on viscosity is not prominent.

High temperature and fire properties of sustainable syntactic foam reinforced by end‐of‐life tyre‐derived rubber particles

AbstractThe management of end‐of‐life tyres faces challenges due to insufficient recycling infrastructure and technologies, as well as limited markets for the materials recovered from them. To mitigate this, waste rubber can be upcycled and used as filler material for polymer matrix composites. Before rubber‐reinforced composites can be certified for fire‐prone applications, their thermal and flammability properties must be understood. This research investigates the effect of rubber fillers on the thermal stability, flammability and flame spread characteristics of epoxy matrix syntactic foam. Thermogravimetric analysis, Fourier Transform Infrared spectrometry (FTIR), scanning electron microscopy and attenuated total reflection FTIR spectrometry were employed to elucidate changes in thermal degradation behaviours. The influence of rubber fillers on the flammability of syntactic foam was assessed using the cone calorimeter. The fire reaction properties of rubber‐reinforced foam were affected by the intensity of the incident heat flux. Regardless of the incident heat flux, an increase in rubber content led to higher total heat release. At the lower heat flux of 35 kW/m2, the fire growth rate increased with rubber content, but at the higher heat flux of 50 kW/m2, the fire growth rate decreased as the rubber content increased. Importantly, all rubber‐reinforced syntactic foams achieved a UL94 HB ranking and exhibited reduced flame spread rates compared to the unmodified foam. This study demonstrated the potential for upcycling waste rubber into sustainable engineering products and expanded the knowledge base on fire reaction properties and flame spread characteristics of such hybrid composite materials.

Mechanical Characteristic and Energy Absorption Behavior of Closed-Cell Pure and A356 Alloyed Aluminum Foams during Compression

The goal of this study is to evaluate the mechanical characteristics and energy absorption capabilities of both closed-cell pure Aluminum foam and closed-cell A356 foam. A portion of the lightweight pure foam samples (17.12, 17.77 and 15.27 g) is produced through casting of raw material (99.9 % pure aluminum) using Titanium Hydride (TiH2) as a foaming agent, which lead to (7.5, 7 and 8) Pores Per Inches (PPI); and samples of A356 foam (38.24, 38.18 and 35.88 g) is produced through casting of A356 alloyed material with same procedure which lead to (11, 10 and 12) PPI. In order to determine the maximum compressive strength, strength-to-weight ratio, energy absorption density, complementary energy, and energy absorption efficiency, a uniaxial compression test is conducted. The results indicate that compression of pure foam structure smashed in a ductile manner and shows a lamellar eutectic structure while A365 foams under compression are crashed with brittle character with complex phases distribution inside (polyhedral and globular morphologies), A noticeable enhancement is observed in the mechanical characteristics of the A356 foam. The maximum compressive strength and specific energy absorption of alloyed foam are increased by a factor nearly of 4 and 2 respectively for all tested samples. Also, the result shows a significant decreasing in compressive strength with increasing of PPI for both pure and alloyed foam. The notable enhancements in the properties of alloyed closed cell foam render these advanced materials a viable option for high-strength applications.