Foaming Temperature Research Articles

Modelling and optimization of experimental parameters for porosity in friction stir processed aluminum foam using response surface methodology

ABSTRACT Aluminium foams are an emerging multifunctional material with a distinct structure and unique properties. However, controlling the porosity and pore morphology is still challenging because of the dependency on a number of the process parameters. This study uses a statistical approach to control porosity and influence of each parameter on porosity in a friction-stir processed aluminium plate. A second-order Response Surface Methodology (RSM) model is developed, and relationship among porosity and process parameters like Weight % TiH2, Weight % Al2O3, number of passes, tool rpm, and foaming temperature has been established and influence of each parameter on porosity is investigated. Experimental results validate the model, optimising 80–85% porosity for multifunctional applications. The optimal parameters are 1.2 wt% TiH2, 2.3 wt% Al2O3, 3 passes, 3000 tool rpm, and 738 °C foaming temperature. It was observed from the ANOVA that most influencing parameter is tool rpm, number of passes, followed by foaming temperature. The Scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS) analyses of the fabricated foam at its optimised condition confirm the uniform distribution of pores and the elements. This statistical optimisation model minimises experimental time and resource usage, demonstrating substantial technical and industrial significance.

Research on a synergistic formula of anionic and betaine type surfactants for natural gas fields

Abstract To further improve the foaming properties, foam stability, salt and temperature resistance, betaine surfactants were combined with sodium dodecyl sulphate-derived multifunctional surfactants synthesized in laboratory. Sodium dodecyl sulphate-derived multifunctional surfactants (HSDS) was synthesized and the changes in performance before and after the addition of hexadecyl betaine (HB) to hydroxymethylated sodium dodecyl sulfate were comprehensively compared by carrying out experiments such as such as measuring foam volume and surface tension. The foaming volume of hexadecyl betaine (HB) compounded with HSDS-4 is found to reach 475 mL with a half-life of 7.72 min. The temperature resistance test shows that the foam volume of HS-4 at 70 °C is 22.9 mL. At a salt content of 200 g L−1, the foam volume of HS-4 is still 355 mL with a half-life of 6.13 min. Finally, the microstructure of the foams produced by the different compounds was measured. The foam produced by HS-4 had the lowest defoaming rate compared to the other compounds. The effectiveness of the compounded product in improving the recovery rate is shown, providing support for the further innovation and utility of this technology.

Process Optimization of Pressure-induced Autoclave Foaming of Polylactide by Supercritical CO<sub>2</sub> Using Central Composite Design of Response Surface Methodology

A pressure-induced autoclave foaming assisted by supercritical CO2 of degradable polylactide (PLA) has been developed. A central composite design (CCD) of response surface methodology (RSM) is used to optimize three distinct process conditions: foaming temperature, pressure, and time. The mathematical model built for examining the effect of process conditions on the foam density and volume expansion ratio was verified and determined to be acceptable with an R-square value derived from the regression model of 0.930 and 0.934, respectively. The experimental and statistical results showed that of the three factors examined, the foaming pressure had the greatest impact on the density and volume expansion ratio of the PLA foams. The foaming temperature and time also had significant interaction impacts on both responses. It was observed that the following conditions are optimal for foaming of PLA, with a maximum VER of 10.107 and a minimum foam density of 0.123 g/cc: foaming temperature of 165.86 °C and foaming pressure of 152.4 bar for 2.38 h of foaming time.

Enhancing melt foam stability, form-filling process, and pore structure evolution of shaped aluminum foam

This study explores the stability of Al–Si–Ca–Mg-Sc melt foams and investigates the melt foam filling process and the dynamic evolution of pore structures in the fabrication of foam aluminum profiles using the melt transfer foaming technique. The results show that Al–Si–Ca–Mg-Sc melt foam maintains high porosity and a stable pore structure even after 30 min of foaming, without any signs of boundary rupture or destabilization. This stability is attributed to the increased viscosity from finely dispersed second-phase particles, which hinder the growth, coalescence, and drainage of the melt foam. Regarding melt foam filling, enhanced filling capability is achieved by elevating the foaming temperature, extending the foaming time, and increasing the TiH2 addition. The melt foam exhibits a smooth flow from the lower part of the mold to the corners, completing the filling process with well-defined edges in the profile. During lateral movement for filling, a gradual increase in porosity, a decrease in pore number, and a slow enlargement of pore size and standard deviation along the lateral (x-axis) are observed. This is due to the slower liquid phase flow compared to the gas phase, resulting in bubble coalescence. After filling is complete, this phenomenon improves, contributing to a slow and stable evolution of the pore structure.Under optimized conditions of 1.4 wt% TiH2 addition at 600°Cfor 9 min of foaming with Al–Si–Ca–Mg-Sc alloy melting, we successfully fabricated foam aluminum profiles with complete filling, a porosity of 81.5%, an average pore size of 2–3 mm, and a uniform pore structure.

Production of lightweight geopolymer concrete with foam glass aggregate derived from cathode-ray glass waste

This work focused on producing an eco-friendly lightweight structure by recycling the cathode ray tube glass waste (CRT-GW)to prepare a foam glass aggregate (FGA) and using metakaolin to prepare a geopolymer binder (GP). The geopolymer binder replaces cement to decrease the release of gas generated during cement production. The silicon carbide (SiC) was used as a foaming agent at 1 wt% to prepare the FGA. The foaming temperature effect was investigated for the FGA characterization included: bulk density, volume expansion, apparent porosity, uniaxial compressive strength, and leaching tests for lead and barium. The foam glass aggregate was sintered at different temperatures 725 °C, 750 °C, 775 °C, and 800 °C. These temperatures were selected depending on heating microscopy analysis results, where the maximum expansion height was 119 % at 800 °C. The main characterization ranges of foam glass were: bulk density 0.58–1.26 g/cm3, volume expansion 8–77 (vol%), uniaxial compressive strengths 1.55–9.98 MPa, and thermal conductivity 0.063–0.097 W/m.K.The lightweight geopolymer (LWGP) was prepared with 30 vol% of FGA sintered at different temperatures and 70 vol% of GP. These samples hardened at room temperature. The bulk density and compressive strength were measured for the lightweight geopolymer samples after a curing time of 28 days. A higher compressive strength was 9.11 MPa with a bulk density of 1.21 g/cm3 for lightweight geopolymer-containing foam glass aggregate sintered at 775 °C.

Utilization of thermoplastic resin as foamed asphalt modifier in cold recycled mixtures

The utilization of foamed virgin asphalt in cold recycled mixtures results in insufficient bonding strength between aggregates, leading to rapid deterioration to the recycled asphalt pavement. This ultimately causes inefficient clean production and increased carbon emissions. The foaming performance of thermoplastic resin modified asphalt (TRA) under different foaming conditions was analyzed. Micro-scale chemical and physical tests were utilized to discover the foaming mechanism of TRA. The road performance of cold recycled mixtures with foamed TRA was evaluated through splitting, rutting and fatigue tests. The results showed that the increase in the TRA polar functional group index led to an increase in its surface tension, thus limiting its expansion capacity. However, the increase in the specific heat capacity of TRA indicated that it preserves a low viscosity level essential for its foaming efficacy post-ejection from the foaming machine, thereby enhancing its half-life. Furthermore, the dynamic viscosity of the TRA with an 8% thermoplastic resin dosage exceeded 40000 Pa s at 60 °C, meeting the specification requirements for high viscosity asphalt, while exhibiting a notably lower viscosity of only 120 mPa s at the foaming temperature of 170 °C. The observed low viscosity of the asphalt is anticipated to favorably enhance the formation of a stable foam structure. The mechanical properties and overall road performance of the cold recycled mixture with foamed TRA were significantly enhanced, especially in terms of moisture damage resistance and low-temperature crack resistance. The purpose of this paper is to serve as a valuable reference for investigating the mechanism of modified asphalt foaming and to enhance the efficiency of cold recycled pavement regeneration processes.

Experimental validation of effective glass transition temperature‐based model for predicting skin thickness in solid‐state microcellular foams

AbstractThe solid‐state foaming process produces microcellular foams with an outer layer of solid skin that encapsulates the cellular core. In this article, we implement a 1D model to predict the thickness of the solid skin based on the effective Tg of the polymer‐gas system for a given foaming temperature. The model is based on the understanding that bubbles nucleate when the foaming temperature exceeds the effective Tg during the foaming process. The model was validated with experimental results on the PC‐CO2 system, which showed that skin thickness decreases with increased foaming temperature. We also developed a linear correlation to accurately predict effective Tg at different CO2 concentrations. The article also explores the model sensitivity to the key input parameters related to gas diffusion.Highlights Linear correlation to accurately predict effective Tg profiles in PC‐CO2 system. Increasing foaming temperature decreases skin thickness. Model is sensitive to the input parameters related to gas diffusion.

A Novel Inorganic Curing Foam for the Prevention of Spontaneous Coal Combustion and Its Characterization

ABSTRACT Aiming at the shortcomings of traditional inorganic curing foam materials, this paper carries out process optimization and ratio selection of inorganic curing foam through orthogonal test and single factor experimental. The performance of the improved inorganic curing foam was also tested by compression test, flexural test, and thermal insulation test. The experimental results show that the curing layer of inorganic curing foam can effectively insulate the heat generated by the spontaneous combustion of coal. The surface temperature of the inorganic curing foam under different heat sources was below 30 degrees. With the increase of hydration reaction time, the compressive strength of the material increased continuously, and the maximum compressive strength reached 3.36 Mpa at 28 days. In addition, the formula for calculating the porosity of inorganic curing foam materials was theoretically derived, and a prediction model for the compressive strength was established based on the porosity calculation formula.

Preparation, pore structure and properties of uniformly porous glass-ceramics sintered from granite powder using SiC@SiO2 foaming agent

Granite sludge produced during the processing of granite blocks should be efficiently recycled for environmental protection and as a sustainable resource. In this work, porous glass-ceramics were prepared by stepwise sintering of granite powder using core-shell SiC@SiO2 foaming agent. The SiC and SiC@SiO2 foaming agents were compared in terms of the sintering and foaming behaviors of the powder compacts by thermal expansion, thermogravimetry and mass spectroscopy. The foaming agent and foaming temperature were investigated to study their effects on the pore structure and properties of the porous glass-ceramics. The SiO2 shells of the SiC@SiO2 particles inhibited the oxidation of the SiC cores and the release of CO2 at the early stage of the sintering process, thus preventing pore coalescence and increasing the densification and specific strength of the sintered glass-ceramics. As the foaming temperature increased, the porous glass-ceramics exhibited a linear relationship between pore size and foaming temperature, and the specific strength first increased and then decreased due to pore coalescence and reduced crystallinity. Furthermore, the linear relationship between thermal conductivity and porosity indicates a closed pore structure, as demonstrated by computed tomography. At a foaming temperature of 1220 °C, the porous glass-ceramic has a porosity of 50.1 %, a specific strength of 16.6 kN⋅m/kg and a thermal conductivity of 0.747 W/(m⋅K). Numerical simulation confirms that lightweight glazed glass-ceramics have potential applications in energy-efficient building tiles.

A statistical approach towards determining the governing parameters in volume expansion behavior of polypropylene foams

This study delves into the complex relationship between molecular structures and properties within polypropylene (PP) foams, with a particular focus on how various material parameters influence foamability. Multiple linear regression was adopted to efficiently assess the impact of eleven material parameters on foam expansion behavior. A primary finding is the significant role of branching index (g'vis) in shaping the expansion profile (i.e., the foaming window, maximum expansion ratio (Φmax), and optimum foaming temperature (Toptimum)). Additionally, Z-average molecular weight (Mz) is identified as crucial factor influencing the foaming window. Furthermore, the Winter-Chambon parameter n, indicator of the relaxation behavior of a resin in the terminal zone, is distinguished as a key parameter in determining Φmax. The crystallization temperature (Tc) also plays a pivotal role, particularly in its relationship with Toptimum. The research further highlights the significance of long-chain branching (LCB) and suggests strategies for cost reduction by minimizing the degree of LCB without compromising foaming performance, achievable through the adjustment of Mz and n. This strategy was exemplified through the comparison of two LCB PP resins, PP-12 and PP-22, demonstrating the feasibility of achieving similar foamability with adjustments in material parameters. The findings offer a detailed assessment of these parameters' influence on foamability, presenting valuable guidelines for optimizing PP foam production and customizing material properties for targeted applications.

Static Factors in Sitting Comfort: Seat Foam Properties, Temperature, and Contact Pressure

The seat characteristics have high relevance in overall comfort on any transportation means. In particular, the foam’s mechanical properties, interface pressure, and contact temperature play an important role in low- or no-vibration situations regarding static comfort. The present work presents the complete protocol for a static evaluation of different foams and seat covers to assess railway seats. Based on the evaluation of the foam’s mechanical properties and interface pressure profiles, it was concluded that higher-density foam (80 kg/m3) is the most favorable. Regarding the foam cover, a thermographic assessment demonstrated that the fabric cover that induces lower temperatures at passenger interface contact promotes higher comfort levels. It should be highlighted that experiments were conducted on real train seat cushions and environments using a thermographic camera and pressure map sensor.

Microcellular foaming-derived strong ultra-high molecular weight polyethylene/high-density polyethylene foams for thermally insulating and oil-water separating applications

Ultra-high molecular weight polyethylene (UHMWPE) has excellent weather & chemical corrosion, abrasive resistances, and hydrophobicity, endowing UHMWPE foams promising perspectives in many applications, such as thermal insulation and oil-water separation, especially in harsh environment. However, the preparation of UHMWPE foams presents significant challenges due to its exceedingly high melt strength. In this study, a self-enhancement strategy was developed to tailor the melt viscoelasticity and foaming behavior of UHMWPE by blending with high-density polyethylene (HDPE). Remarkably, the inclusion of 40 wt% HDPE contributes to the achievement of the maximum expansion ratio reported to date for the UHMWPE foam, up to 36.5, and meanwhile, significantly expanded the foaming temperature range. The incorporation of HDPE notably improved the mechanical properties of the UHMWPE foams. With 30 wt% HDPE, the compressive strength and modulus of the foams increased by 50.9 % and 109.9 %, respectively. The foams with 40 wt% HDPE also demonstrated superior thermal insulation, exhibiting a thermal conductivity as low as 39.81 mW·m⁻¹·K⁻¹, marking a 92 % reduction compared to pure UHMWPE. Furthermore, the open-cell structure of the UHMWPE/HDPE composite foams displayed exceptional oil-water separation efficiency. This study introduces an innovative, eco-friendly approach for crafting UHMWPE foams tailored for multifunctional applications in harsh environmental conditions.

Tuning cellular structure in a previously developed microcellular acrylonitrile butadiene styrene/thermoplastic polyurethane blend foams

AbstractThis study investigates the cell structure control in 50% thermoplastic polyurethane (TPU) and 50% acrylonitrile butadiene styrene (ABS) blend foam using CO2 as a physical blowing agent, focusing on the effects of variable foaming parameters on the microstructure. Samples measuring 25 × 25 × 1 mm were produced and analyzed for foam structure. The foaming process involved saturating the samples with CO2 gas at pressures of 4, 5.5, and 7 MPa, followed by rapid pressure release and immersion in a hot glycerol bath. The foaming parameters included varied temperatures (80, 90, and 120°C) and times (5–80 s). Scanning electron microscope (SEM) analysis provided data on cell size and density. Results indicated that increasing the saturation pressure enhanced CO2 uptake in the ABS/TPU blend, with the CO2 uptake rate peaking early in the process. Higher foaming temperatures and extended foaming times led to increased cell size, cell density, and expansion ratio. These findings highlight the significant role of process parameters in controlling the cell structure of ABS/TPU blend foams, offering valuable insights into optimizing foam properties for industrial applications.Highlights Optimization of foam parameters leads to cell structure control in ABS/TPU composite foams for industrial applications. Increasing saturation pressure significantly boosts CO2 uptake in ABS/TPU composite foams. Increasing the foaming temperature and duration leads to larger cell sizes, higher cell density, and greater expansion ratios in ABS/TPU composite foams.

Compatibilizing and foaming of PC/PMMA composites with nano‐cellular structures in the presence of transesterification catalyst

AbstractCompatibility of polycarbonate (PC) and polymethyl methacrylate (PMMA) alloys was improved by using a transesterification catalyst (SnCl2·2H2O). Modified PC/PMMA alloys exhibit single Tg, and their initial island phase existing in the SEM were transformed into uniform surface. Besides, the transmittance of the modified alloys was increased from original 40% to 85%. Moreover, PC/PMMA alloys and PC foams with micro‐cellular and nano‐cellular structures were prepared by solid‐state CO2 foaming in the presence of transesterification catalyst. Distinctively, there are obvious nano‐cellular structures existing in the PC samples, but no related nanostructures were found in PMMA samples, after treated by same amount of catalyst and foaming process for pure PC and PMMA matrix. Furthermore, the effects of foaming temperature and segment structure on their foaming behavior were also studied. Additionally, a uniaxial stress experiment was conducted at a specific temperature to simulate the biaxial stress during the foaming process for discovering the mechanism of nanopore formation. Therefore, the concept of nano‐cellular structures will point out a direction for the development of high‐performance, heat insulation PC materials of the next generation.Highlights Transesterification catalysts enhanced compatibility between PC and PMMA. Nanopore structures were successfully constructed in PC foams. Segment stretching was the main reason for the formation of nanopores.

Effects of Three Different Kinds of Foaming Medium on the Properties of Expanded Thermal Plastic Polyurethane Prepared via Supercritical Carbon Dioxide Foaming.

Hot air, water, and glycerol were studied as foaming mediums for the production of ETPU to evaluate their influence on the behavior of the foam and compare the optimal particles for each of the foaming temperatures selected. The results showed that the times of water foaming and glycerol foaming were shorter by about 2/3 than with hot-air foaming. The best foaming temperatures for hot-air foaming, glycerol foaming, and water foaming are 110-115 °C, 75 °C, and 90 °C, respectively. The particles of glycerol foam have a matte appearance and their gloss is not very good. However, the particles in hot-air foaming are light, and the gloss is very satisfactory. The gloss of the surface of water-foaming particles is dim. At the same time, there is a faint matte appearance. Particles made with glycerol foaming and water foaming are more even than those made with hot-air foaming. The density of foaming materials from glycerol foaming, hot-air foaming, and water foaming are raised accordingly, while the hardness of foaming materials from glycerol foaming, water foaming, and hot-air foaming are successively increased.

The effect of in‐situ fibrillated polytetrafluoroethylene on the rheological, mechanical, and foaming properties of polystyrene based nanocomposite foams

AbstractPolystyrene/polytetrafluoroethylene (PS/PTFE) in‐situ fibrillated nanocomposites were prepared by melt blending using a HAAKE torque rheometer, and the effects of different contents of in‐situ nanofibrillated PTFE on the properties of PS/PTFE nanocomposites were studied. The results showed that PTFE was in‐situ nanofibrillation in the composites, and the toughness, energy storage modulus and complex viscosity of PS/PTFE nanocomposite are all improved. When the content of PTFE was 3 wt%, the elongation at break was the highest, which was three times that of neat PS. What is more, the addition of PTFE significantly improved the cell morphology of PS/PTFE nanocomposite foams by supercritical fluid foaming. The cell structure and morphology of PS/PTFE (3 wt%) nanocomposite foam was the best under 110°C foaming temperature, and the cell diameter and cell density were 3.27 μm and 1.11 × 1010 cells/cm3, respectively. In addition, the tensile strength of PS/PTFE nanocomposite foams increased from 35.4 MPa of neat PS foam to 39.6 MPa of PS/PTFE (3 wt%) foam.

Effects of ethylene‐octene copolymer and ethylene‐propylene copolymer on crystallization, morphology, and foaming properties of ethylene‐vinyl acetate copolymer

AbstractEthylene‐octene copolymer (EOC, three EOCs with different octene content used in this study) and propene‐ethylene copolymer (EPC, three EPCs with different ethylene content used in this study) can have effects on the crystallization dynamics, crystal structure, and foaming properties of ethylene‐vinyl acetate copolymer (EVA). For unfoamed EVA/EOC and unfoamed EVA/EPC blends, both EVA/EOC and EVA/EPC blends show phase separation structure. The foam cells in EVA/EOC blends have better uniformity compared to those in EVA/EPC blends, which result from the better compatibility of EVA and EOC than EVA and EPC obtained from the morphology analysis. For the blends with different crystallization ability of EOC or EPC, the blends with lower crystallinity has more uniform cell distribution than blends with higher crystallinity, due to the crystallization zone cause heterogeneous crosslinking and foaming of the blend. Both EOC and EPC can impart higher elasticity to EVA foamed materials. EOC was found to be more suitable for blending with EVA for foamed materials, offering the potential to obtain EVA/EOC foamed materials with excellent performance.Highlights Ethylene‐octene copolymer with higher octene content has better effect on foaming property of ethylene‐vinyl acetate copolymer than ethylene‐propylene copolymer. Ethylene‐propylene copolymer can decrease the foaming temperature of ethylene‐vinyl acetate copolymer. A mechanism of foaming for ethylene‐vinyl acetate copolymer/semi‐crystallized polymer blends is proposed. Achieved in‐depth understanding of structure–property relationship about ethylene‐vinyl Acetate copolymer/polyolefin elastomer foamed material.

High strength microcellular thermoplastic polyimide/carbon fiber composite foams containing flexible ether amine, rigid diaminodiphenyl ether, and triaminopyrimidine moieties: Synthesis and fabrication

In this study, pyromellitic dianhydride (PMDA) and polyetheramine D230 were used as the primary polymerization monomers, with 2,4,6-triamino pyrimidine (TAP) as a chain extender. By introducing aromatic ring-containing 4,4′-diaminodiphenyl ether (ODA) and precisely controlling its molar ratio with D230, a highly branched, high-temperature-resistant thermoplastic polyimide (TPI), was successfully developed. The optimal thermal imidization temperature was determined to be 250 °C. Incorporating surface-modified short carbon fibers (SCF) via melt blending significantly improved the mechanical properties, with tensile and impact strengths increasing fourfold and sevenfold, respectively, at 10 phr of SCF. TPI foam prepared using supercritical carbon dioxide (scCO2) foaming technology exhibited excellent performance, achieving a regular hexagonal structure, cell sizes of 10.19 μm, and a cell density of 1.68 × 1010 cells/cm3 at an ODA to D230 molar ratio of 1:9. The TPI/SCF composite foam, with 3 phr SCF under 20 MPa saturation pressure and 120 °C foaming temperature, achieved a 90 % closed-cell ratio and a 300 % increase in compression strength at the same foam density. Compared to traditional thermoset PI foams, TPI/SCF foam offers smaller cell sizes and higher compression strength, demonstrating significant commercial potential. Backward differentiation shows that TPIF compression is constant at 0.035 ± 0.005 in the [0,0,1] lattice direction. This research provides theoretical and practical insights for preparing high-performance TPI foam for high-temperature applications.

Comparative Study of the Foaming Behavior of Ethylene-Vinyl Acetate Copolymer Foams Fabricated Using Chemical and Physical Foaming Processes.

Ethylene-vinyl acetate copolymer (EVA), a crucial elastomeric resin, finds extensive application in the footwear industry. Conventional chemical foaming agents, including azodicarbonamide and 4,4'-oxybis(benzenesulfonyl hydrazide), have been identified as environmentally problematic. Hence, this study explores the potential of physical foaming of EVA using supercritical nitrogen as a sustainable alternative, garnering considerable interest in both academia and industry. The EVA formulations and processing parameters were optimized and EVA foams with densities between 0.15 and 0.25 g/cm3 were produced. Key findings demonstrate that physical foaming not only reduces environmental impact but also enhances product quality by a uniform cell structure with small cell size (50-100 μm), a wide foaming temperature window (120-180 °C), and lower energy consumption. The research further elucidates the mechanisms of cell nucleation and growth within the crosslinked EVA network, highlighting the critical role of blowing agent dispersion and localized crosslinking around nucleated cells in defining the foam's cellular morphology. These findings offer valuable insights for producing EVA foams with a more controllable cellular structure, utilizing physical foaming techniques.

Development and Optimization of a Nanocomposite Gel Foam for Inhibiting Coal Spontaneous Combustion

ABSTRACT A nanocomposite gel foam inhibitor was made by grafting tea polyphenol onto sodium polyacrylate through the graft polymerization reaction, which was then combined with graphene oxide and a foaming agent. Response surface analysis was used to optimize the ratio to improve the water absorption of the inhibitor. The microstructure of the inhibitor was studied using X-ray diffraction and Fourier-transform infrared spectroscopy. The anti-spontaneous combustion performance of the nano-composite gel foam was tested through a leakage wind plugging experiment and a thermogravimetric experiment. The results show that the optimal additions of graphene, tea polyphenol, and potassium persulfate were 0.76%, 2.806%, and 0.727% of acrylic acid, respectively. The ultimate pressures of the gel foam before and after fully forming the gel were 0. 26 kPa and 0. 736 kPa, respectively, which satisfies the demand for leakage wind plugging in a coal mine. The critical temperature and dry cracking temperature of the gel foam were 112.4°C and 201.0°C, respectively, and the quality of the oxygen-absorbing and weight-gaining stage were almost unincreased. The gel foam showed good water retention, oxygen barrier, and antioxidant properties and can play a significant role in inhibiting the coal spontaneous combustion.