Foam Technology Research Articles

Shrinkage and Warpage Minimization of Glass-Fiber-Reinforced Polyamide 6 Parts by Microcellular Foam Injection Molding.

Shrinkage and warpage of injection-molded parts can be minimized by applying microcellular foaming technology to the injection molding process. However, unlike the conventional injection molding process, the optimal conditions of the microcellular foam injection molding process are elusive because of core differences such as gas injection. Therefore, this study aims to derive process conditions to minimize the shrinkage and warpage of microcellular foam injection-molded parts made of glass fiber reinforced polyamide 6 (PA6/GF). Process factors and levels were first determined, with experiments planned accordingly. We simulated designed experiments using injection molding analysis software, and the results were analyzed using the Taguchi method, analysis of variance (ANOVA), and response surface methodology (RSM), with the ANOVA analysis being ultimately demonstrating the influence of the factors. We derived and verified the optimal combination of process factors and levels for minimizing both shrinkage and warpage using the Taguchi method and RSM. In addition, the mechanical properties and cell morphology of PA6/GF, which change with microcellular foam injection molding, were confirmed.

Symmetric Khovanov-Rozansky link homologies

On donne une catégorification de l’évaluation symétrique des toiles 𝔰𝔩 N en utilisant les mousses. On en déduit des théories homologiques d’entrelacs qui catégorifient les invariants quantiques d’entrelacs associés aux puissances symétriques de la représentation standard de 𝔰𝔩 N . Ces théories sont obtenues dans un cadre équivariant. On montre qu’il existe des suites spectrales de l’homologie triplement graduée de Khovanov-Rozansky vers ces homologies symétriques. On donne aussi une interpretation des bimodules de Soergel en terme de mousses.

A lightweight, thermal insulation and excellent weatherability foam crosslinked by electron beam irradiation

Thermal insulation and excellent weatherability microcellular foams based on lightweight polymer are successfully developed from chlorinated polyethylene rubber/polyvinyl chloride (CM/PVC) compounds through electron beam irradiation cross-linking and chemical foaming technology. The effect of electron beam irradiation on the blends of CM/PVC foam prepared with different compositions starting from 70:30 to 50:50 (CM:PVC) with varied radiation doses from 30 to 70 kGy and varied chemical blowing agent contents from 10 to 20 phr has been studied. The aim was to investigate the influence of the different blending ratio, the chemical blowing agent content and the irradiation dose on physical and mechanical properties and morphology of the cellular structure in the produced foams. Thermal conductivity of CM/PVC compounds foams achieved in this study is as low as 0.0374W/mK.

Effect of pore structure on mechanical and tribological properties of paper-based friction materials

To explore the effect of the pore structure of paper-based friction materials on the friction and wear properties, the composites with different pore structures were obtained using physical foaming technology. Results displayed that the bulk density and average pore size of composites increased after the foaming treatment, while the total pore area and porosity showed a tendency to gradually decrease after hot pressing. The tensile and interlaminar shear strength of the composites were improved by 18% and 42% respectively after the optimization of the pore structure. Moreover, the application of foaming technology significantly increased dynamic friction coefficient and reduced wear rate of the friction materials. In particular, the wear rate of paper-based friction materials decreased by 44.6% from 1.57x10−8 cm3/J to 0.87x10−8 cm3/J with the increase of foaming agent content. Most importantly, the pore structure of paper-based friction materials can be effectively changed due to the introduction of physical foaming technology. This research lays a solid foundation for optimizing the pore structure of paper-based friction materials in the future.

Application and Research of Swirling Curtain Dust Collection Technology in Mines

During the production process in mines, large amounts of dusts are produced. The dusts pose a potential hazard to the health and safety of miners. Traditional dust removal methods, such as ventilation, water sprays and foam technology, cannot completely solve the problem of dust pollution, due to low efficiency or high consumption of water or large resistance (>2000 Pa). Therefore, a swirling curtain dust collector (SCDC) was proposed to collect the dust in mines. The device was combined swirling atomization with spray curtain for dust removal. The performance of SCDC was investigated. According to the results, the optimum working condition of the device was: air pressure: 0.35 MPa, water volume: 30 L/h; liquid–gas ratio: 0.15 L/m3; air speed: 14–16 m/s. Under these operation parameters, the suppression efficiency of total dust and respirable dust were over 99.8% and 97%. The proposed device was applied at transfer stations of Luohe Metal Mine in Anhui, China. The application results showed that the dust concentration at the outlet of SCDC in the transfer station is lower than 20 mg/m3, which is stipulated by Chinese standard GB 28661-2012. The proposed device is expected to replace the traditional Venturi wet scrubber in mines.

Ultra-lightweight, super thermal-insulation and strong PP/CNT microcellular foams

The global energy crisis has been widely concerned by the public due to the massive energy requirement caused by rapid-developing economy and society. Ultra-lightweight, super-insulating, and strong polymer foams exhibit a promising prospect, in terms of saving materials and resources, and reducing energy consumption. However, there exists a great challenge to achieve highly expanded microcellular polymer with satisfactory thermal insulation performance. Herein, polypropylene (PP) with carbon nanotubes (CNTs) was used to prepare multifunctional foams by using batch foaming process with carbon dioxide. This cost-efficient and facile process endowed PP/CNT composite a variety of unprecedented advantages, including over 50-fold expansion ratio, a rather low thermal conductivity of 28.69 mW/m·K, and remarkably improved compressive strength. Acting as both crystal and cell nucleating agents, CNTs contributed to the fabrication of such ultralight foams with refined cell structure, which led to significantly reduced solid thermal conduction and enhanced mechanical properties. Moreover, thanks to CNTs’ outstanding infrared radiation shielding capacity, the thermal radiation through the ultra-lightweight PP/CNT foam was significantly suppressed. Thus, ultra-lightweight, super thermal-insulation, and strong PP/CNT composite foams were achieved by using microcellular foaming technology, paving a way for designing and synthesizing multifunctional polymer-based composite foams for high-performance thermally insulating applications.

Parameter Screening Study for Optimizing the Static Properties of Nanoparticle-Stabilized CO2 Foam Based on Orthogonal Experimental Design.

Nanoparticle (NP)-stabilized foam technology has found potential applications in CO2 enhanced oil recovery (EOR) and greenhouse gas geological storage practices and accordingly attracts lots of research interest. To screen the optimal formula for the satisfactory foam performance, orthogonal experimental design (OED) is used in this paper for the complex multifactor multilevel system consisting of five influential factors of NP size, surfactant concentration, NP concentration, temperature, and salinity at four different levels in the range of 7–40 nm, 0–0.15 wt %, 0–0.2 wt %, 25–55 °C, and 0–3 wt %, respectively. Based on the orthogonal principle, only 16 experiments were performed to analyze the effect of various factors on the foam height and foam half-life properties. In addition to showing that the influence of the single factor on foam static properties, OED results reveal that the surfactant concentration and temperature are dominating factors on foamability and stability of the NP-stabilized CO2 foam, respectively. Finally, NP-stabilized CO2 foam with satisfactory static characteristics is obtained with the OED recommended composition of a 0.15 wt % surfactant concentration, 0.1 wt % NP concentration, and NP size of 7 nm in 1 wt % saline solution at temperatures of 30 and 50 °C, validating that the OED method could substantially facilitate the laboratory screening and optimization process for a successful NP-stabilized CO2 foam application.

Development of sustainable and cost efficient textile foam-finishing and its comparison with conventional padding

Conventional padding is a non-sustainable textile processing technique, which consumes excessive water, chemicals and energy. To support the survival of the textile processing industry, researchers have identified the foam technology for application of dyes and finishes. Foam technology is more ecofriendly than the conventional padding. However, the successful foam generation for different finishes is a challenging task. In addition, it is more difficult and complicated task to effectively apply the foam on the fabrics and get the results which should be comparable with the conventional padding. This paper compares the pad-finishing with foam-finishing on the basis of sustainability, cost, productivity, and performance using 11 different non-toxic and sustainable finishes including cross-linkers, oil and water repellents, softeners, and fire retardant on the cotton fabric samples. Cost, productivity, performance and sustainability were estimated through the specific methods. The paper organizes the problem as analytic hierarchy process model and solves the model using super decisions software. The results reveal that the foam-finishing technique is more preferable in terms of cost, productivity and sustainability, if optimized properly. In addition, the successful foam-finishing recipes have been generated and the performance of foam-finishing has been comparable with pad-finishing. For instance, if all the criteria were given the same priority, the foam-finishing recipe with less quantity of chemical was 84.61% better than the pad-finishing. The optimized foam-finishing recipe was 84.55% better than the pad-finishing. In addition, the optimized foam-finishing recipe indicated better finishing performance in term of some important tests as compared to padding.

Experimental study on rheological properties of nanoparticle-stabilized carbon dioxide foam

In relationship with the potential application of nanoparticle (NP) foam technology in CO2 enhanced oil recovery (EOR) and greenhouse geological storage in tight reservoirs, the rheological properties of the NP-stabilized CO2 foam with surfactant (α-olefin sulfonate-AOS) solution were experimentally investigated. The foam was treated as a power-law non-Newtonian fluid, and the relationships between the shear stress and shear rate as well as the apparent viscosity of foam and foam quality were determined under influential parameters including the NP additive, internal gas type, salinity, and oil presence. Critical foam quality values in the range 91–96% were observed for the NP-stabilized foam, whereas no such values were obtained for the corresponding AOS-CO2 foam. The results show the NP-AOS-CO2 foam has lower viscosity compared to the NP-AOS-N2 foam, and the solution salinity decreases the viscosity of the NP-AOS-CO2 foam, whereas oil presence has no obvious effect on the foam viscosity.

Application of Foam Stopping for Mitigation of Spontaneous Heating In Underground Coal Mines

The problem of spontaneous heating is a major threat to safety and productivity in mines all over the world. In India, more than 80% of fires are caused due to Spontaneous Combustion. The applicability of inert gases is expensive, time-consuming and is a very tedious process. Hence the application of advanced technologies becomes essential to be introduced in mines. In this context, Central Mine Planning and Design Institute (CMPDI), Ranchi, India carried out an R&D project entitled “Construction of quick setting stopping in case of fire in an underground mine using expansion foam agent” under the funding from the Ministry of Coal, Government of India. Under this project, two Indian mines were selected in consultation with MCL for carrying out the proposed work in Orient Mine No.3 and Bundia Mine of MCL (Ib Valley AREA). Coals from both the mines have been collected and analysed in the laboratory. The proximate analysis and CPT/IPT results show that both the coals are moderately prone to spontaneous heating. Considering both intrinsic and extrinsic properties, two stoppings were constructed in the Hirakhand Bundia mines and four in orient mines. Periodic supervision along with the altering ingress of air from intake was been checked. After careful supervision of nearly 4 years, the stoppings proved to be strong enough to be leakage proof. This paper describes the application of foam technology as stopping to avoid air entry, thus preventing the occurrences of spontaneous heating/fire in a panel of Indian coal mines.

Research on a noble extinguish material for the underground fire prevention

SummaryThe three‐phase foam consisted of solid, liquid and gas is regarded as a highly effective measure for the underground mine fire prevention. In this study, the three‐phase foam technology is introduced and a visualization platform is established to exhibit the foam flow in a physical goaf. The diffusion rule and extinguishing performance for three‐phase foam are researched. Test results show that the three‐phase foam has a superior heat resistance than expansion foam in the top goaf. The coal heating rate is postponed after the three‐phase foam processing and the active functional groups are suppressed effectively. Increasing the foam expansion ratio is adverse to the three‐phase foam stability. The field application of three‐phase foam was evaluated via the practical extinguishment effect. The marked reduction in the sealed zone temperature and CO concentration proved that the proposed three‐phase foam technology was effective on controlling the concealed goaf fire.

Highly porous ZrO2 cellular ceramics with 3D network architecture

Cellular ceramics with 3D network architecture are attracting ever-increasing attention because of their great application potential in multiple fields. Unfortunately, a daunting challenge still remains for fabricating such materials. A novel methodology is provided in the current work to construct cellular ZrO2 ceramics with such architecture by combining polyurethane foaming and chemical modification technology. Stearic acid grafted ZrO2 powder with improved dispersibility allows the successful assembly into the polyurethane porous framework. The obtained cellular materials possess a three-dimensional network architecture with windows on the cell wall. The resulting ZrO2 cellular ceramic with such unique structure exhibits a relatively high porosity (83.5%) and robust compressive strength (13.5 MPa), which outperforms most of the existing ZrO2-based counterparts. With above advantages, we envision that as-prepared products are promising for filter applications.

Investigation on in Situ Foam Technology for Enhanced Oil Recovery in Offshore Oilfield

An in situ CO2 foams (ISCF) formula is presented to investigate its performance in enhancing oil recovery in homogeneous and heterogeneous formations. Surfactant evaluation, sandpack flooding, and ...

Improved foam application at the tunnel face with large ventilation volume and low pressure supplied water

Due to large energy loss, current foam technology for dust suppression requires high inlet water pressure, but performance is poor where ventilation volume is high. This paper proposes modifying key foam device components, including the agent mixing device, foam generator, and nozzle, to address these problems. A cavitating jet pump was simultaneously employed for accurate agent mixing and flow meter, guaranteeing accurate agent flow and low energy loss. A vertical foam generator was designed to increase foam volume and ensure even foam distribution among the foam nozzles. The two-layered foam nozzles were designed and fabricated using 3D printing to ensure even and thick foam impact area on the dust source, effectively blocking dust escape passages. Experiments were performed in the laboratory and on a real heading face. Ventilation volume was 560–570 m3/min for the field experiment with initial total dust concentration 589–679 mg/m3. The proposed system reduced required inlet water pressure to 0.87 MPa, while achieving 86.8% average total dust suppression efficiency and reducing long-term time average respirable dust concentration to 3.9–5.7 mg/m3. This study will help improve performance and expand application fields for foam dust suppression technology.

Study and application on foam-water mist integrated dust control technology in fully mechanized excavation face

The dust produced by the roadheader during the tunneling process will change with time. Water mist can achieve high dust removal efficiency when the dust production is relatively small, and foam technology can realize high efficiency in the treatment of large dust production. It is necessary to choose water mist and foam dust removal technology freely according to the dust yield. Therefore, this paper puts forward the research of foam and water mist integrated dust removal technology. According to the characteristics of dust production in excavating operation, a new type of flat fan foam nozzle is put forward. Through the internal channel of gradual change, the foam jet is transformed from a cylindrical fluid to a flat one and diffuses at a certain angle. And the outlet area of the nozzle is determined to be 120mm2, with the nozzle’s uniform angle of 6° and the compression angle of 25° as the final angle of the nozzle through simulation and field experiments. Combined with the characteristics of water mist, the function of water atomization is added to foam technology. On the basis of foam nozzle, 10 symmetrical water inlet channels with a diameter of 1.5mm are uniformly arranged on the side wall, and the original foam inlet is changed into air inlet. Through multi-stage atomization of air and water, water mist with fine atomization size and uniform distribution can be produced. Relevant atomization operation conditions are tested through experiments. The test results show that the new technology could greatly reduce the cost, achieve the goal of efficient dust removal, and guarantee the working environment and the health of the workers.

Reinforcing the Tensile Strength of Lightweight and Soft BBIR/EVA Foam with Organic Modified Potassium Titanate Whisker and its Thermal Insulation Performance

It is agreed that the mechanical properties and density of polymer foam material are contradictory. At present, the preparation of low density and high-strength foam material is still a great challenge. In this paper, potassium titanate whisker (PTW) with reinforcement and heterogeneous nucleation modified by γ‑methacryloxypropyltrimethoxysilane (KH-570) was used to prepare brominated butyl rubber/ethylene-vinyl acetate copolymer (KPTW/BBIR/EVA) composite foam through molding foaming technology. Then the physical mechanical and thermal stability properties of it were tested with universal testing machine and thermal gravity analysis (TGA). The effect of KPTW on morphology (cell size, density and distribution) of BBIR/EVA foams was demonstrated by scanning electron micrograph (SEM). The results indicate that the tensile strength of KPTW/BIIR/EVA foam was increased by 75% compared with that of BIIR/EVA foam (1.23 MPa) when its density was 0.25 g/cm3. By introducing KPTW, the mean cell size of PTW/BIIR/EVA foam was reduced from 436.6 to 40.9 μm for KPTW/BIIR/EVA foam. Meanwhile, the KPTW as a foaming nucleating agent increases cell density of KPTW/BIIR/EVA foam and thus increased its thermal insulation performance.

Novel foaming technology to enhance consumer experience while providing optimal mildness in a body cleanser

Novel foaming technology to enhance consumer experience while providing optimal mildness in a body cleanser

Microstructure and properties of microcellular silicone rubber foams with improved surface quality

Supercritical foaming technology is used for producing foamed silicone rubber (SR) materials because of its many advantages, but this technology has been limited by its propensity to prepare microcellular silicone rubber foams (SRF) with surface defects. In this study, a novel method of preparing microcellular SRF without surface defects was successfully developed by investigating the principle of cellular formation during the process of supercritical foaming. Meanwhile, the microstructure, surface profile, mechanical properties, and thermal conductivity of microcellular SRF were investigated in detail. The results show that the plasticity of the SR matrix plays an important role in cellular formation. The maximum tensile strength of the microcellular SRF achieves 4.77 MPa and the elongation at break is 1866.29%. The thermal conductivity of the microcellular SRF achieves a minimum value of 0.14 W/m K, and the thermal insulation property is improved by approximately 39% compared with the SR composites. Based on the mechanism of cellular formation, the cellular formation and postcuring process were separated in this paper. First, the foamed sheets were rested at room temperature for 20 min. Then, the foamed sheets were fully vulcanized in a plate vulcanizing press at 165 °C for 8 min. A novel method of preparing microcellular silicone rubber foams without surface defects has been successfully created.

Upscaling of foam forming technology for pilot scale

The need for production cost savings and changes in the global paper and board industry during recent years have been constants. Changes in the global paper and board industry during past years have increased the need for more cost-efficient processes and production technologies. It is known that in paper and board production, foam typically leads to problems in the process rather than improvements in production efficiency. Foam forming technology, where foam is used as a carrier phase and a flowing medium, exploits the properties of dispersive foam. In this study, the possibility of applying foam forming technology to paper applications was investigated using a pilot scale paper forming environment modified for foam forming from conventional water forming. According to the results, the shape of jet-to-wire ratios was the same in both forming methods, but in the case of foam forming, the achieved scale of jet-to-wire ratio and MD/CD-ratio were wider and not behaving sensitively to shear changes in the forming section as a water forming process would. This kind of behavior would be beneficial when upscaling foam technology to the production scale. The dryness results after the forming section indicated the improvement in dewatering, especially when foam density was at the lowest level (i.e., air content was at the highest level). In addition, the dryness results after the pressing section indicated a faster increase in the dryness level as a function of foam density, with all density levels compared to the corresponding water formed sheets. According to the study, the bonding level of water- and foam-laid structures were at the same level when the highest wet pressing value was applied. The results of the study show that the strength loss often associated with foam forming can be compensated for successfully through wet pressing.

Thermoplastic foaming mechanism and Pb2+ adsorption of poly(vinyl alcohol)/shell powder porous composite

AbstractCombining the respective advantages of PVA and shell in wastewater treatment, poly(vinyl alcohol)/shell powder (PVA/SP) porous composite suitable for the removal of heavy metal ions from wastewater was prepared via thermoplastic foaming technology using water as both plasticizer and physical blowing agent. The effects of SP content on the thermoplastic foaming mechanism including interactions among components, water states and water evaporation behaviors, as well as cell structure and Pb2+ adsorption property of the porous composite were studied. The results showed that SP could form different hydrogen bonding or coordination interactions with water and PVA, making free water in system reduced and nonfreezing water increased, thus realizing the controllable foaming of water and avoiding the formation of the big cells caused by intensive evaporation of water. SP particles could also act as heterogeneous nucleating agents to effectively increase the number of heterogeneous nucleating points in the system, resulting in the formation of denser and more uniform cells. With the increase of SP content, the adsorption capacity of porous composite on Pb2+ increased, and reached the maximum at 10 wt%, that is, 31.1 mg/g, higher than that of pure SP powders, that is, 23.4 mg/g, ascribing to the good dispersion of SP in PVA matrix as well as the high hydrophilicity of PVA porous material.