Papers by Keyword: Foam

Abstract: Metamaterials have emerged as promising candidates for protective structures due to their lightweight design and energy absorption capabilities. While various lattice-based architectures have been explored, further research is needed to optimize their dynamic response and computational modeling. Recent studies highlight the superior strength-to-weight ratios of lattice metamaterials over traditional foams, yet challenges remain in balancing predictive accuracy and computational efficiency.This study introduces novel computational frameworks for the design and analysis of deterministic, hybrid, and stochastic lattice architectures. Using finite element models, different unit cell configurations are evaluated under dynamic loading, comparing beam-based models for efficiency with 3D solid models for accuracy. A comparative assessment with foam materials further examines energy absorption performance.The framework developed in this study provides a versatile tool for the automatic generation and analysis of lattice structures. Moreover, this study provides critical insights into lattice topology, computational trade-offs, and impact resistance.

Abstract: Foam flooding is a promising enhanced oil recovery (EOR) while improving the gas sweep efficiency problem of gas flooding. On the other hand, nanotechnology has paved the way for utilizing nanoparticles in surfactant foam while improving foam stability, lamella thickness, bubble size distribution, and oil recovery. The significant difference between nanoparticles and surfactants as foam stabilizers is the adsorption energy of nanoparticles at gas-liquid interfaces, which is thousands of times bigger than surfactants. However, previous studies on nanoparticles' foam adsorption energy are limited by using only nanoparticles (in the absence of surfactants), though it is hard to generate foam since it does not reduce surface tension significantly. Thus, the objective of this study is to determine the adsorption energy of hydrophilic silicon dioxide (SiO2) and partially hydrophobic silicon dioxide (PH SiO2) nanoparticles in the presence of anionic sodium dodecyl sulfate (SDS) and cationic cetyltrimethylammonium bromide (CTAB) surfactants. Another objective is to analyze and evaluate the effects of adsorption energy on foam stability. Consequently, the particle radius, surface tension, and particle surface wettability were all obtained from the maker, Du Noüy ring tensiometer, and particle surface contact angle. The result shows that the adsorption energy of PH SiO2 was a thousand times greater than hydrophilic SiO2 in the presence or absence of surfactants. Due to PH SiO2 having a slightly bigger particle radius, higher adsorption energy in the PH SiO2 system is mainly by particle hydrophobicity and surface tension. In all systems, the highest adsorption energy is achieved at the lowest concentration of nanoparticles because the increment in nanoparticle concentration reduces the surface tension, eventually lowering the adsorption energy. However, this trend is contradicted with half-life foam stability when it increases with the nanoparticles concentration until the optimum concentration is obtained, then reduced. To sum up, the evaluation of the nanoparticles' foam adsorption energy in this study supports the fundamentals of nanoparticles stabilizing foam that are also influenced by other parameters: the maximum capillary pressure, particle arrangements during film drainage, and growing aggregate and the ‘cork’ formation inside lamella.

Abstract: The article investigates the influence of ultraviolet (UV) on polyurethane foams' structural and mechanical characteristics. To assess the impact of changes and degradation of foam properties, studies were conducted for two groups of samples: those without exposure to UV and those exposed to natural UV for 3 months. According to the analysis of IR spectra, insignificant chemical changes in the structure of the outer surface of the samples were established as a result of three months of UV influence on the foam. No noticeable chemical changes were found in the inner part of such samples. Compression tests of samples of different groups were carried out under static loading to study the change in mechanical characteristics. Based on experimental tests, changes in the values of mechanical, strength, and deformation characteristics were investigated: Young's modulus, elastic strength, yield strength, and degree of deformation recovery. A conclusion was made about the resistance of polyurethane foam to ultraviolet influence for a period of up to three months.

Abstract: This study aims to develop an innovative natural rubber latex foam (NRLF) composite by incorporating coconut shell activated carbon (Ac) and 2% copper-modified Ac (2%Cu/Ac). The NRLF was prepared using the Dunlop process and mixed with Ac and 2%Cu/Ac at concentrations of 0, 5, and 10 phr. The mechanical properties, morphology, crosslink density, and cadmium ion adsorption performance were investigated. SEM analysis revealed that the additives improved the stability of the foam’s open-cell structure. The results demonstrated that copper particles deposited on Ac enhanced the overall properties of the NRLF composite. The mechanical strength at 50% strain increased significantly, from 5.81 mN/m² for neat NRLF to 12.81 mN/m² with the incorporation of 10 phr 2%Cu/Ac. Crosslink density also improved with the addition of Ac and further increased with Cu-modified Ac. In terms of cadmium adsorption, the optimal performance was achieved with 5 phr 2%Cu/Ac, yielding an adsorption capacity of 0.89 mg/g. These findings highlight the potential of 2%Cu/Ac as a superior additive for enhancing the Cadmium adsorption and the performance of NRLF composites.

Abstract: The vibration response of laminated sandwich beams, with a core layer filled with various foam materials, referred to as Foam-based Sandwich Laminated Composite (FSLC) beams, has been studied. First, to precisely capture the varying material properties across the thickness of the sandwich beams, a modified layerwise displacement theory was employed. This approach addresses the inhomogeneity of the foam material in the core, yielding more accurate results than conventional classical laminated plate theories typically used for analyzing laminated composite structures. Secondly, to assess the impact of foam properties on dynamic behavior, FSLC beams incorporating three distinct types of foam have been analyzed. Thirdly, a proof-of-concept experimental test was conducted to demonstrate the functionality of the proposed model under dynamic loading conditions. The natural frequencies and damping coefficients of the FSLC beams have been determined using the modified layerwise theory. The dynamic response of the FSLC beams under impulse loading has also been analyzed. It was observed that the addition of foam in the core layer enhances the damping properties of the sandwich beam by approximately ten percent while reducing the natural frequencies by approximately five percent under all types of loading considered.

Abstract: This study investigates the impact of Niax^TM Silicone L-5440, a silicon-based surfactant, on the foaming behaviors of rigid polyurethane foam (RPUF) filled with aluminium hydroxide (ATH). The aim is to understand the effect of the surfactant on the compression strength, morphology, and flammability of the foam. Various concentrations of the surfactant, ranging from 0.5 to 3 pphp, were incorporated into the RPUF/ATH blend. Five key parameters were examined, including density, closed-cell content, structural characterization using scanning electron microscopy (SEM), compressive strength, and UL-94 rating. The results revealed that adding the silicon surfactant significantly influenced the foam properties. Foam formulations with lower surfactant concentrations resulted in denser foam with a higher percentage of closed cells (86.24%). The morphology of the foams exhibited variation in average pore sizes, initially decreasing and subsequently increasing with increasing surfactant concentration. Notably, the compressive strength of the foam increased when the surfactant concentration reached 1 pphp. Moreover, the inclusion of the surfactant improved the flammability characteristics, as evidenced by a UL-94 rating of V-1 without dripping.

Abstract: This study employed an innovative approach, utilizing prepared dried polyurethane-polyaniline nano-composite, through in-situ polymerization, for continuous remediation of Congo red dye. Response Surface Methodology (RSM) based on the Box-Behnken design (BBD) model was utilized to optimize the processing parameters, including initial dye concentration, flow rate, and pH. The two-factor interaction (2FI) model emerged as the most significant, highlighting the influence of individual and interaction effects of the factors. Optimization of the dye remediation process yielded the optimal conditions of a flow rate of 10 mL/min, acidic pH of 5.00, and dye concentration of 20 mg/L, resulting in an impressive, predicted removal efficiency of 99.09% agreeing with the experimental value. Moreover, the maximum adsorption capacity was determined to be 329.68 mg/g. Characterization of the adsorbent material involved techniques such as Scanning electron microscopy (SEM), Fourier transforms infrared spectra (FTIR), X-ray spectroscopy (XRD), and Zeta potential analysis. This material offers a sustainable alternative in industries to treat Congo red dye before being disposed of into the environment.

Abstract: Lightweight, robust, and anti-rust properties of aluminium foam might be a solution for reducing the effect of traffic accidents and for minimum fuel consumption. This research investigated the crashworthiness of vehicle crash-box filled with aluminum foam by varying its cross-sectional structure and its loading angle such as 0°, 10°, 20°, 30°. The variations consisted of structures for example single wall foam filled and double wall foam filled. The material used to construct the wall was Aluminum Alloy 2024 and Aluminium foam. The finite element model using Abaqus CAE Software was operated for both designing the crash-box and analyzing its crashworthiness. Some parameters were determined To obtain the best crash-box design, the finite element analysis was carried on total energy absorption, specific energy absorption, maximum load, average load, and crush-force efficiency. Double wall foam filled crash-box was shown to have better energy absorption ability and this structure of crush box is considered fpr vehicle structure in future.

Abstract: Large scale buoyant structures typical of offshore wave energy generation devices may be produced using the rotational foam moulding process. Due to the challenging environmental conditions these parts experience during their lifetime at sea, it is important that the structures are optimised to ensure acceptable mechanical performance. Foams containing large cells suffer a reduction in mechanical properties; therefore, an optimal foam contains small, evenly sized, and well distributed bubbles in large numbers. Due to the lower pressures used in the process, this can be challenging to achieve. Careful selection of material and processing conditions is required to achieve an optimal structure. A unique bench-based rig was used to observe developing foam structures. A camera was used to record the foam height change at intervals. Foam height change was obtained using digital image analysis. Several parameters were studied such as the polymer particle size or the mould pressure for example. In addition to the foam height change, foam density were analysed. It is found that mould pressure, polymer particle size, chemical blowing agent concentration, and polymer rheology may be used to control the foamed structures.

Abstract: Previous studies on the physical properties of each Polyethylene (PE) or Ethylene Vinyl Acetate (EVA) foam have been widely reported. The current challenge is how to understand the combination of PE and EVA foam in order to obtain appropriate properties in various applications. Therefore, an experimental breakthrough in order to understand the physical mechanism on the PE:EVA mixed foam in order to maintain many appropriate properties due to their applications was studied. The physical properties of a combination of PE and EVA foam with Azodicarbonamide (ADC) as blowing agent and the addition of Zinc Oxide (ZnO) as accelerated agent in foaming process have been investigated in this study. The foams were prepared via two steps. Firstly, the various content of PE and EVA resins with combination of various content of ZnO and the addition of ADC, stearic acids and antioxidants were mixed by a single screw extrusion as the results of pellets. Furthermore, this intermediate product was pressed by compression moulding at the temperature of 175 °C and pressure of 30 bar for 5 minutes, then the pressure was released for the foaming process. The effect of the addition of ZnO were observed on the density and the mechanical properties of the foams. The density decreased with increasing of ZnO content up to 4 per hundred resin (phr) on the foam with PE content maximum of 20 phr. Interestingly the density of the foam increased with the addition of 6 phr of ZnO. Due to the increasing number of ZnO, we found the formation of foams completely. We observed the approval of the hardness, tensile and compression properties of each formulation, respectively. Furthermore, the morphology observation of the foams was conducted by scanning electron microscopy (SEM) to measure the size and homogeneous of the cells. We observed large size of cells at low density of foams, meanwhile uniform of cell was obtained at the high density of foams. Finally, the Fourier transform infrared (FTIR) spectroscopy confirmed that in general the intensity of the absorption peak at around 2216 cm^-1 - 2223 cm^-1 of each formulation decreased with the addition of ZnO up to 4 phr of ZnO and increased again at 6 phr of ZnO.