Real 3D Structure-Based Finite Element Simulation of Elastomer Foams: Effect of the Foaming Agent Content

Heydari, Amirhossein; Esmizadeh, Elnaz; Vahidifar, Ali; Naderi, Ghasem; Rodrigue, Denis

doi:10.1021/acs.iecr.1c04484

Cited by 7 publications

(9 citation statements)

References 36 publications

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“…A rapid decomposition of AC results in a fast foaming process for PDAP, resulting in a closed multiporous structure. 52 Furthermore, PDAP has a high number-average molecular weight of over 700,000 g/mol, which promotes a highly viscous condition for the foaming process and therefore causes a closed multiporous structure. 53 The profile SEM images of PDAP−PR foams show an enhanced open porous structure in the presence of PR nanosheets (Figure S3, Supporting Information).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…As shown in Figure b–f, both pure PDAP and PDAP–PR foams exhibit a closed/open multiporous structure in the continuous skeleton. A rapid decomposition of AC results in a fast foaming process for PDAP, resulting in a closed multiporous structure . Furthermore, PDAP has a high number-average molecular weight of over 700,000 g/mol, which promotes a highly viscous condition for the foaming process and therefore causes a closed multiporous structure .…”

Section: Resultsmentioning

confidence: 99%

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Eco-Friendly Flame-Retardant Phase-Change Composite Films Based on Polyphosphazene/Phosphorene Hybrid Foam and Paraffin Wax for Light/Heat-Dual-Actuated Shape Memory

Zhou,

Liu,

Zhang

et al. 2024

ACS Appl. Mater. Interfaces

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Multiactuated shape memory materials are a class of promising intelligent materials that have received great interest in the fields of self-healing, anticounterfeiting, biomedical, soft robotic, and smart thermal management applications. To obtain a light/heat-dual-actuated shape memory material for thermal management applications in fire safety, we have designed a type of halogen-free flame-retardant phase-change composite film based on polyaryloxyphosphazene (PDAP)/phosphorene (PR) hybrid foam as a support material and paraffin wax (PW) as a phase-change material (PCM). PDAP was synthesized as a flexible foam matrix through the ring-opening polymerization of hexachlorocyclotriphosphazene, followed by a substitution reaction of aryloxy groups. The porosity of the PDAP foam is improved by introducing PR nanosheets, facilitating a high latent heat capacity of the PDAP−PR/PW composite films for thermal management applications. The PDAP−PR/PW composite films can implement rapid shape recovery within 65 s in the heating process, which is much shorter than that of the corresponding film without PR nanosheets (185 s). Furthermore, the PDAP−PR/PW composite films also exhibit light-actuated shape memory behavior thanks to their good solar-tothermal energy absorption and conversion contributed by PR nanosheets as a highly effective photothermal material. More importantly, the presence of PR nanosheets imparts an excellent flame-retardant property to the PDAP−PR/PW composite films. The PDAP−PR/PW composite film can be self-extinguished within 2 s after the flame. Through an innovative integration of flexible polyphosphazene foam, PR nanosheets, and solid−liquid PCM to obtain a sensitive actuating response to light and heat, this study offers a new approach for developing multiactuated and eco-friendly flame-retardant shape memory materials to meet the requirement of applications with a requirement of fire safety in soft actuators, thermal therapy, control devices, and so on.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Eco-Friendly Flame-Retardant Phase-Change Composite Films Based on Polyphosphazene/Phosphorene Hybrid Foam and Paraffin Wax for Light/Heat-Dual-Actuated Shape Memory

Zhou,

Liu,

Zhang

et al. 2024

ACS Appl. Mater. Interfaces

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“…The density of the unfoamed sample (PA0) is 0.874 g/cm 3 , but when the ADC concentration increased from 2 to 5 phr the foam density decreased from 0.748 to 0.612 g/cm 3 . This trend is related to the higher amount of gas generated with an increasing ADC content [ 61 ]. In other words, the higher gas volume from ADC resulted in a higher foaming ratio from 14.4 to 30.0% for 2 to 5 phr, respectively.…”

Section: Resultsmentioning

confidence: 99%

Experimental and Finite Element Simulation of Polyolefin Elastomer Foams Using Real 3D Structures: Effect of Foaming Agent Content

Rostami‐Tapeh‐Esmaeil

Heydari

Vahidifar

et al. 2022

Polymers

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In this study, polyolefin elastomer (POE) foams were prepared without any curing agent using a single-step foaming technique. The effect of azodicarbonamide (ADC) content as a chemical foaming agent on the foams’ morphology and mechanical properties was studied using scanning electron microscopy (SEM), mechanical properties (tension and compression) and hardness. The results showed that increasing the ADC content from 2 to 3, 4 and 5 phr (parts per hundred rubber) decreased the foam density from 0.75 to 0.71, 0.65 and 0.61 g/cm3, respectively. The morphological analysis revealed that increasing the ADC content from 2 to 4 phr produced smaller cell sizes from 153 to 109 µm (29% lower), but a higher cell density from 103 to 591 cells/mm3 (470% higher). However, using 5 phr of ADC led to a larger cell size (148 µm) and lower cell density (483 cells/mm3) due to cell coalescence. The tensile modulus, strength at break, elongation and hardness properties continuously decreased by 28%, 21%, 16% and 14%, respectively, with increasing ADC content (2 to 5 phr). On the other hand, the compressive properties, including elastic modulus and compressive strength, increased by 20% and 64%, respectively, with increasing ADC content (2 to 5 phr). The tensile and compression tests revealed that the former is more dependent on foam density (foaming ratio), while the latter is mainly controlled by the cellular structure (cell size, cell density and internal gas pressure). In addition, 2D SEM images were used to simulate the foams’ real 3D structure, which was used in finite element methods (FEM) to simulate the stress–strain behavior of the samples at two levels: micro-scale and macro-scale. Finally, the FEM results were compared to the experimental data. Based on the information obtained, a good agreement between the macro-scale stress–strain behavior generated by the FEM simulations and experimental data was obtained. While the FEM results showed that the sample with 3 phr of ADC had the lowest micro-scale stress, the sample with 5 phr had the highest micro-scale stress due to smaller and larger cell sizes, respectively.

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“…The 3D cell structure was obtained from the foam morphology (average cell size), and the element was defined based on a cubic representative volume element (RVE) with a central cell, as described in our previous articles [8,34]. ANSYS workbench 2022 R1 software was used for the material definition and finite element analysis.…”

Section: Geometry and Materials Definitionmentioning

confidence: 99%

“…In 2015, Fang analyzed closed-cell metal foams with 3D numerical simulations and used a general mesoscopic model including several random cells [33]. Heydari et al [34] studied the 3D geometric modeling of NR foams by using scanning electron microscope (SEM) images to build their structure for FEMs and investigated the effect of several factors, such as the relative foam density, on the mechanical properties. But recently, with computers becoming increasingly powerful, researchers succeeded in moving from 2D calculations to 3D ones and performed analyses that are closer to the real morphology of the foam leading to more realistic results.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Internal Gas Pressure on the Compression Properties of Natural Rubber Foams

Heydari,

Rodrigue

2024

Materials

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This study explores the effect of internal gas pressure (P) on closed-cell natural rubber (NR) foams. Three key factors are analyzed using a 3D model during uniaxial compression: (1) the initial gas pressure (P0 = 1, 2, and 3 atm) inside the cells, (2) different cell sizes (D = 0.1, 0.2, 0.3, and 0.4 mm in diameter), and (3) the presence of defects (holes in the cell walls) in terms of their sizes (d = 0.07 to 0.1 mm). The findings reveal a negative relationship between the initial gas pressure and the relative internal gas pressure (α = P/P0) and a direct correlation with stress during compression. For instance, a change from 1 to 3 atm of the initial internal gas pressure results in a 158% decrease in α with only a 3% increase in stress. Larger cell sizes contribute to higher α but lower stress levels during compression. Changing the cell size from 0.1 to 0.4 mm generates a 27% increase in α but a 45% drop in stress. An analysis of hole sizes (cell connection) indicates that larger holes result in higher relative internal gas pressure, while smaller holes lead to higher stress levels because of more flow restriction. For example, increasing the hole size from 0.07 to 0.1 mm leads to an 8% higher α but a 32% stress reduction. These findings highlight the significant effect of the internal gas pressure inside the cells in determining the mechanical properties of rubber foams, which are generally neglected. The results also provide useful insights for better material design and different industrial applications. This study also generates predictive models to understand the relationships between stress, strain, initial gas pressure, cell size, and defects (holes/connections), enabling the production of tailor-made rubber foams by controlling their mechanical behavior.

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Real 3D Structure-Based Finite Element Simulation of Elastomer Foams: Effect of the Foaming Agent Content

Cited by 7 publications

References 36 publications

Eco-Friendly Flame-Retardant Phase-Change Composite Films Based on Polyphosphazene/Phosphorene Hybrid Foam and Paraffin Wax for Light/Heat-Dual-Actuated Shape Memory

Eco-Friendly Flame-Retardant Phase-Change Composite Films Based on Polyphosphazene/Phosphorene Hybrid Foam and Paraffin Wax for Light/Heat-Dual-Actuated Shape Memory

Experimental and Finite Element Simulation of Polyolefin Elastomer Foams Using Real 3D Structures: Effect of Foaming Agent Content

The Effect of Internal Gas Pressure on the Compression Properties of Natural Rubber Foams

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