scholarly journals Correlation Between the Structure and Compressive Property of PMMA Microcellular Foams Fabricated by Supercritical CO2 Foaming Method

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 315 ◽  
Author(s):  
Ruizhi Zhang ◽  
Ju Chen ◽  
Yuxuan Zhu ◽  
Jian Zhang ◽  
Guoqiang Luo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Size ◽  
Supercritical Co2 ◽  
Cellular Structure ◽  
Experimental Testing ◽  
Element Model ◽  
Cellular Structures ◽  
Compressive Property ◽  
Compressive Properties ◽  
Microcellular Foams

In this study, we fabricated poly (methyl methacrylate) (PMMA) microcellular foams featuring tunable cellular structures and porosity, through adjusting the supercritical CO2 foaming conditions. Experimental testing and finite element model (FEM) simulations were conducted to systematically elucidate the influence of the foaming parameters and structure on compressive properties of the foam. The correlation between the cellular structure and mechanical properties was acquired by separating the effects of the cell size and foam porosity. It was found that cell size reduction contributes to improved mechanical properties, which can be attributed to the dispersion of stress and decreasing stress concentration.

scholarly journals Preparation and properties of silicone rubber materials with foam/solid alternating multilayered structures

2021 ◽  
Author(s):  
Wenhuan Zhang ◽  
Zhaoping Deng ◽  
Hongwei Yuan ◽  
Shikai Luo ◽  
Huayin Wen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Silicone Rubber ◽  
Cellular Structure ◽  
Cellular Structures ◽  
Compressive Property ◽  
Solid Layer ◽  
Multilayered Structures ◽  
Element Analysis ◽  
Morphology And Mechanical Properties

AbstractIn this paper, silicone rubber materials with foam/solid alternating multilayered structures were successfully constructed by combining the two methods of multilayered hot-pressing and supercritical carbon dioxide (SCCO2) foaming. The cellular morphology and mechanical properties of the foam/solid alternating multilayered silicone rubber materials were systematically studied. The results show that the growth of the cell was restrained by the solid layer, resulting in a decrease in the cell size. In addition, the introduction of the solid layer effectively improved the mechanical properties of the microcellular silicone rubber foam. The tensile strength and compressive strength of the foam/solid alternating multilayered silicone rubber materials reached 5.39 and 1.08 MPa, which are 46.1% and 237.5% of the pure silicone rubber foam, respectively. Finite element analysis (FEA) was applied and the results indicate that the strength and proportion of the solid layer played important roles in the tensile strength of the foam/solid alternating multilayered silicone rubber materials. Moreover, the small cellular structures in silicone rubber foam can provided a high supporting counterforce during compression, meaning that the microcellular structure of silicone rubber foam improved the compressive property compared to that for the large cellular structure of silicone rubber foam.

Mechanical Behaviour of High Density Polyethylene Based Foams

2009 ◽  
Vol 620-622 ◽  
pp. 781-784
Author(s):  
Juan Lobos ◽  
Miguel A. Rodríguez-Pérez ◽  
Miguel del Carpio ◽  
Jose A. de Saja
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Cell Size ◽  
Surface Quality ◽  
Elastic Properties ◽  
Mechanical Behaviour ◽  
High Density Polyethylene ◽  
Cellular Structure ◽  
High Density ◽  
Linear Relationships

This paper presents the mechanical properties of a collection of high density Polyethylene based foams. The produced materials are characterised by a reduction in density up to 60%, an excellent surface quality, cell sizes in the microcellular range (around 50 microns) and a multi-structured cellular structure (cranial structure) with dense skin and foamed core. The mechanical properties of these materials showed linear relationships between Young’s modulus and density for densities above 0.7 g/cm3. In addition, variations in the cell size did not influence the elastic properties.

Effects of compatilizers on the cellular structures, interfacial morphologies and mechanical properties of PP foam composites

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Ji-Nian Yang ◽  
Zi-Quan Li ◽  
Jin-Song Liu
Keyword(s):  
Mechanical Properties ◽  
Maleic Anhydride ◽  
Cell Size ◽  
Cellular Structures ◽  
Cell Size Distribution ◽  
Foaming Process ◽  
Short Glass Fiber ◽  
Elastomeric Particles ◽  
The Impact ◽  
Short Glass

AbstractThe short glass fiber (SGF)/polypropylene (PP) and ethylene-1-octene copolymer (POE)/SGF/PP foam composites were prepared by extrusion and subsequent post-foaming process in designed dies. The compatilizers, maleic anhydride grafted PP (PP-g-MAH) and maleic anhydride grafted POE (POE-g- MAH), were employed to improve the performance of the foam composites, respectively, and their influences on the cellular structures, interfacial morphologies and mechanical properties of PP foam composites were investigated. It was found that the compatilizers resulted in modified PP foam composites characterized by uniform cell size distribution, reduced cell size and increased cell density except POE/SGF/PP with POE-g-MAH. The obvious enhanced SGF-matrix interfacial bonding was observed from the SEM examination, and POE-g-MAH also facilitated the compatibility between elastomeric particles and matrix. Testing results indicated that, by the introduction of PP-g-MAH or POE-g-MAH, the mechanical properties of PP foam composites were significantly improved, and it seemed that the PP-g-MAH was more effective in strengthening the flexural and compressive strength while POE-g-MAH greatly increased the impact toughness.

scholarly journals The Effect of Microcellular Structure on the Dynamic Mechanical Thermal Properties of High-Performance Nanocomposite Foams Made of Graphene Nanoplatelets-Filled Polysulfone

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 437
Author(s):  
Marcelo Antunes ◽  
Hooman Abbasi ◽  
José Ignacio Velasco
Keyword(s):  
Relative Density ◽  
Supercritical Co2 ◽  
Cellular Structure ◽  
High Performance ◽  
Graphene Nanoplatelets ◽  
Cellular Structures ◽  
Density Range ◽  
Specific Storage ◽  
Glass Transition Temperatures ◽  
Nanocomposite Foams

Polysulfone nanocomposite foams containing variable amounts of graphene nanoplatelets (0–10 wt%) were prepared by water vapor-induced phase separation (WVIPS) and supercritical CO2 (scCO2) dissolution. WVIPS foams with two ranges of relative densities were considered, namely, between 0.23 and 0.41 and between 0.34 and 0.46. Foams prepared by scCO2 dissolution (0.0–2.0 wt% GnP) were obtained with a relative density range between 0.35 and 0.45. Although the addition of GnP affected the cellular structure of all foams, they had a bigger influence in WVIPS foams. The storage modulus increased for all foams with increasing relative density and GnP’s concentration, except for WVIPS PSU-GnP foams, as they developed open/interconnected cellular structures during foaming. Comparatively, foams prepared by scCO2 dissolution showed higher specific storage moduli than similar WVIPS foams (same relative density and GnP content), explained by the microcellular structure of scCO2 foams. As a result of the plasticizing effect of CO2, PSU foams prepared by scCO2 showed lower glass transition temperatures than WVIPS foams, with the two series of these foams displaying decreasing values with incrementing the amount of GnP.

Compressive Properties of Mouse Articular Cartilage Determined in a Novel Micro-Indentation Test Method and Biphasic Finite Element Model

2006 ◽  
Vol 128 (5) ◽  
pp. 766-771 ◽  
Author(s):  
Li Cao ◽  
Inchan Youn ◽  
Farshid Guilak ◽  
Lori A Setton
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Articular Cartilage ◽  
Indentation Test ◽  
Small Animal ◽  
Element Model ◽  
Indentation Testing ◽  
Compressive Properties ◽  
Biphasic Finite Element ◽  
Micro Indentation

The mechanical properties of articular cartilage serve as important measures of tissue function or degeneration, and are known to change significantly with osteoarthritis. Interest in small animal and mouse models of osteoarthritis has increased as studies reveal the importance of genetic background in determining predisposition to osteoarthritis. While indentation testing provides a method of determining cartilage mechanical properties in situ, it has been of limited value in studying mouse joints due to the relatively small size of the joint and thickness of the cartilage layer. In this study, we developed a micro-indentation testing system to determine the compressive and biphasic mechanical properties of cartilage in the small joints of the mouse. A nonlinear optimization program employing a genetic algorithm for parameter estimation, combined with a biphasic finite element model of the micro-indentation test, was developed to obtain the biphasic, compressive material properties of articular cartilage. The creep response and material properties of lateral tibial plateau cartilage were obtained for wild-type mouse knee joints, by the micro-indentation testing and optimization algorithm. The newly developed genetic algorithm was found to be efficient and accurate when used with the finite element simulations for nonlinear optimization to the experimental creep data. The biphasic mechanical properties of mouse cartilage in compression (average values: Young’s modulus, 2.0MPa; Poisson’s ratio, 0.20; and hydraulic permeability, 1.1×10−16m4∕N‐s) were found to be of similar orders of magnitude as previous findings for other animal cartilages, including human, bovine, rat, and rabbit and demonstrate the utility of the new test methods. This study provides the first available data for biphasic compressive properties in mouse cartilage and suggests a promising method for detecting altered cartilage mechanics in small animal models of osteoarthritis.

scholarly journals Mechanical Properties of a Chiral Cellular Structure with Semicircular Beams

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2887
Author(s):  
Yalei Bai ◽  
Tong Zhao ◽  
Chengxu Yuan ◽  
Weidong Liu ◽  
Haichao Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Elastic Properties ◽  
Cellular Structure ◽  
Raw Material ◽  
Cellular Structures ◽  
Tensile Shear ◽  
Element Analysis ◽  
Chiral Structure ◽  
Shear Moduli

Compliant cellular structures are good candidates for morphing applications. This paper proposes a novel chiral cellular structure composed of circular beams with great elastic properties and potential for morphing. The tensile and shear elastic properties of the structure are studied through theoretical derivations and then verified by finite element analysis. Results show that this novel chiral structure exhibits extremely low in-plane tensile and shear moduli, which are many orders of magnitude lower than that of the raw material. The structure also shows tensile–shear and shear–tensile coupling effects that cannot be ignored. The tensile and shear properties of the structure can provide a reference for employing this structure in engineering applications.

Using a 3-Steps Supercritical Fluids Assisted Process for the Generation of Nanostructured Biopolymeric Scaffolds

2019 ◽  
Vol 12 (1) ◽  
pp. 7-14
Author(s):  
Stefano Cardea
Keyword(s):  
Mechanical Properties ◽  
Extracellular Matrix ◽  
Lactic Acid ◽  
Supercritical Fluids ◽  
Supercritical Co2 ◽  
Cellular Structure ◽  
High Porosity ◽  
Polymeric Gel ◽  
Very High

Background: Scaffolds can be used to substitute the extracellular matrix and to favour the generation of tissues and organs. Until now, various processes have been implemented for scaffolds generation, but they are characterized by several limits. Methods: In this work, we tested a supercritical fluids assisted process for the generation of nano-structured biopolymeric scaffolds; it is characterized by three steps: generation of a polymeric gel (loaded with a porogen), drying of the gel using supercritical CO2, waterwashing to remove the porogen. Results: 3D Poly(D,L-lactic acid) scaffolds have been obtained, characterized by very high porosity (> 90%) and surface are (> 200 m2/g), and by a fibrous nanostructure (fibres ranging between 60 and 400 nm) superimposed to a micrometric cellular structure. Conclusion: Moreover, suitable mechanical properties (up to 125 KPa) and very low solvents residue (< 5 ppm) have been obtained.

scholarly journals Effective Dispersion of Carbon Nanotube in Epoxy Grout for Structural Rehabilitation

2018 ◽  
Vol 65 ◽  
pp. 08005
Author(s):  
Kar Sing Lim ◽  
Seng Hai Kam ◽  
Libriati Zardasti ◽  
Nordin Yahaya ◽  
Norhazilan Md Noor
Keyword(s):  
Mechanical Properties ◽  
Control Sample ◽  
Strength Properties ◽  
Compressive Property ◽  
Repair System ◽  
Compressive Properties ◽  
Roll Mill ◽  
Effective Dispersion ◽  
Good Material ◽  
Infill Material

The industry nowadays is incorporating the composite repair system for repairing pipelines rather than the conventional steel repair. The mechanism of this repair method usually consists of three components which are the composite wrapping, infill material and the adhesive. However, there has been very little research on the function of the infill in the repair mechanism. This work is concerning the enhancement of the performance or the strength properties of the infill material in pipeline repair by reinforcing the putty with carbon nanotubes (CNT). The enhancement of the performance of the infill has been carried out by dispersing the CNT into epoxy resin with a three roll mill. In the mechanical properties testing, it is found that the CNT is an effective material to improve the tensile strength of the epoxy grout. However, the CNT-modified samples in the compressive property test show a contrast to the tensile test. All the CNT-modified samples exhibit a lower compressive strength than the control sample and the milled down sample. In conclusion, CNT shows the potential to be a very good material to enhance the mechanical properties of epoxy grout, however, with this specific brand of epoxy grout that contains steel filler in the resin, the CNT only improve the tensile properties but the compressive properties of the epoxy grout has been compromised as compared to the control sample.

Mechanical properties of FeAlSi powders prepared by mechanical alloying from different initial feedstock materials

2019 ◽  
Vol 107 (2) ◽  
pp. 207 ◽  
Author(s):  
Jaroslav Čech ◽  
Petr Haušild ◽  
Miroslav Karlík ◽  
Veronika Kadlecová ◽  
Jiří Čapek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Alloying ◽  
Young’S Modulus ◽  
Milling Time ◽  
Young's Modulus ◽  
Element Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Particles ◽  
Complete Homogenization

FeAl20Si20 (wt.%) powders prepared by mechanical alloying from different initial feedstock materials (Fe, Al, Si, FeAl27) were investigated in this study. Scanning electron microscopy, X-ray diffraction and nanoindentation techniques were used to analyze microstructure, phase composition and mechanical properties (hardness and Young’s modulus). Finite element model was developed to account for the decrease in measured values of mechanical properties of powder particles with increasing penetration depth caused by surrounding soft resin used for embedding powder particles. Progressive homogenization of the powders’ microstructure and an increase of hardness and Young’s modulus with milling time were observed and the time for complete homogenization was estimated.

Sign in / Sign up

Export Citation Format

Share Document