Auxetic Polymer Foams: Production, Modeling and Applications

2021 ◽  
Vol 04 ◽  
Author(s):  
Ouassim Hamdi ◽  
Denis Rodrigue
Keyword(s):  
Poisson Ratio ◽  
High Impact ◽  
Polymer Foams ◽  
Processing Conditions ◽  
Auxetic Materials ◽  
Potential Applications ◽  
Mechanical Performances ◽  
Production Modeling ◽  
Fabrication Parameters ◽  
Impact Absorption

: Auxetic materials have high potential due to their exceptional properties resulting from their negative Poisson ratio. Recently, several auxetic polymer-based materials have been developed. In fact, several applications are looking for a lightweight (less material consumed in production and transport) while having high mechanical performances (impact absorption, rigidity, strength, resistance, etc.). So, a balance between density and toughness/strength is of high importance, especially for military, sporting, and transport applications. So auxetic materials (especially foams) can provide high impact protection while limiting the material’s weight. This article presents a review of recent advances with a focus on auxetic polymers, with particular emphasis on the auxetic polymer foams in terms of their fabrication methods and processing conditions (depending on the nature of the cellular structure), the effect of the fabrication parameters on their final properties, as well as their models and potential applications.

Postmortem and in situ TEM methods to study the mechanism of failure in controlled-morphology high-impact polystrene resin

1996 ◽  
Vol 54 ◽  
pp. 178-179
Author(s):  
R. C. Cieslinski ◽  
M. T. Dineen ◽  
J. L. Hahnfeld
Keyword(s):  
Poisson Ratio ◽  
Acrylonitrile Butadiene Styrene ◽  
High Impact ◽  
In Situ Tem ◽  
Styrene Copolymers ◽  
Controlled Morphology ◽  
Point Bend ◽  
Mechanism Of Failure ◽  
Impact Energies

Advanced Styrenic resins are being developed throughout the industry to bridge the properties gap between traditional HIPS (High Impact Polystyrene) and ABS (Acrylonitrile-Butadiene-Styrene copolymers) resins. These new resins have an unprecedented balance of high gloss and high impact energies. Dow Chemical's contribution to this area is based on a unique combination of rubber morphologies including labyrinth, onion skin, and core-shell rubber particles. This new resin, referred as a controlled morphology resin (CMR), was investigated to determine the toughening mechanism of this unique rubber morphology. This poster will summarize the initial studies of these resins using the double-notch four-point bend test of Su and Yee, tensile stage electron microscopy, and Poisson Ratio analysis of the fracture mechanism.

scholarly journals The use of auxetic materials in tissue engineering

2020 ◽  
Vol 8 (8) ◽  
pp. 2074-2083 ◽  
Author(s):  
Paul Mardling ◽  
Andrew Alderson ◽  
Nicola Jordan-Mahy ◽  
Christine Lyn Le Maitre
Keyword(s):  
Tissue Engineering ◽  
Biological Tissues ◽  
Auxetic Materials ◽  
Potential Applications ◽  
Poissons Ratio

A number of biological tissues have been shown to behave in an auxetic manner, defined by having a negative poissons ratio. Thus mimicking this environment has a number of potential applications especially in tissue engineering.

Auxetic materials and their potential applications in textiles

2014 ◽  
Vol 84 (15) ◽  
pp. 1600-1611 ◽  
Author(s):  
Zhengyue Wang ◽  
Hong Hu
Keyword(s):  
Auxetic Materials ◽  
Potential Applications

Adaptive Impact Absorption – The Concept and Potential Applications

2015 ◽  
Vol 6 (2) ◽  
pp. 357-377 ◽  
Author(s):  
Jan Holnicki-Szulc ◽  
Cezary Graczykowski ◽  
Grzegorz Mikulowski ◽  
Arkadiusz Mróz ◽  
Piotr Pawlowski ◽  
...  
Keyword(s):  
Potential Applications ◽  
Impact Absorption

The Flocculation and Stability of TiO2 Nanoparticles

2012 ◽  
Vol 548 ◽  
pp. 138-142
Author(s):  
Xiao Ying Liu ◽  
Xiao Dong Hao ◽  
Chun Xiang Gu ◽  
Yu Xin Zhang ◽  
Xin Lu Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Digital Camera ◽  
Processing Conditions ◽  
X Ray Diffraction ◽  
Thermogravimetric Method ◽  
X Ray ◽  
Transmission Electron ◽  
Potential Applications ◽  
Solvent Washing

In this work, TiO2nanoparticles (NPs) were prepared through a well-developed hydrothermal method. The dry products were characterized by digital camera, transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermogravimetric method (TGA). These results suggested that TiO2NPs were well-crystallized and oleic acid-capped (OA-capped; 33.42 wt.%). In order to investigate the flocculation and stability of TiO2NPs colloids, redispersed experiments were carried out by altering the preparative parameters (e.g., redispersion solvent, washing times). In addition, the compounding stability of TiO2NPs colloids with AuNPs colloids and MnO4-solution under processing conditions (e.g., aging with stirring and under UV irradiation) were also studied. In principle, systematic investigations of flocculation and stability of TiO2NPs will be useful for their potential applications including novel photocatalysts and biosensors.

Detection of Voids in Carbon/Epoxy Laminates and Their Influence on Mechanical Properties

2017 ◽  
Vol 25 (5) ◽  
pp. 371-380 ◽  
Author(s):  
Luca Di Landro ◽  
Aurelio Montalto ◽  
Paolo Bettini ◽  
Stefania Guerra ◽  
Fabrizio Montagnoli ◽  
...  
Keyword(s):  
Composite Laminates ◽  
Mechanical Performance ◽  
Thermal Analyses ◽  
Void Content ◽  
Processing Conditions ◽  
Micro Computed Tomography ◽  
Sem Image ◽  
Beam Shear ◽  
Mechanical Performances ◽  
Curing Cycle

Defects, such as voids and delaminations, may significantly reduce the mechanical performance of components made of composite laminates. Distributed voids and porosity are generated during composite processing and are influenced by prepreg characteristics as well as by curing cycle parameters. On the basis of rheological and thermal analyses, as well as observations of laminates produced by different processing conditions, curing pressure appears the most influent factor affecting the void content. This work compares different methods for void analysis and quantitative evaluation (ultrasonic scan, micro-computed tomography, acid digestion, SEM image analysis) evidencing their applicative limitations. Carbon/epoxy laminates were produced in autoclave or oven by vacuum bag technique, using different processing conditions, so that void contents ranging from 0% to 7% volume were obtained. Effects of porosity over laminates mechanical performances are analysed. The results of tensile and compressive tests are discussed, considering the effect that different curing cycles have over void content as well as over fibre/resin fraction. Interlaminar strength, as measured by short beam shear tests, which is a matrix-dominated property, exhibits a reduction of failure strength up to 25% in laminates with the highest void content, compared to laminates with no porosity.

Correlation of Morphology, Mechanical Properties and Processing Conditions of Modified High Impact Polystyrene

1983 ◽  
pp. 27-30
Author(s):  
V. V. Abramov ◽  
V. D. Yenalyev ◽  
M. S. Akutin ◽  
N. M. Tchalaya ◽  
V. I. Melnichenko ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Impact ◽  
Processing Conditions ◽  
High Impact Polystyrene

scholarly journals Injection-moulding of nitrogen-foamed bio-based microcellular poly(butylene succinate): Processing conditions/foam structure/flexural properties relationship

2020 ◽  
Vol 11 (1-2) ◽  
pp. 30-46
Author(s):  
Nazim Ykhlef ◽  
Eric Lafranche
Keyword(s):  
Cell Density ◽  
Processing Parameters ◽  
Back Pressure ◽  
Flexural Properties ◽  
Processing Conditions ◽  
Butylene Succinate ◽  
Melt Temperature ◽  
Thickness Change ◽  
Foam Structure ◽  
Mechanical Performances

This paper aims to identify the main processing parameters that optimize as well the microcellular structure (cell size, cell density) of nitrogen (N2) foamed injection-moulded poly(butylene succinate) (PBS) as the resultant flexural properties of the part. The part beam geometry was designed so as to reproduce some geometrical shapes (e.g. thickness change, ribs, bosses or holes) occurring on most of industrial parts. A Taguchi L9 design of experiments (DOE) has been first used to quantify the effects of processing conditions on microcellular structure and mechanical performances. Among the processing parameters, the melt temperature, gas content, injection volumetric flow rate and back pressure were chosen for the DOE due to their level of influence on gas dissolution and nucleation phases. An analysis of variance (ANOVA) showed that the microcellular structure depended mainly on nitrogen content and, to a lesser extent, on back pressure representation of gas pressure saturation in the PBS/N2 system during the feeding stage. The resultant specific flexural properties were controlled by the skin/core ratio as well as the finesse of foam structure (cell sizes, cell density) but a 15% loss in specific performances was noted compared with the unfoamed part. The microcellular structure/mechanical performances could be thus established from the microstructure analysis. In a second step, the foamed microcellular structure has been improved by introduction of micro-talc in the PBS acting as cell nucleating agent (heterogeneous nucleation). A significant increase in cell density and cell reduction (40%) were observed.

scholarly journals Estimation of Ge nanocrystals size by Raman, X-rays, and HRTEM techniques

2008 ◽  
Vol 14 (S3) ◽  
pp. 61-64 ◽  
Author(s):  
S.R.C. Pinto ◽  
P. Caldelas ◽  
A.G. Rolo ◽  
A. Chahboun ◽  
M.J.M. Gomes
Keyword(s):  
Flash Memory ◽  
Nonvolatile Memory ◽  
High Dielectric Constant ◽  
Memory Systems ◽  
X Rays ◽  
Processing Conditions ◽  
Flash Memories ◽  
Potential Applications ◽  
High Dielectric ◽  
Ge Nanocrystals

Ge NCs have attracted considerable attention because of their potential applications in nonvolatile memory and integrated optoelectronics. A number of groups have already proposed integrate flash memories based on Ge NCs embedded SiO2 matrix. Since Al2O3 presents a high dielectric constant comparatively to SiO2, it is a good candidate to replace silica in flash memory systems, and therefore improve their performances. Moreover, Al2O3 presents good mechanical properties, and supports high temperature, which leads it to be an ideal material for Si processing conditions. However, a few studies have been reported on Ge NCs embedded in Al2O3 matrix.

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