A coupled MD-FE methodology to characterize mechanical interphases in polymeric nanocomposites

This contribution introduces an unconventional procedure to characterize spatial profiles of elastic and inelastic properties inside polymer interphases around nanoparticles. Interphases denote those regions in the polymer matrix whose mechanical properties are influenced by the filler surfaces and thus deviate from the bulk properties. They are of particular relevance in case of nano-sized filler particles with a comparatively large surface-to-volume ratio and hence can explain the frequent observation that the overall properties of polymer nanocomposites cannot be determined by classical mixing rules, which only consider the behavior of the individual constituents.Interphase characterization for nanocomposites poses hardly solvable challenges to the experimenter and is still an unsolved problem in many cases. Instead of real experiments, we perform pseudo experiments using our recently developed Capriccio method, which is an MD-FE domain-decomposition tool specifically designed for amorphous polymers. These pseudo-experimental data then serve as input for a typical inverse parameter identification. With this procedure, spatially varying mechanical properties inside the polymer are, for the first time, translated into intuitively understandable profiles of continuum mechanical parameters.As a model material, we employ silica-enforced polystyrene, for which our procedure reveals exponential saturation profiles for Young's modulus and the yield stress inside the interphase, where the former takes about seven times the bulk value at the particle surface and the latter roughly triples. Interestingly, hardening coefficient and Poisson's ratio of the polymer remain nearly constant inside the interphase. Besides gaining insight into the constitutive influence of filler particles, these unexpected and intriguing results also offer interesting explanatory options for the failure behavior of polymer nanocomposites.

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Effect of Carbon Nanofiber Heat Treatment on Physical Properties of Polymeric Nanocomposites—Part I

Journal of Nanomaterials ◽

10.1155/2007/52729 ◽

2007 ◽

Vol 2007 ◽

pp. 1-6 ◽

Cited By ~ 15

Author(s):

Khalid Lafdi ◽

William Fox ◽

Matthew Matzek ◽

Emel Yildiz

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Carbon Nanofiber ◽

Treatment Temperature ◽

Polymeric Nanocomposites ◽

Graphene Layers ◽

Maximum Improvement ◽

Definition Of ◽

The Individual ◽

Strength Of Adhesion

The definition of a nanocomposite material has broadened significantly to encompass a large variety of systems made of dissimilar components and mixed at the nanometer scale. The properties of nanocomposite materials also depend on the morphology, crystallinity, and interfacial characteristics of the individual constituents. In the current work, vapor-grown carbon nanofibers were subjected to varying heat-treatment temperatures. The strength of adhesion between the nanofiber and an epoxy (thermoset) matrix was characterized by the flexural strength and modulus. Heat treatment to 1800C∘demonstrated maximum improvement in mechanical properties over that of the neat resin, while heat-treatment to higher temperatures demonstrated a slight decrease in mechanical properties likely due to the elimination of potential bonding sites caused by the elimination of the truncated edges of the graphene layers. Both the electrical and thermal properties of the resulting nanocomposites increased in conjunction with the increasing heat-treatment temperature.

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Role of Compatibilization in Polymer Nanocomposites

Rubber Chemistry and Technology ◽

10.5254/1.3557009 ◽

2009 ◽

Vol 82 (3) ◽

pp. 340-368 ◽

Cited By ~ 10

Author(s):

Robert D. Kroshefsky ◽

Jack L. Price ◽

Duryodhan Mangaraj

Keyword(s):

Carbon Nanotubes ◽

Polymer Blends ◽

Polymer Nanocomposites ◽

Particle Surface ◽

Surface Interactions ◽

Polymeric Nanocomposites ◽

Matrix Resin ◽

Basic Principles ◽

Improved Performance

Abstract Polymeric nanocomposites based on nanoclay, nanosilica, carbon nanotubes, and ceramic or mineral nanoparticles have been developed for a variety of applications. The large surface-to-mass ratios of these particles require good adsorption of the polymeric material on the particle surface to provide the adhesion levels between the filler and matrix resin necessary for improved performance. We review the basic principles underlying these surface interactions and their application in the preparation of a variety of these nanocomposites, as well as in explaining their performance. We demonstrate that the principles underlying the compatibilization of polymer blends and alloys can be successfully used to design nanocomposites and understand their performance.

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Synergic Effect of TiO2 Filler on the Mechanical Properties of Polymer Nanocomposites

Polymers ◽

10.3390/polym13122017 ◽

2021 ◽

Vol 13 (12) ◽

pp. 2017

Author(s):

Cristina Cazan ◽

Alexandru Enesca ◽

Luminita Andronic

Keyword(s):

Mechanical Properties ◽

Polymer Nanocomposites ◽

Polymer Matrix ◽

Time Pressure ◽

Volume Fraction ◽

Interfacial Area ◽

Polymeric Matrix ◽

Inorganic Filler ◽

Polymeric Nanocomposites ◽

Technological Parameters

Nanocomposites with polymer matrix offer excellent opportunities to explore new functionalities beyond those of conventional materials. TiO2, as a reinforcement agent in polymeric nanocomposites, is a viable strategy that significantly enhanced their mechanical properties. The size of the filler plays an essential role in determining the mechanical properties of the nanocomposite. A defining feature of polymer nanocomposites is that the small size of the fillers leads to an increase in the interfacial area compared to traditional composites. The interfacial area generates a significant volume fraction of interfacial polymer, with properties different from the bulk polymer even at low loadings of the nanofiller. This review aims to provide specific guidelines on the correlations between the structures of TiO2 nanocomposites with polymeric matrix and their mechanical properties. The correlations will be established and explained based on interfaces realized between the polymer matrix and inorganic filler. The paper focuses on the influence of the composition parameters (type of polymeric matrix, TiO2 filler with surface modified/unmodified, additives) and technological parameters (processing methods, temperature, time, pressure) on the mechanical strength of TiO2 nanocomposites with the polymeric matrix.

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An experimental investigation on mechanical properties of hybrid polymer nanocomposites

Materials Today Proceedings ◽

10.1016/j.matpr.2019.07.755 ◽

2019 ◽

Vol 19 ◽

pp. 691-699 ◽

Cited By ~ 1

Author(s):

G. Naveen Kumar ◽

C. Suresh Kumar ◽

G.V.R. Seshagiri Rao

Keyword(s):

Mechanical Properties ◽

Experimental Investigation ◽

Polymer Nanocomposites ◽

Hybrid Polymer

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A Generalized Approach for Evaluating the Mechanical Properties of Polymer Nanocomposites Reinforced with Spherical Fillers

Nanomaterials ◽

10.3390/nano11040830 ◽

2021 ◽

Vol 11 (4) ◽

pp. 830

Author(s):

Julio Cesar Martinez-Garcia ◽

Alexandre Serraïma-Ferrer ◽

Aitor Lopeandía-Fernández ◽

Marco Lattuada ◽

Janak Sapkota ◽

...

Keyword(s):

Mechanical Properties ◽

Polymeric Nanocomposites ◽

Mechanical Reinforcement ◽

Future Studies ◽

Three Phase ◽

Theoretical Predictions ◽

Filler Network ◽

New Research ◽

Good Agreement ◽

Research Avenue

In this work, the effective mechanical reinforcement of polymeric nanocomposites containing spherical particle fillers is predicted based on a generalized analytical three-phase-series-parallel model, considering the concepts of percolation and the interfacial glassy region. While the concept of percolation is solely taken as a contribution of the filler-network, we herein show that the glassy interphase between filler and matrix, which is often in the nanometers range, is also to be considered while interpreting enhanced mechanical properties of particulate filled polymeric nanocomposites. To demonstrate the relevance of the proposed generalized equation, we have fitted several experimental results which show a good agreement with theoretical predictions. Thus, the approach presented here can be valuable to elucidate new possible conceptual routes for the creation of new materials with fundamental technological applications and can open a new research avenue for future studies.

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Nonlinear modelling of the seismic response of masonry structures: Calibration strategies

Bulletin of Earthquake Engineering ◽

10.1007/s10518-021-01104-1 ◽

2021 ◽

Author(s):

Antonio Maria D’Altri ◽

Francesco Cannizzaro ◽

Massimo Petracca ◽

Diego Alejandro Talledo

Keyword(s):

Mechanical Properties ◽

Numerical Models ◽

Shear Stiffness ◽

Model Material ◽

National Standards ◽

National Standard ◽

Masonry Structures ◽

Nonlinear Modelling ◽

Various Boundary Conditions ◽

Panel Stiffness

AbstractIn this paper, a simple and practitioners-friendly calibration strategy to consistently link target panel-scale mechanical properties (that can be found in national standards) to model material-scale mechanical properties is presented. Simple masonry panel geometries, with various boundary conditions, are utilized to test numerical models and calibrate their mechanical properties. The calibration is successfully conducted through five different numerical models (most of them available in commercial software packages) suitable for nonlinear modelling of masonry structures, using nonlinear static analyses. Firstly, the panel stiffness calibration is performed, focusing the attention to the shear stiffness. Secondly, the panel strength calibration is conducted for several axial load ratios by attempts using as reference the target panel strength deduced by well-known analytical strength criteria. The results in terms of panel strength for the five different models show that this calibration strategy appears effective in obtaining model properties coherent with Italian National Standard and Eurocode. Open issues remain for the calibration of the post-peak response of masonry panels, which still appears highly conventional in the standards.

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Study of biaxial mechanical properties of the passive pig heart: material characterisation and categorisation of regional differences

International Journal of Mechanical and Materials Engineering ◽

10.1186/s40712-021-00128-4 ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Fulufhelo Nemavhola

Keyword(s):

Mechanical Properties ◽

Constitutive Model ◽

Computational Models ◽

Heart Diseases ◽

Interventricular Septum ◽

Model Material ◽

Biaxial Test ◽

Material Behaviour ◽

Material Parameters ◽

Biaxial Tests

AbstractRegional mechanics of the heart is vital in the development of accurate computational models for the pursuit of relevant therapies. Challenges related to heart dysfunctioning are the most important sources of mortality in the world. For example, myocardial infarction (MI) is the foremost killer in sub-Saharan African countries. Mechanical characterisation plays an important role in achieving accurate material behaviour. Material behaviour and constitutive modelling are essential for accurate development of computational models. The biaxial test data was utilised to generated Fung constitutive model material parameters of specific region of the pig myocardium. Also, Choi-Vito constitutive model material parameters were also determined in various myocardia regions. In most cases previously, the mechanical properties of the heart myocardium were assumed to be homogeneous. Most of the computational models developed have assumed that the all three heart regions exhibit similar mechanical properties. Hence, the main objective of this paper is to determine the mechanical material properties of healthy porcine myocardium in three regions, namely left ventricle (LV), mid-wall/interventricular septum (MDW) and right ventricle (RV). The biomechanical properties of the pig heart RV, LV and MDW were characterised using biaxial testing. The biaxial tests show the pig heart myocardium behaves non-linearly, heterogeneously and anisotropically. In this study, it was shown that RV, LV and MDW may exhibit slightly different mechanical properties. Material parameters of two selected constitutive models here may be helpful in regional tissue mechanics, especially for the understanding of various heart diseases and development of new therapies.

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