Direct Observation of Fracture Mechanisms in Polymer-Layered Silicate Nanocomposites

1996 ◽  
Vol 457 ◽  
Author(s):  
Evangelos Manias ◽  
Wook Jin Han ◽  
Klaus D. Jandt ◽  
Edward J. Kramer ◽  
Emmanuel P. Giannelis
Keyword(s):  
Fracture Toughness ◽  
Polymer Nanocomposites ◽  
Direct Observation ◽  
Failure Mechanisms ◽  
Layered Silicate ◽  
Fracture Mechanisms ◽  
Three Point Bending ◽  
Silicate Nanocomposites

AbstractConventional three point bending and TEM techniques are employed to determine the fracture toughness and identify the failure mechanisms in model layered-silicate polymer nanocomposites.

Materials for food packaging applications based on bio-based polymer nanocomposites

2015 ◽  
Vol 30 (2) ◽  
pp. 143-173 ◽  
Author(s):  
Seyed Ahmad Attaran ◽  
Azman Hassan ◽  
Mat Uzir Wahit
Keyword(s):  
Polymer Nanocomposites ◽  
Food Packaging ◽  
Layered Silicate ◽  
Barrier Properties ◽  
Packaging Materials ◽  
Natural Polymer ◽  
Plastic Packaging ◽  
Aspect Ratios ◽  
Nanoparticle Surface ◽  
Silicate Nanocomposites

Concerns about environmental waste problems caused by non-biodegradable petrochemical-based plastic packaging materials as well as consumer demand for high-quality food products have led to increased interest in the development of biodegradable packaging materials using annually renewable natural biopolymers. Inherent shortcomings of natural polymer-based packaging materials such as low mechanical properties and low barrier properties can be recovered by applying nanocomposite technology. Polymer nanocomposites, especially natural biopolymer-layered silicate nanocomposites, exhibit markedly improved packaging properties due to large nanoparticle surface area and their significant aspect ratios. Additionally, natural biopolymer is susceptible to microorganisms, resulting in good biodegradability, which is one of the most promising aspects of its incorporation in packaging materials and industries. The present review article explains the various categories of nanoclay and bio-based polymer-based composites with particular regard to their application as packaging materials. It also gives an overview of the most recent advances and emerging new aspects of nanotechnology for development of composites for environmentally compatible food packaging materials.

Effect of Competing Mechanisms on Fracture Toughness of Polycrystalline Metals

2015 ◽  
Author(s):  
Yan Li ◽  
Min Zhou
Keyword(s):  
Fracture Toughness ◽  
Failure Mechanisms ◽  
Fracture Mechanisms ◽  
Ductile Materials ◽  
Polycrystalline Metals ◽  
Inadequate Knowledge ◽  
Az31 Mg Alloy ◽  
Plastic Dissipation ◽  
Explicit Simulation ◽  
Material Fracture

Fracture toughness in ductile materials is the combined effect of the plastic dissipation and the energy spent in creating new surfaces. The design of polycrystalline metals with improved fracture toughness requires in-depth understanding of two levels of competitions: the competition between plastic deformation and crack formation as well as the competition between transgranular and intergranular fracture. Currently, no systematic approach exists to address the two competitions. The fundamental challenges lie in the difficulty in separating the two energy dissipations and inadequate knowledge about the correlation between fracture mechanisms and material fracture toughness. In this paper, a Cohesive Finite Element Method (CFEM) based multiscale framework is introduced to quantify the two levels of competitions. The fracture toughness of ductile materials is predicted by calculating the J-integral at the macroscale. The fracture surface energy for different type of failure mechanisms is evaluated through explicit simulation of crack propagation at the microstructure level. The calculations carried out here concern AZ31 Mg alloy. Results indicate that the mixed transgranular and intergranular failure can lead to optimized fracture toughness. Microstructures with refined grain size and grain boundary bonding strength can best promote the favorable failure mechanisms.

Thermally-cured and e-beam-cured epoxy layered-Silicate nanocomposites

2003 ◽  
Vol 49 (6) ◽  
pp. 473-480 ◽  
Author(s):  
Chenggang Chen ◽  
David Curliss
Keyword(s):  
Layered Silicate ◽  
Silicate Nanocomposites

Fracture behaviors of HVFA-SCC mixed with seawater and sea-sand under three-point bending

2022 ◽  
pp. 136943322110273
Author(s):  
Lingzhu Zhou ◽  
Yu Zheng ◽  
Linsheng Huo ◽  
Yuxiao Ye ◽  
Xiaolu Wang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Fly Ash ◽  
Unstable Fracture ◽  
Replacement Ratio ◽  
Three Point Bending ◽  
Model Code ◽  
Softening Curve ◽  
Sea Sand ◽  
Fracture Behaviors ◽  
Tensile Softening

This paper aims to study the fracture behaviors of high-volume fly ash-self-compacting concrete (HVFA-SCC) mixed with seawater and sea-sand (SWSS) or freshwater and river sand (FWRS). Three-point bending test were performed on 24 notched beams fabricated with varying in replacement ratio of fly ash (0%, 30%, 50%, and 70%) and the type of water and sand (SWSS and FWRS). The initial and unstable fracture toughness of these test specimens are determined by the double- K fracture model. The effect of fly ash replacement ratio and type of water and sand on the fracture parameters is analyzed and discussed. In addition, the cohesive fracture toughness of all the test specimens is calculated by using Gauss–Chebyshev integral method and the weight function method based on the bilinear tensile softening curve given in CEP-FIP Model Code. A comparison of fracture toughness parameters of determined from the experimental approach and analytical approaches is presented in these SCC specimens. Results show that SCC mixed with SWSS replacing FWRS can improve the unstable fracture toughness and fracture energy, and decrease its brittleness behavior. The cohesive fracture toughness of SWSS-SCC specimens is underestimated by these analytical methods based on the tensile softening curve given in CEP-FIP Model Code.

The Role of Interface on the Toughening and Failure Mechanisms of Thermoplastic Nanocomposites Reinforced with Nanofibrillated Rubber

Nanoscale ◽  
2021 ◽  
Author(s):  
Mahdi Zeidi ◽  
Chun Il Kim ◽  
Chul B B. Park
Keyword(s):  
Polymer Nanocomposites ◽  
Functional Properties ◽  
Crucial Role ◽  
Failure Mechanisms

Interface plays a crucial role on the physical and functional properties of polymer nanocomposites, yet its effects have not been fully recognized in the setting of classical continuum-based modeling. In...

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