Filling of Mater-Bi with Nanoclays to Enhance the Biofilm Rigidity

We investigated the efficacy of several nanoclays (halloysite, sepiolite and laponite) as nanofillers for Mater-Bi, which is a commercial bioplastic extensively used within food packaging applications. The preparation of Mater-Bi/nanoclay nanocomposite films was easily achieved by means of the solvent casting method from dichloroethane. The prepared bio-nanocomposites were characterized by dynamic mechanical analysis (DMA) in order to explore the effect of the addition of the nanoclays on the mechanical behavior of the Mater-Bi-based films. Tensile tests found that filling Mater-Bi with halloysite induced the most significant improvement of the mechanical performances under traction force, while DMA measurements under the oscillatory regime showed that the polymer glass transition was not affected by the addition of the nanoclay. The tensile properties of the Mater-Bi/halloysite nanotube (HNT) films were competitive compared to those of traditional petroleum plastics in terms of the elastic modulus and stress at the breaking point. Both the mechanical response to the temperature and the tensile properties make the bio-nanocomposites appropriate for food packaging and smart coating purposes. Here, we report a preliminary study of the development of sustainable hybrid materials that could be employed in numerous industrial and technological applications within materials science and pharmaceutics.

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Effects of different gums on tensile properties of cellulose nanofibrils (CNFs)-reinforced starch

Polymers and Polymer Composites ◽

10.1177/0967391120923440 ◽

2020 ◽

pp. 096739112092344 ◽

Cited By ~ 1

Author(s):

Razieh Eslami ◽

Alireza Azizi ◽

Mohsen Najafi

Keyword(s):

Mechanical Properties ◽

Tensile Properties ◽

Food Packaging ◽

Negative Impact ◽

Cellulose Nanofibrils ◽

Tensile Tests ◽

Nanocomposite Films ◽

Infrared Analysis ◽

Solution Casting Method ◽

Starch Films

This research is focused on the development of a new starch-based nanocomposite films reinforced with cellulose nanofibrils (CNFs) for food packaging purposes. A series of starch films were produced by the solution casting method with various concentrations of glycerin, CNF, and citric acid (CA). Mechanical properties of the films were investigated using tensile tests. Based on the results, the best formulation with optimal mechanical properties was introduced by different amounts of various gums to study the effects of the gums on tensile properties of the samples. Fourier-transform infrared analysis was performed to study posttreatment chemical structure of the sample to confirm the cross-linking and esterifying of the nanocomposite films. Results revealed that the tragacanth gum had a negative impact on the mechanical properties, while the frankincense gum (F-gum) and Arabic gum positively influenced the mechanical properties through strengthening the network structure. The sample containing 0.3 g of F-gum (10% w/w, relative to the starch weight) showed the best results compared to the control films.

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Interface Engineering of CNT/Polymer Nanocomposites With Tunable Damping Properties

Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation, and Control of Adaptive Systems; Integrated System Design and Implementation ◽

10.1115/smasis2018-8066 ◽

2018 ◽

Author(s):

Michela Talò ◽

Giulia Lanzara ◽

Maryam Karimzadeh ◽

Walter Lacarbonara

Keyword(s):

Load Transfer ◽

Mechanical Response ◽

Material Design ◽

Tensile Tests ◽

Nanocomposite Films ◽

Damping Capacity ◽

Interfacial Region ◽

Material Damping ◽

Stick Slip ◽

Multi Walled Carbon Nanotubes

In this work, the arising of stick-slip dissipation as well as the global mechanical response of carbon nanotube (CNT) nanocomposite films are tailored by exploiting a three-phase nanocomposite. The three phases are represented by the CNTs, a polymer coating localized on the CNTs surface and a hosting matrix. In particular, a polystyrene (PS) layer coats multi-walled carbon nanotubes (MWNTs) that are randomly dispersed in a polyimide (PI) matrix. The coating phase is strongly bonded to the CNTs outer sidewalls ensuring the effectiveness of the load transfer mechanism and reducing the material damping capacity. The coating phase can be thermally-activated to modify, and in particular, decrease the CNT-matrix interfacial shear strength (ISS) thus facilitating the stick-slip onset in the nanocomposite. The ISS decrease finds its roots in a partial degradation of the coating phase and, in particular, in the formation of voids. By weakening the CNT/polymer interfacial region, a significant enhancement in the material damping capacity is observed. An extensive experimental campaign consisting of monotonic and cyclic tensile tests proved the effectiveness of this novel multi-phase material design.

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Decoupling between calorimetric and dynamical glass transitions in high-entropy metallic glasses

10.21203/rs.3.rs-164172/v1 ◽

2021 ◽

Author(s):

Jiang Jing ◽

Zhen Lu ◽

Jie Shen ◽

Takeshi Wada ◽

Hidemi Kato ◽

...

Keyword(s):

Glass Transition ◽

Metallic Glasses ◽

Materials Science ◽

Configurational Entropy ◽

Mechanical Analysis ◽

Glass Transitions ◽

Solid State Physics ◽

High Entropy ◽

Sluggish Diffusion ◽

Mechanical Performances

Abstract Glass transition is one of the unresolved critical issues in solid-state physics and materials science, during which a viscous liquid is frozen into a solid or structurally arrested state. On account of the uniform arrested mechanism, the calorimetric glass transition temperature (Tg) always follows the same trend as the dynamical glass transition (or α-relaxation) temperature (Tα) determined by dynamic mechanical analysis (DMA). Here, we explored the correlations between the calorimetric and dynamical glass transitions of three prototypical high-entropy metallic glasses (HEMGs) systems. We found that the HEMGs present a depressed dynamical glass transition phenomenon, i.e. HEMGs with moderate calorimetric Tg represent the highest Tα and the maximum activation energy. These decoupled glass transitions from thermal and mechanical measurements reveal the effect of high configurational entropy on the structure and dynamics of supercooled liquids and metallic glasses, which are associated with sluggish diffusion and decreased dynamic and spatial heterogeneities from high mixing entropy. The results have important implications in understanding the entropy effect on the structure and properties of metallic glasses for designing new materials with plenteous physical and mechanical performances.

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Decoupling between calorimetric and dynamical glass transitions in high-entropy metallic glasses

Nature Communications ◽

10.1038/s41467-021-24093-w ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Jing Jiang ◽

Zhen Lu ◽

Jie Shen ◽

Takeshi Wada ◽

Hidemi Kato ◽

...

Keyword(s):

Glass Transition ◽

Metallic Glasses ◽

Materials Science ◽

Configurational Entropy ◽

Mechanical Analysis ◽

Glass Transitions ◽

Solid State Physics ◽

High Entropy ◽

Sluggish Diffusion ◽

Mechanical Performances

AbstractGlass transition is one of the unresolved critical issues in solid-state physics and materials science, during which a viscous liquid is frozen into a solid or structurally arrested state. On account of the uniform arrested mechanism, the calorimetric glass transition temperature (Tg) always follows the same trend as the dynamical glass transition (or α-relaxation) temperature (Tα) determined by dynamic mechanical analysis (DMA). Here, we explored the correlations between the calorimetric and dynamical glass transitions of three prototypical high-entropy metallic glasses (HEMGs) systems. We found that the HEMGs present a depressed dynamical glass transition phenomenon, i.e., HEMGs with moderate calorimetric Tg represent the highest Tα and the maximum activation energy of α-relaxation. These decoupled glass transitions from thermal and mechanical measurements reveal the effect of high configurational entropy on the structure and dynamics of supercooled liquids and metallic glasses, which are associated with sluggish diffusion and decreased dynamic and spatial heterogeneities from high mixing entropy. The results have important implications in understanding the entropy effect on the structure and properties of metallic glasses for designing new materials with plenteous physical and mechanical performances.

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Effect of Fabric Architecture on Tensile Behaviour of the High-Molecular-Weight Polyethylene 3-Dimensional Interlock Composite Reinforcements

Polymers ◽

10.3390/polym12051045 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1045 ◽

Cited By ~ 2

Author(s):

Mengru Li ◽

Peng Wang ◽

François Boussu ◽

Damien Soulat

Keyword(s):

Tensile Properties ◽

Optimal Solution ◽

Tensile Tests ◽

Influential Factors ◽

Uniaxial Tensile ◽

Tensile Behaviour ◽

Warp Yarn ◽

Main Category ◽

3 Dimensional ◽

Mechanical Performances

As promising fibrous reinforcements in the thick composites manufacturing, 3-dimensional warp interlock fabrics (3DWIFs) are recognised more and more in the industry for their outstanding mechanical properties compared to the 2D laminates. The present work shows the influence of the fabric’s architecture on the tensile behaviour of 3DWIFs. Five kinds of 3D fabrics with different interlock structures have been designed according to the main category of binding warp yarn evolution. These five 3DWIFs, containing both binding and stuffer warp yarns and produced with the same warp and weft densities, are experimentally tested via uniaxial tensile tests. The experimental results of the different 3DWIFs have been compared to find the optimal solution based on several mechanical performances. Fabric structures have an impact on tensile properties both in the warp and weft directions. Furthermore, other influential factors, for example, the yarn crimps during the weaving process and the crimp angles of binding warp yarns in 3DWIFs, are investigated and discussed in the paper. The influence of the total crimp angles related to the binding path on the tensile properties of 3DWIFs via the inter yarns friction is summarised.

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Water-Tree Resistant Characteristics of Crosslinker-Modified-SiO2/XLPE Nanocomposites

Materials ◽

10.3390/ma14061398 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1398

Author(s):

Yong-Qi Zhang ◽

Xuan Wang ◽

Ping-Lan Yu ◽

Wei-Feng Sun

Keyword(s):

Electric Fields ◽

Tree Growth ◽

Mechanical Analysis ◽

Water Molecules ◽

Crosslinking Degree ◽

Water Tree ◽

Tree Resistance ◽

Alternating Electric Fields ◽

Trimethylolpropane Triacrylate ◽

Mechanical Performances

Trimethylolpropane triacrylate (TMPTA) as a photoactive crosslinker is grafted onto hydrophobic nanosilica surface through click chemical reactions of mercapto double bonds to prepare the functionalized nanoparticles (TMPTA-s-SiO2), which are used to develop TMPTA-s-SiO2/XLPE nanocomposites with improvements in mechanical strength and electrical resistance. The expedited aging experiments of water-tree growth are performed with a water-knife electrode and analyzed in consistence with the mechanical performances evaluated by means of dynamic thermo-mechanical analysis (DMA) and tensile stress–strain characteristics. Due to the dense cross-linking network of polyethylene molecular chains formed on the TMPTA-modified surfaces of SiO2 nanofillers, TMPTA-s-SiO2 nanofillers are chemically introduced into XLPE matrix to acquire higher crosslinking degree and connection strength in the amorphous regions between polyethylene lamellae, accounting for the higher water-tree resistance and ameliorated mechanical performances, compared with pure XLPE and neat-SiO2/XLPE nanocomposite. Hydrophilic TMPTA molecules grafted on the nano-SiO2 surface can inhibit the condensation of water molecules into water micro-beads at insulation defects, thus attenuating the damage of water micro-beads to polyethylene configurations under alternating electric fields and thus restricting water-tree growth in amorphous regions. The intensified interfaces between TMPTA-s-SiO2 nanofillers and XLPE matrix limit the segment motions of polyethylene molecular chains and resist the diffusion of water molecules in XLPE amorphous regions, which further contributes to the excellent water-tree resistance of TMPTA-s-SiO2/XLPE nanocomposites.

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Microstructure, Hardness, and Tensile Properties of Vacuum Carburizing Gear Steel

Metals ◽

10.3390/met11020300 ◽

2021 ◽

Vol 11 (2) ◽

pp. 300

Author(s):

Wu Chen ◽

Xiaofei He ◽

Wenchao Yu ◽

Maoqiu Wang ◽

Kefu Yao

Keyword(s):

Tensile Properties ◽

Tensile Tests ◽

Case Depth ◽

Strain Hardening Exponent ◽

Austenitizing Temperature ◽

Vacuum Carburizing ◽

Experimental Steel ◽

Strain Behavior ◽

Carburized Steel ◽

Vacuum Carburization

We investigated the effects of the austenitizing temperature on the microstructure, hardness, and tensile properties of case-carburized steel after vacuum carburization at 930 °C and then re-austenitization at 820–900 °C followed by oil quenching and tempering. The results show that fractures occurred early with the increase in the austenitizing temperature, although all the carburized specimens showed a similar case hardness of 800 HV0.2 and case depth of 1.2 mm. The highest fracture stress of 1919 MPa was obtained for the experimental steel when the austenitizing temperature was 840 °C due to its fine microstructure and relatively high percentage of retained austenite transformed into martensite during the tensile tests. We also found that the stress–strain behavior of case-carburized specimens could be described by the area-weighted curves of the carburized case and the core in combination. The strain hardening exponent was about 0.4 and did not vary with the increase in the austenitizing temperature. We concluded that the optimum austenitizing temperature was around 840 °C for the experimental steel.

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Influence of Mechanical Vibration Moulding Process on the Tensile Properties of TiC Reinforced LM6 Alloy Composite Castings

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.66-68.1207 ◽

2011 ◽

Vol 66-68 ◽

pp. 1207-1212 ◽

Cited By ~ 2

Author(s):

Mohd Sayuti ◽

Shamsuddin Sulaiman ◽

B.T. Hang Tuah Baharudin ◽

M.K.A.M. Arifin ◽

T.R. Vijayaram ◽

...

Keyword(s):

Tensile Strength ◽

Titanium Carbide ◽

Tensile Properties ◽

Mechanical Vibration ◽

Weight Fraction ◽

Tensile Tests ◽

Alloy Matrix ◽

Remarkable Effect ◽

Moulding Process ◽

Particulate Reinforced

Vibrational moulding process has a remarkable effect on the properties of castings during solidification processing of metals, alloys, and composites. This research paper discusses on the investigation of mechanical vibration mould effects on the tensile properties of titanium carbide particulate reinforced LM6 aluminium alloy composites processed with the frequencies of 10.2 Hz, 12 Hz and 14 Hz. In this experimental work, titanium carbide particulate reinforced LM6 composites were fabricated by carbon dioxide sand moulding process. The quantities of titanium carbide particulate added as reinforcement in the LM6 alloy matrix were varied from 0.2% to 2% by weight fraction. Samples taken from the castings and tensile tests were conducted to determine the tensile strength and modulus of elasticity. The results showed that tensile strength of the composites increased with an increase in the frequency of vibration and increasing titanium carbide particulate reinforcement in the LM6 alloy matrix.

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Mechanical, Thermal and Rheological Properties of Polyethylene-Based Composites Filled with Micrometric Aluminum Powder

Materials ◽

10.3390/ma13051242 ◽

2020 ◽

Vol 13 (5) ◽

pp. 1242

Author(s):

Olga Mysiukiewicz ◽

Paulina Kosmela ◽

Mateusz Barczewski ◽

Aleksander Hejna

Keyword(s):

Mechanical Properties ◽

Melt Flow Index ◽

Tensile Tests ◽

Mechanical Analysis ◽

Flow Index ◽

Scanning Calorimetry ◽

Metal Composites ◽

Pre Treatment ◽

The Impact ◽

Properties Of Composites

Investigations related to polymer/metal composites are often limited to the analysis of the electrical and thermal conductivity of the materials. The presented study aims to analyze the impact of aluminum (Al) filler content (from 1 to 20 wt%) on the rarely investigated properties of composites based on the high-density polyethylene (HDPE) matrix. The crystalline structure, rheological (melt flow index and oscillatory rheometry), thermal (differential scanning calorimetry), as well as static (tensile tests, hardness, rebound resilience) and dynamic (dynamical mechanical analysis) mechanical properties of composites were investigated. The incorporation of 1 and 2 wt% of aluminum filler resulted in small enhancements of mechanical properties, while loadings of 5 and 10 wt% provided materials with a similar performance to neat HDPE. Such results were supported by the lack of disturbances in the rheological behavior of composites. The presented results indicate that a significant content of aluminum filler may be introduced into the HDPE matrix without additional pre-treatment and does not cause the deterioration of composites’ performance, which should be considered beneficial when engineering PE/metal composites.

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Mechanical Properties and Microstructural Aspects of Two High-Manganese Steels with TWIP/TRIP Effects: A Comparative Study

Metals ◽

10.3390/met11010024 ◽

2020 ◽

Vol 11 (1) ◽

pp. 24

Author(s):

Matías Bordone ◽

Juan Perez-Ipiña ◽

Raúl Bolmaro ◽

Alfredo Artigas ◽

Alberto Monsalve

Keyword(s):

Mechanical Response ◽

Volume Fraction ◽

Tensile Tests ◽

Optical Microscope ◽

Chemical Compositions ◽

High Manganese ◽

Microstructural Changes ◽

Ε Martensite ◽

High Manganese Steels ◽

Manganese Steels

This article is focused on the mechanical behavior and its relationship with the microstructural changes observed in two high-manganese steels presenting twinning-induced plasticity (TWIP) and transformation-induced plasticity (TRIP), namely Steel B and Steel C, respectively. Chemical compositions were similar in manganese, but carbon content of Steel B approximately doubles Steel C, which directly impacted on the stacking fault energy (SFE), microstructure and mechanical response of each alloy. Characterization of as-cast condition by optical microscope revealed a fully austenitic microstructure in Steel B and a mixed microstructure in Steel C consisting of austenite grains and thermal-induced (εt) martensite platelets. Same phases were observed after the thermo-mechanical treatment and tensile tests, corroborated by means of X-Ray Diffraction (XRD), which confirms no phase transformation in Steel B and TRIP effect in Steel C, due to the strain-induced γFCC→εHCP transformation that results in an increase in the ε-martensite volume fraction. Higher values of ultimate tensile strength, yield stress, ductility and impact toughness were obtained for Steel B. Significant microstructural changes were revealed in tensile specimens as a consequence of the operating hardening mechanisms. Scanning Electron Microscopy (SEM) observations on the tensile and impact test specimens showed differences in fracture micro-mechanisms.

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