Interface Engineering of CNT/Polymer Nanocomposites With Tunable Damping Properties

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.

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

2018 ◽  
Vol 9 (4) ◽  
pp. 60 ◽  
Author(s):  
Giuseppe Cavallaro ◽  
Giuseppe Lazzara ◽  
Lorenzo Lisuzzo ◽  
Stefana Milioto ◽  
Filippo Parisi
Keyword(s):  
Tensile Properties ◽  
Food Packaging ◽  
Mechanical Response ◽  
Materials Science ◽  
Traction Force ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Nanocomposite Films ◽  
Preliminary Study ◽  
Mechanical Performances

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.

Mechanical response of carbon nanotube reinforced particulate composites with implications for polymer bonded explosives

2021 ◽  
pp. 002199832199086
Author(s):  
Eliseo E Iglesias ◽  
Tyler Rowe ◽  
Kyle Fernandez ◽  
Sidney Chocron ◽  
Justin Wilkerson
Keyword(s):  
Energetic Materials ◽  
Load Transfer ◽  
Mechanical Response ◽  
Particulate Composites ◽  
Binder Phase ◽  
Static Compression ◽  
Performance Effects ◽  
Polymer Bonded Explosives ◽  
Multi Walled Carbon Nanotubes ◽  
Quasi Static Compression

Modern polymer bonded explosives (PBX) are often characterized by a sensitive response to external thermomechanical insult that in some cases lead to accidental detonation. Current strategies for desensitizing PBXs come at the expense of a significant reduction in performance. A possible method for desensitizing PBX without adverse performance effects is the multifunctional tailoring of mechanical properties through strategic incorporation of multi-walled carbon nanotubes (MWCNTs) directly into the binder phase. In this work, a fabrication method is presented that produces polymer bonded simulants (PBS) of PBX that incorporate MWCNTs into the binder phase, hydroxyl-terminated polybutadiene (HTPB). These materials were characterized via microscopy and unconfined quasi-static compression testing to determine the effects of MWCNTs. Quasi-static compression showed evidence of a MWCNT induced structural skeleton effect that provided the binder with an increased strength, load transfer, and a greater ability to resist strain localizations prior to failure. These enhancements demonstrate the potential of using MWCNTs to enhance energetic materials.

Modeling of Vertically Aligned Carbon Nanotube Composites for Vibration Damping

2009 ◽  
Author(s):  
J. Y. Jia ◽  
W. H. Liao
Keyword(s):  
Load Transfer ◽  
Epoxy Composite ◽  
Maxwell Model ◽  
Stick Slip ◽  
Slip Mechanism ◽  
Nanotube Composites ◽  
Multi Walled Carbon Nanotubes ◽  
Transfer Behavior ◽  
Vertically Aligned ◽  
Walled Carbon Nanotubes

High density aligned multi-walled carbon nanotubes (CNTs) and the CNT/epoxy composite are fabricated. To predict the energy dissipation in composites with vertically aligned multi-walled CNTs, a structural damping model of composite unit cell composed of resin, sheath and nanotube is developed. In this paper, the resin is described as viscoelastic material using Maxwell model. The CNT/epoxy composite is modeled based on the “stick-slip” mechanism, to describe the load transfer behavior between the CNT and its sheath. In order to further study the damping mechanism of the CNT composite, key parameters, such as length, center-to-center distance and critical stress of CNTs that are expected to affect the composite damping performances are studied. The simulation results show that loss factor of the CNT composite with varying parameters is sensitive to the applied stress.

scholarly journals Effect of Nano-Reinforcement Topologies on the Viscoelastic Performance of Carbon Nanotube/Carbon Fiber Hybrid Composites

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1213
Author(s):  
Suma Ayyagari ◽  
Marwan Al-Haik ◽  
Yixin Ren ◽  
Dhriti Nepal
Keyword(s):  
Glass Transition ◽  
Carbon Fiber ◽  
Load Transfer ◽  
Elevated Temperatures ◽  
Hybrid Composites ◽  
Thermal Analyses ◽  
Tensile Tests ◽  
Fiber Reinforced Polymer Composites ◽  
Multi Walled Carbon Nanotubes ◽  
Tan Δ

In this investigation, multi-walled carbon nanotubes (MWCNTs) were grown over carbon fiber fabrics via a relatively nondestructive synthesis technique. The MWCNTs patches were grown into three different topologies: uniform, fine patterned and coarse patterned. Hybrid carbon fiber-reinforced polymer composites (CFRPs) were fabricated based on the patterned reinforcements. Tensile tests, dynamic mechanical thermal analyses (DMTA) and flexure load relaxation tests were carried out to investigate the effect of the patterned nano-reinforcement on the static, dynamic, glass transition, and viscoelastic performance of the hybrid composites. Results revealed that the hybrid composite based on fine-patterned topology achieved better performance over all other configurations as it exhibited about 19% improvement in both the strength and modulus over the reference composite with no MWCNTs. Additionally, the increase in glass transition for this composite was as high as 13%. The damping parameter (tan δ) was improved by 46%. The stress relaxation results underlined the importance of patterned MWCNTs in minimizing the stress decay at elevated temperatures and loading conditions. Utilizing patterned MWCNTs topology significantly reduced the stress decay percentage at the thermomechanical conditions 60 MPa and 75 °C from 16.7% to 7.8%. These improvements are attributed to both the enhanced adhesion and large interface area by placing MWCNTs and by inducing an interlocking mechanism that allows the interaction of the three constituents in load transfer, crack deflection and hindering undesired viscoelastic deformations under different thermomechanical loadings.

Ultra-Long Nanocomposite Wire Ropes

2019 ◽  
Author(s):  
Marco Marini ◽  
Michela Talò ◽  
Giulia Lanzara ◽  
Walter Lacarbonara
Keyword(s):  
Ad Hoc ◽  
Mechanical Response ◽  
Weight Ratio ◽  
High Strength ◽  
Polymer Nanocomposite ◽  
Tensile Tests ◽  
Extrusion Process ◽  
Damping Capacity ◽  
Strengthening Effect ◽  
Neat Polymer

Abstract Carbon nanotubes (CNT) represent an effective filler to be incorporated into polymer matrices. Their physical properties allow them to exert a remarkable strengthening effect, while their nano-scale leaves the polymer weight unaltered. Exploiting their high strength-to-weight ratio, CNT/polymer nanocomposites appear to be the ideal materials to be shaped as wires and fibers. In this work, an ad-hoc innovative extrusion process is proposed to fabricate though and ultralong CNT/polymer nanocomposite wires. The process parameters are finely tuned to produce nanocomposite filaments exhibiting optimized mechanical properties. Optical analyses validate the morphological features of the fabricated filaments having an averaged diameter of 350 μm. Monotonic tensile tests are carried out to investigate the mechanical response of wires with CNTs content ranging from 1 wt% to 3 wt%. Young’s modulus and tensile strength registered increments of 47% and 43%, respectively, when comparing the 3 wt% CNT nanocomposite wires with the neat polymer wires. Finally, cyclic tensile tests are employed to investigate the change in damping capacity that accompanies the integration of CNTs into the polymer matrix. Such optimized CNTs nanocomposite wires can be easily integrated into several devices or assembled into ropes and yarns with multifunctional, improved properties.

Preparation of Electron Transparent Metal-Matrix Composites

1968 ◽  
Vol 26 ◽  
pp. 334-335 ◽  
Author(s):  
M. R. Pinnel ◽  
A. Lawley
Keyword(s):  
Stainless Steel ◽  
Load Transfer ◽  
Volume Fraction ◽  
Steel Wire ◽  
Initial Step ◽  
Interfacial Region ◽  
Matrix Composites ◽  
Specific Test ◽  
The Matrix ◽  
The One

Numerous phenomenological descriptions of the mechanical behavior of composite materials have been developed. There is now an urgent need to study and interpret deformation behavior, load transfer, and strain distribution, in terms of micromechanisms at the atomic level. One approach is to characterize dislocation substructure resulting from specific test conditions by the various techniques of transmission electron microscopy. The present paper describes a technique for the preparation of electron transparent composites of aluminum-stainless steel, such that examination of the matrix-fiber (wire), or interfacial region is possible. Dislocation substructures are currently under examination following tensile, compressive, and creep loading. The technique complements and extends the one other study in this area by Hancock.The composite examined was hot-pressed (argon atmosphere) 99.99% aluminum reinforced with 15% volume fraction stainless steel wire (0.006″ dia.).Foils were prepared so that the stainless steel wires run longitudinally in the plane of the specimen i.e. the electron beam is perpendicular to the axes of the wires. The initial step involves cutting slices ∼0.040″ in thickness on a diamond slitting wheel.

scholarly journals Understanding Covalent Grafting of Nanotubes onto Polymer Nanocomposites: Molecular Dynamics Simulation Study

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2621
Author(s):  
Seunghwa Yang
Keyword(s):  
Molecular Dynamics ◽  
Load Transfer ◽  
Cell Model ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Covalent Grafting ◽  
Modelling Strategies ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
External Loads

Here, we systematically interrogate the effects of grafting single-walled (SWNT) and multi-walled carbon nanotubes (MWNT) to polymer matrices by using molecular dynamics (MD) simulations. We specifically investigate key material properties that include interfacial load transfer, alteration of nanotube properties, and dispersion of nanotubes in the polymer matrix. Simulations are conducted on a periodic unit cell model of the nanocomposite with a straight carbon nanotube and an amorphous polyethylene terephthalate (PET) matrix. For each type of nanotube, either 0%, 1.55%, or 3.1% of the carbon atoms in the outermost nanotubes are covalently grafted onto the carbon atoms of the PET matrix. Stress-strain curves and the elastic moduli of nanotubes and nanocomposites are determined based on the density of covalent grafting. Covalent grafting promotes two rivalling effects with respect to altering nanotube properties, and improvements in interfacial load transfer in the nanocomposites are clearly observed. The enhanced interface enables external loads applied to the nanocomposites to be efficiently transferred to the grafted nanotubes. Covalent functionalization of the nanotube surface with PET molecules can alter the solubility of nanotubes and improve dispersibility. Finally, we discuss the current limitations and challenges in using molecular modelling strategies to accurately predict properties on the nanotube and polymers systems studied here.

Cure and Dynamic-Mechanical Behaviors of Vinyl Ester Resinfilled with Multi-Walled Carbon Nanotubes

2010 ◽  
Vol 150-151 ◽  
pp. 1413-1416 ◽  
Author(s):  
Hong Yan Chen ◽  
Zhen Xing Kong ◽  
Ji Hui Wang
Keyword(s):  
Carbon Nanotubes ◽  
Vinyl Ester ◽  
Mechanical Response ◽  
Cure Kinetics ◽  
Crosslinking Density ◽  
Vinyl Ester Resin ◽  
Scanning Calorimetry ◽  
Dynamic Mechanical ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The cure kinetics of Derakane 411-350, a kind of vinyl ester resin, and its suspensions containing multi-walled carbon nanotubes( MWCNTs) were investigated via non-isothermal dynamic scanning calorimetry (DSC) measurements. The results showed that incorporation of MWCNTs into vinyl ester resin excessively reduces polymerization degree and crosslinking density of vinyl ester resin. For suppressing the negative effect caused by nanotubes, the higher temperature initiator combined with the initiator MEKP was used. Dynamic-mechanical Behavior testing was then carried out on the cured sample in order to relate the curing behavior of MWCNTs modified resin suspensions to mechanical response of their resulting nanocomposites. It was revealed that nanocomposites containing MWCNTs possessed larger storage modulus values as well as higher glass transition temperatures (Tg) as compared to those without MWCNTs after using mixed intiators system to improve the degree of cure.

Experimental Investigation of Morphological and Electrical Characteristics of PS/MWCNT Nanocomposite Films

2018 ◽  
Vol 915 ◽  
pp. 104-109
Author(s):  
Barış Demirbay ◽  
Şaziye Uğur
Keyword(s):  
Annealed Film ◽  
Nanocomposite Films ◽  
Electrical Characteristics ◽  
Liquid Form ◽  
Mwcnt Content ◽  
Electrical Percolation ◽  
Glass Substrates ◽  
Multi Walled Carbon Nanotubes ◽  
Electrical Percolation Threshold ◽  
Walled Carbon Nanotubes

Electrical characteristics and morphology of nanocomposite films composed of two different polystyrene (PS) latexes impregnated with multi-walled carbon nanotubes (MWCNT) in the range between 0 wt% and 20 wt% were assessed by considering photon transmission (UV-Vis) technique and electrical conductivity measurements. Emulsion polymerization technique was employed both to synthesize very fine PS particles dispersed in water and to tailor the sizes of the PS particles as 382 nm and 560 nm, respectively. PS/MWCNT nanocomposite films were obtained from the liquid form on glass substrates via drop-casting method and all they dried at 40 QUOTE C. Each dried sample was then annealed at varying temperatures between 100 QUOTE C and 250 QUOTE C for 10 min. The surface conductivity QUOTE of each annealed film at 250 QUOTE C was measured and was found to increase dramatically above a certain mass fraction of MWCNT content, QUOTE . Each set of PS/MWCNT nanocomposite film had a similar electrical percolation threshold of QUOTE =1.5 wt% as the MWCNT content and critical exponents of QUOTE were found to be 2.64 and 1.19 for 382 nm and 560 nm PS latex systems, respectively.

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

Metals ◽  
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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