Plain para-aramid/phenolic multiwall carbon nanotubes prepreg/multistiched preform composites: Experimental characterization of mode-I toughness

2018 ◽  
Vol 53 (13) ◽  
pp. 1847-1864 ◽  
Author(s):  
K Bilisik ◽  
E Sapanci
Keyword(s):  
Fracture Toughness ◽  
Multiwall Carbon Nanotubes ◽  
Beam Theory ◽  
Mode I ◽  
Multiwall Carbon Nanotube ◽  
Axial Filament ◽  
Pull Out ◽  
Fiber Bridging ◽  
Nanotube Composites ◽  
Multiwall Carbon

The fracture toughness (mode-I) properties of nanostitched para-aramid/phenolic multiwall carbon nanotube prepreg composites were investigated. The fracture toughness (GIC) of the stitching and nanostitched composites showed 42-fold and 41-fold (beam theory), 18-fold and 21-fold (modified beam theory) increase compared to the control, respectively. The prepreg para-aramid stitching yarn and nanostitched yarn were dominant parameters. The toughness resistance to arrest crack growth in the nanostitched composite was primarily due to nanostitching fiber bridging and pull-out, and was secondarily due to nanotubes and biaxial fiber bridging and pull-out. The failed surfaces of the nanostitched and stitching composites had tensile filament failures in the aramid stitching fibers where filament/matrix/nanotube debonding and axial filament fibrillar splitting were found. The results indicated that stitching yarn and the nanotubes arrested the crack propagation. Therefore, the nanostitched and stitched para-aramid/phenolic composites displayed a better damage resistance performance compared to those of the control or nanotube composites.

Seawater effects on interlaminar fracture toughness of glass fiber/epoxy laminates modified with multiwall carbon nanotubes

2020 ◽  
pp. 002199832095078
Author(s):  
Julio A Rodríguez-González ◽  
Carlos Rubio-González
Keyword(s):  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Glass Fiber ◽  
Composite Laminates ◽  
Multiwall Carbon Nanotubes ◽  
Mode I ◽  
Mode Ii ◽  
Interlaminar Fracture Toughness ◽  
Multiscale Composite ◽  
Multiwall Carbon

In this work, the effect of seawater ageing on mode I and mode II interlaminar fracture toughness ([Formula: see text] and [Formula: see text]) of prepreg-based woven glass fiber/epoxy laminates with and without multiwall carbon nanotubes (MWCNTs) has been investigated. The first part of the investigation reports the moisture absorption behavior of multiscale composite laminates exposed to seawater ageing for ∼3912 h at 70 °C. Then, the results of mode I and mode II fracture tests are presented and a comparison of [Formula: see text] and [Formula: see text] for each type of material group and condition is made. Experimental results showed the significant effect of seawater ageing on [Formula: see text] of multiscale composite laminates due to matrix plasticization and fiber bridging. The improvement in [Formula: see text] of the wet glass fiber/epoxy laminate was about 50% higher than that of the neat laminate (without MWCNTs) under dry condition. It was also found that the presence of MWCNTs into composite laminates promotes a moderate increase (8%) in their [Formula: see text] as a result of the additional toughening mechanisms induced by CNTs during the delamination process. Scanning electron microscopy analysis conducted on fracture surface of specimens reveals the transition from brittle (smooth surface) to ductile (rough surface) in the morphology of composite laminates due to the influence of seawater ageing on the polymeric matrix and fiber/matrix interface.

Preparation and Properties of PP/PLA /Multiwall Carbon Nanotube Composites Filaments Obtained by Melt Compounding

2009 ◽  
Vol 620-622 ◽  
pp. 465-468 ◽  
Author(s):  
Jing Zou ◽  
Ying Chen Zhang ◽  
J.N. Huang ◽  
Hong Yan Wu ◽  
Y.P. Qiu
Keyword(s):  
Multiwall Carbon Nanotubes ◽  
Atmospheric Pressure Plasma ◽  
Tensile Tests ◽  
Multiwall Carbon Nanotube ◽  
Test Results ◽  
Dsc Studies ◽  
Melt Compounding ◽  
Nanotube Composites ◽  
Moderate Change ◽  
Multiwall Carbon

The present paper studied the thermal and mechanical properties of atmospheric pressure plasma jet (APPJ) treated multiwall carbon nanotubes/polypropylene/polylactic acid nanocomposite filaments. The experiments included tensile tests, differential scanning calorimeter (DSC), Scanning electron microscopy (SEM) experiments. DSC studies showed that there were a distinct shift in Tg and a relatively moderate change in Tm for different systems. The activation volumes of CNTs/PP/PLA nanocomposite filaments have been calculated to describe strain rate sensitive behavior of CNTs/PP/PLA nanocomposite filaments by following Eyring’s equation based on the tensile test results.

scholarly journals Raman Features of Linear-Carbon-Chain and Multiwall Carbon Nanotube Composites

2021 ◽  
Author(s):  
Yahachi Saito ◽  
Koji Asaka
Keyword(s):  
Arc Discharge ◽  
Resonance Effect ◽  
Low Frequency ◽  
Multiwall Carbon Nanotubes ◽  
Carbon Chain ◽  
Multiwall Carbon Nanotube ◽  
Carbon Chains ◽  
Structural And Electronic Properties ◽  
Nanotube Composites ◽  
Multiwall Carbon

Structural and electronic properties of multiwall carbon nanotubes (MWCNTs) containing linear carbon chains (LCCs), which were produced by arc-discharge between carbon electrodes in an atmospheric pressure, have been studied by Raman spectroscopy as well as electron microscopy. Spectral features of Raman scattering from the LCC/MWCNT composites were reviewed with emphasis on the spectra obtained with a low energy photon (1.58 eV, 785 nm) excitation, which have not been described in detail so far. Characteristic frequencies of LCC stretching modes with the 785 nm laser excitation are observed at around 1740, 1759, and 1789 cm−1. In a low frequency region, radial breathing modes (RBMs) of the innermost tube within MWCNTs are observed at specific frequencies of 293, 341, 402, and 510 cm−1; the highest RBM frequency is tentatively assigned to a tube with the chiral index (4,3), whose diameter is expected to 0.50 nm. LCC bands observed with various excitation wavelengths from 488 to 785 nm show that the band consists of several peaks, and the relative intensities of constituent peaks change with the excitation wavelengths due to the resonance effect; the higher the excitation photon energy is, the higher the intensity of high-frequency LCC modes.

Mode-II toughness of nanostitched carbon/epoxy multiwall carbon nanotubes prepreg composites: Experimental investigation by using end notched flexure

2019 ◽  
Vol 53 (28-30) ◽  
pp. 4249-4271 ◽  
Author(s):  
Kadir Bilisik ◽  
Gulhan Erdogan ◽  
Erdal Sapanci ◽  
Sila Gungor
Keyword(s):  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Multiwall Carbon Nanotubes ◽  
Fold Increase ◽  
Woven Fabric ◽  
Woven Composites ◽  
Mode Ii ◽  
Stick Slip ◽  
Pull Out ◽  
Multiwall Carbon

The mode-II interlaminar fracture toughness properties following the end notched flexure method of nanostitched carbon/epoxy nanoprepreg composites were studied. The fracture toughness (GIIC) of the nanostitched and stitched composites showed 3.4 fold and 2.7 fold increase compared to the control, respectively. Thus, the nanostitching improved the mode-II toughness of all the carbon/epoxy composites with regard to the nano, and base composites. It was assumed that the type of stitch fiber as well as fabric pattern, in particular prepreg carbon stitching fiber and satin prepreg woven fabric, was effective. The basic mechanism for the enhancement of the GIIC toughness in the nanostitched composite was the interlaminar resin layer failure especially as a form of shear hackle marks where nanostitching arrested the delamination in the stitching zone during crack propagations. Multiwall carbon nanotubes in the matrix and filament also mitigated the stress concentration probably as an outline of debonding/pull-out/stick-slip/friction. Therefore, nanostitched as well as stitched carbon/epoxy woven composites exhibited improved damage tolerance performance with regard to the base composites.

The Humidity Sensitive Behavior of Poly(Ethyleneimine)/Multiwall Carbon Nanotube Composite Films

2012 ◽  
Vol 531-532 ◽  
pp. 588-591
Author(s):  
Tao Zhu ◽  
Guang Zhong Xie ◽  
Ya Dong Jiang ◽  
Jian Liao ◽  
Hui Ling Tai
Keyword(s):  
Carbon Nanotube ◽  
Relative Humidity ◽  
Composite Films ◽  
Multiwall Carbon Nanotube ◽  
Sensing Material ◽  
Nanotube Composites ◽  
Interdigitated Microelectrode ◽  
Carbon Nanotube Composite ◽  
Multiwall Carbon ◽  
Sensitive Behavior

In this paper, a novel humidity sensor based on polymer-carbon nanotube composites was prepared and characterized. Two different methods were adopted to fabricate the humidity-sensing film for these sensors. The surface of the films was observed by a scanning electron microscope (SEM). The sensing material made up of poly(ethyleneimine) and multiwall carbon nanotube was sprayed on the interdigitated microelectrode pairs(IDTs). The resistance between the two electrodes was measured at different relative humidity levels at 19°C. The data shows that the resistance increases with the rise of the relative humidity over the range of 5-90% RH and that, the resistance increases almost linearly in the range of 5-71% RH. The response of the sensors to NO2 and NH3 were also examined, and the results reveal that the sensor is not sensitive to both of them.

Electroless Coating of Silver on Multiwall Carbon Nanotubes

2012 ◽  
Vol 710 ◽  
pp. 774-779
Author(s):  
Niraj Nayan ◽  
S.V.S. Narayana Murty ◽  
S.C. Sharma ◽  
K. Sreekumar ◽  
Parameshwar Prasad Sinha
Keyword(s):  
Carbon Nanotubes ◽  
Surface Modification ◽  
Multiwall Carbon Nanotubes ◽  
Activation Process ◽  
Multiwall Carbon Nanotube ◽  
Effective Utilization ◽  
Electroless Coating ◽  
Silver Matrix ◽  
Electrical Brush ◽  
Multiwall Carbon

Silver reinforced with carbon nanotubes, instead of graphite, would increase both the electrical conductivity, hardness and wear resistance of the electrical brush materials. The effective utilization of carbon nanotubes in the Ag/CNT composite depends strongly on its uniform distribution and strong interfacial adhesion to the silver matrix and thus demands for its surface modification. In order to carry out the surface modification of carbon nanotubes, electroless coating was given to them after liquid phase oxidation, sensitization and activation process. The room-temperature chemical treatment results in a nominally complete coating over the entire outer surface of multiwall carbon nanotube. The surface morphology of the carbon nanotubes after each step has been studied using TGA, DSC, XRD, FTIR and SEM.

Effect of Cellulose Functionalization on Thermal and Mechanical Properties of Epoxy Resin

2017 ◽  
Vol 757 ◽  
pp. 62-67 ◽  
Author(s):  
Kritsanachai Leelachai ◽  
Supissara Ruksanak ◽  
Tarakol Hongkeab ◽  
Supakeat Kambutong ◽  
Raymond A. Pearson ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Diglycidyl Ether ◽  
Cellulose Content ◽  
Thermal And Mechanical Properties ◽  
Chemical Surface ◽  
Pull Out ◽  
Fiber Bridging ◽  
Surface Modified ◽  
Modified Epoxy

In this study, diglycidyl ether of bisphenol A (DGEBA) cured cycloaliphatic polyamine was modified with functionalized celluloses for improved thermal and mechanical properties. Three different types of surface-modified cellulose, polyacrylamide-g-cellulose (PGC), aminopropoxysilane-g-cellulose (SGC), and carboxymethyl cellulose (CMC), were investigated and used as reinforcing agents in epoxy resins. The storage modulus of these modified epoxy systems was found to significantly increase with addition of cellulose fillers (up to 1 wt. % cellulose content). An improved fracture toughness (KIC) was also observed with increasing cellulose loading content with PGC and SGC. Among the surface-modified celluloses, epoxy modified with SGC was found to have the highest fracture toughness followed by PGC and CMC at 1.0 wt.% cellulose addition due to the chemical surface compatibility. The toughening mechanisms of the cellulose/epoxy composites, measured by scanning electron microscopy (SEM), revealed that fiber-debonding, fiber-bridging, and fiber-pull out were responsible for increased toughness.

Sign in / Sign up

Export Citation Format

Share Document