Catalytic growth of multi-walled carbon nanotubes using NiFe2O4 nanoparticles and incorporation into epoxy matrix for enhanced mechanical properties

2016 ◽  
Vol 36 (1) ◽  
pp. 53-64 ◽  
Author(s):  
Hassan Javed ◽  
Mohammad Islam ◽  
Nasir Mahmood ◽  
Amine Achour ◽  
Asad Hameed ◽  
...  

Abstract Mechanical properties of multi-walled carbon nanotubes (CNT) reinforced epoxy nanocomposites, with and without any structural defect, were investigated using different weight percent values of pristine and covalently functionalized CNT. First, nickel ferrite (NiFe2O4) catalyst nanoparticles were prepared using the co-precipitate method followed by CNT growth via chemical vapor deposition, using acetylene as carbon feedstock. Through a combination of magnetic stirring and ultrasound vibration treatments in acetone, pristine, COOH-, or NH2-functionalized CNTs at 0.15, 0.60, 1.10 and 1.50 wt% were added to the Epon 828 epoxy. During each stage, extensive materials characterization was carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA)/differential thermal analysis (DTA) techniques. Tensile testing of the specimens revealed an increase in the elastic modulus and tensile strength values with maximum increase registered in the case of nanocomposites made from 1.1 wt% CNT-NH2 (+73%) or CNT-COOH (67%) addition. The energy absorbed during impact testing also increased by 86% upon addition of 1.50 wt% CNT-NH2. The presence of a small notch in the nanocomposite specimens yielded superior mechanical properties to those of the neat epoxy. Such enhancement in the mechanical properties can be attributed to better CNT dispersion in the nanocomposites and good interfacial bonding, as confirmed from microstructural examination of the fractured surfaces.

2015 ◽  
Vol 15 (10) ◽  
pp. 8086-8092 ◽  
Author(s):  
Jeong Hee Yang ◽  
Jae Yun Lee ◽  
In-Joo Chin

Polylactide (PLA) nanocomposites with multi-walled carbon nanotubes (MWNTs) grafted with poly(L-lactide) or poly(D-lactide) were prepared by solution casting, and their thermal and mechanical properties were evaluated. MWNTs containing hydroxyl groups were treated by ring-opening polymerization of either L-lactide or D-lactide. Fourier transform infrared spectroscopy confirmed that the MWNT surfaces had been modified by the PLLA or PDLA chains. The thermal properties were measured by differential scanning calorimetry and thermogravimetric analysis. The mechanical properties were examined using a universal testing machine. The morphology of the fractured surfaces of the PLA nanocomposites was observed by scanning electron microscopy and transmission electron microscopy. PDLA-g-MWNTs were dispersed more uniformly compared to PLLA-g-MWNTs in the PLA matrix. The incorporation of PDLA-g-MWNTs greatly improved the tensile strength of the nanocomposites regardless of the contents. Thermal analysis revealed different characteristics at specific composites depending on the type of modification.


2013 ◽  
Vol 669 ◽  
pp. 55-62 ◽  
Author(s):  
Yi Na Xiong ◽  
Xiao Hua Chen ◽  
Qun Huang ◽  
Long Shan Xu

Polypropylene (PP)-coated multi-walled carbon nanotubes (MWNTs) composite with MWNTs exceptional alignment dispersed and improved mechanical properties was prepared with maleic anhydride (MAH) as a compatibilizer and poly (butyl methacrylate) (PBMA) as a binding. Scanning electron microscopy (SEM) results showed that MWNTs within composite were aligned without aggregation and the oriented MWNTs were connected by matrix. High-resolution transmission electron microscopy (HRTEM) results demonstrated that the nanotubes were densely coated with a PP layer. Infrared spectroscopy (IR) results revealed that there was covalently linkage of MWNTs with PP via MAH. The interactions between MWNTs-PP and MWNTs-PBMA induced orientation of MWNTs. The improved mechanical properties of PP - coated MWNTs composite was also shown.


2008 ◽  
Vol 8 (5) ◽  
pp. 2671-2675 ◽  
Author(s):  
Mei-Hui Tsai ◽  
Dong-Sen Chen ◽  
Pei-Chun Chiang ◽  
Hsin-Chuan Lin ◽  
Jih-Mirn Jehng

The polyimide/multi-walled carbon nanotubes (PI/MWNTs) nanocomposite film has been successfully synthesized in this study. The source of MWNTs is prepared by chemical vapor deposition (CVD) method. Then the MWNTs are washed with acid for purification before being added into the polymer matrix. The acid-modified procedure aids in dispersing MWNTs in N,N-dimethylacetamide (DMAc) solvent. Based on the results of field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), the MWNTs are embedded in PI and well-dispersed within the PI matrix. The dynamic mechanical analysis (DMA) shows that the storage modulus of nanocomposite film is increased by 68% with the addition of 1 wt% MWNTs into PI. The nanocomposite films start to decompose at or above 400 °C and lose 5% of its weight at 545 °C according to thermogravimetric analysis (TGA). Meanwhile, the electrical conductivity of the nanocomposite film with 3 wt% MWNTs, is raised more than 10 orders of magnitude from 10−15 to 10−5 S/cm.


2007 ◽  
Vol 121-123 ◽  
pp. 101-104
Author(s):  
Xiao Ping Zou ◽  
H. Abe ◽  
Toru Shimizu ◽  
A. Ando ◽  
H. Tokumoto ◽  
...  

A simple thermal chemical vapor deposition (STCVD) growth technique of multi-walled carbon nanotubes (MWCNTs) is present. Carbon nanotube film was synthesized on the Pt plate substrates by pyrolysis of ethyl alcohol as carbon source at lower reaction temperature at atmospheric pressure by using simple apparatus. The as-synthesized MWCNTs were characterized by both scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The electrical property of an individual MWCNT was evaluated by I-V measurement. The electrical resistance of single MWCNT is about 450 k/ in linear region under bias voltage between 2 to 4 V. It can undergo a large current of 6 2A at 4 V


Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 224 ◽  
Author(s):  
Jung-Eun Park ◽  
Yong-Seok Jang ◽  
Tae-Sung Bae ◽  
Min-Ho Lee

Multi walled carbon nanotubes-hydroxyapatite (MWCNTs-HA) with various contents of MWCNTs was synthesized using the sol-gel method. MWCNTs-HA composites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). HA particles were generated on the surface of MWCNT. Produced MWCNTs-HA nanocomposites were coated on pure titanium (PT). Characteristic of the titanium coated MWCNTs-HA was evaluated by field-emission scanning electron microscopy (FE-SEM) and XRD. The results show that the titanium surface was covered with MWCNTs-HA nanoparticles and MWCNTs help form the crystalized hydroxyapatite. Furthermore, the MWCNTs-HA coated titanium was investigated for in vitro cellular responses. Cell proliferation and differentiation were improved on the surface of MWCNT-HA coated titanium.


2017 ◽  
Vol 54 (1) ◽  
pp. 41-44 ◽  
Author(s):  
Maria Adina Vulcan ◽  
Celina Damian ◽  
Paul Octavian Stanescu ◽  
Eugeniu Vasile ◽  
Razvan Petre ◽  
...  

This paper deals with the synthesis of polyurea and its use as polymer matrix for nanocomposites reinforced with multi-walled carbon nanotubes (MWCNT). Two types of materials were obtained during this research, the first cathegory uses the polyurea as matrix and the second one uses a mixture between epoxy resin and polyurea. The nanocomposites were characterized by Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM) and Tensile Tests .The elastomeric features of nanocomposites were highlighted by the results which showed low value of Tg. Also higher thermal stability with ~40oC compared with commercial products (M20) were observed, but lower mechanical properties compared to neat polyurea.


2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Shuang-Xi Xue ◽  
Qin-Tao Li ◽  
Xian-Rui Zhao ◽  
Qin-Yi Shi ◽  
Zhi-Gang Li ◽  
...  

Multi-walled carbon nanotubes (MWCNTs) were irradiated by 1.2 keV Ar ion beams for 15–60 min at room temperature with current density of 60 µA/cm2. The morphology and microstructure are investigated by scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that carbon nanofibers are achieved after 60 min ion irradiation and the formation of carbon nanofibers proceeds through four periods, carbon nanotubes—amorphous carbon nanowires—carbon nanoparticles along the tube axis—conical protrusions on the nanoparticles surface—carbon nanofibers from the conical protrusions.


2008 ◽  
Vol 14 (S2) ◽  
pp. 304-305
Author(s):  
M Ellis ◽  
T Jutarosaga ◽  
S Smith ◽  
Y Wei ◽  
S Seraphin

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008


2015 ◽  
Vol 19 (04) ◽  
pp. 622-630 ◽  
Author(s):  
Saeed Rayati ◽  
Zahra Sheybanifard

In the present work, oxidation of alkenes with hydrogen peroxide in the presence of meso-tetrakis(4-hydroxyphenyl)porphyrinatoiron(III) chloride supported onto surface of functionalized multi-wall carbon nanotubes (FMWCNT), [ Fe ( THPP ) Cl@MWCNT ], is reported. The simple heterogeneous catalyst was characterized by FT-IR spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and also thermal analysis. The amount of the catalyst loaded on the nanotubes was determined by atomic absorption spectroscopy. This heterogeneous catalyst proved to be an efficient and green catalyst and was successfully able to activate hydrogen peroxide without any additive toward the oxidation of alkenes in ethanol as a green solvent. Performance of the catalyst in oxidation of various alkenes was inspected under reflux, ultrasonic irradiation and mechanical stirring. Moreover, the catalyst can be reused several times under similar conditions.


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