Thermal and mechanical properties of cyanate ester resin modified with acid-treated multiwalled carbon nanotubes

2016 ◽  
Vol 30 (1) ◽  
pp. 38-46 ◽  
Author(s):  
Hongfeng Li ◽  
Jiyou Gu ◽  
Changwei Liu ◽  
Dezhi Wang ◽  
Chunyan Qu
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Plane Strain ◽  
Multiwalled Carbon Nanotubes ◽  
Cyanate Ester ◽  
Resin Matrix ◽  
Resin System ◽  
Multiwalled Carbon ◽  
Cyanate Ester Resin ◽  
Modified Resin

Multiwalled carbon nanotubes (MWCNTs) that were treated with mixed acids were used to reinforce the cyanate ester resin. Meanwhile, the relationship among structure, morphology, and property of the modified resin was investigated. The treated MWCNTs were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis, and X-ray photoelectron spectroscopy (XPS). The XPS results showed that the oxygen content in the treated MWCNTs was higher than that of untreated MWCNTs and the FTIR results indicated the presence of oxygen-containing functional groups on the treated MWCNTs. The microstructure of the resin was characterized by scanning electron microscopy and transmission electron microscopy. The results showed that the dispersion properties of the treated MWCNTs in the resin matrix were improved and compared with the untreated analogue. Addition of MWCNTs to the resin had little effect on the thermodynamic properties of the resin system. Upon addition of 0.8 wt% of MWCNTs to the resin, the glass transition temperature of the cured resin changed from 298°C to 285°C, maintaining a relatively high value. For the resins containing 0.6 wt% of treated MWCNTs, the plane strain critical stress intensity factor and plane strain critical strain energy release rate in the system were determined to be 1.39 Pa·m0.5 and 364 J m−2, respectively, and the fracture toughness is increased by 45.7 and 76.0%, respectively. Furthermore, the modified resin system exhibits excellent toughness and thermal properties. Therefore, the modified resin may be suitable for future applications involving high performance composites and adhesives.

SILK FIBROIN FILMS CRYSTALLIZED BY MULTIWALLED CARBON NANOTUBES

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1807-1812 ◽  
Author(s):  
H.-S. KIM ◽  
W.-I. PARK ◽  
Y. KIM ◽  
H.-J. JIN
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Silk Fibroin ◽  
Composite Films ◽  
Tensile Modulus ◽  
Multiwalled Carbon ◽  
Regenerated Silk Fibroin ◽  
Silk Films ◽  
Β Sheet

Silk films prepared from regenerated silk fibroin are normally stabilized by β-sheet formation through the use of solvents (methanol, water etc.). Herein, we report a new method of preparing water-stable films without a β-sheet conformation from regenerated silk fibroin solutions by incorporating a small amount (0.2 wt%) of multiwalled carbon nanotubes (MWCNTs). To extend the biomaterial utility of silk proteins, forming water-stable silk-based materials with enhanced mechanical properties is essential. Scanning electron microscopy and transmission electron microscopy were used to observe the morphology of the MWCNT-incorporated silk films. The wide-angle X-ray diffraction provided clear evidence of the crystallization of the silk fibroin induced by MWCNT in the composite films without any additional annealing processing. The tensile modulus and strength of the composite films were improved by 108% and 51%, respectively, by the incorporation of 0.2 wt% of MWCNTs, as compared with those of the pure silk films. The method described in this study will provide an alternative means of crystallizing silk fibroin films without using an organic solvent or blending with any other polymers, which may be important in biomedical applications.

scholarly journals Surface Properties of Silica–MWCNTs/PDMS Composite Coatings Deposited on Plasma Activated Glass Supports

2021 ◽  
Vol 11 (19) ◽  
pp. 9256
Author(s):  
Michał Chodkowski ◽  
Iryna Ya. Sulym ◽  
Konrad Terpiłowski ◽  
Dariusz Sternik
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Multiwalled Carbon Nanotubes ◽  
Composite Coatings ◽  
Thermal Analyses ◽  
Sol Gel ◽  
Visible Range ◽  
Multiwalled Carbon ◽  
Scanning Electron

In this paper, we focus on fabrication and physicochemical properties investigations of silica–multiwalled carbon nanotubes/poly(dimethylsiloxane) composite coatings deposited on the glass supports activated by cold plasma. Air or argon was used as the carrier gas in the plasma process. Multiwalled carbon nanotubes were modified with poly(dimethylsiloxane) in order to impart their hydrophobicity. The silica–multiwalled carbon nanotubes/poly(dimethylsiloxane) nanocomposite was synthesized using the sol–gel technique with acid-assisted tetraethyl orthosilicate hydrolysis. The stability and the zeta potential of the obtained suspension were evaluated. Then, the product was dried and used as a filler in another sol–gel process, which led to the coating application via the dip-coating method. The substrates were exposed to the hexamethyldisilazane vapors in order to improve their hydrophobicity. The obtained surfaces were characterized by the wettability measurements and surface free energy determination as well as optical profilometry, scanning electron microscopy, and transmittance measurements. In addition, the thermal analyses of the carbon nanotubes as well as coatings were made. It was found that rough and hydrophobic coatings were obtained with a high transmittance in the visible range. They are characterized by the water contact angle larger than 90 degrees and the transmission at the level of 95%. The X-ray diffraction studies as well as scanning electron microscopy images confirmed the chemical and structural compositions of the coatings. They are thermally stable at the temperature up to 250 °C. Moreover, the thermal analysis showed that the obtained composite material has greater thermal resistance than the pure nanotubes.

Covalent functionalization of multiwalled carbon nanotubes with super-hydrophobic property

2018 ◽  
Vol 38 (6) ◽  
pp. 537-543 ◽  
Author(s):  
Minghua Li ◽  
Zhiyuan Xu ◽  
Jinyang Chen ◽  
San-E Zhu
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Chemical Interaction ◽  
Hydrophobic Property ◽  
Covalent Functionalization ◽  
Multiwalled Carbon ◽  
Surface Contact Angle ◽  
Loading Ratio ◽  
Functionalized Mwcnts

AbstractSurface covalent functionalization of multiwalled carbon nanotubes (MWCNTs) is carried out by coupling of isocyanate-decorated MWCNTs with hydroxyl-terminated polydimethylsiloxane (HTPS), resulting in the formation of functionalized MWCNTs. Thermogravimetry analysis (TGA) of functionalized MWCNTs-1,2,3 exhibits the similar peaks in the temperature range of 200–500°C, which all correspond to the degradation of chemically grafted polyurethane on the nanotube surface. Field emission scanning electron microscopy (FE-SEM) reveals that as the polyurethane grafted onto the surface of MWCNTs loading ratio increased, the surface roughness of the MWCNTs is reduced. The chemical interaction of HTPS with isocyanate-decorated nanotube surface using the grafting-to strategy in a one-step process is confirmed by Fourier transform infrared spectroscopy (FT-IR). The surface contact angle of MWCNTs-3 with the largest content of polyurethane reached 171°, indicating that the surface covered with low surface energy polyurethane shows a super-hydrophobic property. The good dispersion of polyurethane-functionalized MWCNT-3, particularly at high content in the NR nanocomposites, is evidenced from transmission electron microscopy (TEM).

Morphology and thermal properties of nanocomposites based on chiral poly(ester-imide) matrix reinforced by vitamin B1 functionalized multiwalled carbon nanotubes

2016 ◽  
Vol 51 (16) ◽  
pp. 2291-2300 ◽  
Author(s):  
Shadpour Mallakpour ◽  
Samaneh Soltanian
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Multiwalled Carbon Nanotubes ◽  
Vitamin B1 ◽  
Multiwalled Carbon ◽  
Transmission Electron ◽  
Functionalized Multiwalled Carbon Nanotubes ◽  
Scanning Electron

Chemical functionalization of carboxylated multiwalled carbon nanotubes with vitamin B1 was carried out under ultrasonic irradiation. The functionalized nanotubes were embedded in a chiral and biodegradable poly(ester-imide) to prepare multiwalled carbon nanotubes reinforced polymer nanocomposites. Optically active poly(ester-imide) was synthesized by step-growth polymerization of aromatic diol and amino acid based diacid. The vitamin B1 functionalized multiwalled carbon nanotubes and the resulting nanocomposites were examined using Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, transmission electron microscopy, and field-emission scanning electron microscopy. Thermogravimetric analysis results indicated that temperature at 10% weight loss was increased from 409℃ for pure PEI to 419℃, 427℃, and 430℃ for nanocomposites containing 5%, 10%, and 15% functionalized multiwalled carbon nanotubes, respectively. The Fourier-transform scanning electron microscopy and transmission electron microscopy images exhibited that the functionalized multiwalled carbon nanotubes were separated individually and enwrapped by polymer chains.

scholarly journals One-Step Route to Synthesize Multiwalled Carbon Nanotubes Filled with MgO Nanorods

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Jing Liu ◽  
Chunli Guo ◽  
Xiaojian Ma ◽  
Changhui Sun ◽  
Fengxia Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Transmission Electron Microscopy ◽  
Multiwalled Carbon Nanotubes ◽  
Multiwalled Carbon ◽  
X Ray ◽  
Transmission Electron ◽  
Good Crystallinity ◽  
One Step ◽  
Walled Cnts

Multiwalled carbon nanotubes filled with MgO nanorods were synthesized through the reaction of ethanol and Mg powder in the presence ofTiO2at 400C°. X-ray powder diffraction indicated that the sample was composed of graphite and cubic MgO. Transmission electron microscopy studies showed that multi-walled CNTs with the outer diameters of 70–130 nm were filled with discontinuous MgO nanorods whose diameter was in the range of 25–40 nm. The ratios of the band intensities(ID/IG=0.67)in Raman spectrum implied that carbon nanotubes had good crystallinity. The influence of correlative reaction factors on the morphology of the sample and the possible formation mechanism were discussed.

Experimental and theoretical studies on the mechanism for chemical oxidation of multiwalled carbon nanotubes

RSC Advances ◽  
2014 ◽  
Vol 4 (55) ◽  
pp. 28826-28831 ◽  
Author(s):  
B. M. Maciejewska ◽  
M. Jasiurkowska-Delaporte ◽  
A. I. Vasylenko ◽  
K. K. Kozioł ◽  
S. Jurga
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Transmission Electron Microscopy ◽  
Raman Spectroscopy ◽  
Multiwalled Carbon Nanotubes ◽  
Chemical Oxidation ◽  
Theoretical Studies ◽  
Multiwalled Carbon ◽  
Transmission Electron ◽  
Experimental And Theoretical Studies

In this study, the oxidation of multiwalled carbon nanotubes (MWCNTs) sonicated and/or refluxed in acids (H2SO4/HNO3) was investigated using a combination of high-resolution transmission electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, and ab initio computational methods.

Multiwalled Carbon Nanotubes-Incorporated Polyurethane Nanocomposites

2008 ◽  
Vol 47-50 ◽  
pp. 1109-1112
Author(s):  
Ye Seul Kim ◽  
Rira Jung ◽  
Hun Sik Kim ◽  
Hyoung Joon Jin
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Multiwalled Carbon Nanotubes ◽  
Physical And Mechanical Properties ◽  
High Reactivity ◽  
Multiwalled Carbon ◽  
Contact Points ◽  
Conductive Fillers

Polyurethane was used as adhesive due to high reactivity, high flexibility, and mechanical properties. Electrically conductive adhesives (ECAs) are an alternative to tin-lead solder in order to provide conductive paths between two electrical device components, which typically consist of a polymeric resin that contributes physical and mechanical properties, and conductive fillers. However, ECAs have low electrical conductivity and unstable network due to large contact points of the few micrometer-sized metal particles. In order to overcome these restrictions, multiwalled carbon nanotubes (MWCNTs) with high aspect ratio and smaller nanometer scale can be used as conductive fillers. In this study, ECAs were based on polyurethane filled with two kinds of fillers, raw MWCNTs and acid treated MWCNTs, respectively. Electrical conductivity was measured by using four-point probe. Morphology and dispersibility of fillers were observed by scanning electron microscopy and transmission electron microscopy.

scholarly journals CVD Synthesis of Hierarchical 3D MWCNT/Carbon-Fiber Nanostructures

2008 ◽  
Vol 2008 ◽  
pp. 1-7 ◽  
Author(s):  
Toma Susi ◽  
Albert G. Nasibulin ◽  
Hua Jiang ◽  
Esko I. Kauppinen
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Carbon Fiber ◽  
Multiwalled Carbon Nanotubes ◽  
Carbon Fibers ◽  
Gas Flow ◽  
Carbon Precursor ◽  
Optimal Temperature ◽  
Multiwalled Carbon ◽  
Cvd Synthesis

Multiwalled carbon nanotubes (MWCNTs) were synthesized by CVD on industrially manufactured highly crystalline vapor-grown carbon fibers (VGCFs). Two catalyst metals (Ni and Fe) and carbon precursor gases (C2H2and CO) were studied. The catalysts were deposited on the fibers by sputtering and experiments carried out in two different reactors. Samples were characterized by electron microscopy (SEM and TEM). Iron was completely inactive as catalyst with bothC2H2and CO for reasons discussed in the paper. The combination of Ni andC2H2was very active for secondary CNT synthesis, without any pretreatment of the fibers. The optimal temperature for CNT synthesis was750∘C, with total gas flow of 650 cm3min⁡−1ofC2H2,H2, and Ar in 1.0:6.7:30 ratio.

scholarly journals Bromate Removal from Water Using Doped Iron Nanoparticles on Multiwalled Carbon Nanotubes (CNTS)

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Aasem Zeino ◽  
Abdalla Abulkibash ◽  
Mazen Khaled ◽  
Muataz Atieh
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Adsorption Capacity ◽  
Multiwalled Carbon Nanotubes ◽  
Iron Nanoparticles ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Scanning Calorimetry ◽  
Multiwalled Carbon ◽  
Transmission Electron

The raw carbon nanotubes (CNTs) were prepared by the floating catalyst chemical vapor deposition method. The raw carbon nanotubes were functionalized, impregnated with iron nanoparticles, and characterized using high resolution transmission electron microscopy (HRTEM), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), and thermogravimetric analysis (TGA). The three types of these multiwalled carbon nanotubes were applied as adsorbents for the removal of bromate from drinking water. The effects of the pH, the concentration ofBrO3-anion, the adsorbent dose, the contact time, and the coanions on the adsorption process have been investigated. The results concluded that the highest adsorption capacities were 0.3460 and 0.3220 mg/g through using CNTs-Fe and raw CNTs, respectively, at the same conditions. The results showed that the CNTs-Fe gives higher adsorption capacity compared with the raw CNTs and the functionalized CNTs. The presence of nitrate (NO3-) in the solution decreases the adsorption capacity of all CNTs compared with chloride (Cl-) associated with pH adjustment caused by nitric acid or hydrochloric acid, respectively. However, the adsorption of all MWNCTs types increases as the pH of solution decreases.

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