Pure and doped Polyvinylidene difluoride (PVDF) films, for the detection of infrared radiation, have been well documented using the mechanism of pyroelectricity. Alternatively, the electrical properties of films made ...Pure and doped Polyvinylidene difluoride (PVDF) films, for the detection of infrared radiation, have been well documented using the mechanism of pyroelectricity. Alternatively, the electrical properties of films made from Polyvinyl Alcohol (PVA) have received considerable attention in recent years. The investigation of surface resistivities of both such films, to this point, has received far less consideration in comparison to pyroelectric effects. In this research, we report temperature dependent surface resistivity measurements of commercial, and of multiwall carbon nanotubes (MWCNT), or Ag-nanoparticle doped PVA films. Without any variation in the temperature range from 22°C to 40°C with controlled humidity, we found that the surface resistivity decreases initially, reaches a minimum, but rises steadily as the temperature continues to increase. This research was conducted with the combined instrumentation of the Keithley Model 6517 Electrometer and Keithley Model 8009 resistivity test fixture using both commercial and in-house produced organic thin films. With the objective to quantify the suitability of PVDF and PVA films as IR detector materials, when using the surface resistivity phenomenon, instead of or in addition to the pyroelectricity, surface resistivity measurements are reported when considering bolometry. We found that the surface resistivity measurements on PVA films were readily implemented.展开更多
Multi-walled carbon nanotube (MWCNT)-Fe composites were prepared via the metal organic chemical vapor deposi- tion by depositing iron pentacarbonyl on the surface of MWCNTs. The structural and morphological analyses...Multi-walled carbon nanotube (MWCNT)-Fe composites were prepared via the metal organic chemical vapor deposi- tion by depositing iron pentacarbonyl on the surface of MWCNTs. The structural and morphological analyses demonstrated that Fe nanoparticles were deposited on the surface of the MWCNTs. The electromagnetic properties of the MWCNTs were significantly changed, and the absorbing capacity evidently improved after the Fe deposition on the MWCNT surface. A minimum reflection loss of -29.4 dB was observed at 8.39 GHz, and the less than -10 dB bandwidth was about 10.6 GHz, which covered the whole X band (8.2-12.4 GHz) and the whole Ku band (12.4-18 GHz), indicating that the MWCNT-Fe composites could be used as an effective microwave absorption material.展开更多
A sensitive electroanalytical method for quantification of pheniramine in pharmaceutical formulation has been investigated on the basis of the enhanced electrochemical response at glassy carbon electrode modified with...A sensitive electroanalytical method for quantification of pheniramine in pharmaceutical formulation has been investigated on the basis of the enhanced electrochemical response at glassy carbon electrode modified with multi-walled carbon nanotubes in the presence of sodium lauryl sulfate.The experimental results suggest that the phcniramine in anionic surfactant solution exhibits electrocatalytic effect resulting in a marked enhancement of the peak current response.Peak current response is linearly dependent on the concentration of pheniramine in the range 200-1500 μg/mL with correlation coefficient 0.9987.The limit of detection is 58.31 μg/m L.The modified electrode shows good sensitivity and repeatability.展开更多
Carbon black (CB) or multi walled carbon nanotubes (MWCNT) loaded polyurethane conductive foams are used as heaters, electrodes, radar absorbers and shielding. This paper discusses the performance of an innovative fle...Carbon black (CB) or multi walled carbon nanotubes (MWCNT) loaded polyurethane conductive foams are used as heaters, electrodes, radar absorbers and shielding. This paper discusses the performance of an innovative flexible thermal radiator (FTR) constructed with CB filled or MWCNT filled conductive foam and powering electrode structure constructed with textiles manufacturing process (knitting, weaving or nonwoven). Silver (Ag) yarns are used for the powering electrodes construction. This paper discusses the construction, electro-thermal analysis, performance and applications of FTR. Also this paper compare the thermal and electrical characteristics of CB filled and MWCNT filled FTRs. The electro-thermal model is simulated by using finite element methods.展开更多
Natural rubber (NR)/multi-walled carbon nanotube (MWCNTs) composites were prepared by combining self-assembly and latex compounding techniques.The acid-treated MWCNTs (H2SO4:HNO3=3:1,volume ratio) were self-as...Natural rubber (NR)/multi-walled carbon nanotube (MWCNTs) composites were prepared by combining self-assembly and latex compounding techniques.The acid-treated MWCNTs (H2SO4:HNO3=3:1,volume ratio) were self-assembled with poly (diallyldimethylammonium chloride) (PDDA) through electrostatic adhesion.In the second assembling,NR/MWCNTs composites were developed by mixing MWCNTs/PDDA solution with NR latex.The results show that MWCNTs are homogenously distributed throughout the NR matrix as single tube and present a great interfacial adhesion with NR phase when MWCNTs contents are less than 3 wt%.Moreover,the addition of the MWCNTs brings about the remarkable enhancement in tensile strength and crosslink density compared with the NR host,and the data peak at 2 wt% MWCNTs loadings.When more MWCNTs are loaded,aggregations of MWCNTs are gradually generated,and the tensile strength and crosslink both decrease to a certain extent.展开更多
Multi-walled carbon nanotube doped silica aerogels(MWCNT-SAs) were synthesized from a wet gel of well-dispersed MWCNT by one-step solvent exchange/surface modification and ambient pressure drying(APD). Waterglass ...Multi-walled carbon nanotube doped silica aerogels(MWCNT-SAs) were synthesized from a wet gel of well-dispersed MWCNT by one-step solvent exchange/surface modification and ambient pressure drying(APD). Waterglass was employed as a precursor to prepare wet gel. The content of MWCNT varied from 0 to 15% volume by wet gel. The surface group, thermal stability and microstructure of pure silica aerogel and MWCNT-SAs were investigated by FTIR, DTA, and TEM. Experimental results show that MWCNT-SAs are hydrophobic when the temperature is below 400 ℃, MWCNT-SAs exhibit a mesoporous network structure, and they achieve the largest scale with least shrinkage and lowest density when doped with 5 vol% MWCNT.展开更多
The effect of multi-walled carbon nanotubes(MWCNTs) on the mechanical properties and microstructure of sulfur aluminate cement(SAC) composites was investigated. The dispersed MWCNTs were added into SAC in various ...The effect of multi-walled carbon nanotubes(MWCNTs) on the mechanical properties and microstructure of sulfur aluminate cement(SAC) composites was investigated. The dispersed MWCNTs were added into SAC in various weight contents.The results of mechanical properties of the MWCNTs/SAC composites indicated that the addition of 0.08 wt% MWCNTs can improve the SAC compressive strength, flexural strength, and bend-press ratio by 15.54%, 52.38%, and 31.30% at maximum, respectively. The degree of SAC hydration and porosity and pore size distribution of the matrix were measured by X-ray diffraction(XRD), thermal analysis(TG/DTG), and mercury intrusion porosimetry(MIP). Results show that the addition of MWCNTs in SAC composites can promote the hydration of SAC and the formation of C-S-H gel, reduce the porosity and refine the pore size distribution of the matrix. The microstructure was characterized by scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS). It is found that the MWCNTs have been dispersed homogeneously between the hydration products of SAC paste and act as bridges and networks between cracks and voids, which prevents the development of the cracks and transfers the load.展开更多
Amidst <span><span><span style="font-family:;" "="">the </span></span></span><span><span><span style="font-family:;" "="&...Amidst <span><span><span style="font-family:;" "="">the </span></span></span><span><span><span style="font-family:;" "="">COVID-19 pandemic, environmental problems such as ener<span>gy crisis, global warming, and contamination from pathogenic mi</span>cro-organisms <span>are still prevailed and strongly demanded progress in high</span></span></span></span><span><span><span style="font-family:;" "="">-</span></span></span><span><span><span style="font-family:;" "="">performance</span></span></span><span><span><span style="font-family:;" "=""> energy storing and anti-microbial materials. The nanocomposites are materials <span>that have earned large interest owing to their promising applications for</span> countering global issues related to sustainable energy and</span></span></span><span><span><span style="font-family:;" "=""> a</span></span></span><span><span><span style="font-family:;" "=""> flourishing environ<span>ment. Here, polypyrrole </span></span></span></span><span><span><span style="font-family:;" "="">coated</span></span></span><span><span><span style="font-family:;" "=""> hybrid nanocomposites of multi-walled</span></span></span><span><span><span style="font-family:;" "=""> carbon nanotube and cadmium sulfide quantum dots named MCP were synthe<span>sized using facile and low-cost <i>in-situ</i> oxidative polymerization method.</span> Cha<span>racterization techniques confirmed the synthesis. Electrochemical studies</span> showed that the nanocomposite <span>1-MCP<i> </i></span>showed an impressively higher super capacitance behavior in comparison to f-MWCNT, 7-MCP and 5-MCP. The improved performance of the nanocomposites was attributed mainly to the good conductivity of carbon nanotubes and polypyrrole, high surface area, and stability of the carbon nanotubes and the high electrocatalytic activity of the cadmium sulfide quantum dots. Owing to the synergistic effect of MWCNT, <span>CdS, and PPy the synthesized ternary nanocomposite also inhibited the</span> growth and multiplication of tested bacteria such as <i>S. aureus</i>, and <i>E. coli</i> completely within 24 h. On the whole, the assimilated nanocomposite MCP opens promising aspects for the development of upcoming energy storage devices and as<span style="color:red;"> </span></span></span></span><span><span><span style="font-family:;" "="">an </span></span></span><span><span><span style="font-family:;" "="">antibacterial agent.</span></span></span>展开更多
The present study aims to the development of Out of Autoclave (OoA) Carbon Fiber Reinforced Polymers (CFRPs) with increased interlaminar fracture toughness by using MWCNTs. The introduction of MWCNTs into the structur...The present study aims to the development of Out of Autoclave (OoA) Carbon Fiber Reinforced Polymers (CFRPs) with increased interlaminar fracture toughness by using MWCNTs. The introduction of MWCNTs into the structure of CFRPs has been succeeded by using carbon nanotube-enriched sizing agent for the pretreatment of the fiber preform using an in-house developed methodology that can be easily scaled up. The positive effect of the proposed methodology on the interlaminar fracture toughness of the CFRP laminate was assessed by the increase of Mode I and Mode II interlaminar fracture toughness of the composites. Different wt% MWCNTs concentrations were used (namely 0.5%, 1%, 1.5% and 2.5%). It was found that the nanomodified composites exhibit a significant increase of the interlaminar critical strain energy release rate GIC and GIIC of the order of 103% and 62% respectively, in the case of 1.5 wt% MWCNTs weight content. Scanning Electron Microscopy (SEM) of the fracture surfaces of CFRP samples revealed the contribution and the associated synergistic mechanisms of MWCNTs to the increase of the crack propagation resistance in the case of nano-modified CFRPs compared to the reference material.展开更多
This paper used a new approach of preparing poly-composites by covalent linkage between the MWCNT’s by imine group. The Poly (Imine)/MWCNT Composite was synthesized by the solution blending method from reacted amino ...This paper used a new approach of preparing poly-composites by covalent linkage between the MWCNT’s by imine group. The Poly (Imine)/MWCNT Composite was synthesized by the solution blending method from reacted amino multi-walled carbon nanotubes (MWCNT-NH2) with Terephthalaldehyde (TPAL). The obtained poly-composite was characterized by FT-IR, UV-Vis, XRD, TEM, SEM, TGA, DSC and DC electrical conductivity. The formation of Poly (Imine)/MWCNT composite was confirmed. The DC electrical conductivity of poly-composites was within the range 2.3 × 10–4 - 5.3 × 10–4 S/cm due to the interaction between the nanotubes.展开更多
A possible way to increase thermal conductivity of working fluids, while keeping pressure drop at acceptable levels, is through nanofluids. Nanofluids are nano-sized particles dispersed in conventional working fluids....A possible way to increase thermal conductivity of working fluids, while keeping pressure drop at acceptable levels, is through nanofluids. Nanofluids are nano-sized particles dispersed in conventional working fluids. A great number of materials have potential to be used in nanoparticles production and then in nanofluids;one of them is Multi-Walled Carbon Nano Tubes (MWCNT). They have thermal conductivity around 3000 W/mK while other materials used as nanoparticles like CuO have thermal conductivity of 76.5 W/mK. Due to this fact, MWCNT nanoparticles have potential to be used in nanofluids production, aiming to increase heat transfer rate in energy systems. In this context, the main goal of this paper is to evaluate from the synthesis to the experimental measurement of thermal conductivity of nanofluid samples based on functionalized (-OH) MWCNT nanoparticles. They will be analyzed nanoparticles with different functionalization degrees (4% wt, 6% wt, and 9% wt). In addition, it will be quantified other thermophysical properties (dynamic viscosity, specific heat and specific mass) of the synthetized nanofluids. So, the present work can contribute with experimental data that will help researches in the study and development of MWCNT nanofluids. According to the results, the maximum increment obtained in thermal conductivity was 10.65% in relation to the base fluid (water).展开更多
Different oxygen and nitrogen containing functional groups were created on the surface of the multiwalled carbon nanotubes. The multi-walled carbon nanotubes were treated in ultrasonic bath with sulfuric or nitric aci...Different oxygen and nitrogen containing functional groups were created on the surface of the multiwalled carbon nanotubes. The multi-walled carbon nanotubes were treated in ultrasonic bath with sulfuric or nitric acid. Furthermore the surface texture was modified by increase of the roughness. In particular after treatment with the oxidizing nitric acid, in comparison to the H2SO4 or ultra-sonic treated samples,craters and edges are dominating the surface structures. Manganese oxide was deposited on the multiwalled carbon nanotubes by precipitation mechanism. Various manganese oxides are formed during the deposition process. The samples were characterized by elemental analysis, microscopy, thermal analysis,Raman spectroscopy, and by the zeta potential as well as X-ray diffraction measurements. It was shown that the deposited manganese oxides are stabilized rather by surface texture of the multi-walled carbon nanotubes than by created functional groups.展开更多
Multi-walled carbon nanotube(MWCNT) sheet was fabricated from a drawable MWCNT forest and then deposited on poly(methyl methacrylate) film. The film was further coated with a natural antimicrobial peptide nisin. W...Multi-walled carbon nanotube(MWCNT) sheet was fabricated from a drawable MWCNT forest and then deposited on poly(methyl methacrylate) film. The film was further coated with a natural antimicrobial peptide nisin. We studied the effects of nisin coating on the attachment of Bacillus anthracis spores, the germination of attached spores, and the subsequent biofilm formation from attached spores. It was found that the strong adsorptivity and the super hydrophobicity of MWCNTs provided an ideal platform for nisin coating. Nisin coating on MWCNT sheets decreased surface hydrophobicity, reduced spore attachment, and reduced the germination of attached spores by 3.5 fold, and further inhibited the subsequent biofilm formation by 94.6% compared to that on uncoated MWCNT sheet. Nisin also changed the morphology of vegetative cells in the formed biofilm.The results of this study demonstrated that the anti-adhesion and antimicrobial effect of nisin in combination with the physical properties of carbon nanotubes had the potential in producing effective anti-biofilm formation surfaces.展开更多
The microstructural evolution and oxidation resistance of multi-walled carbon nanotubes (MWCNTs) by di- rectly heating silicon powder and MWCNTs in a coke bed from 1000 to 1500 ~C are investigated with the aid of X-...The microstructural evolution and oxidation resistance of multi-walled carbon nanotubes (MWCNTs) by di- rectly heating silicon powder and MWCNTs in a coke bed from 1000 to 1500 ~C are investigated with the aid of X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and thermogravimetry-differential scanning calorimetry (TG-DSC). The results showed that the morphology and microstructure of MWCNTs did not change much after being treated from 1000 ~C to 1200 ~C. An obvious SiC coating was formed on the surface of MWCNTs from 1300 to 1400 ~C. Up to 1500 ~C, nearly all the MWCNTs transformed into SiC nanowires. The oxidation resistance of the treated MWCNTs was improved compared with as-received ones. Non-isothermal kinetics showed that the oxidation activation energy of the treated MWCNTs reached 208 kJ/mol, much higher than 264 k J/tool of as-received ones.展开更多
We propose a method to estimate the natural frequencies of the multi-walled carbon nanotubes (MWCNTs) embedded in an elastic medium. Each of the nested tubes is treated as an individual bar interacting with the adja...We propose a method to estimate the natural frequencies of the multi-walled carbon nanotubes (MWCNTs) embedded in an elastic medium. Each of the nested tubes is treated as an individual bar interacting with the adjacent nanotubes through the inter-tube Van der Waals forces. The effect of the elastic medium is introduced through an elastic model. The mathematical model is finally reduced to an eigen value problem and the eigen value problem is solved to arrive at the inter-tube resonances of the MWCNTs. Variation of the natural frequencies with different parameters are studied. The estimated results from the present method are compared with the literature and results are observed to be in close agreement.展开更多
文摘Pure and doped Polyvinylidene difluoride (PVDF) films, for the detection of infrared radiation, have been well documented using the mechanism of pyroelectricity. Alternatively, the electrical properties of films made from Polyvinyl Alcohol (PVA) have received considerable attention in recent years. The investigation of surface resistivities of both such films, to this point, has received far less consideration in comparison to pyroelectric effects. In this research, we report temperature dependent surface resistivity measurements of commercial, and of multiwall carbon nanotubes (MWCNT), or Ag-nanoparticle doped PVA films. Without any variation in the temperature range from 22°C to 40°C with controlled humidity, we found that the surface resistivity decreases initially, reaches a minimum, but rises steadily as the temperature continues to increase. This research was conducted with the combined instrumentation of the Keithley Model 6517 Electrometer and Keithley Model 8009 resistivity test fixture using both commercial and in-house produced organic thin films. With the objective to quantify the suitability of PVDF and PVA films as IR detector materials, when using the surface resistivity phenomenon, instead of or in addition to the pyroelectricity, surface resistivity measurements are reported when considering bolometry. We found that the surface resistivity measurements on PVA films were readily implemented.
文摘Multi-walled carbon nanotube (MWCNT)-Fe composites were prepared via the metal organic chemical vapor deposi- tion by depositing iron pentacarbonyl on the surface of MWCNTs. The structural and morphological analyses demonstrated that Fe nanoparticles were deposited on the surface of the MWCNTs. The electromagnetic properties of the MWCNTs were significantly changed, and the absorbing capacity evidently improved after the Fe deposition on the MWCNT surface. A minimum reflection loss of -29.4 dB was observed at 8.39 GHz, and the less than -10 dB bandwidth was about 10.6 GHz, which covered the whole X band (8.2-12.4 GHz) and the whole Ku band (12.4-18 GHz), indicating that the MWCNT-Fe composites could be used as an effective microwave absorption material.
文摘A sensitive electroanalytical method for quantification of pheniramine in pharmaceutical formulation has been investigated on the basis of the enhanced electrochemical response at glassy carbon electrode modified with multi-walled carbon nanotubes in the presence of sodium lauryl sulfate.The experimental results suggest that the phcniramine in anionic surfactant solution exhibits electrocatalytic effect resulting in a marked enhancement of the peak current response.Peak current response is linearly dependent on the concentration of pheniramine in the range 200-1500 μg/mL with correlation coefficient 0.9987.The limit of detection is 58.31 μg/m L.The modified electrode shows good sensitivity and repeatability.
文摘Carbon black (CB) or multi walled carbon nanotubes (MWCNT) loaded polyurethane conductive foams are used as heaters, electrodes, radar absorbers and shielding. This paper discusses the performance of an innovative flexible thermal radiator (FTR) constructed with CB filled or MWCNT filled conductive foam and powering electrode structure constructed with textiles manufacturing process (knitting, weaving or nonwoven). Silver (Ag) yarns are used for the powering electrodes construction. This paper discusses the construction, electro-thermal analysis, performance and applications of FTR. Also this paper compare the thermal and electrical characteristics of CB filled and MWCNT filled FTRs. The electro-thermal model is simulated by using finite element methods.
基金Funded by the National Natural Science Foundation of China (No.50763006)Ministry of Science and Technology R & D Research Institutes (No.2008EG134285)973 Program Special Fund (No.2010CB635109)
文摘Natural rubber (NR)/multi-walled carbon nanotube (MWCNTs) composites were prepared by combining self-assembly and latex compounding techniques.The acid-treated MWCNTs (H2SO4:HNO3=3:1,volume ratio) were self-assembled with poly (diallyldimethylammonium chloride) (PDDA) through electrostatic adhesion.In the second assembling,NR/MWCNTs composites were developed by mixing MWCNTs/PDDA solution with NR latex.The results show that MWCNTs are homogenously distributed throughout the NR matrix as single tube and present a great interfacial adhesion with NR phase when MWCNTs contents are less than 3 wt%.Moreover,the addition of the MWCNTs brings about the remarkable enhancement in tensile strength and crosslink density compared with the NR host,and the data peak at 2 wt% MWCNTs loadings.When more MWCNTs are loaded,aggregations of MWCNTs are gradually generated,and the tensile strength and crosslink both decrease to a certain extent.
基金Funded by the Fundamental Research Funds for the Central Universities (No.DUT11NY11)the State Key Laboratory of Coastal and Offshore Engineering (No.LP1109)
文摘Multi-walled carbon nanotube doped silica aerogels(MWCNT-SAs) were synthesized from a wet gel of well-dispersed MWCNT by one-step solvent exchange/surface modification and ambient pressure drying(APD). Waterglass was employed as a precursor to prepare wet gel. The content of MWCNT varied from 0 to 15% volume by wet gel. The surface group, thermal stability and microstructure of pure silica aerogel and MWCNT-SAs were investigated by FTIR, DTA, and TEM. Experimental results show that MWCNT-SAs are hydrophobic when the temperature is below 400 ℃, MWCNT-SAs exhibit a mesoporous network structure, and they achieve the largest scale with least shrinkage and lowest density when doped with 5 vol% MWCNT.
基金Funded by the National Natural Science Foundation of China(No.51578108)Special Fund for Scientific Research in the Public Interest by Ministry of Water Resource of the People’s Republic of China(No.201501003)Dalian Projects of Construction Technology(No.201307)
文摘The effect of multi-walled carbon nanotubes(MWCNTs) on the mechanical properties and microstructure of sulfur aluminate cement(SAC) composites was investigated. The dispersed MWCNTs were added into SAC in various weight contents.The results of mechanical properties of the MWCNTs/SAC composites indicated that the addition of 0.08 wt% MWCNTs can improve the SAC compressive strength, flexural strength, and bend-press ratio by 15.54%, 52.38%, and 31.30% at maximum, respectively. The degree of SAC hydration and porosity and pore size distribution of the matrix were measured by X-ray diffraction(XRD), thermal analysis(TG/DTG), and mercury intrusion porosimetry(MIP). Results show that the addition of MWCNTs in SAC composites can promote the hydration of SAC and the formation of C-S-H gel, reduce the porosity and refine the pore size distribution of the matrix. The microstructure was characterized by scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS). It is found that the MWCNTs have been dispersed homogeneously between the hydration products of SAC paste and act as bridges and networks between cracks and voids, which prevents the development of the cracks and transfers the load.
文摘Amidst <span><span><span style="font-family:;" "="">the </span></span></span><span><span><span style="font-family:;" "="">COVID-19 pandemic, environmental problems such as ener<span>gy crisis, global warming, and contamination from pathogenic mi</span>cro-organisms <span>are still prevailed and strongly demanded progress in high</span></span></span></span><span><span><span style="font-family:;" "="">-</span></span></span><span><span><span style="font-family:;" "="">performance</span></span></span><span><span><span style="font-family:;" "=""> energy storing and anti-microbial materials. The nanocomposites are materials <span>that have earned large interest owing to their promising applications for</span> countering global issues related to sustainable energy and</span></span></span><span><span><span style="font-family:;" "=""> a</span></span></span><span><span><span style="font-family:;" "=""> flourishing environ<span>ment. Here, polypyrrole </span></span></span></span><span><span><span style="font-family:;" "="">coated</span></span></span><span><span><span style="font-family:;" "=""> hybrid nanocomposites of multi-walled</span></span></span><span><span><span style="font-family:;" "=""> carbon nanotube and cadmium sulfide quantum dots named MCP were synthe<span>sized using facile and low-cost <i>in-situ</i> oxidative polymerization method.</span> Cha<span>racterization techniques confirmed the synthesis. Electrochemical studies</span> showed that the nanocomposite <span>1-MCP<i> </i></span>showed an impressively higher super capacitance behavior in comparison to f-MWCNT, 7-MCP and 5-MCP. The improved performance of the nanocomposites was attributed mainly to the good conductivity of carbon nanotubes and polypyrrole, high surface area, and stability of the carbon nanotubes and the high electrocatalytic activity of the cadmium sulfide quantum dots. Owing to the synergistic effect of MWCNT, <span>CdS, and PPy the synthesized ternary nanocomposite also inhibited the</span> growth and multiplication of tested bacteria such as <i>S. aureus</i>, and <i>E. coli</i> completely within 24 h. On the whole, the assimilated nanocomposite MCP opens promising aspects for the development of upcoming energy storage devices and as<span style="color:red;"> </span></span></span></span><span><span><span style="font-family:;" "="">an </span></span></span><span><span><span style="font-family:;" "="">antibacterial agent.</span></span></span>
文摘The present study aims to the development of Out of Autoclave (OoA) Carbon Fiber Reinforced Polymers (CFRPs) with increased interlaminar fracture toughness by using MWCNTs. The introduction of MWCNTs into the structure of CFRPs has been succeeded by using carbon nanotube-enriched sizing agent for the pretreatment of the fiber preform using an in-house developed methodology that can be easily scaled up. The positive effect of the proposed methodology on the interlaminar fracture toughness of the CFRP laminate was assessed by the increase of Mode I and Mode II interlaminar fracture toughness of the composites. Different wt% MWCNTs concentrations were used (namely 0.5%, 1%, 1.5% and 2.5%). It was found that the nanomodified composites exhibit a significant increase of the interlaminar critical strain energy release rate GIC and GIIC of the order of 103% and 62% respectively, in the case of 1.5 wt% MWCNTs weight content. Scanning Electron Microscopy (SEM) of the fracture surfaces of CFRP samples revealed the contribution and the associated synergistic mechanisms of MWCNTs to the increase of the crack propagation resistance in the case of nano-modified CFRPs compared to the reference material.
文摘This paper used a new approach of preparing poly-composites by covalent linkage between the MWCNT’s by imine group. The Poly (Imine)/MWCNT Composite was synthesized by the solution blending method from reacted amino multi-walled carbon nanotubes (MWCNT-NH2) with Terephthalaldehyde (TPAL). The obtained poly-composite was characterized by FT-IR, UV-Vis, XRD, TEM, SEM, TGA, DSC and DC electrical conductivity. The formation of Poly (Imine)/MWCNT composite was confirmed. The DC electrical conductivity of poly-composites was within the range 2.3 × 10–4 - 5.3 × 10–4 S/cm due to the interaction between the nanotubes.
文摘A possible way to increase thermal conductivity of working fluids, while keeping pressure drop at acceptable levels, is through nanofluids. Nanofluids are nano-sized particles dispersed in conventional working fluids. A great number of materials have potential to be used in nanoparticles production and then in nanofluids;one of them is Multi-Walled Carbon Nano Tubes (MWCNT). They have thermal conductivity around 3000 W/mK while other materials used as nanoparticles like CuO have thermal conductivity of 76.5 W/mK. Due to this fact, MWCNT nanoparticles have potential to be used in nanofluids production, aiming to increase heat transfer rate in energy systems. In this context, the main goal of this paper is to evaluate from the synthesis to the experimental measurement of thermal conductivity of nanofluid samples based on functionalized (-OH) MWCNT nanoparticles. They will be analyzed nanoparticles with different functionalization degrees (4% wt, 6% wt, and 9% wt). In addition, it will be quantified other thermophysical properties (dynamic viscosity, specific heat and specific mass) of the synthetized nanofluids. So, the present work can contribute with experimental data that will help researches in the study and development of MWCNT nanofluids. According to the results, the maximum increment obtained in thermal conductivity was 10.65% in relation to the base fluid (water).
文摘Different oxygen and nitrogen containing functional groups were created on the surface of the multiwalled carbon nanotubes. The multi-walled carbon nanotubes were treated in ultrasonic bath with sulfuric or nitric acid. Furthermore the surface texture was modified by increase of the roughness. In particular after treatment with the oxidizing nitric acid, in comparison to the H2SO4 or ultra-sonic treated samples,craters and edges are dominating the surface structures. Manganese oxide was deposited on the multiwalled carbon nanotubes by precipitation mechanism. Various manganese oxides are formed during the deposition process. The samples were characterized by elemental analysis, microscopy, thermal analysis,Raman spectroscopy, and by the zeta potential as well as X-ray diffraction measurements. It was shown that the deposited manganese oxides are stabilized rather by surface texture of the multi-walled carbon nanotubes than by created functional groups.
基金supported by the US Army Research Office(ARO)(#W911NF-10-1-0160)support from the Golden Leaf Foundation for major research instruments and facilities
文摘Multi-walled carbon nanotube(MWCNT) sheet was fabricated from a drawable MWCNT forest and then deposited on poly(methyl methacrylate) film. The film was further coated with a natural antimicrobial peptide nisin. We studied the effects of nisin coating on the attachment of Bacillus anthracis spores, the germination of attached spores, and the subsequent biofilm formation from attached spores. It was found that the strong adsorptivity and the super hydrophobicity of MWCNTs provided an ideal platform for nisin coating. Nisin coating on MWCNT sheets decreased surface hydrophobicity, reduced spore attachment, and reduced the germination of attached spores by 3.5 fold, and further inhibited the subsequent biofilm formation by 94.6% compared to that on uncoated MWCNT sheet. Nisin also changed the morphology of vegetative cells in the formed biofilm.The results of this study demonstrated that the anti-adhesion and antimicrobial effect of nisin in combination with the physical properties of carbon nanotubes had the potential in producing effective anti-biofilm formation surfaces.
基金supported by the Natural Science Foundation of Hubei Province (No.2009CDA050)the New Century Excellent Talents in University (No. NCET-10-0137)the National Natural Science Foundation of China (No. 51072143)
文摘The microstructural evolution and oxidation resistance of multi-walled carbon nanotubes (MWCNTs) by di- rectly heating silicon powder and MWCNTs in a coke bed from 1000 to 1500 ~C are investigated with the aid of X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and thermogravimetry-differential scanning calorimetry (TG-DSC). The results showed that the morphology and microstructure of MWCNTs did not change much after being treated from 1000 ~C to 1200 ~C. An obvious SiC coating was formed on the surface of MWCNTs from 1300 to 1400 ~C. Up to 1500 ~C, nearly all the MWCNTs transformed into SiC nanowires. The oxidation resistance of the treated MWCNTs was improved compared with as-received ones. Non-isothermal kinetics showed that the oxidation activation energy of the treated MWCNTs reached 208 kJ/mol, much higher than 264 k J/tool of as-received ones.
文摘We propose a method to estimate the natural frequencies of the multi-walled carbon nanotubes (MWCNTs) embedded in an elastic medium. Each of the nested tubes is treated as an individual bar interacting with the adjacent nanotubes through the inter-tube Van der Waals forces. The effect of the elastic medium is introduced through an elastic model. The mathematical model is finally reduced to an eigen value problem and the eigen value problem is solved to arrive at the inter-tube resonances of the MWCNTs. Variation of the natural frequencies with different parameters are studied. The estimated results from the present method are compared with the literature and results are observed to be in close agreement.