Properties improvement of multiwall carbon nanotubes-reinforced cement-based composites

2019 ◽  
Vol 54 (18) ◽  
pp. 2379-2387 ◽  
Author(s):  
Baomin Wang ◽  
Bo Pang
Keyword(s):  
Carbon Nanotubes ◽  
Growth Rate ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Isothermal Calorimetry ◽  
Multiwall Carbon Nanotubes ◽  
Hydration Reaction ◽  
Cement Composites ◽  
X Ray ◽  
Multiwall Carbon

Multiwall carbon nanotubes with extraordinary mechanical properties have been widely used as effective nano-reinforcer of cement-based composites. In this research, multiwall carbon nanotubes were dispersed uniformly in aqueous solution using N,N-dimethylformamide as dispersant with ultrasonication. The structure and micromorphology of multiwall carbon nanotubes were characterized via X-ray photoelectron spectroscopy and transmission electron microscopy. The effect of N,N-dimethylformamide on multiwall carbon nanotubes dispersion was better than that of previous dispersants. The multiwall carbon nanotubes/cement composites with different multiwall carbon nanotubes contents were prepared and the mechanical performances of multiwall carbon nanotubes/cement composites were researched. Results showed that the flexural strength growth rate of multiwall carbon nanotubes/cement composites was 21.7% and the compressive strength growth rate of the multiwall carbon nanotubes/cement composites was 2.9% incorporating with 0.04 wt% multiwall carbon nanotubes at 28 days. The ratio of compressive strength to flexural strength of decline rate of multiwall carbon nanotubes/cement composites was 15.9% with 0.04 wt% multiwall carbon nanotubes at 28 days. The isothermal calorimetry (TAM Air) showed that multiwall carbon nanotubes could accelerate the hydration reaction. The X-ray diffraction and thermal gravity analysis (TG/DTG) suggested that multiwall carbon nanotubes could improve the hydration process and increase the number of hydration products. The mercury intrusion porosimetry revealed the porosity of multiwall carbon nanotubes/cement composites was decreased. There is an effect of multiwall carbon nanotubes on inhibiting the extension of cracks and promoting the degree of compactibility of the cement-based composites. The micromorphology of multiwall carbon nanotubes/cement composites was observed through scanning electron microscope.

Effect of Carbon Nanotubes on Mechanical Properties of Cement Composites

2014 ◽  
Vol 915-916 ◽  
pp. 768-771
Author(s):  
Yun Feng Li ◽  
Jing Zhou ◽  
Lei Wen Gao
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Brittle Failure ◽  
Cement Composites ◽  
Toughness Index ◽  
Different Content ◽  
Positive Effect

Nanotubes exhibiting great mechanical properties are expected to produce significantly stronger and tougher cement composites. The effects of Carbon Nanotubes to cement based composites are investigated in this paper. The flexural strength and the compressive strength of the CNTs cement composites under different content of are tested and the toughness indexes are analyzed. The results show that CNTs have a positive effect on the brittle failure of cement composites, and that the compressive strength and flexural strength of 0.10% CNTs cement composites are significantly increased. The toughness index of 0.05% CNTs cement composites is relatively higher.

scholarly journals Composite Nanofibers Containing Multiwall Carbon Nanotubes as Biodegradable Membranes in Reconstructive Medicine

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 63 ◽  
Author(s):  
Andrzej Hudecki ◽  
Dorota Łyko-Morawska ◽  
Wirginia Likus ◽  
Magdalena Skonieczna ◽  
Jarosław Markowski ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Maxillofacial Surgery ◽  
Multiwall Carbon Nanotubes ◽  
Dermal Fibroblasts ◽  
Hydroxyl Groups ◽  
X Ray ◽  
Biological Responses ◽  
Transmission Electron ◽  
Multiwall Carbon

We have tested titanium (Ti) plates that are used for bone reconstruction in maxillofacial surgery, in combination with five types of novel long-resorbable biomaterials: (i) PCL0—polycaprolactone without additives, (ii) PCLMWCNT—polycaprolactone with the addition of multiwall carbon nanotubes (MWCNT), (iii) PCLOH—polycaprolactone doped with multiwall carbon nanotubes (MWCNT) containing –OH hydroxyl groups, (iv) PCLCOOH—polycaprolactone with the addition of multiwall carbon nanotubes (MWCNT) containing carboxyl groups, and (v) PCLTI—polycaprolactone with the addition of Ti nanoparticles. The structure and properties of the obtained materials have been examined with the use of Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and/or X-ray powder diffraction (XRD). Titanium BR plates have been covered with: (i) PCL0 fibers (PCL0BR—connection plates), (ii) PCLMWCNT fibers (PCLMWCNTBR—plates), (iii) PCLOH fibers (PCLOHBR—plates), (iv) PCLCOOH (PCLCOOHBR—plates), (v) PCLTI fiber (PCLTIBR—connection plates). Such modified titanium plates were exposed to X-ray doses corresponding to those applied in head and neck tumor treatment. The potential leaching of toxic materials upon the irradiation of such modified titanium plates, and their effect on normal human dermal fibroblasts (NHDF) have been assessed by MTT assay. The presented results show variable biological responses depending on the modifications to titanium plates.

Bimetallic PtRu Nanoparticles Supported on Functionalized Multiwall Carbon Nanotubes as High Performance Electrocatalyst for Direct Methanol Fuel Cells

NANO ◽  
2016 ◽  
Vol 11 (02) ◽  
pp. 1650022 ◽  
Author(s):  
Chunhui Tan ◽  
Juhui Sa ◽  
Feipeng Cai ◽  
Bo Jiang ◽  
Gai Yang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Fuel Cells ◽  
Methanol Oxidation ◽  
Direct Methanol Fuel Cells ◽  
Multiwall Carbon Nanotubes ◽  
X Ray ◽  
Direct Methanol ◽  
Methanol Fuel Cells ◽  
Multiwall Carbon ◽  
Ptru Nanoparticles

PtRu nanoparticles (NPs) supported on acid treated multiwall carbon nanotubes (Pt1Ru1/MWCNTs) were prepared by a modified polyol method without adding any other surfactant or protective agent. The structural and compositional properties of the as-obtained samples were characterized by transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) and X-ray photoelectron (XPS) spectroscopy. The electrocatalytic performance of the catalyst was evaluated by cyclic voltammetry (CV), CO stripping voltammetry and chronoamperometry, indicating a high catalytic activity, excellent CO tolerance and stability for methanol oxidation. Interestingly, a series of accurate controllable experiments have been designed to explore the enhancement mechanism of Pt1Ru1/MWCNTs for methanol oxidation reaction. Most importantly, Pt1Ru1/MWCNTs composites were used as an anode catalyst in the direct methanol fuel cells (DMFCs) exhibiting outstanding power density (126.1 mW/cm[Formula: see text] 1.7 times higher than that of the commercial catalyst of Pt1Ru1/C (74.1 mW/cm[Formula: see text] (E-TEK).

scholarly journals Effect Of Carbon Nanotubes On The Properties Of Spark Plasma Sintered ZrO2/CNT Composites

2015 ◽  
Vol 60 (2) ◽  
pp. 1315-1318 ◽  
Author(s):  
D.H. Shim ◽  
S.S. Jung ◽  
H.S. Kim ◽  
H. Cho ◽  
J.K. Kim ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Flexural Strength ◽  
Multiwall Carbon Nanotubes ◽  
Wear Properties ◽  
Plasma Sintering ◽  
Close Relationship ◽  
Spark Plasma ◽  
Friction And Wear Properties ◽  
Multiwall Carbon

Abstract Zirconia matrix ZrO2/CNT composite materials reinforced with multiwall carbon nanotubes were fabricated using a spark plasma sintering technique. The effects of the amount of CNTs addition, sintering temperature and sintering pressure on the properties of the resulting ZrO2/CNT composites were examined. 0 to 9 vol. % CNTs were dispersed in zirconia powder, and the resulting mixture was sintered. The electrical conductivity, hardness, flexural strength, and density were measured to characterize the composites. The friction and wear properties of the composites were also tested. The flexural strength and friction coefficient of the composites were improved with up to 6 vol.% of CNT addition and the flexural strength showed a close relationship with the relative density of the composite. The electrical conductivity increased with increasing proportion of the CNTs, but the efficiency was reduced at more than 6 vol.% CNTs.

X-RAY PROPAGATION IN MULTIWALL CARBON NANOTUBES

2010 ◽  
Vol 25 (supp01) ◽  
pp. 208-216
Author(s):  
P A CHILDS ◽  
S Y ONG ◽  
D C HERBERT ◽  
A G O'NEILL
Keyword(s):  
Carbon Nanotubes ◽  
Bragg Reflection ◽  
Semiconductor Industry ◽  
Grazing Angle ◽  
Multiwall Carbon Nanotubes ◽  
Angle Of Incidence ◽  
Bragg Structure ◽  
X Ray ◽  
Extreme Uv ◽  
Multiwall Carbon

There is considerable interest in the development of inexpensive lithography techniques for applications in the area of nanoscale electronics. The semiconductor industry is pursuing the development of photolithography techniques such as extreme UV and x-ray. However these techniques are extremely expensive and not suitable for smaller scale applications. In this paper we describe research on the feasibility of exploiting x-ray propagation within carbon nanotubes (CNTs) for the fabrication and characterisation of nanoscale devices. A description is given of a test structure designed to explore experimentally the possibility of x-ray propagation in carbon nanotubes. As x-ray propagation requires a grazing angle of incidence the nanotubes need to be straight and reproducible. In order to alleviate this problem the possibility of using Bragg reflection is investigated. This approach to the problem is stimulated by the inherent Bragg structure of multiwall carbon nanotubes. It is further encouraged by the recent development of coatings using materials such as WS2. Results from simulations presented in this paper show that although Bragg reflection in as-grown multiwall carbon nanotubes is weak the potential for exploitation of this phenomenon in suitably coated nanotubes exists.

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