Abstract: The applications of carbon nanotubes benefit to a wide range of engineering, applied
physics and biomaterials areas for their superior mechanical and electrical properties. Recently,
coiled carbon nanotube (CCNT) has opened a new alternative to reinforce traditional advanced
composites. Their coiled shapes are considered to induce mechanical interlocking between the
nanotubes and matrix which result in the enhancement of fracture toughness and mechanical
strength of the composites. In this study, nanomechanical properties of CCNT reinforced epoxy
composites with varying weight percentages (0, 1, 3, and 5 wt %) of nanotubes were measured by
the nanoindentation technique. Hardness and elastic modulus measurement of the composites were
Abstract: The carbon nanotubes were prepared by catalytic decompose of benzene using floating
transition method at 1100~1200°C. Benzene was used as carbon source and iron as catalyst with
sulfur. The carbon nanotubes are straight with diameter 30~80nm, internal diameter 10~50nm and
length 50~100μm. The carbon nanotubes and epoxy resin were sufficiently mixed. The mixture
was smeared on to a pure aluminum plate layer by layer until the thickness of the composite layer
reached 1.0 mm. The coating resin was cured by heating under infrared radiation. Complex
permittivity, permeability and microwave reflectivity of carbon nanotubes reinforced epoxy resin
coating had been investigated at the frequency ranges of 8.2~12.4GHz and 2~18GHz respectively.
The real part (ε′) of complex permittivity of this coating ranges from 14.87 to 13.86, and the
imaginary part (ε″), from 6.42 to 5.87, the loss tangent tgδε (ε″/ε′), from 0.42 to 0.45. The real part
(μ′) of complex permeability of this coating ranges from 1.02 to 1.14, and the imaginary part (μ″),
from 0.08 to 0.11, the loss tangent tgδμ (μ″/μ′), from 0.06 to 0.11. The maximum absorbing peak of
the carbon nanotube reinforced epoxy resin coating is 22.89 dB at 11.40GHz. The band width
(R<-10dB) of this coating with thickness of 1.0 mm is 3.0GHz, band width (R<-5dB) is 4.7GHz at
the frequency range of 8~18GHz. This carbon nanotube reinforced epoxy resin coating would be a
good candidate for microwave absorbing material.
Abstract: The filling of multi-walled carbon nanotubes (MWNTs) with metallic silver nanowires
via wet chemistry method was investigated. The carbon nanotubes were filled with long continuous
silver nanowires. The carbon nanotubes were almost opened and cut after being treated with
concentrated nitric acid. Silver nitrate solution filled carbon nanotubes by capillarity. Carbon
nanotubes were filled with silver nanowires after calcinations by hydrogen. The diameters of silver
nanowires were in the range of 20-40nm, and lengths of 100nm-10μm. We studied the
micromorphology of the silver nanowires filled in carbon nanotubes by transmission electron
microscopy (TEM) and X-ray diffraction (XRD). Based on the experimental results, a formation
mechanism of the Ag nanowire-filled carbon nanotubes was proposed. And the microwave
permittivity of the carbon nanotubes filled with metallic silver nanowires was measured in the
frequency range from 2 GHz to 18 GHz. The loss tangent of the carbon nanotubes filled with
metallic silver nanowires is high. So the carbon nanotubes filled with metallic silver nanowires
would be a good candidate for microwave absorbent.
Abstract: The tribological and mechanical properties of polytetrafluoroethylene (PTFE)
composites filled with carbon nano-fiber (CNF), short carbon fiber (SCF) and the combination of
them were studied. The results indicate that the wear volume loss of the PTFE composite filled
with CNF or SCF, in comparison with that of pure PTFE, decreases by 1~2 orders of magnitude.
And the best wear resistant composition is achieved by the combination of SCF with CNF; as an
example, PTFE+2 wt% CNF+18 wt% SCF exhibits a specific wear volume loss of 0.88 mm3,
which is about 11 times lower when compared to the PTFE composite filled with 18 wt% SCF.
Meanwhile, the results also show that the tensile strength of SCF or CNF filled PTFE composites
is better than that of pure PTFE. However, the combination of the two fillers decreases the
tensile strength of PTFE composites. Worn surfaces were investigated using a scanning electron
microscope, from which it is assumed that a mechanism of rolling effect, due to the filling of
nanoparticles, which has a positive protective effect for PTFE matrix.
Abstract: A series of nanocomposites, SiCN/A3S2 ceramics, were prepared by hot-pressing method.
The nanometer SiCN powder is characterized of high dielectric dissipation. The dielectric
properties of the SiCN/A3S2 nanocomposites were investigated. XRD and SEM were conducted to
study the phases and microstructure of the nanocomposites. Compared with the pure A3S2 ceramic,
the grain size in the nanocomposites is reduced due to the addition of nanometer SiCN powder. The
relative densities of the nanocomposites are also lower than that of the pure A3S2 ceramic. Both the
real and imaginary parts of the complex permittivity of nanocomposites in X band increase as the
content of SCN powder in the samples rises obviously. When the contents of SiCN powder in
samples are same, the real and imaginary parts of the samples vary with the sintering temperature.
The tanδ of the nanocomposites reduces from 1.9 to 1.4 when sintering temperature increases from
1450OC to 1650 OC. SAED pattern reveals that structure of the SiCN in SiCN/ A3S2 sintered at
higher temperatures tend to crystallize. The real, imaginary parts and dissipation factor of the
nanocomposites sintered at higher temperature is lower than those sintered at 1450 °C.
Abstract: Hydroxyapatite reinforced ultrahigh molecular weight polyethylene (HA/UHMWPE)
nanocomposites with HA volume fraction 0.1~0.5 are processed by twin-screw extrusion
compounding and compression molding followed by hot drawing. SEM micrographs show that HA
nano-particles are homogeneously dispersed in the highly oriented UHMWPE inter-fibrils. Tensile
tests show that the modulus increases, while the strength and ductility decrease, with the increase of
HA content. A good combination of mechanical properties can be obtained in the composite with
HA nano-particles volume fraction 0.3.
Abstract: Although many studies have been conducted in the past few years on the possibility of
using carbon nanotube (CNT) to improve the performance of polymer-based materials, some of the
results were contradictory and lack of coherence. Thus, the in-depth understanding of CNT
composites is required. In this paper, single-walled carbon nanotubes (SWNTs), which were
functionalized by sonicating with nitric and sulfuric acids, will be used to fabricate a SWNT/epoxy
composite. There are two reasons for functionalizing the SWNTs, they are (i) to improve the
dispersion of the SWNTs in polymer, and (ii) to improve the interfacial bonding properties between
the SWNTs and polymer matrix. Tensile property test and micro-hardness test will be carried out to
examine the mechanical properties of the composites with different SWNT contents.
Thermogravimetry Analysis (TGA) will be used to evaluate the thermal properties of the composites.
Scanning Electron Microscope (SEM) will also be used to investigate the failure mechanism of the
composites after tensile test. A comparison of the composites with functionalized and
non-functionalized SWNTs will be given to elaborate the effect of nanotube functionalization.
Abstract: The dynamic properties of multi-walled carbon nanotubes (MWNTS)/epoxy
nanocomposite beams were investigated experimentally and numerically. The MWNTs/epoxy
nanocomposite beams were fabricated by hot press method. In experiment, the dynamic properties of
the nanocomposite beams, such as natural frequency, and damping ratio, were obtained. A shaker was
used to provide the vibration source at the fixed base of the specimens. The vibration signals of the
nanocomposite beams were detected by a laser sensor, and the frequency responses were obtained by
a computer-aided signal analyzer. The half power method was used to find the damping ratios of the
nanocomposite beams for each mode. In analysis, the mechanical properties of MWNTs/epoxy
nanocomposites were obtained and used in the free vibration analysis by the finite element method.
The natural frequencies and mode shapes of the nanocomposite beams were calculated numerically.
The effect of the weight percentage of MWNTs on the dynamic properties of the nanocomposite
beams was investigated. The numerical results were found to be in good agreement with the