CdS composites

447

CARBON 85 (2015) 445– 449

Nitric acid oxidation also improved the mechanical performance

fiber debonding and pull-out from the matrix. The C/C composites

and thermal stability of the composites. The adhesion between

possessed the highest thermal conductivity (69.09 W/(m K) in the

PU and nitric acid-oxidized CFs was better than that between

parallel direction and 25.28 W/(m K) in the vertical direction), which

PU and fibers treated with silane coupling agents.

can be accounted for by the high thermal conductivity of the pyro-

[New Carbon Materials 2014, 29(6): 454–460]

carbon matrix, a low porosity of the composites, a long phonon mean free path and fewer structural defects.

http://dx.doi.org/10.1016/j.carbon.2014.12.078

[New Carbon Materials 2014, 29(6): 467–472]

Effect of heat treatment temperature on the microstructure and

http://dx.doi.org/10.1016/j.carbon.2014.12.080

properties of polyimide-based carbon fibers Ang Lia, Zhao-kun Maa, Huai-he Songa, Kang Lua, Zhan-jun Liub,

Structure and electrical conductivity of amorphous solid-core

Quan-gui Guob

carbon nanofibers produced in flames

a

Xiang Qia,b, Zhao-kai Menga, Chun-xu Pana,c

State Key Laboratory of Chemical Resource Engineering, College of

Materials Science and Engineering, Beijing University of Chemical

a

Department of Physics, Wuhan University, Wuhan 430072, China

Technology, Beijing 100029, China

b

Faculty of Materials, Optoelectronics and Physics, Xiangtan University,

b

Xiangtan 411105, China

Key Laboratory of Carbon Materials, Institute of Coal Chemistry,

c

Chinese Academy of Sciences, Taiyuan 030001, China

Key Laboratory of Artificial Micro- and Nano-structures of Ministry of

Education, Wuhan University, Wuhan 430072, China Polyimide(PI)-based carbon fibers with different properties were prepared by carbonization of PI fibers at 800 °C, followed by

The microstructures of amorphous solid-core carbon nanofi-

heat treatment from 800 to 2800 °C. The effect of heat treatment

bers (CNFs) synthesized in flames show long-range disorder,

temperature (HTT) on elemental composition, surface morphol-

which makes it difficult to reconstruct their three-dimensional

ogy, mechanical properties, and the thermal and electrical conduc-

atom configurations by popular characterization methods.Using

tivities of PI-based carbon fibers were investigated by elemental

a reverse Monte Carlo method, the atom configurations of CNFs

analysis, SEM, HRTEM, Raman spectroscopy, mechanical testing,

were derived from X-ray diffraction data, and these were used

and electrical and thermal conductivity measurements. Results

to calculate the Fermi levels, density of electronic states and elec-

showed that as a result of HTT the carbon content increased from

trical conductivity of the CNFs. The calculated electronic struc-

78.97% to 99.72%, the tensile strength exhibited a maximum of

tures

924.4 MPa, and the degree of graphitization and the size of graphite

semiconducting. Experimentally, the I–V curve of the CNFs was

crystallites were both increased. Distinct reductions in strain-to-

investigated and shown to be symmetrical and nonlinear, indicat-

failure and electrical resistivity were observed with increasing

ing the semiconductivity of the CNFs, which is good agreement

HTT. The thermal conductivity can reach 228.4 W m

1

K

1

after

heat treatment at 2800 °C. PI fiber may be a good precursor for car-

of

CNFs

indicate

that

the

amorphous

CNFs

are

with calculated results. [New Carbon Materials 2014, 29(6): 473–480]

bon fibers with a high thermal conductivity. [New Carbon Materials 2014, 29(6): 461–466] http://dx.doi.org/10.1016/j.carbon.2014.12.079

http://dx.doi.org/10.1016/j.carbon.2014.12.081

One-pot

synthesis

of

ordered

mesoporous

carbon/CdS

composites Preparation and properties of carbon fiber-reinforced carbon and

Ai-bing Chen, Yi-feng Yu, Man-ling Jia, Ting-ting Xing, Yun-hong

ceramic composites through a combination of chemical vapor

Yu, Yue-tong Li

infiltration and polymer impregnation pyrolysis Hai-peng Qiu, Ming-wei Chen, Xiu-qian Li, Yu Wang, Wei-jie Xie

College of Chemical and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China

National Key Laboratory of Advanced Composites, AVIC Composite Material Technology Center, Beijing 101300, China

Ordered mesoporous carbon/CdS composites have been synthesized by a “one-pot” assembly strategy associated with a

Carbon fiber-reinforced carbon composites (C/C), carbon fiber

direct carbonization process using phenolic resol as the carbon

reinforced-carbon and silicon carbide binary matrix composites

source, thiocarbamide and cadmium nitrate as matrix precursor

(C/C–SiC) and carbon fiber reinforced carbon–silicon–zirconium–

and amphiphilic tri block copolymer Pluronic F127 as a template.

oxygen matrix composites (C/C–Si–Zr–O) were prepared through a

The composite structure was characterized by XRD, BET and TEM.

combination of chemical vapor infiltration (CVI) and polymer

The obtained mesoporous CdS/carbon composites with ordered

impregnation pyrolysis. The microscopic morphology, phase struc-

mesostructures have uniform pore sizes (3.5–4.1 nm) and high

ture, mechanical properties and thermal conductivity of the C/C, C/

specific surface areas (554.2 m2/g). The CdS nanoparticles were

C–SiC and C/C–Si–Zr–O composites were investigated by SEM, XRD,

dispersed evenly on the mesoporous carbon surface. The meso-

EDA and laser flash thermal conductive measurements. Results

structure ordering decreases with the increase of CdS content.

showed that the flexural strength of the C/C–Si–Zr–O composites

[New Carbon Materials 2014, 29(6): 481–485]

was higher than that of the C/C and the C/C–SiC composites, which can be ascribed to their energy absorption mechanisms, such as

http://dx.doi.org/10.1016/j.carbon.2014.12.082