Elevated-Temperature Thermal Conductivity for PEEK-Matrix Composite with Carbon Fibers, Graphite Flakes and PTFE

Author(s):  
SALVADOR MENDEZ SANTOS ◽  
SHUREN QU ◽  
SU SU WANG
Author(s):  
A. Miyase ◽  
S. Qu ◽  
K. H. Lo ◽  
S. S. Wang

Abstract A combined experimental and micromechanics investigation is conducted on elevated-temperature thermal expansion of PTFE/PEEK polymer-matrix composite reinforced with randomly oriented short carbon fibers (CF) and graphite flakes (Gr). In the experimental phase of the study, PTFE/PEEK polymer blends with different amounts of PTFE and four-phase CF/Gr/PTFE/PEEK composites with different volume fractions of graphite flakes were made from compression molding. Scanning electron microscopy was performed to evaluate the microstructure of the PTFE/PEEK matrix and the composite, especially the interface, and the size and dispersion of the particles. X-ray diffraction (XRD) was conducted to provide morphological information on the semi-crystalline PTFE/PEEK matrix of the composite. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were carried out to determine transition temperatures and thermomechanical properties of the composite and its constituent phases at the elevated temperature. Thermal expansions of neat PTFE and neat PEEK, the PTFE/PEEK polymer matrix, and the CF/Gr/PTFE/PEEK composite were obtained with a thermal–mechanical analyzer (TMA) in a dilatometric mode. Coefficients of thermal expansion (CTEs) of the PTFE/PEEK matrix and its CF/Gr/PTFE/PEEK composite were then determined from 25 °C up to an elevated temperature 240 °C. To augment the experimental study, micromechanics analyses are also conducted to determine thermal expansion coefficients of the PTFE/PEEK matrix and the CF/GR/PTFE/PEEK composite. The micromechanics solutions elucidate individual roles of different composite constituents, contributions of individual constituent materials’ temperature-dependent thermal and mechanical properties, the importance of composite microstructure and morphology, and the issue of thermal–mechanical coupling on the thermal expansion behavior of the complex CF/Gr/PTFE/PEEK composite at high temperature.


2019 ◽  
Vol 32 (5-6) ◽  
pp. 243-251 ◽  
Author(s):  
Dongmei Xu ◽  
Guiquan Wang ◽  
Xiang Chen ◽  
Yanxiang Li ◽  
Yuan Liu ◽  
...  

2005 ◽  
Vol 46 (2) ◽  
pp. 148-151 ◽  
Author(s):  
Yibin Xu ◽  
Yoshihisa Tanaka ◽  
Masaharu Murata ◽  
Kazushige Kamihira ◽  
Yukihiro Isoda ◽  
...  

2017 ◽  
Vol 51 (28) ◽  
pp. 3941-3953 ◽  
Author(s):  
Xiangyang Dong ◽  
Yung C Shin

High thermal conductivity is one important factor in the selection or development of ceramics or composite materials. Predicting the thermal conductivity would be useful to the design and application of such materials. In this paper, a multi-scale model is developed to predict the effective thermal conductivity in SiC particle-reinforced aluminum metal matrix composite. A coupled two-temperature molecular dynamics model is used to calculate the thermal conductivity of the Al/SiC interface. The electronic effects on the interfacial thermal conductivity are studied. A homogenized finite element model with embedded thin interfacial elements is used to predict the properties of bulk materials, considering the microstructure. The effects of temperatures, SiC particle sizes, and volume fractions on the thermal conductivity are also studied. A good agreement is found between prediction results and experimental measurements. The successful prediction of thermal conductivity could help a better understanding and an improvement of thermal transport within composites and ceramics.


2021 ◽  
Vol 36 (4) ◽  
pp. 417-422
Author(s):  
Y. Hamid ◽  
P. Svoboda

Abstract Ethylene-butene copolymer (EBC)/carbon-fiber (CF) composites can be utilized as an electromechanical material due to their ability to change electric resistance with mechanical strain. The electro-mechanical properties and thermal conductivity of ethylene butene copolymer (EBC) composites with carbon fibers were studied. Carbon fibers were introduced to EBC with various concentrations (5 to 25 wt%). The results showed that carbon fibers’ addition to EBC improves the electric conductivity up to 10 times. Increasing the load up to 2.9 MPa will raise the electric resistance change by 4 500% for a 25% fiber sample. It is also noted that the EBC/CF composites’ electric resistance underwent a dramatic increase in raising the strain. For example, the resistance change was around 13 times higher at 15% strain compared to 5% strain. The thermal conductivity tests showed that the addition of carbon fibers increases the thermal conductivity by 40%, from 0.19 to 0.27 Wm–1K–1.


Carbon ◽  
1994 ◽  
Vol 32 (3) ◽  
pp. 379-391 ◽  
Author(s):  
H.A. Katzman ◽  
P.M. Adams ◽  
T.D. Le ◽  
C.S. Hemminger

1989 ◽  
Vol 4 (6) ◽  
pp. 1339-1346 ◽  
Author(s):  
C. T. Ho ◽  
D. D. L. Chung

Unidirectional and continuous carbon fiber tin-matrix composites were used for the packaging of the high-temperature superconductor YBa2Cu3O7–δ by diffusion bonding at 170 °C and 500 psi. Tin served as the adhesive and to increase the ductility, the normal-state electrical conductivity, and the thermal conductivity. Carbon fibers served to increase the strength and the modulus, both in tension along the fiber direction and in compression perpendicular to the fiber layers, though they decreased the strength in compression along the fiber direction. Carbon fibers also served to increase the thermal conductivity and the thermal fatigue resistance. At 24 vol. % fibers, the tensile strength was approximately equal to the compressive strength perpendicular to the fiber layers. With further increase of the fiber content, the tensile strength exceeded the compressive strength perpendicular to the fiber layers, reaching 134 MPa at 31 vol. % fibers. For fiber contents less than 30 vol. %, the compressive ductility perpendicular to the fiber layers exceeded that of the plain superconductor. At 30 vol. % fibers, the tensile modulus reached 15 GPa at room temperature and 27 GPa at 77 K. The tensile load was essentially sustained by the carbon fibers and the superconducting behavior was maintained after tension almost to the point of tensile fracture. Neither Tc nor Jc was affected by the composite processing.


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