Mesophase Pitch-Based Carbon Fibers: Accelerated Stabilization of Pitch Fibers under Effective Plasma Irradiation-Assisted Modification

Stabilization is the most complicated and time-consuming step in the manufacture of carbon fibers (CFs), which is important to prepare CFs with high performance. Accelerated stabilization was successfully demonstrated under effective plasma irradiation-assisted modification (PIM) of mesophase pitch fibers (PFs). The results showed that the PIM treatment could obviously introduce more oxygen-containing groups into PFs, which was remarkably efficient in shortening the stabilization time of PFs with a faster stabilization heating rate, as well as in preparing the corresponding CFs with higher performance. The obtained graphitized fiber (GF-5) from the PF-5 under PIM treatment of 5 min presented a higher tensile strength of 2.21 GPa, a higher tensile modulus of 502 GPa, and a higher thermal conductivity of 920 W/m·K compared to other GFs. Therefore, the accelerated stabilization of PFs by PIM treatment is an efficient strategy for developing low-cost pitch-based CFs with high performance.

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Carbon fiber reinforced tin-superconductor composites

Journal of Materials Research ◽

10.1557/jmr.1989.1339 ◽

1989 ◽

Vol 4 (6) ◽

pp. 1339-1346 ◽

Cited By ~ 8

Author(s):

C. T. Ho ◽

D. D. L. Chung

Keyword(s):

Thermal Conductivity ◽

Tensile Strength ◽

Compressive Strength ◽

Carbon Fiber ◽

Carbon Fibers ◽

Tensile Modulus ◽

Tensile Load ◽

Tensile Fracture ◽

Fiber Direction ◽

Continuous Carbon Fiber

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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Carbon Fiber Composite Molecular Sieves for Gas Separation

MRS Proceedings ◽

10.1557/proc-344-77 ◽

1994 ◽

Vol 344 ◽

Cited By ~ 3

Author(s):

M. Jagtoyen ◽

F. Derbyshire ◽

N. Brubaker ◽

Y. Q. Fel ◽

G. Kimber ◽

...

Keyword(s):

Tensile Strength ◽

Carbon Fibers ◽

Molecular Sieves ◽

High Performance ◽

Fiber Composite ◽

High Strength ◽

Mesophase Pitch ◽

High Concentration ◽

Carbon Fiber Composite ◽

Temperature Oxidation

IntroductionCarbon fibers are produced commercially from rayon, phenolics, polyacrylonitrile (PAN), or pitch. The last are further divided into fibers produced from isotropic pitch precursors, and those derived from pitch that has been pretreated to introduce a high concentration of carbonaceous mesophase. Over the past few decades, interest in research and manufacturing carbon fibers has overwhelmingly centered on producing fibers with high tensile strength and high modulus for lightweight, high performance composites, where polymers, metals, and carbon can form the continuous matrix. The fibers most commonly used in advanced materials are produced from PAN or mesophase pitch. Graphitized mesophase pitch fibers tend to have higher modulus and lower tensile strength than the PAN-based equivalents. They have advantages in applications requiring high stiffness, high electrical and thermal conductivity, low thermal expansion, and high temperature oxidation resistance, while PAN fibers are employed where high strength is required.

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Morphology of High-Performance Rigid-Rod Polymer Fibers and Molecular Composites

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010015366x ◽

1989 ◽

Vol 47 ◽

pp. 338-339

Author(s):

W.W. Adams ◽

S. J. Krause

Keyword(s):

Tensile Strength ◽

High Performance ◽

Liquid Crystalline ◽

Molecular Level ◽

Synergistic Effects ◽

Tensile Modulus ◽

Commercial Development ◽

The Matrix ◽

Molecular Composites ◽

Rigid Rod

Rigid-rod polymers such as PBO, poly(paraphenylene benzobisoxazole), Figure 1a, are now in commercial development for use as high-performance fibers and for reinforcement at the molecular level in molecular composites. Spinning of liquid crystalline polyphosphoric acid solutions of PBO, followed by washing, drying, and tension heat treatment produces fibers which have the following properties: density of 1.59 g/cm3; tensile strength of 820 kpsi; tensile modulus of 52 Mpsi; compressive strength of 50 kpsi; they are electrically insulating; they do not absorb moisture; and they are insensitive to radiation, including ultraviolet. Since the chain modulus of PBO is estimated to be 730 GPa, the high stiffness also affords the opportunity to reinforce a flexible coil polymer at the molecular level, in analogy to a chopped fiber reinforced composite. The objectives of the molecular composite concept are to eliminate the thermal expansion coefficient mismatch between the fiber and the matrix, as occurs in conventional composites, to eliminate the interface between the fiber and the matrix, and, hopefully, to obtain synergistic effects from the exceptional stiffness of the rigid-rod molecule. These expectations have been confirmed in the case of blending rigid-rod PBZT, poly(paraphenylene benzobisthiazole), Figure 1b, with stiff-chain ABPBI, poly 2,5(6) benzimidazole, Fig. 1c A film with 30% PBZT/70% ABPBI had tensile strength 190 kpsi and tensile modulus of 13 Mpsi when solution spun from a 3% methane sulfonic acid solution into a film. The modulus, as predicted by rule of mixtures, for a film with this composition and with planar isotropic orientation, should be 16 Mpsi. The experimental value is 80% of the theoretical value indicating that the concept of a molecular composite is valid.

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Development of an Additive Manufacturing System for the Deposition of Thermoplastics Impregnated with Carbon Fibers

Journal of Manufacturing and Materials Processing ◽

10.3390/jmmp3020035 ◽

2019 ◽

Vol 3 (2) ◽

pp. 35 ◽

Cited By ~ 1

Author(s):

Miguel Reis Silva ◽

António M. Pereira ◽

Nuno Alves ◽

Gonçalo Mateus ◽

Artur Mateus ◽

...

Keyword(s):

Tensile Strength ◽

Additive Manufacturing ◽

Carbon Fibers ◽

Low Cost ◽

Deposition Process ◽

Processing Parameters ◽

Yarn Diameter ◽

Thermoplastic Matrix ◽

Anisotropic Mechanical Properties ◽

Long Carbon Fiber

This work presents an innovative system that allows the oriented deposition of continuous fibers or long fibers, pre-impregnated or not, in a thermoplastic matrix. This system is used in an integrated way with the filamentary fusion additive manufacturing technology and allows a localized and oriented reinforcement of polymer components for advanced engineering applications at a low cost. To demonstrate the capabilities of the developed system, composite components of thermoplastic matrix (polyamide) reinforced with pre-impregnated long carbon fiber (carbon + polyamide), 1 K and 3 K, were processed and their tensile and flexural strength evaluated. It was demonstrated that the tensile strength value depends on the density of carbon fibers present in the composite, and that with the passage of 2 to 4 layers of fibers, an increase in breaking strength was obtained of about 366% and 325% for the 3 K and 1 K yarns, respectively. The increase of the fiber yarn diameter leads to higher values of tensile strength of the composite. The obtained standard deviation reveals that the deposition process gives rise to components with anisotropic mechanical properties and the need to optimize the processing parameters, especially those that lead to an increase in adhesion between deposited layers.

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Experimental investigation of the microstructures and tensile properties of polyacrylonitrile-based carbon fibers exposed to elevated temperatures in air

Journal of Engineered Fibers and Fabrics ◽

10.1177/1558925019850010 ◽

2019 ◽

Vol 14 ◽

pp. 155892501985001 ◽

Cited By ~ 1

Author(s):

Chenggao Li ◽

Guijun Xian

Keyword(s):

Tensile Strength ◽

Carbon Fiber ◽

Carbon Fibers ◽

Elevated Temperatures ◽

Tensile Modulus ◽

Fiber Reinforced Polymer ◽

Carbon Fiber Reinforced Polymer ◽

Fiber Reinforced ◽

Reinforced Polymer ◽

Carbon Fiber Reinforced

The elevated temperature resistance and even fire resistance of carbon fiber-reinforced polymer composites were critical concerns in many applications. These properties of a carbon fiber-reinforced polymer depend not only on the degradation of the polymer matrix but also on that of the carbon fibers under elevated temperatures. In this study, influences of elevated temperatures (by 700°C for 30 min) in air on the mechanical properties and microstructures of a carbon fiber were investigated experimentally. It was found that the tensile strength and modulus as well as the diameters of the carbon fibers were reduced remarkably when the treatment temperatures exceeded 500°C. At the same time, the content of the structurally ordered carbonaceous components on the surface of carbon fibers and the graphite microcrystal size were reduced, while the graphite interlayer spacing ( d002) was enhanced. The deteriorated tensile modulus was attributed to the reduced graphite microcrystal size and the reduced thickness of the skin layer of the carbon fiber, while the degraded tensile strength was mainly attributed to the weakened cross-linking between the graphite planes.

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Young’s modulus, thermal conductivity, electrical resistivity and coefficient of thermal expansion of mesophase pitch-based carbon fibers

Carbon ◽

10.1016/j.carbon.2014.07.068 ◽

2014 ◽

Vol 79 ◽

pp. 274-293 ◽

Cited By ~ 52

Author(s):

Francisco G. Emmerich

Keyword(s):

Thermal Conductivity ◽

Electrical Resistivity ◽

Thermal Expansion ◽

Young’S Modulus ◽

Carbon Fibers ◽

Coefficient Of Thermal Expansion ◽

Young's Modulus ◽

Mesophase Pitch

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Experimental investigations into mechanical and thermal properties of rapid manufactured copper parts

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406219875483 ◽

2019 ◽

Vol 234 (1) ◽

pp. 82-95 ◽

Cited By ~ 11

Author(s):

Gurminder Singh ◽

Pulak M Pandey

Keyword(s):

Thermal Conductivity ◽

Tensile Strength ◽

Thermal Properties ◽

Ultimate Tensile Strength ◽

Heating Rate ◽

Sintering Temperature ◽

Mechanical And Thermal Properties ◽

Surface Porosity ◽

Soaking Time ◽

Ultrasonic Assisted

In the present paper, mechanical and thermal properties of rapidly manufactured copper parts were studied. The combination of three-dimensional printing and ultrasonic assisted pressureless sintering was used to fabricate copper parts. First, the ultimate tensile strength and thermal conductivity were compared between ultrasonic assisted and conventional pressureless sintered samples. The homogenously mixing of particles and local heat generation by ultrasonic vibrations promoted the sintering driving process and resulted in better mechanical and thermal properties. Furthermore, response surface methodology was adopted for the comprehensive study of the ultrasonic sintering parameters (sintering temperature, heating rate, and soaking time with ultrasonic vibrations) on ultimate tensile strength and thermal conductivity of the fabricated sample. Analysis of variance was performed to identify the significant factors and interactions. The image processing method was used to identify the surface porosity at different parameter levels to analyse the experimental results. High ultimate tensile strength was obtained at high sintering temperature, long soaking time, and slow heating rate with low surface porosity. After 60 min of soaking time, no significant effect was observed on the thermal conductivity of the fabricated sample. The significant interactions revealed less effect of soaking time at low sintering temperatures for ultimate tensile strength and less effect of heating rate at low sintering temperatures for thermal conductivity. Multi-objective optimization was carried out to identify parameters for maximum ultimate tensile strength and maximum thermal conductivity.

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Compressive Strength of high Performance Fibers

MRS Proceedings ◽

10.1557/proc-134-363 ◽

1988 ◽

Vol 134 ◽

Cited By ~ 13

Author(s):

Satish Kumar ◽

T. E. Helminiak

Keyword(s):

Tensile Strength ◽

Compressive Strength ◽

High Performance ◽

Tensile Modulus ◽

Direct Result ◽

Polymeric Fibers ◽

Aerospace Applications ◽

The Poor ◽

Significant Research ◽

Axial Compressive Strength

ABSTRACTSignificant research efforts have been carried out to improve the tensile modulus and tensile strength of high performance carbon and polymeric fibers. Experimental polymeric fibers (ordered polymer fibers) have been prepared with moduli >50 MPSI and tensile strength approaching one MPSI. However, the benefits of the above improvements in tensile properties for aerospace applications are limited because composites of these fibers have low axial compressive strength, which is a direct result of the poor axial fiber compressive strength. The poor axial fiber compressive strength has usually been attributed to the microfibrillar/fibrillar buckling. However, questions concerning the intrinsic limitations at the molecular level and the effects of intermolecular interactions are also considered important. Better understanding of these aspects will help in determining the theoretically achievable compressive strength and may aid in the development of higher compressive strength high performance fibers. These and other issues related to the compressive strength of high performance polymeric and carbon fibers are discussed in this paper.

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