Preparation and Characterization of Ribbon-shaped Mesophase Pitch-based Carbon Fibers with Different Crystal Orientations

doi:10.15541/jim20140101

Abstract

Abstract:

Using mesophase pitch as the raw material, with the rectangular-section spinnerets at different aspect ratios (length divided by width), ribbon-shaped mesophase pitch-based carbon fibers with various cross-section sizes and crystal orientations were prepared by adjusting the spinning rate. Effects of the heat-treatment temperature and aspect ratio of spinnerets on structure and properties of the ribbon-shaped carbon fibers were investigated. The results show that the aspect ratio of spinneret and the spinning rate of pitch fibers have a significant influence on the crystal orientation of carbon fibers. Within the specified spinning rate of pitch fibers, the crystal orientation of carbon fibers varies from a parallel-fold structure to a vertical-radial structure with the decrease of the aspect ratio of the spinnerets. The electrical conductivity and the mechanical property of ribbon-shaped carbon fibers significantly increase with the increase of heat-treatment temperature. With increase in spinning rate, there is no obvious change in the room-temperature axial electrical resistivity along the longitudinal direction of fiber, whereas obvious changes in the mechanical property are observed. At 30:1 of the aspect ratio of the spinneret and 75 m/min of spinning rate, the tensile strength and young’s modulus of the graphite fibers heat-treated at 2500℃ are up to 2.53 GPa and 234.77 GPa, respectively.

Key words: ribbon-shaped mesophase pitch-based carbon fiber, crystal orientation, electrical resistivity, mechanical property

CLC Number:

TB332

XIONG Xiao-Qing, YUAN Guan-Ming, LI Xuan-Ke, DONG Zhi-Jun, ZHANG Zhong-Wei, WANG Jun-Shan. Preparation and Characterization of Ribbon-shaped Mesophase Pitch-based Carbon Fibers with Different Crystal Orientations[J]. Journal of Inorganic Materials, 2014, 29(11): 1186-1192.

Figures/Tables 9

Fig. 1 Diagram of rectangular-section of spinneret

Table 1 Dimensions and aspect ratios of three rectangular-section spinnerets

No.	L/mm	W/mm	L/W
a	3	0.1	30:1
b	2	0.4	5:1
c	1	0.4	2.5:1.0

Fig. 2 SEM images (a1, b1 and c1) and carbon-layer orientation diagrams (a2, b2 and c2) of 2500℃ treated graphite fibers prepared from different spinnerets

Fig. 3 Relationship between spinning rate and cross-sectional area of mesophase pitch based fiber

Fig. 4 XRD patterns of ribbon-shape graphite fibers prepared at the spinning rate of 45 m/min after heat-treatment at different temperatures (a) and prepared at various spinning rates after heat-treatment at 2500℃ (b)

Table 2 Microcrystalline parameters of ribbon-shaped graphite fibers prepared at various spinning rates after heat-treatment at 2500℃

Spinning rate/(m·min^-1)	Peak width₍₀₀₂₎/(°)	d₀₀₂ /nm	L_c002/nm	g/%
15	0.3243	0.3373	24.88	77.8
30	0.3020	0.3373	26.72	78.4
45	0.3192	0.3374	25.28	76.7
60	0.3346	0.3376	24.11	74.9
75	0.3260	0.3374	24.11	76.2

Fig. 5 SEM images and carbon-layer orientation diagrams of graphite fibers prepared at different spinning rates after heat-treatment at 2500℃

Fig. 6 Relationship between electrical resistivity and spinning rate as well as heat-treatment temperature

Fig. 7 Relationship of tensile strength (a) and young’s modulus (b) with spinning rate as well as heat-treatment temperature of ribbon-shaped carbon fibers

References 21

[1]	LIU C Q, CHENG T, YU J M, et al. Preparation and study of mesophase pitch-based carbon firers. Carbon Techniques, 2002(5): 1-4.
[2]	CALLEGO N C, EDIE D D. Structure-property relationships for high thermal conductivity carbon fibers. Composites: Part A, 2001, 32(8): 1031-1038.
[3]	QIU H P, LIU L. Carbon matrix function materials of high thermal conductivity. New Carbon Materials, 2002, 17(4): 80.
[4]	QIU H P, GUO Q G, SONG Y Z, et al. Study of the relationship between thermal conductivity and microcrystalline parameters of bulk graphite. New Carbon Materials, 2002, 17(1): 36-40.
[5]	LIU J Q, SHI J L, GAO X Q.et al. The study on formation mechanism of radial structure of mesophase pitch-based carbon fibers. New Carbon Materials, 2010, 19(2): 19-87.
[6]	CHI W D, SHEN Z M, LIU J, et al. Influence of spinneret constructure on the section shape of non-circle shape mesophase bitch-based fiber. Carbon Techniques, 1999, 5: 5-8.
[7]	LI M W, WANG C Y. Preparation and properties of mesophase pitch-based ribbon-shaped carbon fibers. Chinese Journal of Materials Research, 1998, 12(5): 535-538.
[8]	EDIE D D, ROBBINSON K E, FLEUROT O, et al. High thermal conductivity ribbon fibers from naphthalene-based mesophase. Carbon, 1994, 32(6): 1045-1054.
[9]	EDIE D D, HAYES G J, RAST H E, et al. Processing of noncircular pitch-based carbon fiber. High Temperatures-High Pressure, 1990, 22: 289-298.
[10]	MOCHIDA I, YOON S H, KORAI Y. Control of transversal texture in circular mesophase pitch-based carbon fiber using noncircular spinning nozzles. Journal of Materials Science, 1993, 28(9): 2331-2336.
[11]	LU S L, BRIAN RAND. Large diameter carbon filaments from mesophase pitch for thermal management applications. New Carbon Materials, 2000, 15(1): 1-5.
[12]	MOCHIDA I, YOON S H, KORAI Y. Preparation and structure of mesophase pitch-based thin carbon tape. Carbon, 1993, 31(6): 941-949.
[13]	ROBINSON K K, EDIE D D. Microstructure and texture of ribbon fibers for thermal management. Carbon, 1996, 34(1): 11-36.
[14]	LI M W, WANG C Y. Research and applications of mesophase pitch-based carbon fibers. Carbon Techniques, 1998, 2: 31-35.
[15]	FORTIN F, YOON S H, KORAI Y, et al. Structure and properties of thin, slit-shaped carbon fibers prepared from mesophase pitch. Carbon, 1994, 32(6): 1119-1127.
[16]	EDIE D D, FAIN C C, ROBINSON C C, et al. Ribbon-shaped carbon fibers for thermal management. Carbon, 1993, 31(6): 941-949.
[17]	MA Z K, LIU L, LIU J. Effect of spinning process on the oriented structure and thermal conductivity of the mesophase pitch-based graphite friber. Journal of Inorganic Materials, 2010, 25(10): 989-993.
[18]	YUAN G M, LI X K, DONG Z J, et al. Preparation and characterization of highly oriented ribbon shape pitch-based carbon fibers. Journal of Inorganic Materials, 2011, 26(10): 1025-1030.
[19]	YUAN G M, LI X K, DONG Z J, et al. The structure and properties of ribbon-shaped carbon fibers with high orientation. Carbon, 2014, 68: 426-439.
[20]	YUAN G M, LI X K, DONG Z J, et al. Microstructure analyses of mesophase pitch-based carbon fibers with high thermal conductivity. Journal of Functional Materials, 2011, 42(10): 1806-1809.
[21]	ZHANG X, FUJIWARA S, FUJII M. Measurement of thermal conductivity and electrical resistivity of a single carbon fiber. Inter. J. Thermophys, 2000, 21(4): 965-980.