以中间相沥青为粘结剂的低密度高导热炭纤维网络体的研究

doi:10.15541/jim20190062

摘要/Abstract

摘要：

以中间相沥青为粘结剂, 采用500 ℃低温炭化炭纤维, 经低压模压成型、炭化和石墨化后得到低密度高导热炭纤维网络体。与以1300 ℃炭化炭纤维为原料和以酚醛为粘结剂制备的炭纤维网络体进行了比较。对粘结剂炭收率(热重分析)、样品微观形貌(扫描电子显微分析)、石墨化度及微晶尺寸(X射线衍射分析)等进行了表征。研究结果表明: 由于高炭收率和高片层取向度的中间相沥青与500 ℃低温炭化处理炭纤维共同经历后续热处理时呈现出相近的热收缩率, 因而具备良好的相互粘结性和石墨片层铆接效应, 其制备的炭纤维网络体经石墨化后密度为0.317 g?cm ^-3, 由此制备的相变复合材料的面内热导率为19.30 W·m ^-1·K ^-1, 较纯相变材料(石蜡)提升了80倍, 明显高于以1300 ℃炭化炭纤维为原料, 以中间相沥青和酚醛分别为粘结剂制备样品的面内热导率(17.03和14.47 W·m ^-1·K ^-1)。

关键词: 中间相沥青, 炭纤维, 高导热, 相变复合材料

Abstract:

The carbon bonded carbon fiber network was prepared by using carbon fibers carbonized at 500 ℃ with mesophase pitch as binder. The sample was compared with the one prepared by using carbon fibers carbonized at 1300 ℃and the one prepared by using phenolic resin as the binder. The carbon yields of binders, microstructure, graphitization degree and crystallite size of samples were characterized and thermal conductivity was obtained for the samples soaked into phase change materials (PCM) to form PCM composites. Results showed that a good “in-plane” bonding effect was formed between the highly aligned graphene layers of binders and graphite fibers. The density of the carbon fiber network after graphitization is 0.317 g?cm ^-3, and the in-plane thermal conductivity of its PCM composite is 19.30 W?m ^-1?K ^-1, increased by 80-folds as hhat of pure PCMs.

Key words: mesophase pitch, carbon fiber, high thermal conductivity, phase change materials composite

中图分类号:

TQ174

欧阳婷, 陈云博, 蒋朝, 费又庆. 以中间相沥青为粘结剂的低密度高导热炭纤维网络体的研究[J]. 无机材料学报, 2019, 34(10): 1030-1034.

OUYANG Ting, CHEN Yun-Bo, JIANG Zhao, FEI You-Qing. Evaluation of Low Density and Highly Thermal Conductive Carbon Bonded Carbon Fiber Network with Mesophase Pitch as Binder[J]. Journal of Inorganic Materials, 2019, 34(10): 1030-1034.

图/表 5

图1 中间相沥青、酚醛树脂及预氧化纤维在N2中的热重曲线(a)及热分析曲线(b)

Fig. 1 Thermogravimetic curves (a) and differential thermogravimetric curves (b) of mesophase pitch, phenolic resin and preoxidized fiber under nitrogen atmosphere

图2 不同炭纤维网络体的SEM照片

Fig. 2 Microstructures of different carbon fiber networks after carbonization or graphitization (a1) SCF500-MP1300; (b1) SCF1300-MP1300; (c1) SCF1300-PR1300; (a2) SCF500-MP2850; (b2) SCF1300-MP2850; (c2) CF1300-PR2850

图3 炭纤维网络体拉曼光谱(a)及XRD图谱(b)

Fig. 3 Raman spectra (a) and XRD patterns (b) of carbon fiber networks

表1 石墨化炭纤维网络体的微晶参数

Table 1 Microcrystalline parameters of graphitized carbon fiber networks

Sample	ρ/(g·cm^-3)	d₍₀₀₂₎/nm	g/%	FWHM (002)	FWHM (100)	L_c/nm	L_a/nm	R(I_D/I_G)
SCF500-MP2850	0.317	0.3371	79.8	0.303	0.432	28.2	40.4	0.253
SCF1300-MP2850	0.324	0.3369	82.8	0.304	0.231	28.1	75.5	0.245
SCF1300-PR2850	0.305	0.3364	88.7	0.393	0.480	21.7	36.4	0.245

表2 炭纤维网络体增强相变储能复合材料的导热性能

Table 2 Thermal conductivity of phase change composites enhanced by carbon fiber network

Sample	ρ/ (g·cm^-3)	k/(W·m^-1·K^-1)		Anisotropic index (AI)
Sample	ρ/ (g·cm^-3)	x, y (in plane)	z (out of plane)	Anisotropic index (AI)
SCF500- MP1300PCM	1.03	1.21	0.53	2.26
SCF1300- MP1300PCM	1.07	1.17	0.59	2.03
SCF1300- PR1300PCM	1.03	1.16	0.63	1.86
SCF500- MP2850PCM	1.05	19.30	3.45	5.59
SCF1300- MP2850PCM	1.09	17.03	2.42	7.03
SCF1300- PR2850PCM	1.09	14.47	4.53	3.20

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