氧化石墨烯掺杂的电纺聚酰亚胺基石墨纳米纤维的导热性能
Thermal conductivity of graphite nanofibers electrospun from graphene oxide-doped polyimide
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摘要: 本文将氧化石墨烯（GO）分散在N,N-二甲基乙酰胺（DMAc）中，以均苯四甲酸二酐（PMDA）和二氨基二苯醚（ODA）为单体聚合成聚酰亚胺（PI）的前驱体溶液，通过静电纺丝得到平行取向的纳米纤维薄膜，经热亚胺化制得聚酰亚胺纤维。用偏振红外光谱仪测试C ＝ O键在平行和垂直纤维方向的吸收强度，随着GO添加量的增加，平行纤维轴向的方向上吸收强度逐渐增强，至0.1%GO添加量达到最大值。这是由于GO通过提高静电纺丝溶液电导率，提高了PI分子链的取向程度。经炭化和石墨化，PI纤维转化为石墨纤维。石墨纤维的XRD显示（002）面间距随GO含量增加而减少，说明GO的添加提高了石墨化程度。这是因为GO诱导了石墨化过程。石墨纤维的拉曼光谱显示D峰随着GO的添加逐渐减小，表明了石墨微晶的缺陷逐渐减少。这些都是石墨纤维热导率增加的原因。通过稳态T型法测量得到的GO/PI基石墨纤维的热导率中，0.1%GO含量对应于最高的热导率，达到331 W m−1 K−1。本文发现极少量GO（0.1%）就可以显著提高PI基石墨纳米纤维的热导率，该方法具备巨大的应用潜力。Abstract: Aromatic polyimide (PI)-based graphite nanofibers were obtained from the graphitization of graphene oxide (GO)-doped electrospun PI nanofibers. GO improves the PI molecular orientation, crystalline structure and thermal conductivity of the resulting nanofibers. The degree of PI molecular orientation in the nanofibers is increased by the GO during fiber preparation. This improvement in molecular orientation produces an increase in the thermal conductivity of the graphite nanofibers, and the addition of only 0.1% GO has a significant effect. The GO not only affects the thermal conductivity, but improves the PI molecular orientation and its role as nucleation centers during graphitization. This approach and the resulting high thermal conductivity materials show great potential for practical applications.
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