氧化石墨烯诱导聚酰亚胺薄膜碳化制备高垂直导热石墨膜

Preparation of graphite films with high vertical thermal conductivity by graphene oxide inducing carbonization of polyimide films

随着电子设备的小型化、轻量化,高导热石墨膜受到广泛关注。本文使用对苯二胺(p-PDA)与4,4′-二氨基二苯醚(ODA)、均苯四甲酸二酐(PMDA)共聚,并通过机械共混法添加多种二维碳纳米材料,包括氧化石墨烯(GO)、还原氧化石墨烯(rGO)和石墨烯(GP),制备了一系列纳米复合薄膜。薄膜经过2 850℃高温烧结得到相应的石墨膜,对石墨膜的微观形貌和晶型进行分析。结果表明:含二维碳纳米材料的石墨膜表面平整,具有更好的柔韧性、更高的石墨化程度以及更大的晶体粒度,片层间距也更加接近理想石墨。添加GO质量分数为2%的石墨膜水平导热系数为1 207 W/(m·K),垂直导热系数为8.38 W/(m·K)。因此,GO纳米片能够高温诱导聚酰亚胺薄膜的石墨化,烧结形成的石墨膜具有优异的导热性能。

With the miniaturization and light-weighting of electronic equipment, graphite films with high thermal conductivity attract extensive attention. In this paper, a series of nanocomposite films were prepared by copolymerizing pphenylenediamine(p-PDA) with 4, 4′-oxybisbenzenamine(ODA) and 1, 2, 4, 5-benzenetetracarboxylic anhydride(PMDA),and various two-dimensional carbon nanomaterials, including graphene oxide(GO), reduced graphene oxide(rGO), and graphene(GP), were added via mechanical mixing. And then corresponding graphite films were obtained after hightemperature sintering of polyimide films at 2 850℃, the morphology and crystal type of graphite films were analyzed. The results show that graphite films with two-dimensional carbon nanomaterials are flat, they exhibit more flexible, higher degree of graphitization, and larger crystal size, and the lamellar spacing is closer to the ideal graphite. In particular, the horizontal thermal conductivity and vertical thermal conductivity of graphite film containing 2% of GO nanosheets is 1 207W/(m·K) and 8.38 W/(m·K), respectively. It is concluded that GO nanosheets can induce graphitization of polyimide films under high temperature, and the graphite sheet sintered shows excellent thermal conductivity.