Liu Dongxu, Ma Chuanguo, Chi Hongtao, Li Shihui, Zhang Ping, Dai Peibang
School of Material Science and Engineering, Guilin University of Electronic Technology Guilin 541004 China
Guangxi Key Laboratory of Information Materials Guilin 541004 China.
RSC Adv. 2020 Nov 24;10(69):42584-42595. doi: 10.1039/d0ra08048a. eCollection 2020 Nov 17.
To improve the perfection of a three-dimensional thermally conductive network in polyimide (PI) composite film and with respect to the economy and simplicity of processing, a strategy of the two-step synergism of AlO microspheres and hexagonal boron nitride (BN) nanosheets was proposed. First, BN nanosheet-coated AlO microspheres (AlO@BN) were prepared by electrostatic self-assembly method for the first step of the synergism. Then, the AlO@BN&BN/PI composite film containing AlO@BN and BN was fabricated by a two-step method for the second step of the synergism, and was systematically characterized. With an optimized mass ratio of 2 : 1 of AlO@BN to BN, the thermal conductivity of the 35 wt% AlO@BN&BN/PI composite film reached 3.35 W m K, and was increased by 1664% compared to that of pure PI. The synergism of the AlO and BN was the most significant in the AlO@BN&BN/PI composite film with the thermal conductivity, which was 36.6%, 23% and 22% higher than that of the AlO/PI, BN/PI and AlO@BN/PI composite films, respectively. The enhancement mechanism of heat conduction was clearly demonstrated. The BN coated on the surface of AlO mainly played a bridging role between the AlO and the BN network, which improved the perfection of the thermally conductive network. The AlO@BN segregated the PI matrix to construct the BN network with the typical segregated structure in the composite film, resulting in an efficient thermally conductive network. This work provided a novel strategy for the preparation of conductive polymer composites.
为提高聚酰亚胺（PI）复合薄膜中三维导热网络的完善程度，并考虑到加工的经济性和简便性，提出了一种AlO微球与六方氮化硼（BN）纳米片两步协同的策略。首先，通过静电自组装法制备BN纳米片包覆的AlO微球（AlO@BN），作为协同作用的第一步。然后，采用两步法制备含AlO@BN和BN的AlO@BN&BN/PI复合薄膜，作为协同作用的第二步，并对其进行系统表征。当AlO@BN与BN的质量比优化为2∶1时，35 wt%的AlO@BN&BN/PI复合薄膜的热导率达到3.35 W m⁻¹ K⁻¹，与纯PI相比提高了1664%。AlO和BN的协同作用在AlO@BN&BN/PI复合薄膜中最为显著，其热导率分别比AlO/PI、BN/PI和AlO@BN/PI复合薄膜高36.6%、23%和22%。明确阐述了热传导增强机制。包覆在AlO表面的BN主要在AlO与BN网络之间起桥梁作用，提高了导热网络的完善程度。AlO@BN使PI基体分离，在复合薄膜中构建了具有典型分离结构的BN网络，形成了高效的导热网络。这项工作为制备导电聚合物复合材料提供了一种新策略。
