Jin Jeong-Un, Hahn Jae Ryang, You Nam-Ho
Institute of Advanced Composite Materials, Korea Institute of Science and Technology (KIST), Jeonbuk 55324, Republic of Korea.
Department of Chemistry and Research Institute of Physics and Chemistry, Jeonbuk National University, Jeonju 54896, Republic of Korea.
ACS Omega. 2022 Jul 12;7(29):25565-25572. doi: 10.1021/acsomega.2c02731. eCollection 2022 Jul 26.
In this study, polyimide (PI) with high carbonization yield was used as a precursor to prepare graphite films with high thermal conductivity. The crystallinity, grain size, and thermal conductivity of the graphite films were characterized and found to vary according to the chemical structure of the PI precursor. Aromatic PIs containing ortho-substituted hydroxyl groups in the PI main chain (DHB-BPDA) were synthesized by the polycondensation reaction of 3,3'-dihydroxybenzidine (DHB) and 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA). The DHB-BPDA is converted to a polybenzoxazole (PBO) structure through thermolysis reaction during carbonization. The PBO containing a benzene ring and a heterocycle group can provide a strong main chain and high thermal stability due to its resonant structure. The graphite film prepared from DHB-BPDA exhibited a large grain size (63.727 nm) and a high thermal conductivity of 916 W/(mK).
在本研究中，具有高碳化产率的聚酰亚胺（PI）被用作前驱体制备具有高导热率的石墨薄膜。对石墨薄膜的结晶度、晶粒尺寸和导热率进行了表征，发现它们会根据PI前驱体的化学结构而变化。通过3,3'-二羟基联苯胺（DHB）与3,3',4,4'-联苯四甲酸二酐（BPDA）的缩聚反应合成了在PI主链中含有邻位取代羟基的芳香族PI（DHB-BPDA）。在碳化过程中，DHB-BPDA通过热解反应转化为聚苯并恶唑（PBO）结构。含有苯环和杂环基团的PBO由于其共振结构可提供强大的主链和高的热稳定性。由DHB-BPDA制备的石墨薄膜表现出较大的晶粒尺寸（63.727 nm）和916 W/(mK)的高导热率。
