Liu Yiwu, Tang Ao, Tan Jinghua, Chen Chengliang, Wu Ding, Zhang Hailiang
National and Local Joint Engineering Center of Advanced Packaging Materials R & D Technology, Key Laboratory of Advanced Packaging Materials and Technology of Hunan Province, School of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007, P. R. China.
Key Laboratory of Polymeric Materials and Application Technology of Hunan Province, Key Laboratory of Advanced Functional Polymer Materials of Colleges, Universities of Hunan Province, College of Chemistry, Xiangtan University, Xiangtan 411105, P. R. China.
ACS Omega. 2021 Feb 4;6(6):4273-4281. doi: 10.1021/acsomega.0c05278. eCollection 2021 Feb 16.
A novel diamine (FAPDA) bearing rigid planar fluorene and amide groups was successfully synthesized. Using such diamine and pyromellitic dianhydride (PMDA), a high-barrier polyimide (FAPPI) was obtained. FAPPI exhibits an outstanding gas barrier. Its water vapor transmission rate (WVTR) and oxygen transmission rate (OTR) are as low as 0.51 g·m·day and 0.43 cm·m·day, respectively. Additionally, FAPPI shows excellent thermal stability with a coefficient of thermal expansion (CTE) of 5.8 ppm·K and a glass transition temperature ( ) of 416 °C. Molecular simulations, positron annihilation, and X-ray diffraction were utilized to gain insight on the microstructures for the enhanced barrier properties. Introducing fluorene moieties and amide groups improves the regularity and rigidity of molecular chains and increases interchain interaction of PI, resulting in low free volumes and decreased movement capacity of the chain. The low free volumes of FAPPI restrain the gas diffusivity and solubility. Meanwhile, the decreased chain movement reduces the diffusivity of gases. Consequently, barrier performances of FAPPI are improved. The polyimide possesses widespread application in the microelectronics packaging fields.
一种带有刚性平面芴和酰胺基团的新型二胺（FAPDA）被成功合成。使用这种二胺和均苯四甲酸二酐（PMDA），获得了一种高阻隔聚酰亚胺（FAPPI）。FAPPI表现出优异的气体阻隔性能。其水蒸气透过率（WVTR）和氧气透过率（OTR）分别低至0.51 g·m⁻²·day⁻¹和0.43 cm³·m⁻²·day⁻¹。此外，FAPPI显示出优异的热稳定性，热膨胀系数（CTE）为5.8 ppm·K，玻璃化转变温度（Tg）为416℃。利用分子模拟、正电子湮没和X射线衍射来深入了解增强阻隔性能的微观结构。引入芴基和酰胺基团提高了分子链的规整性和刚性，并增加了聚酰亚胺的链间相互作用，导致自由体积降低和链的运动能力下降。FAPPI的低自由体积抑制了气体的扩散率和溶解度。同时，链运动的减少降低了气体的扩散率。因此，FAPPI的阻隔性能得到改善。该聚酰亚胺在微电子封装领域具有广泛的应用。
