The relationships between the structure and the dielectric properties of polyimides (PIs) were extensively studied to construct universal correlations of dielectric constant (D_k) and dissipation factor (D_f) on the structural parameters. In this study, 36 kinds of PIs with a plethora of functional groups including ether, fluorine, amide, ester, ketone, sulfide, sulfone, and alkane groups were prepared by polyaddition and thermal imidization. Accordingly, their thermal, mechanical, and dielectric properties were systematically investigated. The experimental results showed highly correlated relationships between the D_k values and two structural parameters of fluorine content (F%) and volume polarizability (P/V) with a correlation coefficient of 0.98 and 0.90, respectively. Likewise, the D_f value was highly correlated to the imide group content (Imide%) with a correlation coefficient of 0.95. However, a multiple positive trend was found in the relationship between the D_f values and the volume dipole moment (μ/V) for the PIs. The discrepancy might be resulted from the difficulty to elucidate local molecular motions in the unit structure of PIs. Nevertheless, the D_f values still presented a nontrivial relation to the orientational polarization and dipole moment of the unit structures. Collectively, our experimental results revealed the structure–dielectric properties relationships of the PIs by rational definition on a series of structural parameters and warrant further investigation. Meanwhile, this work provides systematic guidelines for molecular structure design of PIs which are promising for high frequency applications on the fifth-generation (5G) mobile communications technology.

中文翻译：

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在10 GHz高频下，将聚酰亚胺的分子结构与介电常数和耗散因数相关联

对聚酰亚胺（PI）的结构与介电性能之间的关系进行了广泛研究，以构建介电常数（D _k）和耗散因数（D _f）在结构参数上的通用关系。在这项研究中，通过加成和热酰亚胺化制备了36种具有过多官能团的PI，包括醚，氟，酰胺，酯，酮，硫化物，砜和烷烃基。因此，系统地研究了它们的热，机械和介电性能。实验结果表明，D _k值与两个结构参数的氟含量（F％）和体积极化率（P/ V）的相关系数分别为0.98和0.90。同样，D _f值与酰亚胺基含量（酰亚胺％）高度相关，相关系数为0.95。但是，在PI的D _f值与体积偶极矩（μ/ V）之间的关系中发现了多个正趋势。差异可能是由于难以阐明PI的单位结构中的局部分子运动。尽管如此，D _f值仍然呈现出与单元结构的定向极化和偶极矩无关的关系。总体而言，我们的实验结果通过合理定义一系列结构参数揭示了PI的结构-介电性能关系，值得进一步研究。同时，这项工作为PI的分子结构设计提供了系统的指导方针，有望在第五代（5G）移动通信技术上用于高频应用。