폴리이미드의 주쇄 화학결합 구조와 주파수에 따른 유전 상수 및 손실 계수 간의 상관관계

초록

The rapid growth of 5G, AI computing, IoT, and high-density electronics has increased demand for polymeric insulators with low signal delay, low energy loss, and high thermal and chemical stability. While polyimides (PIs) are widely used for their thermal resistance and mechanical strength, conventional PIs often fail to meet the stringent dielectric requirements of modern high-frequency applications, prompting the need for new molecular designs. The dielectric behavior of PIs is closely related to the chemical structure of their dianhydride and diamine monomers. In particular, the electronic density, chain rigidity, aromatic content, and substituents of the dianhydride moiety significantly influence the dielectric constant (Dk) and dissipation factor (Df ) of the resulting PI across a wide frequency range. In this study, four representative dianhydrides-pyromellitic dianhydride (PMDA), 4,4’-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), 4,4’-biphthalic anhydride (BPDA), and 3,3’,4,4’-oxydiphthalic anhydride (ODPA)-were polymerized with a common diamine, 4,4’-oxydianiline (ODA), to synthesize a series of low dielectric PI films. The resulting PIs were characterized to evaluate the effects of backbone chemical linkage structure on Dk and Df over a range of frequencies. Additionally, thermal properties were assessed using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermomechanical analysis (TMA). This work aims to elucidate structure-property relationships in PI systems and provide design guidelines for high-performance polymeric insulators tailored for next-generation electronic and communication technologies.

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