Low dielectric constant (low-k) polymers play a crucial role in electronic communications by improving the signal transmission speed and reducing the signal loss. In this study, five siloxane-containing benzoxazines were designed and synthesized. The effect of different substituents on the benzene ring on the ring-opening curing of benzoxazine monomers was studied by nonisothermal differential scanning calorimetry and density functional theory. The corresponding polybenzoxazine models constructed using molecular simulation were employed to calculate the glass transition temperature and dielectric constant. Among them, PP-aptmds with tert-butyl substituted group on the benzene ring exhibited the best dielectric properties, with a dielectric constant of 2.44 and a dielectric loss of 0.0053 at 10 GHz. In addition, the relationship between the structure and dielectric properties of polybenzoxazines was analyzed based on dipole moment, polarizability, number density, and the highest occupied molecular orbital–lowest unoccupied molecular orbital gap. This method is expected to provide theoretical guidance for the design and development of low-k polybenzoxazines.

中文翻译：

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基于分子模拟的低k聚苯并恶嗪结构-性能关系

低介电常数（低k）聚合物可提高信号传输速度并减少信号损耗，在电子通信中发挥着至关重要的作用。本研究设计并合成了五种含硅氧烷的苯并恶嗪。采用非等温差示扫描量热法和密度泛函理论研究了苯环上不同取代基对苯并恶嗪单体开环固化的影响。采用分子模拟构建相应的聚苯并恶嗪模型来计算玻璃化转变温度和介电常数。其中，苯环上带有叔丁基取代基的PP-aptmds表现出最好的介电性能，在10 GHz时介电常数为2.44，介电损耗为0.0053。此外，还根据偶极矩、极化率、数密度以及最高占据分子轨道-最低未占据分子轨道间隙分析了聚苯并恶嗪的结构与介电性能之间的关系。该方法有望为低k聚苯并恶嗪的设计和开发提供理论指导。