为进一步弥补液晶聚芳酯(LCP)在高频通讯应用中介电性能的不足,采用超支化聚芳酯(HBP)改性的策略制备HBP/LCP共混体系,有效降低LCP的介电常数和介电损耗。以双酚A和均苯三甲酰氯为单体,通过调节单体配比制备不同支化度的HBP,研究HBP的结构和性能,并通过分子动力学模拟与实验验证相结合的方法,揭示HBP的支化度、含量与HBP/LCP共混体系介电性能的构效关系:HBP支化度的提升可有效增加LCP/HBP共混体系的自由体积分数,含20% HBP-3的LCP的自由体积分数较LCP空白样增大21%,使介电常数最低从3.10降至2.53,介电损耗从0.012降至0.0053。采用“结构-自由体积-介电性能”模型为新型低介电材料设计提供了理论指导,HBP改性LCP的方法为高频通信器件的介质材料开发开辟了新途径。
To further address the limitations in the dielectric properties of liquid crystal polymer (LCP) for high-frequency communication applications,a strategy employing hyperbranched polyarylate (HBP) to modify LCP was adopted to prepare an HBP/LCP blend system,significantly reducing both the dielectric constant and dielectric loss of LCP.By adjusting the monomer ratio of bisphenol A and trimesoyl chloride,HBPs with different branching degree were synthesized,and their structure and properties of HBP were investigated.The structure-property relationships between HBP branching degree,content and the dielectric performance of HBP/LCP blends were investigated through combining molecular dynamics simulation and experimental verification.The results demonstrated that increasing HBP branching degree significantly enhanced fractional free volume in LCP/HBP blends.Specifically,a 21% increase in fractional free volume was achieved in the LCP blend with 20% HBP-3 liquid crystalline polyarylate compared to the pure LCP.This structural optimization achieved a remarkable reduction in dielectric constant from 3.10 to 2.53 and dielectric loss from 0.012 to 0.0053.The “structure-free volume-dielectric property” model provides theoretical guidance for designing novel low-dielectric materials and this HBP-modified LCP approach opens a novel approach for developing dielectric materials in high-frequency communication devices.
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基金资助
国家重点研发计划项目(2021YFB3700105),国家自然科学基金项目(52402102)
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