改性热塑性胶黏剂对超材料复合叠层性能影响研究

Study on the Influence of Modified Thermoplastic Adhesive on the Properties of Metamaterial Composite Laminates

摘要: 高频聚酰亚胺柔性覆铜板(FCCL)因其低介电损耗的电气性能，可动态反复弯曲的物理机械综合性能等常作为制备超材料功能层的关键材料之一。本文对比了两种高频聚酰亚胺柔性覆铜板的材料性能及其制备的超材料功能层的电性能及其复合叠层的力学性能，其中掺杂了改性热塑性聚酰亚胺(TPI)薄膜胶黏剂的FCCL具有更低的介电常数(2.61@12GHz)和损耗角正切(0.0016@12GHz)，使得超材料功能层的S21透波曲线谐振频点相对无胶材料向高频频偏约620MHz，利用S参数反演得到超材料功能层的等效介电常数和等效磁导率曲线呈现相同趋势。此外由于胶粘剂PI分子链中引入的扭曲非共平面的杂萘联苯结构，大分子链更容易相互缠结，增强了改性TPI聚合物的粘结力，含改性TPI的复合叠层的层间断裂韧性是无胶材料的1.74倍。掺杂改性TPI的高频FCCL在实现超材料功能层设计优化及推动超材料复合叠层在武器装备实现结构功能一体化方面具有较大的应用价值。

Abstract: The high-frequency polyimide flexible copper-clad laminate (FCCL) is commonly used as a key material for preparing functional layers in metamaterials due to its low dielectric loss electrical properties and the ability to dynamically bend repeatedly, exhibiting comprehensive physical and mechanical performance. This study compares the material properties of two high-frequency polyimide flexible copper-clad laminates and investigates the electrical properties of the prepared metamaterial functional layers, as well as the mechanical properties of the composite layers. The FCCL, doped with thermoplastic polyimide (TPI) film adhesive, exhibits lower dielectric constants (2.61@12GHz) and loss tangent values (0.0016@12GHz). This results in a relative shift of approximately 620MHz towards higher frequencies in the resonance frequency of the S21 transmission curve of the metamaterial functional layer, compared to the adhesive-free material. The inverted S parameters reveal similar trends in the equivalent dielectric constant and magnetic permeability curves of the metamaterial functional layer. Furthermore, due to the introduction of twisted non-coplanar heterocyclic benzene structures in the PI molecular chains of the adhesive, the larger molecular chains are more prone to entanglement, enhancing the bonding strength of the TPI polymer. The interlinear fracture toughness of the composite layers containing TPI adhesive is 1.74 times that of the adhesive-free material. The incorporation of TPI in high-frequency FCCL holds significant value in optimizing the design of metamaterial functional layers and advancing the integration of structural and functional aspects in metamaterial composite layers for weapon systems.