Achieving Low Dielectric Loss and High Humidity Stability Polyimide Through the Synergistic Effect of Copolymer Monomer Optimization and Aggregation State Regulation

Polyimide (PI) has excellent comprehensive performance and a wide range of applications, but its high molecular chain rigidity, poor flexibility, and difficulty in processing and molding limit its further applications. Introducing flexible groups, fluorinated groups, and copolymer modification are effective methods to improve PI performance. Among them, ether bonds can enhance the mobility of molecular chains and optimize processing performance, trifluoromethyl groups can improve material crystallinity and high-frequency dielectric properties, and copolymer modification can achieve the regulation of aggregated structures. In this study, the rigid TFMB-BPDA polyimide system was used as the matrix, and various ether-bond-containing diamine monomers were introduced through copolymerization, to explore the effects of different types of ether-bond-containing diamines and the soft-to-hard segment ratios on the aggregated structure and high-frequency dielectric properties of PI films. The goal is to optimize the comprehensive performance of PI materials through molecular structure design.