Dual-Structural Models of Porous Polyimide Thermal Insulation Materials: Heat-Transfer Mechanism, Fabrication, and Modification Strategies

The excellent intrinsic physicochemical properties of polyimide (PI)-based materials lead to their popularity in the field of thermal insulation, with widespread use in aerospace, construction, microelectronics, and other areas. This work undertakes a comprehensive review of recent advances in porous PI thermal insulation materials and proposes a novel pore structure-based classification criterion. First, the analysis of the specific models reveals the characteristics of pore structures and the internal heat transfer mechanism. Second, the main preparation and molding methods of each structure are compiled, and the modification schemes for optimize the thermal insulation effect are listed and analyzed. Finally, a comprehensive discussion on the merits and drawbacks associated with the two distinct structural characteristics is provided. It further explores the optimal application pathways for each characteristic, along with potential avenues for enhancement of the design and the expansion of the application domains. The insights derived from this study are anticipated to serve as a robust theoretical foundation and a crucial technical reference for the design and advancement of high-performance PI-class thermal insulation materials.