Scalable Fabrication of Lightweight, Heat‐Resistant, and Controllable Sizes Polyimide Hollow Microspheres

Polyimide hollow microspheres (PIHMs) possess lightweight and excellent thermal resistance, making them highly valuable for various applications in aerospace, catalysis, and irradiation. Co‐polymerized PIHMs (PIHM BMD s) are fabricated through powder foaming combined with a gradient heating strategy in this work. The diameter of PIHM BMD s ranged from 364 to 1230 µm, which can be designed by regulating the size of polyester ammonium salts (PEASs). The PIHM BMD s possess intact morphology with a breakage rate of 3%–10% and low bulk density with a density ranging from 28.3 to 62.9 kg m −3 . Furthermore, PIHM BMD s exhibit excellent thermal properties with a 5% weight loss temperature and glass transition temperature of 525.0 and 282.5 °C, respectively, making it an ideal material for fabricating lightweight and high‐temperature‐resistant multifunctional composites. Moreover, the proposed method is simple, efficient, and easily scalable, which is suitable for industrial applications to manufacture large quantities of PIHMs.