Fabrication of Hydroxyl Modified Hollow Glass Microsphere Composite Isocyanate-Based Polyimide Foam and Optimization Strategy Based on Different Bonding Mechanisms

In this study, the hydroxyl modified hollow glass microsphere (HM-HGM) is added to different foaming slurries of isocyanate-based polyimide foam (IBPIF) at varying ratios, and different bonding effects are formed to optimize the dispersion behavior. Then, the novel HGM composited IBPIF (IBPIF/HGM) is prepared. Hydroxyl groups on HM-HGM establish hydrogen bonding effect with pyromellitic acid dimethyl ester and dimethyl formamide in the white slurry and react with isocyanate groups in the black slurry. The cell structure of IBPIF is altered to improve its sound absorption performance and mechanical behaviors. Compared with IBPIF/HGM-0, the average cell size of IBPIF/HGM-1 and BPIF/HGM-5 decreases significantly. The sound absorption performance and mechanical behaviors of them are improved to some extent. Compared with samples in which the HM-HGM is added alone to a single slurry, when the dosage ratio of HM-HGM in black and white slurries is 1:1, IBPIF/HGM-3 has more uniform cell structure. The change of IBPIF cell structure by the introduction of HM-HGM and the unique structure of HM-HGM can enhance the sound absorption performance and mechanical behaviors of IBPIF. The design idea of different bonding mechanisms significantly provides technical assistance to enhance the acoustic performance of polymeric foam materials.