Research on Acoustic Absorption Properties of Aramid Honeycomb Composite Material Reinforced by Polyimide Foam

To endue sound absorption behavior for aramid honeycomb core (ARHC), isocyanate-based polyimide foam (IBPIF) with excellent thermal insulation and acoustic properties produced by a new formulation of foaming slurry is filled into ARHC by the free foaming route. As a core factor to adjust the cellular structure of IBPIF, the effect of water dosage on the acoustic behavior of IBPIF and IBPIF filled ARHC (IBPIF/ARHC) is studied, and the optimal formula to produce IBPIF/ARHC is filtered out. Results suggest that water dosage effectively regulates the cellular structure of IBPIF. When water dosage is 7.2 g, IBPIF has a large windows opening rate, which plays a positive role in sound absorption performance. IBPIF/ARHC-3 has the best sound absorption property, which possesses a maximum sound absorption coefficient (alpha) of 0.9 at 1500 Hz. Its average alpha increases to 0.78 and shows an increase of 680% compared to ARHC. Meanwhile, the density of IBPIF/ARHC is only about 59 kg m(-3). In 300-600 Hz range, IBPIF-3 and ARHC show obvious synergy effects in sound absorption behavior. The average alpha of IBPIF-3 and ARHC is only 0.3 and 0.06, respectively, and that of IBPIF/ARHC-3 reaches up to 0.42. The thermal insulation performance of ARHC is also improved, and thermal conductivity decreases from 0.067 to 0.047-0.049 W (m K)(-1).

Automated summary

By filling aramid honeycomb core with isocyanate-based polyimide foam with excellent thermal insulation and acoustic properties, the cellular structure was optimized to enhance acoustic performance, leading to a significant improvement in sound absorption and thermal insulation. The study identified an optimal formula to produce the best combination, achieving higher sound absorption coefficient and reduced thermal conductivity.