Enhanced sound absorption property of polyimide aerogels by the incorporation of macropores

Polyimide (PI) aerogels hold immense potential in the fields of thermal insulation and sound absorption. However, their sound absorption capabilities have been hindered by the high air flow resistance. To mitigate the air flow resistance and enhance the sound absorption performance of PI aerogels, we employed a self-sacrificing templating strategy to introduce macropores into the PI aerogels, thus creating PI aerogels with microporous (MPI). Investigation into the insulating properties and sound absorption performance of MPI revealed a thermal conductivity of 35.82 mW m−1 K−1. Within the frequency range of 500–6300 Hz, MPI exhibited peak absorption coefficients ranging from 0.66 to 0.78, with peaks occurring between 1250 Hz and 2000 Hz. This represents a significant improvement over traditional PI aerogels, which have an absorption coefficient of 0.39 at 3150 Hz. And a notable shift of the peak absorption coefficient of MPI towards lower frequencies. The introduction of macropores significantly enhances the sound absorption performance of PI aerogels.