Innovative strategy for controlling resonant frequencies of syntactic polymer foams regulating by hollow microspheres

This study aims to precisely control the resonant frequency of synthetic composite foam materials with fixed dimensions. By incorporating rigid hollow glass microspheres XLD3000(XLD) and flexible hollow polymer microspheres MFL-81GCA(MFL) into the base resin (EP), we prepared synthetic composite foams containing different volume fractions of hollow microspheres (EP-XLD and EP-MFL). We conducted tests and analyses on the density, mechanical properties, resonant frequency, and microstructure of the EP-XLD and EP-MFL systems. Results indicate that as the volume fraction of hollow microspheres increases, the flexural specific modulus of the EP-XLD and EP-MFL systems, respectively, exhibits a linear increase and decrease, and the resonant frequency shifts linearly towards higher and lower frequencies. This trend aligns with theoretical predictions, affirming that the material's resonant frequency is closely related to its flexural modulus. This research not only deepens the understanding of the control mechanisms for the resonant frequency of synthetic composite foams but also proposes an innovative material design strategy with broad application potential, particularly in the fields of acoustics, damping, and structural materials, where it promises to significantly enhance material performance and meet specific engineering needs.