Polyvinylidene fluoride composite foam material as well as preparation method and application thereof

The invention relates to a polyvinylidene fluoride composite foam material preparation method, which comprises: carrying out extrusion granulation on polyvinylidene fluoride, polymethyl methacrylate and a carbon material to obtain composite particles; and carrying out foaming molding on the composite particles by an injection molding foaming method to obtain the polyvinylidene fluoride composite foam material. The invention also relates to the polyvinylidene fluoride composite foam material prepared by the preparation method and application of the polyvinylidene fluoride composite foam material in preparation of piezoelectric devices. The content of beta-phase crystals in the prepared polyvinylidene fluoride composite foam material accounts for about 80% of the total crystal content, and the compression strength can be improved to 12MPa, so that the polyvinylidene fluoride composite foam material has excellent piezoelectric property and mechanical property, and can be used as a piezoelectric material for prep