High-purity polymer foam with very small cells for use e.g. in plasma physics or as insulating material, obtained by emulsion polymerisation of styrene monomer and crosslinker using a highly concentrated internal phase

摘要

Polymer foam (I) obtained by emulsion polymerisation with a highly concentrated internal phase, made from a crosslinked hydrocarbon polymer based on styrene monomers (II), with a density of 40-260 mg/cm 3> and an average cell diameter of not more than 10 microns. An independent claim is also included for a method for the production of (I) by (a) making an emulsion from an organic phase containing (II) plus a surfactant and an aqueous phase containing an electrolyte and an initiator, so that the volume of the aqueous phase is at least 74% of the total volume of the two phases, (b) subjecting the emulsion to shear so as to reduce the diameter of the water bubbles, (c) polymerising the monomers to give a solid foam and (d) washing and drying the foam.