| abstract |
Composite magnetizable microspheres formed of a core consisting of magnetizable charges distributed uniformly in a network of a polysilsesquioxane (SiVi) exhibiting ethylenic unsaturations and of a shell made of a crosslinked organosilicon polymer derived from the hydrosilylation of an organohydrogenpolysiloxane (SiH) with the ethylenically unsaturated groups of the polysilsesquioxane SiVi.n n n They are obtained by dispersion in a solvent of an aqueous suspension of magnetizable fillers not coated with a dispersing agent, dissolution of an alkoxysilane or of an alkoxysiloxane having ethylenic unsaturations, polycondensation into a polysilsesguioxane SiVi, elimination of water, dissolution in the organic phase of the SiH polymer, crosslinking, elimination of water, separation of the microspheres and possibly redispersion in water.n n n Use as active support in biology. |