Life Technologies as

Sintef

Turid Ellingsen

Arvid Trygve Berge

John Ugelstad

Geir Fonnum

Astrid Evenroed Molteberg

Elin Marie Aksnes

Ellen Weng

Rolf Nordal

Solveig Staale

Finn Hansen

Oddvar Aune

Henning Pettersen

Oskar B Helgee

Silje Nordbø

John Bjørgum

Arne Jørgedal

Tollef Taarneby

Silje Nordbo

John Bjorgum

Tollef Tårneby

Arne Jorgedal

A process for the preparation of monodisperse polymer particles which are formed by contacting monomers with aqueous dispersions comprising monodisperse swellable seed polymers/oligomers, and initiating polymerization in the presence of a steric stabilizer. The resulting swollen seed particles are characterized by the particle mode diameter.

Process for the preparation of monodisperse polymer particles

Magnetic polymer particles prepared by treating compact or porous polymer particles with a solution of iron salts and, if desired, salts of other metals which are capable of forming magnetic ferrites, in which the solution swells or penetrates into the particles. Iron hydroxide and possible other metal hydroxides are precipitated, for instance by raising the pH value, and the particles are optionally heated. In the iron salts used the ratio between di- and trivalent iron is suitably such that magnetic iron oxide is formed directly. It is also possible to use oxidizing or reducing groups or additives to obtain such a ratio. When other metal salts are used in addition to iron salts, the operation is carried out in the same manner. For instance, when Mn.sup.++, Co.sup.++ or Ni.sup.++ salts are used in addition to Fe.sup.++ salts, the divalent iron is oxidized to trivalent so that magnetic ferrite is obtained. The polymer particles which are treated with metal salts preferably contain metal-binding groups. Such groups are incorporated for instance by using monomers which contain said groups for the preparation of the polymer particles, or the groups are incorporated in the polymer particles prepared. The magnetic polymer particles are spherical and have a uniform concentration of magnetic material. They may be used for medical, diagnostic or other purposes.

Process for preparing magnetic polymer particles

Magnetic polymer particles and process for the preparation thereof

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Trondheim, Norway

Turid Ellingsen