Evonik Degussa Gmbh

United Initiatiors Gmbh & Co. Kg

United Initiators Gmbh & Co. Kg

Harald Herzog

Stipan Katusic

Peter Kress

Peter Albers

Konrad Rockstein

Harald Alff

Aristidis Ioannidis

Iris Nagl

Martin Kunz

Armin Wiegand

Hanno Wolf

Peter Kreß

Core-shell particles containing crystalline iron oxide in the core and amorphous silicon dioxide in the shell and in which

Iron-silicon oxide particles having an improved heating rate

Provided is a composite material which is in pellet form and which has particles with a core-shell structure, where the core of the particles has one or more magnetic materials, and the shell is made of silicon dioxide, and the pellet has one or more crosslinkable polyethylene and/or polyethylene-containing copolymers. Also provided is a process for crosslinking polyethylenes, by mixing the composite material, one or more free radical initiators, and at least one polyethylene, and heating the mixture inductively.

Composite material comprising polyethylene and magnetic particles

Iron-silicon oxide particles with a core and an outer shell have improved heating rates in a magnetic field. The core contains maghemite, magnetite, and haematite. The outer shell is essentially or exclusively silicon dioxide. The crystallite diameter of the haematite determined by X-ray diffraction is greater than 120 nm. A ratio of the brightness of the Debye-Scherrer diffraction ring by electron diffraction at a lattice plane spacing of 0.20+/&#x2212;0.02 nm, comprising maghemite and magnetite, to the brightness of the Debye-Scherrer diffraction ring by electron diffraction at a lattice plane spacing of 0.25+/&#x2212;0.02 nm, comprising maghemite, magnetite and haematite, is no more than 0.2.

Iron-silicon oxide particles having an improved heating rate in an alternating magnetic and electromagnetic field

Composite material comprising&#x2014;one or more heat-activatable free-radical initiators selected from the group consisting of organic peroxides and/or initiators having labile carbon-carbon bonds and particles which have a core-shell structure and the core of which comprises one or more magnetic materials, while the shell comprises silicon dioxide.

Heat-activatable free-radical initiators and composite material which comprises magnetic particles

Iron-silicon oxide particles with a core-shell structure, which have a) a BET-surface area of 10 to 80 m/g, b) a thickness of the shell of 2 to 30 nm and c) a content of iron oxide of 60 to 90% by weight, of silicon dioxide of 10 to 40% by weight, based in each case on the enveloped particles, where d) the proportion of iron, silicon and oxygen is at least 99% by weight, based on the enveloped particles, and where e) the core is crystalline and the iron oxides comprise haematite, magnetite and maghemite, f) the shell consists of amorphous silicon dioxide and g) at least one compound or a plurality of compounds consisting of the elements silicon, iron and oxygen is/are present between shell and core.

Iron-silicon oxide particles with a core-shell structure

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Karlstein, Germany

Harald Herzog