Abstract: The invention relates to a material consisting of an aqueous dispersion of PEG-coated nanoparticles of maghemite. The process for preparing said material consists in polymerizing ethylene oxide in the presence of nanoparticles of maghemite in an aqueous dispersion. The polymerization is initiated using reactive groups which are capable of initiating the polymerization of ethylene oxide without the addition of a catalyst, and which are attached to the nanoparticles of maghemite by means of a coupling agent comprising an alkoxysilyl group and one or more of said reactive groups. Applications: contrast agent for MRI.

Abstract: The invention concerns a polymer dispersion free of water and volatile organic solvent for preparing a lubricating composition for glass yarns and for finishing glass yarns and assembling glass yarns, in particular for grids and fabrics. The dispersion comprises the product of polymerization of a vinyl monomer in the presence of a free radical initiator in a reactive organic dispersion medium.

Abstract: The invention relates to a material consisting of an aqueous dispersion of PEG-coated nanoparticles of maghemite. The process for preparing said material consists in polymerizing ethylene oxide in the presence of nanoparticles of maghemite in an aqueous dispersion. The polymerization is initiated using reactive groups which are capable of initiating the polymerization of ethylene oxide without the addition of a catalyst, and which are attached to the nanoparticles of maghemite by means of a coupling agent comprising an alkoxysilyl group and one or more of said reactive groups. Applications: contrast agent for MRI.

Abstract: The present invention relates to a polymer dispersion devoid of water and of volatile organic solvent intended for the preparation of sizing compositions for glass strands and of coating compositions for glass strands and assemblages of such strands, in particular grids or woven fabrics. The dispersion comprises the product from the polymerization of at least one vinyl monomer in the presence of a radical initiator in a reactive organic dispersing medium. The dispersion includes 20 to 70% by weight of polymer in the form of fine substantially spherical particles with a size of less than 40 ?m. It is stable under the normal storage conditions.

Abstract: The invention relates to a composition based on a grafted metal oxide, its preparation and its use in a process of polymerization by opening oxygenated rings such as alkyl oxides, cyclic esters or cyclic carbonates. The composition comprises a support chosen from the group of metal oxides capable of containing hydroxyl functions, onto which is grafted a group of formula (1) —M(OR)n in which M is an element chosen from scandium, zirconium, hafnium, niobium, tantalum, rare-earth metals and actinides, R is an organic group and n is an integer greater than or equal to 1. The composition is prepared by forming a suspension of the abovementioned support and then placing in contact and reacting this suspension with a compound of formula (2) M(OR)n+1 in which M, R and n are defined as above.