Abstract: An interconnected microcellular material, a method for preparing said material using low-value waste from the paper industry, such as industrial lignin, and the use thereof for the production of items such as catalysts, filters or absorbent elements.

Abstract: An interconnected microcellular material, a method for preparing said material using low-value waste from the paper industry, such as industrial lignin, and the use thereof for the production of items such as catalysts, filters or absorbent elements.

Abstract: The invention relates to a polyHIPE material provided with high mechanical strength, which material comprises at least one N-alkenyltriazole monomer and a cross-linking monomer in a weight ratio of cross-linking monomer/N-alkenyltriazole monomer of 1/100 to 60/100. It also relates to a process and an emulsion allowing this emulsion to be prepared, and to an article formed in whole or in part of this material, and notably a catalyst support for heterogeneous catalysis, a particle filter, metal ion adsorbent, or gas sensor.

Abstract: The present invention relates to: a novel process for the preparation of mesophasic polyborazylene. Said process is of particular value in that it affords a quality product from an appropriate polyborazylene, rapidly (virtually instantaneously), reproducibly and with a good yield. Furthermore, said process is easy to carry out. Said process comprises the preparation of polyborazylene by the polycondensation of borazine in a closed reactor and the addition, to said polyborazylene obtained by polycondensation, of a solvent selected from aromatic solvents, borazine solvents and mixtures thereof, mesophasic polyborazylene which is novel in that it is in the presence of a particular solvent and/or by virtue of its quality, the use of said polyborazylene of the invention, and/or prepared according to the invention, as a boron nitride precursor.

Abstract: A boron and silicon oxynitride obtained by preparing a polyborosiloxane precursor, conducting nitriding pyrolysis of the precursor to obtain an amorphous boron and silicon oxynitride, and optionally conducting additional pyrolysis to obtain a crystallized boron and silicon oxynitride. The polyborosiloxane precursor is prepared by condensation, in the presence of a catalyst, of (2) a polychlorosilane represented by the formula R3R4SiCl2 in which the substituents R3 and R4 are identical or different and each represents a hydrogen atom, a chlorine atom, a linear or branched alkyl or alkenyl or alkynyl radical having 5 or less carbon atoms, or an aryl or aralkyl radical having 6 to 18 carbon atoms, with (2) an alkyl borate represented by the formula (R5O)3B in which R5 represents a linear or branched alkyl radical having 1 to 5 carbon atoms.

Abstract: Silicon carbonitride ceramic materials are produced by (a) hardening a fusible polycarbosilane containing at least two .tbd.SiH groups per molecule by intimately contacting such fusible polycarbosilane with an effective hardening amount of the vapors of sulfur, next (b) heat treating the infusible polycarbosilane which results under an ammonia atmosphere to such extent as to introduce nitrogen into the infusible polycarbosilane without completely removing the carbon therefrom, and then (c) heat treating the nitrogenated polycarbosilane in a vacuum or in an inert atmosphere to such extent as to essentially completely convert it into a ceramic silicon carbonitride.

Abstract: Extrudable pre-ceramic polycarbosilanes are prepared by intimately contacting a crude polycarbosilane containing a fraction of high molecular weight polymers (e.g., molecular weights greater than about 25,000) with ethyl acetate, whereby selectively dissolving desired extrudable polycarbosilane essentially devoid of such fraction of high molecular weight polymers in the ethyl acetate, and then recovering such dissolved polycarbosilane from the ethyl acetate solvent.

Abstract: Silicon nitride ceramic materials are produced by (a) hardening a fusible polycarbosilane containing at least two .dbd.SiH groups per molecule by intimately contacting such fusible polycarbosilane with an effective hardening amount of the vapors of sulfur, and then (b) pyrolyzing the infusible polycarbosilane which results under an ammonia atmosphere.