Rhone-poulenc Chimie

Societe Europeenne De Propulsion

Rhone-poulenc Industries

Societe Nationale D'etude Et De Construction De Moteurs D'aviation-snecma

L'etat Francais, Represente Par Le Delegue General Pour L'armement

Jacques Dunogues

Jean-Paul Pillot

Marc Birot

Pierre Olry

Eric Bacque

Francoise Duboudin

Rene Pailler

Claude Biran

Odile Babot

Marcel Lefort

Roger Naslain

Yves Laurent

Xavier Bourrat

Christian Simonnet

Ren&eacute; Pailler

Paul L'Haridon

Raphael Bodet

Raymond Calas

Laurence Bois

Gerard Deleris

Paulette Lapouyade

Patrick Pujol

Olivier Manfe

Eric Bouillon

Preparation of mesophasic polyborazylene mesophasic polyborazylene and use as a BN precursor

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 R,R,SiCl,in which the substituents R,and R,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 (R,O),B in which R,represents a linear or branched alkyl radical having 1 to 5 carbon atoms.

Method of preparing silicon and boron oxynitrides

Infusible and insoluble polycarbosilanes, readily pyrolyzed into silicon carbide ceramic materials, e.g., SiC fibers, are produced by hardening a fusible polycarbosilane containing at least two .tbd.SiH groups per molecule via intimately contacting such fusible polycarbosilane with an effective hardening amount of the vapors of sulfur.

Production of infusible polycarbosilanes convertible into silicon

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.

Conversion of polycarbosilanes into silicon carbonitride ceramics

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.

Conversion of polycarbosilanes into silicon nitride ceramics

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.

Extrudable pre-ceramic polycarbosilanes

The present invention relates to copolymers containing --Si--N-- and --Si--Si-- bonds, which are obtained by the polycondensation of

Copolymers containing si-n and si-si bonds, polycarbosilazanes obtained

The present invention relates to functional 1,3-dihydrogeno disilazanes of formula: ##STR1## in which: R and R.sub.1, identical or different, represent an atom of hydrogen or a hydrocarbon such as an alkyl, alkenyl or alkynyl, cycloalkyl or cycloalkenyl, aryl, alkylaryl, alkenylaryl, alkynylaryl, arylalkyl, arylalkenyl or arylalkynyl radical, possibly functional, R also being able to represent a radical ##STR2## and R.sub.2 represents an atom of halogen, an OR group or an --NRR.sub.1 group, when R and R.sub.1 are both hydrocarbon radicals.

Functional 1,3-dihydrogeno disilazanes

The present invention relates to a process for preparing disilylmethanes, wherein the magnesian reaction is carried out between methylene chloride and at least one chlorosilane in a donor solvent.

Process for preparing disilylmethanes

A process for preparing hydrogenosilanes by hydrogenating disilanes, especially halogenated disilanes, under relatively mild reaction conditions is disclosed. The hydrogenation is effected in the presence of a catalytic system containing an aprotic compound and a nickel catalyst which consists essentially of finely divided nickel and is obtained by preliminary or in situ reduction of a nickel compound.

Process for the preparation of hydrogenosilanes

Growing community of inventors

Talence, France

Jacques Dunogues