New organic silazane polymers and their prepn. - for use in prepn. of ceramic mouldings and coatings

摘要

Silazane polymers (I) are prepd. by (1) mixing (i) at least one organosilane of formula SiHCl2R1 (1), (ii) one or more bis(chlorosilyl)alkanes of formula Cl-SiR2R3-(CH2)n-SiR2R3-Cl and opt. (iii) 1 or more chlorosilanes of formula (3) SiR4Cl3(3); (2) reacting with excess NH3 in inert solvent to form ammonolysis prod.; and (3) polymerising prod. in presence of basic catalyst capable of deprotonating. In the formulae R' = Cl, H, 1-4C alkyl, or Ph; R2,R3 = Cl, 1-4C alkyl, or Ph; R4 = Cl, 1-4C alkyl, vinyl or Ph; n = 4-14. (B) Also claimed is process for prepn. of ceramic material (II) by forming (I) as in (A) then sintering it. USE/ADVANTAGE - Prepn. of ceramic coatings and fibres or matrix materials for prepn. of mouldings from ceramic or metal powder or ceramic fibres. (I) are highly suitable for prepn. of (II), e.g. have good solubility, fusibility, and shapeability and give high ceramic yield, (II) are obtd. simply, with high purity, in desired shape, and with excellent physical properties.