Polymeric chlorosilazanes, process for their preparation, ceramic materials containing silicon nitride which can be manufactured therefrom, and their manufacture

US5182411A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Tilo Vaahs · Kelkheim, DE
• Marcellus Peuckert · Hofheim, DE
• Martin Bruck · Hofheim, DE

Key dates

• Filing date: Nov 30, 1989
• Grant date: Jan 26, 1993
• Expiry date: Nov 30, 2009

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C04B35/589
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The invention relates to novel polymeric chlorosilazanes, to their preparation, to their processing to form ceramic material containing silicon nitride, and to said material itself. The polymeric chlorosilazanes are prepared by reacting a mixture of oligosilazanes of formula (I) ##STR1## in which n is about 2 to about 12, and oligosilazanes of formula (II), (RSiHNH).sub.m, in which m is about 3 to about 12, with at least one of the chlorosilanes Cl.sub.2 R.sup.2 Si--CH.sup.2 --CH.sub.2 --SiR.sup.2 Cl.sub.2, Cl.sub.3 Si--CH.sub.2 --CH.sub.2 --SiR.sup.3 Cl.sub.2, R.sup.4 SiCl.sup.3 or R.sup.5 SiHCl.sub.2 at 30.degree. C. to 300.degree. C., where R and R.sup.1 to R.sup.5 are C.sub.1 -C.sub.6 alkyl or C.sub.2 -C.sub.6 alkenyl groups which can be identical or different. The polymeric chlorosilazanes according to the invention can be converted into polysilazanes by reaction with ammonia, and these in turn can be pyrolyzed to form ceramic materials containing silicon nitride.