Polysubstituted chlorine-containing silazane polymers, process for their preparation, ceramic materials containing silicon nitride which can be manufactured therefrom, and their manufacture

US5196556A · 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: Mar 23, 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 polysubstituted chlorine-containing silazane polymers, to their preparation, to their processing to form ceramic material containing silicon nitride, and to said material itself. The chlorine-containing silazane polymers are prepared by reating oligosilazanes of formula (I) ##STR1## in which at least one of the indices a or b and at least one of the indices c or d are not equal to 0 and n is about 2 to about 12, with at least one of the chlorosilanes Cl.sub.2 R.sup.6 Si--CH.sub.2 CH.sub.2 --SiR.sup.6 Cl.sub.2, Cl.sub.3 Si--CH.sub.2 CH.sub.2 --SiR.sup.7 Cl.sub.2, R.sup.8 SiCl.sub.3 or R.sup.9 SiHCl.sub.2 at 30.degree. C. to 300.degree. C., where the radicals independently of one another have the following meanings: R.sup.1, R.sup.2, R.sup.4 =H, C.sub.1 -C.sub.6 alkyl or C.sub.2 -C.sub.6 alkenyl and R.sup.3, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9 =C.sub.1 -C.sub.6 alkyl or C.sub.2 -C.sub.6 alkenyl. The polysubstituted chlorine-containing silazane polymers 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.