High temperature ceramics derived from linear carborane-(siloxane or silane)-acetylene copolymers

A boron-carbon-silicon ceramic made by a method comprising the step of:

• pyrolyzing at a temperature and for a time an organoboron thermoset polymer having a repeating unit of formula (I):
• wherein:
• (1) n and n′ are integers from 1 to 12 and u, u′, y, y′ and y″ are positive integers;
• (2) wherein
• represent cross-linked alkenyl moieties and wherein n and n′ are as previously indicated;
• (3) R1, R2, R3, R4, R5, R6, R7 and R8 are selected from the group consisting of saturated aliphatic, unsaturated aliphatic, aromatic, fluorocarbon moieties and mixtures thereof;
• (4)
• represents a carboranyl group;
• (5) q and q′ are integers from 3 to 16;
• (6) x and x′ represent integers between 0 to 2000;
• (7) A is selected from the group consisting of O, an aliphatic bridge, an aryl bridge and mixtures thereof;
• (8) E is selected from the group consisting of O, an aliphatic bridge, an aryl bridge and mixtures thereof;
• and
• (9) wherein E and A may be the same or different.