| 摘要 |
The present invention relates to a polyorganoborosilane ceramic precursor polymer comprising a plurality of repeating units of the formula: <IMAGE> with the segments being linked together by second units of the formula: -(R2)-Si-R3)-q, where R1 is lower alkyl, cycloalkyl, phenyl, or <IMAGE> and R2 and R3 are each independently selected from hydrogen, lower alkyl, vinyl, cycloalkyl, or aryl, n is an integer between 1 and 100; p is an integer between 1 and 100; and q is an integer between 1 and 100. These materials are prepared by combining an organoborohalide of the formula R4-B-(X1)2 where R4 is selected from halogen, lower alkyl, cycloalkyl, or aryl, and an organohalosilane of the formula : R2 (R3) Si(X2)2 where R2 and R3 are each independently selected from lower alkyl, cycloalkyl, or aryl, and X1 and X2 are each independently selected from halogen, in an anhydrous aprotic solvent having a boiling point at ambient pressure of not greater than 160 DEG C. with in excess of four equivalents of an alkali metal, heating the reaction mixture and recovering the polyorganoborosilane. These silicon boron polymers are useful to generate high-temperature ceramic materials, such as SiC, SiB4, and B4C, upon thermal degradation above 600 DEG C.
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