| 摘要 |
<p>A method for forming carbon-carbon composites consists of impregnating structures with carbon-forming precursor compounds comprising multi-functional benzoxazine compounds. The impregnated structures are pyrolyzed to form carbonaceous char which serves to fill the interstices in the structure, thus densifying the composites. The process of impregnation and pyrolysis is repeated as many times as required to obtain the composite density desired. Unusually high char yields are produced by multi-functional benzoxazine compounds in which benzoxazine structures are joined to each other through a bridge characterized by having conjugated unsaturation associated therewith. A number of preferred compounds providing unexpectedly high yields of char are disclosed, enabling the desired densification to be achieved with a minimum number of impregnation and pyrolysis cycles, thereby reducing the costs of forming the composites.</p> |
