Ceramics formed by pyrolysis of either linear or thermosetting carborane (siloxane or silane) acetylene based precursor polymers
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorsTeddy M. Keller, Leslie J. Henderson, Jr.
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Abstract
Ceramics that are formed from high temperature oxidatively stable thermosetting polymers which, in turn, are formed from linear polymeric materials having repeat units that contain at least one alkynyl group for cross-linking purposes and at least one bis(silyl or siloxanyl)carboranyl group.
Claims30
A boron-carbon-silicon ceramic made by a method comprising the step of:
- pyrolyzing an organoboron thermoset polymer having a repeating unit of the formula:
- ##STR18## wherein:
- (1) n is an integer from 1 to 12 and u and y are positive integers;
- (2) ##STR19## represents said unsaturated cross-linked moiety;
- (3) R.sup.1, R.sup.2, R.sup.3 and R.sup.4 represent hydrocarbon or aromatic moieties:
- (4) ##STR20## represents said carboranyl group;
- (5) q and q' are integers from 3 to 16;
- (6) x represents an integer greater than or equal to zero (x.gtoreq.0);
- and wherein said thermoset has a ceramic yield of at least 82% by weight.
A method for making a boron-carbon-silicon ceramic comprising the step of:
- pyrolyzing an organoboron thermoset polymer having a repeating unit:
- of the formula:
- ##STR21## wherein:
- (1) n is an integer from 1 to 12 and u and y are positive integers;
- (2) ##STR22## represents said unsaturated cross-linked moiety;
- (3) R.sup.1,R.sup.2,R.sup.3 and R.sup.4 represent hydrocarbon or aromatic moieties;
- (4) ##STR23## represents said carboranyl group;
- (5) q and q' are integers from 3 to 16;
- (6) x represents an integer greater than or equal to zero (x.gtoreq.0);
- and
- wherein said thermoset has a ceramic yield of at least 82% by weight.
The method of claim 28 wherein said pyrolyzing step further comprises heating said organoboron thermoset polymer between 450.degree. C. to 2750.degree. C. in an inert atmosphere.
Dependencies are inferred from the claim text.