Crosslinkers for silazane polymers
AssigneeDow Corning Corporation
InventorsThomas Duncan Barnard, Duane Ray Bujalski, Gregg Alan Zank
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Abstract
A method of crosslinking a silazane polymer having Si--H bonds in which the polymer is mixed with a crosslinker selected from alkenyl functional cyclosiloxanes and alkenyl functional cyclosilazanes and a crosslinking promoter and then heated to a temperature sufficient to crosslink the silazane polymer. The mixture of the silazane polymer, crosslinker and promoter is useful in the formation of ceramic matrix composites.
Claims4
A method of forming a ceramic matrix composite comprising
- preparing a mixture comprising a silazane polymer having Si--H bonds, a crosslinker selected from the group consisting of alkenyl functional cyclosiloxanes and alkenyl functional cyclosilazanes and a crosslinking promoter;
- impregnating an assembly of fibers with the mixture;
- heating the impregnated fibers to a temperature sufficient to crosslink the silazane polymer to produce a pre-preg;
- and
- pyrolyizing the pre-pre at a temperature sufficient to ceramify the pre-preg.
A method of densifying a porous ceramic comprising:
- preparing a mixture comprising a silazane polymer having Si--H bonds, greater than about 15 wt % of a crosslinker selected from the group consisting of alkenyl functional cyclosiloxanes and alkenyl functional cyclosilazanes and a crosslinking promoter;
- impregnating a porous ceramic with the mixture;
- heating the impregnated porous ceramic to a temperature sufficient to crosslink the silazane polymer;
- and
- pyrolyzing the porous ceramic containing the cured silazane polymer to a temperature sufficient to ceramify the polymer.
A solvent free method of densifying a porous ceramic comprising:
- preparing a mixture consisting essentially of a silazane polymer having Si--H bonds, greater than about 15 wt % of a crosslinker selected from the group consisting of alkenyl functional cyclosiloxanes and alkenyl functional cyclosilazanes and a crosslinking promoter;
- impregnating a porous ceramic with the mixture;
- heating the impregnated porous ceramic to a temperature sufficient to crosslink the silazane polymer;
- and
- pyrolyzing the porous ceramic containing the cured silazane polymer to a temperature sufficient to ceramify the polymer.
Dependencies are inferred from the claim text.