Abstract: Ultra-high temperature, light-weight, black ceramic insulation having a density ranging from about 0.12 g/cc. to 0.6 g/cc. such as ceramic tile is obtained by pyrolyzing siloxane gels derived from the reaction of at least one organo dialkoxy silane and at least one tetralkoxy silane in an acid or base liquid medium. The reaction mixture of the tetra- and dialkoxy silanes also may contain an effective amount of a mono- or trialkoxy silane to obtain the siloxane gels. The siloxane gels are dried at ambient temperatures and pressures to form siloxane ceramic precursors without significant shrinkage. The siloxane ceramic precursors are subsequently pyrolyzed, in an inert atmosphere, to form the black ceramic insulation comprising atoms of silicon, carbon and oxygen. The ceramic insulation can be characterized as a porous, uniform ceramic tile resistant to oxidation at temperatures ranging as high as 1700° C.

Abstract: Non-flammable, fibrous-siloxane cured composites derived from the polymerization of dialkoxysilanes, trialkoxysilanes and tetraalkoxysilanes, in an aqueous medium, to obtain viscous polysiloxane resins. These siloxane resins are used to impregnate or coat various fibrous materials such as carbon fibers or glass cloth which are subsequently subjected to heat and pressure to form cured, non-flammable siloxane-impregnated composites e.g. panels having a density of about 1 to 3 g/cc. and a limited oxygen index above 30. These non-flammable, fibrous-siloxane composites are particularly useful in the manufacture of fire-proof materials for various transportation vehicles and for building materials e.g. panels as a fire barrier.

Abstract: Ultra-high temperature, light-weight, black ceramic insulation having a density ranging from about 0.12 g/cc. to 0.6 g/cc. such as ceramic tile is obtained by pyrolyzing siloxane gels derived from the reaction of at least one organo dialkoxy silane and at least one tetralkoxy silane in an acid or base liquid medium. The reaction mixture of the tetra- and dialkoxy silanes also may contain an effective amount of a mono- or trialkoxy silane to obtain the siloxane gels. The siloxane gels are dried at ambient temperatures and pressures to form siloxane ceramic precursors without significant shrinkage. The siloxane ceramic precursors are subsequently pyrolyzed, in an inert atmosphere, to form the black ceramic insulation comprising atoms of silicon, carbon and oxygen. The ceramic insulation can be characterized as a porous, uniform ceramic tile resistant to oxidation at temperatures ranging as high as 1700° C.

Abstract: Ultra-high temperature, light-weight, ceramic insulation such as ceramic tile is obtained by pyrolyzing a siloxane gel derived from the reaction of at least one organo dialkoxy silane and at least one tetralkoxy silane in an acid or base liquid medium. The reaction mixture of the tetra- and dialkoxy silanes may contain also an effective amount of a mono- or trialkoxy silane to obtain the siloxane gel. The siloxane gel is dried at ambient pressures to form a siloxane ceramic precursor without significant shrinkage. The siloxane ceramic precursor is subsequently pyrolyzed, in an inert atmosphere, to form the black ceramic insulation comprising atoms of silicon, carbon and oxygen. The ceramic insulation, can be characterized as a porous, uniform ceramic tile resistant to oxidation at temperatures ranging as high as 1700° C. and is particularly useful as lightweight tiles for spacecraft and other high-temperature insulation applications.

Abstract: High-temperature, lightweight, ceramic carbon insulation is prepared by coating or impregnating a porous carbon substrate with a siloxane gel derived from the reaction of an organodialkoxy silane and an organotrialkoxy silane in an acid or base medium in the presence of the carbon substrate. The siloxane gel is subsequently dried on the carbon substrate to form a ceramic carbon precursor. The carbon precursor is pyrolyzed, in an inert atmosphere, to form the ceramic insulation containing carbon, silicon, and oxygen. The carbon insulation is characterized as a porous, fibrous, carbon ceramic tile which is particularly useful as lightweight tiles for spacecraft.

Abstract: Ceramics are or protected from high temperature degradation, including high temperature, oxidative, aeroconvective degradation by a high temperature and oxidation resistant coating of a room temperature curing, hydrolyzed and partially condensed liquid polyorganosiloxane applied to the surface of the ceramic. The liquid polyorganosiloxane is formed by the hydrolysis and partial condensation of an alkyltrialkoxysilane with water or a mixture of an alkyltrialkoxysilane and a dialkyldialkoxysilane with water. The liquid polyorganosiloxane cures at room temperature on the surface of the ceramic to form a hard, protective, solid coating which forms a high temperature, oxidation resistant ceramic upon exposure to a high temperature environment, and is also used as an adhesive for adhering a repair plug in major damage to the ceramic. This has been found useful for protecting and repairing porous, rigid ceramics of a type used on reentry space vehicles.

Abstract: Rigid and flexible porous ceramics, including thermal insulation of a type used on space vehicles, are waterproofed by a treatment which comprises applying an aqueous solution of an organopolysiloxane waterproofing agent having reactive silanol groups to the surface of the ceramic and then heating the treated ceramic to form a waterproofed ceramic. The organopolysiloxane is formed by the hydrolysis and partial condensation of di- and trialkoxyfunctional alkylalkoxysilanes having 1-10 carbon atom hydrocarbyl groups.

Abstract: Lightweight, monolithic ceramics resistant to oxidation in air at high temperatures are made by impregnating a porous carbon preform with a sol which contains a mixture of tetraethoxysilane, dimethyldiethoxysilane and trimethyl borate. The sol is gelled and dried on the carbon preform to form a ceramic precursor. The precursor is pyrolyzed in an inert atmosphere to form the ceramic which is made of carbon, silicon, oxygen and boron. The carbon of the preform reacts with the dried gel during the pyrolysis to form a component of the resulting ceramic. The ceramic is of the same size, shape and form as the carbon precursor. Thus, using a porous, fibrous carbon precursor, such as a carbon felt, results in a porous, fibrous ceramic. Ceramics of the invention are useful as lightweight tiles for a reentry spacecraft.

Abstract: The present invention concerns novel high strength ceramic fibers derived from boron, silicon, and carbon organic precursor polymers. The ceramic fibers are thermally stable at and above 1200.degree. C. in air. The method for preparation of the boron-silicon-carbon fibers from a low oxygen content organosilicon boron precursor polymers of the general formula Si(R.sub.2)BR.sup.1 by melt-spinning, crosslinking and pyrolysis. Specifically, the crosslinked (or cured) precursor organic polymer fibers do not melt or deform during pyrolysis to form the silicon-boron-carbon ceramic fiber. These novel silicon-boron-carbon ceramic fibers are useful in high temperature applications because they retain tensile and other properties up to 1200.degree. C., from 1200.degree. to 1300.degree. C., and in some cases higher than 1300.degree. C.

Abstract: The present invention relates to a process for the production of an organoborosilicon preceramic polymer of the structure: ##STR1## wherein R.sup.1 is selected from alkyl having from 1 to 10 carbon atoms or phenyl, and x is selected from 0, 1, 2 or 3;which is pyrolyzable to produce a refractory material comprising inorganic compounds of Si, C and B, which process comprises:contacting a silicon containing compound of the structure:(R.sup.1).sub.x --Si--(CH.dbd.CH.sub.2).sub.4-x or (R.sup.1).sub.x Si--(C.tbd.CH).sub.4-xwith a boron containing compound selected from H.sub.3 B:BH.sub.3, H.sub.3 B:NH.sub.3, BH.sub.3 :N(R.sup.2).sub.3 wherein R.sub.2 is selected from methyl, ethyl, propyl, butyl or phenyl in an inert atmosphere at a temperature of between about 90.degree. and 170.degree. C. for between about 0.1 and 20 hr and recovering the prepolymer. The prepolymer is pyrolyzed to produce a ceramic article useful in high temperature (e.g., aerospace) or extreme environmental applications.

Abstract: The present invention relates to a process for the production of an organoborosilicon preceramic polymer of the structure: ##STR1## wherein R.sup.1 is selected from alkyl having from 1 to 10 carbon atoms or phenyl, and x is selected from 0, 1, 2 or 3;which is pyrolyzable to produce a refractory material comprising inorganic compounds of Si, C and B, which process comprises:contacting a silicon containing compound of the structure:(R.sup.1).sub.x --Si (CH.dbd.CH.sub.2).sub.4-x or (R.sup.1).sub.x Si(C.dbd.CH).sub.4-xwith a boron containing compound selected from H.sub.3 B:BH.sub.3, H.sub.3 B:NH.sub.3, BH.sub.3 :N(R.sup.2).sub.3 wherein R.sup.2 is selected from methyl, ethyl, propyl, butyl or phenyl in an inert atmosphere at a temperature of between about 90.degree. and 170.degree. C. for between about 0.1 and 20 hr and recovering the prepolymer. The prepolymer is pyrolyzed to produce a ceramic article useful in high temperature (e.g., aerospace) or extreme environmental applications.

Abstract: The present invention relates to a polyorganoborosilane ceramic precursor polymer comprising a plurality of repeating units of the formula: ##STR1## with the segments being linked together by second units of the formula: --[(R.sup.2)--Si--R.sup.3)--q, where R.sup.1 is lower alkyl, cycloalkyl, phenyl, or ##STR2## and R.sup.2 and R.sup.3 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 R.sup.4 --B--(X.sup.1).sub.2 where R.sup.4 is selected from halogen, lower alkyl, cycloalkyl, or aryl, and an organohalosilane of the formula: R.sup.2 (R.sup.3) Si(X.sup.2).sub.2 where R.sup.2 and R.sup.3 are each independently selected from lower alkyl, cycloalkyl, or aryl, and X.sup.1 and X.sup.

Abstract: The present invention relates to a polyorganoborosilane ceramic precursor polymer comprising a plurality of repeating units of the formula: ##STR1## with the segments being linked together by second units of the formula: --(R.sup.2)--Si--R.sup.3)--q, where R.sup.1 is lower alkyl, cycloalkyl, phenyl, or ##STR2## and R.sup.2 and R.sup.3 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 R.sup.4 -B-(X.sup.1).sub.2 where R.sup.4 is selected from halogen, lower alkyl, cycloalkyl, or aryl, and an organohalosilane of the formula : R.sup.2 (R.sup.3) Si(X.sup.2).sub.2 where R.sup.2 and R.sup.3 are each independently selected from lower alkyl, cycloalkyl, or aryl, and X.sup.1 and X.sup.

Abstract: The present invention relates to a method of preparing B-trichloroborazine, B.sub.3 N.sub.3 Cl.sub.3 H.sub.3. Generally, the method includes the combination of gaseous boron trichloride in an anhydrous aprotic organic solvent followed by addition of excess gaseous ammonia at ambient temperature or below. The reaction mixture is heated to between about 100.degree. to 140.degree. C. followed by cooling, removal of the solid ammonium chloride at ambient temperature, distillation of the solvent under vacuum if necessary at a temperature of up to about 112.degree. C., and recovery of the B-trichloroborazine. Solvents include, toluene, benzene, xylene, chlorinated hydrocarbons, chlorinated aromatic compounds, or mixtures thereof. Toluene is a preferred solvent. The process provides a convenient synthesis of a material which often decomposes on standing. B-trichloroborazine is useful in a number of chemical reactions, and particularly in the formation of high temperature inorganic polymers and polymer precursors.

Abstract: Vinyl pyridines including vinyl stilbazole materials and vinyl styrylpyridine oligomer materials are disclosed. These vinylpyridines form copolymers with bismaleimides which copolymers have good fire retardancy and decreased brittleness. The cure temperatures of the copolymers and substantially below the cure temperatures of the bismaleimides alone. Reinforced composites made from the cured copolymers are disclosed as well.

Abstract: Vinyl pyridines including vinyl stilbazole materials and vinyl styrylpyridine oligomer materials are disclosed. These vinylpyridines form copolymers with bismaleimides which copolymers have good fire retardancy and decreased brittleness. The cure temperatures of the copolymers are substantially below the cure temperatures of the bismaleimides alone. Reinforced composites made from the cured copolymers are disclosed as well.

Abstract: When vinyl pyridines including vinyl stilbazole materials and vinyl styrylpyridine oligomer materials are admixed with bismaleimides and cured to form copolymers the cure temperatures of the copolymers are substantially below the cure temperatures of the bismaleimides alone.

Abstract: The present invention relates to mixed bismaleimide/biscitraconimide resins. Mixtures of the two resins produces materials which have better handling, processing or mechanical and thermal properties, particularly in graphite composites, than materials made with the individual resins. The mechanical strength of cured graphite composites prepared from a 1:1 copolymer of such bisimide resins is excellent at both ambient and elevated temperatures. The copolymer mixture provides improved composites which are lighter than metals and replace metals in many aerospace applications.

Abstract: Perfluoroether triazine elastomers having improved properties are prepared from oligomeric imidoylamidines that have, in turn, been prepared by the process of (a) reacting a perfluorodinitrile with liquid ammonia to yield a perfluorodiamidine, (b) isolating the perfluorodiamidine, (c) reacting the isolated diamidine with a perfluorodinitrile to yield a perfluoro(imidoylamidine) dinitrile, and then repeating steps (a), (b), and (c) to sequentially grow an oligomer of desired molecular size. The isolated amidine and nitrile intermediates are also disclosed. The elastomers can be fashioned into seals, gaskets, sealing components and the like.

Abstract: Vinyl pyridines including vinyl stilbazole materials and vinyl styrylpyridine oligomer materials are disclosed. These vinylpyridines form copolymers with bismaleimides which copolymers have good fire retardancy and decreased brittleness. The cure temperatures of the copolymers are substantially below the cure temperatures of the bismaleimides alone. Reinforced composites made from the cured copolymers are disclosed as well.