Abstract: A composition includes a siloxane of the formula: (RMe2SiO1/2)a(MeRSiO2/2)b(RSiO3/2)c(SiO4/2)d wherein a is at least 2, b is from 3 to 20, c is from 0 to 10, d is from 0 to 10, and each R is independently of the formula —CR?2—CR?2—Y—Z or CR?2—CR?2—Z, wherein each R? is independently a hydrogen atom or a C1 to C10 hydrocarbyl free of aliphatic unsaturation so long as at least one R? is a hydrogen atom, Y is a divalent organic group, and Z is a polycyclic group containing at least one aromatic ring. A method of making the siloxane includes charging (HMe2SiO1/2)a(MeHSiO2/2)b(HSiO3/2)c(SiO4/2)d, a platinum catalyst, and an alkene of the formula CR?2?CR?—Y—Z or CR?2?CR?—Z into a reactor to form the siloxane. The siloxane is useful as a component in holographic storage media for photopolymer-based holographic data storage applications. The siloxane exhibits excellent compatibility when mixed with a polymerizable component before the polymerizable component is cured.

Abstract: A composition includes a siloxane of the formula: (RMe2Si01/2)a(MeRSi02/2)b(RSi03/2)o(Si04/2)d wherein a is at least 2, b is from 3 to 20, c is from 0 to 10, d is from 0 to 10, and each R is independently of the formula —CR?2-CR?2-Y—Z or —CRVCRVZ, wherein each R1 is independently a hydrogen atom or a Ci to C1O hydrocarbyl free of aliphatic unsaturation so long as at least one R? is a hydrogen atom, Y is a divalent organic group, and Z is a polycyclic group containing at least one aromatic ring. A method of making the siloxane includes charging (HMe2SiO i/2)a(MeHSi?2/2)b(HSi?3/2)c(Si?4/2)d, a platinum catalyst, and an alkene of the formula CR2=CR—Y—Z or CR2=CR—Z into a reactor to form the siloxane. The siloxane is useful as a component in holographic storage media for photopolymer-based holographic data storage applications. The siloxane exhibits excellent compatibility when mixed with a polymerizable component before the polymerizable component is cured.

Abstract: Herein is disclosed a resin solution, comprising (a) about 0.1 solids wt % to about 50 solids wt % of an organosiloxane resin comprising the formula (RSiO3/2)x(R′SiO3/2)y, wherein R is selected from the group consisting of C4-C24 alkyl, C4-C24 alkenyl, C4-C24 alkoxy, C8-C24 alkenoxy, and C4-C24 substituted hydrocarbon; R′ is selected from the group consisting of —H, C1-C4 unsubstituted hydrocarbon, and C1-C4 substituted hydrocarbon; x is from about 5 mole % to about 75 mole %; y is from about 10 mole % to about 95 mole %; and x+y is at least about 40 mole %; and (b) about 50 solids wt % to about 99.9 solids wt % of a resin comprising at least about 90 mole % of the formula HSiO3/2.

Abstract: Herein is disclosed a resin solution, comprising (a) about 0.1 solids wt % to about 50 solids wt % of an organosiloxane resin comprising the formula (RSiO3/2)x(R′SiO3/2)y, wherein R is selected from the group consisting of C4-C24 alkyl, C4-C24 alkenyl, C4-C24 alkoxy, C8-C24 alkenoxy, and C4-C24 substituted hydrocarbon; R′ is selected from the group consisting of —H, C1-C4 unsubstituted hydrocarbon, and C1-C4 substituted hydrocarbon; x is from about 5 mole % to about 75 mole %; y is from about 10 mole % to about 95 mole %; and x+y is at least about 40 mole %; and (b) about 50 solids wt % to about 99.9 solids wt % of a resin comprising at least about 90 mole % of the formula HSiO3/2.

Abstract: The present invention describes a novel method for crosslinking polysilazane polymers having Si--H or N--H bonds. The method comprises mixing the polysilazane with a silazane crosslinker having at least 2 boron functional groups which can react with the Si--H or N--H bonds of the polysilazane and then facilitating crosslinking.

Abstract: The present invention describes a novel method for crosslinking polysilazane polymers having Si--H or N--H bonds. The method comprises mixing the polysilazane with a silazane crosslinker having at least 2 boron functional groups which can react with the Si--H or N--H bonds of the polysilazane and then facilitating crosslinking.

Abstract: A process for the preparation of substantially polycrystalline silicon carbide fibers are provided. The fibers may be fabricated to have a small diameter and are thermally stable at high temperature. The process is carried out by initially forming fibers from a preceramic polymeric precursor comprising phenyl-containing polyorganosiloxane resins. The fibers are then infusibilized to render them nonmelting followed by a pyrolysis step in which the fibers are heated to a temperature in excess of 1600.degree. C. in a nonoxidizing atmosphere to form substantially polycrystalline silicon carbide fibers. The substantially polycrystalline silicon carbide fibers which are formed have at least 75% crystallinity and have a density of at least about 2.9 gm/cm.sup.3. The polymeric precursor or the fibers contain, or have incorporated therein, at least about 0.2 % by weight boron.

Abstract: Alkylpoly(polysilyl)azanes are prepared by the reaction of chlorine-containing polysilane preceramic polymers and various disilazanes. The alkylpoly(polysily)azanes may be converted to ceramic materials by pyrolysis at elevated temperatures.

Abstract: Chlorine or bromine-containing polysilanes of the general formula (R.sub.2 Si)(RSi)(R'Si) are disclosed. In these polysilanes there are also bonded to the silicon atoms other silicon atoms and chlorine or bromine atoms, R is an alkyl radical containing 1 to 4 carbon atoms, and R' is selected from the group consisting of alkyl radicals of at least six carbon atoms, phenyl radicals, and radicals of the formula A.sub.y X.sub.(3-y) Si(CH.sub.2).sub.z -- wherein each A is independently selected from a hydrogen atom or alkyl radicals containing 1 to 4 carbon atoms, y is an integer equal to 0 to 3, X is chlorine or bromine, and z is an integer greater than or equal to 1. These preceramic polymers can be pyrolyzed at elevated temperatures under an inert atmosphere to yield ceramic materials or articles. These polysilanes may also be converted into other preceramic polymers which can be pyrolyzed to ceramic materials or articles.

Abstract: A method is described to prepare preceramic polysilanes which contain at least one weight percent vinyl. To ensure the survival of the vinyl groups in the polysilane the reaction and process conditions must be carefully controlled. The vinyl-containing polysilanes can be formed into fibers, cured either thermally or by UV irradiation, and then pyrolyzed to form ceramic fibers. Thermal curing and pyrolysis can be combined into a single process step.

Abstract: Vinyl-containing polysilanes are described wherein the vinyl groups are attached to endblocking sites of intermediate reactivity. These vinyl-containing polysilanes are prepared by reacting a halogen-endblocked polysilane with, first, a non-vinyl-containing Grignard reagent or a non-vinyl organolithium compound whereby the most reactive halogen endblocking groups are replaced; then, second, reacting the resulting polysilane with vinyl Grignard reagent or vinyllithium whereby the halogen endblocking groups of intermediate reactivity are replaced; and, third, reacting the resulting polysilane with a non-vinyl-containing Grignard reagent or a non-vinyl organolithium compound whereby the least reactive halogen endblocking groups are replaced. The vinyl-containing polysilanes can be coverted to ceramic materials, including ceramic fibers, by pyrolysis.

Abstract: A process for preparing ceramic materials with reduced carbon levels is described. The process involves treating a silicon-containing preceramic polymer with ammonia at a temperature of 550.degree.-800.degree. C. for a time sufficient to reduce the carbon content prior to pyrolysis at 900.degree.-1500.degree. C. Another process also involves the pyrolysis of a silicon-containing preceramic polymer in an ammonia atmosphere. The carbon level of ceramic materials produced by this invention can be controlled to a given, desired level by varying the process conditions. Suitable silicon-containing preceramic polymers include polycarbosilanes, polysilazanes, polysilanes, organosilsesquioxane-containing sol-gels, and organopolysiloxanes which are capable of being converted to ceramic materials when fired to elevated temperatures. Ceramic fibers can be prepared by the processes disclosed which contain less than 0.25 weight percent carbon.

Abstract: A method of preparing ceramic materials with increased levels of crystalline SiC and/or Si.sub.3 N.sub.4 is described. The method consists of firing a mixture of a R.sub.3 SiNH-containing silazane polymer and an inorganic compound selected from the group consisting of iron compounds, cobalt compounds, nickel compounds, and copper compounds to an elevated temperature of at least 750.degree. C. under an inert atmosphere or in a vacuum until a ceramic material with increased levels of crystalline SiC and/or Si.sub.3 N.sub.4 is obtained.

Abstract: A method is disclosed for increasing the ceramic yield of a ceramic material obtained by firing a polycarbosilane to an elevated temperature in an inert atmosphere or in a vacuum. The method involves adding iron (II) octoate or iron (III) octoate to the polycarbosilane prior to firing.

Abstract: A method is disclosed for increasing the ceramic yield of a ceramic material obtained by firing a R.sub.3 SiNH-containing silazane polymer to an elevated temperature in an inert atmosphere or in a vacuum. The method involves adding certain boron compounds to the R.sub.3 SiNH-containing silazane polymer prior to firing. Suitable boron compounds include, among others, metaboric acid, orthoboric acid, and organoboron compounds of the general formula BR.sub.3 " where R" is selected from the group consisting of alkyl radicals containing 1 to 5 carbon atoms, phenyl radicals, and --OR'" radicals where R'" is an alkyl radical containing 1 to 4 carbon atoms.

Abstract: A method is disclosed for increasing the ceramic yield of a ceramic material obtained by firing a R.sub.3 SiNH-containing silazane polymer to an elevated temperature in an inert atmosphere or in a vacuum. The method involves adding certain metallic compounds to the R.sub.3 SiNH-containing silazane polymer prior to firing. Metallic compounds which increase the ceramic yield include ruthenium compounds, palladium compounds, silver compounds, indium compounds, iridium compounds, and platinum compounds.