Abstract: A polysiloxane having a refractive index of about 1.

Abstract: In a process for the preparation of a solution of a stable silicone resin comprising SiO4/2 units and units selected from RSiO3/2, RR′SiO2/2, and RR′2SiO1/2 units, where R is an alkyl, alkenyl, substituted alkyl, cycloalkyl, aryl or aralkyl group imparting desired physical or chemical properties to the resin, for example a thermally labile group, and each R′ is a different alkyl, substituted alkyl, cycloalkyl, aryl or aralkyl group, or a hydrogen atom, a hydrosiloxane resin comprising HSiO3/2 units and the said units selected from RSiO3/2, RR′SiO2/2, and RR′2SiO1/2 units is treated with a base to condense at least some of the HSiO3/2 units to form SiO4/2 units. The base is preferably a solution of an alkali metal salt of a weak acid, such as sodium acetate.

Abstract: This invention pertains to a siloxane resin composition comprising R1SiO3/2 siloxane units, R2SiO3/2 siloxane units and (R3O)bSiO(4-b)/2 siloxane units wherein R1 is an alkyl group having 1 to 5 carbons, hydrogen, or mixtures thereof; R2 is a monovalent organic group having 6 to 30 carbons; R3 is a branched alkyl group having 3 to 30 carbons, b is from 1 to 3; and the siloxane resin contains from 2.5 to 85 mole percent R1SiO3/2 units, 2.5 to 50 mole percent R2SiO3/2 units and 5 to 95 mole percent (R3O)bSiO(4-b)/2 units. The siloxane resin is useful to make insoluble porous resin and insoluble porous coatings. Heating a substrate coated with the siloxane resin at a sufficient temperature effects removal of the R2 and R3O groups to form an insoluble insoluble porous coating having a porosity of 1 to 60 volume percent and a dielectric constant in the range of 1.5 to 3.0.

Abstract: This invention pertains to a siloxane resin composition comprising HSiO3/2 siloxane units, and (R2O)bSiO(4-b)/2 siloxane units wherein R2 is independently selected from the group consisting of branched alkyl groups having 3 to 30 carbon atoms and substituted branched alkyl groups having 3 to 30 carbon atoms, b is from 1 to 3. The siloxane resin contains a molar ratio of HSiO3/2 units to (R2O)bSiO(4-b)/2 units of 0.5:99.5 to 99.5. The siloxane resin is useful to make insoluble porous resins and insoluble porous coatings. Heating a substrate with the siloxane resin at a sufficient temperature effects removal of the R2O groups to form an insoluble porous coating having a porosity in a range of 1 to 40 volume percent and a modulus in the range of 4 to 80 GPa.