This invention relates to a curable silicone composition comprising: (A) a straight-chain organopolysiloxane having at least two alkenyl groups in a molecule; (B) an organopolysiloxane represented by the following average unit formula: (R.sup.1SiO.sub.3/2).sub.a(R.sup.1.sub.2SiO.sub.2/2).sub.b(R.sup.1.sub.3SiO.sub.1/2).sub.c(SiO.sub.4/2).sub.d(XO.sub.1/2).sub.e wherein, R.sup.1 each independently represent an alkyl group having from 1 to 12 carbons, an alkenyl group having from 2 to 12 carbons, an aryl group having from 6 to 20 carbons, an aralkyl group having from 7 to 20 carbons, or a group in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms, with the proviso that at least two R.sup.1 in a molecule are the alkenyl groups, X is a hydrogen atom or an alkyl group, a is a number from 0 to 0.3, b is 0 or a positive number, c is a positive number, d is a positive number, e is a number from 0 to 0.4, a+b+c+d=1, c/d is a number from 0 to 10, and b/d is a number from 0 to 0.5; (C) an organopolysiloxane having at least two silicon-bonded hydrogen atoms in a molecule; (D) a cerium-containing organopolysiloxane; and (E) a hydrosilylation reaction catalyst. The curable silicone composition does not develop cracks due to thermal aging and can form a cured product having little yellow discoloration.

This invention relates to a curable silicone composition comprising: (A) a straight-chain organopolysiloxane having at least two alkenyl groups in a molecule; (B) an organopolysiloxane represented by the following average unit formula: (R.sup.1SiO.sub.3/2).sub.a(R.sup.1.sub.2SiO.sub.2/2).sub.b(R.sup.1.sub.3SiO.sub.1/2).sub.c(SiO.sub.4/2).sub.d(XO.sub.1/2).sub.e wherein, R.sup.1 each independently represent an alkyl group having from 1 to 12 carbons, an alkenyl group having from 2 to 12 carbons, an aryl group having from 6 to 20 carbons, an aralkyl group having from 7 to 20 carbons, or a group in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms, with the proviso that at least two R.sup.1 in a molecule are the alkenyl groups, X is a hydrogen atom or an alkyl group, a is a number from 0 to 0.3, b is 0 or a positive number, c is a positive number, d is a positive number, e is a number from 0 to 0.4, a+b+c+d=1, c/d is a number from 0 to 10, and b/d is a number from 0 to 0.5; (C) an organopolysiloxane having at least two silicon-bonded hydrogen atoms in a molecule; (D) a cerium-containing organopolysiloxane; and (E) a hydrosilylation reaction catalyst. The curable silicone composition does not develop cracks due to thermal aging and can form a cured product having little yellow discoloration.

Disclosed is a method of fabricating a preceramic polymer for making a ceramic material including a metal boride. The method includes providing a starting preceramic polymer that includes a silicon-containing backbone chain and first and second reactive side groups extending off of the silicon-containing backbone chain, reacting a boron-containing material with the first reactive side group to bond a boron moiety to the silicon-containing backbone chain, and reacting a metal-containing material with the second reactive side group to bond a metal moiety to the silicon-containing backbone chain such that the preceramic polymer includes the boron moiety and the metal moiety extending as side groups off of the silicon-containing backbone chain. Also disclosed is a preceramic polymer composition and a metal-boride-containing ceramic article fabricated from the preceramic polymer.

Disclosed is a method of fabricating a preceramic polymer for making a ceramic material including a metal boride. The method includes providing a starting preceramic polymer that includes a silicon-containing backbone chain and first and second reactive side groups extending off of the silicon-containing backbone chain, reacting a boron-containing material with the first reactive side group to bond a boron moiety to the silicon-containing backbone chain, and reacting a metal-containing material with the second reactive side group to bond a metal moiety to the silicon-containing backbone chain such that the preceramic polymer includes the boron moiety and the metal moiety extending as side groups off of the silicon-containing backbone chain. Also disclosed is a preceramic polymer composition and a metal-boride-containing ceramic article fabricated from the preceramic polymer.

The invention relates to a fluorescent siloxane elastomer, to a method for producing same, and to the use. The fluorescent siloxane elastomer contains the following structural elements in the network structure thereof: (I) and (II) or (III), wherein: R1 and R2 are the same or different and mean, independently of each other, a methyl, phenyl, vinyl substituent or an H atom; X means a saturated or unsaturated hydrocarbon group having 2 to 6 C atoms; A is an oxygen, nitrogen, or sulfur atom; R3 is a fluorescent dye substituent from the families of the BODIPY or BODIPY and coumarin or BODIPY and naphthalimide or coumarin and naphthalimide fluorophores. The polysiloxanes according to the invention cause a shift in the emission range out of the UV light or expansion of the emission range into the range of visible light having wavelengths of up to 800 nm, and therefore the polysiloxanes are especially suited for detectors having the maximum efficiency thereof in the range. In the combination of the optical, electrical, mechanical, and thermal properties of the polysiloxanes, the polysiloxanes differ substantially from polysiloxanes according to the prior art. The polysiloxanes form the basis for a material that meets the high requirements for high-voltage devices and can be used in particular for monitoring the aging process of insulating means in high-voltage systems. Partial electrical discharges can be reliably optically detected and localized by means of the polysiloxanes.

The present invention provides a gas-permeable membrane comprising a partial structure represented by formula (I) or formula (II), (wherein R.sup.1 and R.sup.2 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyloxy group having 2 to 6 carbon atoms, an aryl group or an aryloxy group, M.sup.1, M.sup.2 and M.sup.3 each independently represents a metal atom, m1 represents an integer, n1, n2 and n3 each independently represents an integer of 1 to 3, * represents a bonding hand), a composition for forming the gas-permeable membrane and a production process of the gas-permeable membrane.

##STR00001##

The present invention provides a gas-permeable membrane comprising a partial structure represented by formula (I) or formula (II), (wherein R.sup.1 and R.sup.2 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyloxy group having 2 to 6 carbon atoms, an aryl group or an aryloxy group, M.sup.1, M.sup.2 and M.sup.3 each independently represents a metal atom, m1 represents an integer, n1, n2 and n3 each independently represents an integer of 1 to 3, * represents a bonding hand), a composition for forming the gas-permeable membrane and a production process of the gas-permeable membrane.

##STR00001##

A method of preparing an organotin containing hyperbranched polysiloxane structure includes the following steps: (1) by weight, 0.5-1.5 portions of hyperbranched polysiloxane with reactive functional groups is dissolved in 50-100 portions of an alcohol solvent, to obtain a solution A; (2) by weight, 0.5-0.9 portions of a tin-based initiator and 50-100 portions of the alcohol solvent are mixed to obtain a solution B, wherein said tin-based initiator is selected from dihydroxy butyl tin chloride, butyl tin trichloride, and dibutyl tin dichloride; and (3) dropping the solution B into the solution A at the temperature of 0 C.-60 C., reacting for 3-6 h, filtering and drying to obtain the organotin containing hyperbranched polysiloxane structure.

A method of preparing an organotin containing hyperbranched polysiloxane structure includes the following steps: (1) by weight, 0.5-1.5 portions of hyperbranched polysiloxane with reactive functional groups is dissolved in 50-100 portions of an alcohol solvent, to obtain a solution A; (2) by weight, 0.5-0.9 portions of a tin-based initiator and 50-100 portions of the alcohol solvent are mixed to obtain a solution B, wherein said tin-based initiator is selected from dihydroxy butyl tin chloride, butyl tin trichloride, and dibutyl tin dichloride; and (3) dropping the solution B into the solution A at the temperature of 0 C.-60 C., reacting for 3-6 h, filtering and drying to obtain the organotin containing hyperbranched polysiloxane structure.

A self-healing polymer includes metal ions and a polymer network including polymer chains cross-linked through coordination bonds with the metal ions. Each polymer chain includes ligands within a backbone of the polymer chain, and the ligands include metal ion coordination sites.