Methods and materials are described for preparing organic-inorganic hybrid gel compositions where a sulfur-containing cross-linking agent covalently links the organic and inorganic components. The gel compositions are further dried to provide porous gel compositions and aerogels. The mechanical and thermal properties of the dried gel compositions are also disclosed.

Methods and materials are described for preparing organic-inorganic hybrid gel compositions where a sulfur-containing cross-linking agent covalently links the organic and inorganic components. The gel compositions are further dried to provide porous gel compositions and aerogels. The mechanical and thermal properties of the dried gel compositions are also disclosed.

The invention relates to silane mixtures comprising a silane of the formula I
(R.sup.1).sub.y(R.sup.2).sub.3-ySi—R.sup.3—(S—R.sup.4).sub.n—S.sub.x—R.sup.5  (I)
and a silane of the formula II
(R.sup.1).sub.y(R.sup.2).sub.3-ySi—R.sup.3—Si(R.sup.1).sub.y(R.sup.2).sub.3-y  (II)
where the molar ratio of silane of the formula I to silane of the formula II is 15:85-90:10. The silane mixture according to the invention can be prepared by mixing the silanes of the formula I and silanes of the formula II.

The invention relates to silane mixtures comprising a silane of the formula I
(R.sup.1).sub.y(R.sup.2).sub.3-ySi—R.sup.3—(S—R.sup.4).sub.n—S.sub.x—R.sup.5  (I)
and a silane of the formula II
(R.sup.1).sub.y(R.sup.2).sub.3-ySi—R.sup.3—Si(R.sup.1).sub.y(R.sup.2).sub.3-y  (II)
where the molar ratio of silane of the formula I to silane of the formula II is 15:85-90:10. The silane mixture according to the invention can be prepared by mixing the silanes of the formula I and silanes of the formula II.

The invention relates to a copolymer of ethylene and of a 1,3-diene of formula CH.sub.2═CR—CH═CH.sub.2, which copolymer bears a silanol or alkoxysilane function, the symbol R representing a hydrocarbon chain having from 3 to 20 carbon atoms. Such a copolymer improves the compromise between the content of ethylene in the polymer, its crystallinity and the stiffness of a rubber composition containing it.

The invention relates to a sulfur-crosslinkable rubber mixture and to a pneumatic vehicle tire comprising at least one rubber component made of the sulfur-vulcanized rubber mixture.

The rubber mixture contains 10-60 phr (parts by weight, based on 100 parts by weight of the total rubbers in the mixture) of at least one functionalized polybutadiene A,
wherein the functionalized polybutadiene A is functionalized at one chain end with an organosilyl group containing amino groups and/or ammonium groups,
and wherein the functionalized polybutadiene A is functionalized at the other chain end with an amino group, up to 90 phr of at least one further diene rubber and 30-350 phr of at least one filler.

Provided is a rubber composition having excellent low heat generating properties. The rubber composition of the present disclosure contains a rubber component, a filler containing silica, and a silane coupling agent, where the rubber component contains a conjugated diene-based polymer modified with a modifier containing a compound represented by the formula (1), and the silane coupling agent is a compound represented by the formula (2).

##STR00001##

Provided is a rubber composition having excellent low heat generating properties. The rubber composition of the present disclosure contains a rubber component, a filler containing silica, and a silane coupling agent, where the rubber component contains a conjugated diene-based polymer modified with a modifier containing a compound represented by the formula (1), and the silane coupling agent is a compound represented by the formula (2).

##STR00001##

The present invention relates to a modified conjugated diene-based polymer, a method for preparing the same and a rubber composition including the same, and relates to a modified conjugated diene-based polymer which is prepared by continuous polymerization and has excellent processability, a mooney large relaxation area of 300 MU-s to 1000 MU-s, and narrow molecular weight distribution, and if compounded into a rubber composition, shows improved tensile properties and viscoelasticity properties, particularly, a tan δ value at a high temperature (60° C.) among viscoelasticity properties, and excellent low hysteresis properties and fuel consumption properties, and a rubber composition including the same.

Provided is a rubber composition that realizes excellent low heat generating properties while maintaining good steering stability when applied to a tire. The rubber composition of the present disclosure contains a rubber component containing a copolymer having a conjugated diene unit and an aromatic vinyl unit, and a filler, where the copolymer is a modified copolymer having a content of the aromatic vinyl unit of less than 10 mass % and modified with a modifier containing a compound represented by the formula (1).

##STR00001##