The present invention is directed to a medium for preserving cells at non-cryogenic freezing temperatures. The medium comprises a hydrophilic and nontoxic polymer or other macromolecule, an aqueous liquid, and a cryoprotectant. The molecules of the macromolecule form compact three-dimensional structures that are spherical in shape when dissolved in the aqueous liquid. The medium of the present invention can be used for long-term storage of cells at non-cryogenic temperatures with outcomes similar to those seen with storage at cryogenic temperatures.

An elastomeric composition that has a high tensile strength and high hardness is produced by a method that is cost-efficient and easy to carry out. The object is attained by an elastomeric composition that contains at least one base elastomer, at least one hydrophilic polymer, and at least one inorganic salt. The object is furthermore attained by a method for producing an elastomeric composition in which at least one rubber, at least one hydrophilic polymer and at least one inorganic salt are mixed and subsequently vulcanized, the elastomeric composition is then at least partially brought into contact with water, and afterwards the water is at least partially removed from the elastomeric composition. The elastomeric composition according to the invention can, for example, be used in vehicles and machines as a seal, grommet, disc, coupling or membrane.

An elastomeric composition that has a high tensile strength and high hardness is produced by a method that is cost-efficient and easy to carry out. The object is attained by an elastomeric composition that contains at least one base elastomer, at least one hydrophilic polymer, and at least one inorganic salt. The object is furthermore attained by a method for producing an elastomeric composition in which at least one rubber, at least one hydrophilic polymer and at least one inorganic salt are mixed and subsequently vulcanized, the elastomeric composition is then at least partially brought into contact with water, and afterwards the water is at least partially removed from the elastomeric composition. The elastomeric composition according to the invention can, for example, be used in vehicles and machines as a seal, grommet, disc, coupling or membrane.

An elastomeric composition that has a high tensile strength and high hardness is produced by a method that is cost-efficient and easy to carry out. The object is attained by an elastomeric composition that contains at least one base elastomer, at least one hydrophilic polymer, and at least one inorganic salt. The object is furthermore attained by a method for producing an elastomeric composition in which at least one rubber, at least one hydrophilic polymer and at least one inorganic salt are mixed and subsequently vulcanized, the elastomeric composition is then at least partially brought into contact with water, and afterwards the water is at least partially removed from the elastomeric composition. The elastomeric composition according to the invention can, for example, be used in vehicles and machines as a seal, grommet, disc, coupling or membrane.

A polyether polymer composition containing 200 parts by weight or more of a metal-containing powder per a total of 100 parts by weight of a cationic group-containing low molecular weight polyether polymer composed of 10 to 200 oxirane monomer units, wherein at least a part of the oxirane monomer units is an oxirane monomer unit having a cationic group, and a high molecular weight polyether polymer composed of more than 200 oxirane monomer units is provided.

A polyether polymer composition containing 200 parts by weight or more of a metal-containing powder per a total of 100 parts by weight of a cationic group-containing low molecular weight polyether polymer composed of 10 to 200 oxirane monomer units, wherein at least a part of the oxirane monomer units is an oxirane monomer unit having a cationic group, and a high molecular weight polyether polymer composed of more than 200 oxirane monomer units is provided.

A cross-linkable rubber composition including a polyether rubber, a cross-linking agent, and zinc peroxide is provided, the polyether rubber including 0.1 to 30 mol % of a unit represented by the following general formula (1) and 1 to 15 mol % of an unsaturated oxide monomer unit:

##STR00001##

wherein A.sup.+ is a group containing a cationic nitrogen-containing aromatic heterocyclic ring; the group containing a cationic nitrogen-containing aromatic heterocyclic ring bonds to a carbon atom at the position 2 shown in the above general formula (1) through one of nitrogen atoms constituting the cationic nitrogen-containing aromatic heterocyclic ring.

A cross-linkable rubber composition including a polyether rubber, a cross-linking agent, and zinc peroxide is provided, the polyether rubber including 0.1 to 30 mol % of a unit represented by the following general formula (1) and 1 to 15 mol % of an unsaturated oxide monomer unit:

##STR00001##

wherein A.sup.+ is a group containing a cationic nitrogen-containing aromatic heterocyclic ring; the group containing a cationic nitrogen-containing aromatic heterocyclic ring bonds to a carbon atom at the position 2 shown in the above general formula (1) through one of nitrogen atoms constituting the cationic nitrogen-containing aromatic heterocyclic ring.

A cross-linkable rubber composition including a polyether rubber, a cross-linking agent, and zinc peroxide is provided, the polyether rubber including 0.1 to 30 mol % of a unit represented by the following general formula (1) and 1 to 15 mol % of an unsaturated oxide monomer unit:

##STR00001##

wherein A.sup.+ is a group containing a cationic nitrogen-containing aromatic heterocyclic ring; the group containing a cationic nitrogen-containing aromatic heterocyclic ring bonds to a carbon atom at the position 2 shown in the above general formula (1) through one of nitrogen atoms constituting the cationic nitrogen-containing aromatic heterocyclic ring.

The present invention aims to provide rubber compositions and tires which provide improved overall performance in terms of wet grip performance and dry grip performance. The present invention relates to a rubber composition having a hardness that reversibly changes with water and satisfying the following relationship (1):
Hardness when dry?Hardness when water-wet?10(1)
wherein each hardness represents the JIS-A hardness at 25? C. of the rubber composition.