Abstract: Polycarbodiimide is present as a solid phase in a liquid polyorganosiloxane, preferably being formed therein by mixing a polyisocyanate with the polysiloxane followed by a carbodiimidization catalyst. If the polyorganosiloxane contains hydroxyl groups it can be chemically bonded to the polycarbodiimide. The composition can be cured to solid plastic masses of superior properties by adding a curing agent for the polysiloxane.

Abstract: Polyurethane is present as a solid phase in a liquid polyorganosiloxane, preferably being formed therein by mixing a polyhydroxy-containing material with the polysiloxane followed by addition of a polyisocyanate. If the polyorganosiloxane contains hydroxyl groups it can be chemically bonded to the polyurethane. The composition can be cured to solid plastic masses of superior properties by adding a curing agent for the polysiloxane.

Abstract: A polysiloxane composition which can be cross-linked under atmospheric conditions and which consists essentially of:A. 100 parts by weight of an .alpha.,.omega.-dihydroxymethylphenylpolysiloxane with about 7-15 mole % of diphenylsiloxy units or about 14-28 mole % of methylphenylsiloxy units, and having a viscosity of between about 1,000 and 500,000 cSt (at 20.degree. C),b. about 1 to 40 parts by weight of an uncoated reinforcing filler consisting essentially of SiO.sub.2 having a specific surface area of about 40 to 500 m.sup.2 /g by the BET method, andC. about 1 to 10 parts by weight of a cross-linking agent of the formulaRSiX.sub.3whereinR is an alkyl, halogenoalkyl, aryl, or arylalkyl radical, andX is an alkoxy, acyloxy, oximato or alkylamino radical.A curing catalyst may also be present. The composition is clear as are the silicone rubbers produced upon curing.

Abstract: In a storable plastic organopolysiloxane composition which can be converted into a rubbery-elastic mass under the action of water and prepared by mixing an .alpha.,.omega.-dihydroxypolydiorganosiloxane with a silicon-containing crosslinking agent, the improvement which comprises incorporating in said mixture about 1 to 20% by weight of at least one material selected from the group consisting of dioxane, acrylonitrile, acetonitrile, trichloroethylene, butanesultone, butyl acetate and carbon tetrachloride. There may be included up to about 70% by weight of .alpha.,.omega.-bis-(triorganosiloxy)-polydiorganosiloxane, up to about 5% by weight of at least one heavy metal salt or amine as a crosslinking accelerant, and about 10 to 70% by weight of at least one inert filler.