Abstract: Impregnated silica is manufactured by passing a substantially anhydrous solution of a polar organic compound in a non-polar organic diluent through a bed of substantially anhydrous silica particles, under a pressure of at least 200 bars so as to modify the adsorbent properties of the silica particles with the selective properties of the polar compound without impairing the silica particle adsorbing efficiency.

Abstract: Heavy fuel-oil composition of improved stability under storage conditions, comprising a petroleum residue obtained from a straight run distillation, a vacuum distillation or a viscosity reduction of petroleum materials, a diluent such as a steam-cracking residue, a viscosity reduction gas oil or a mixture thereof, and a minor proportion of a sequenced copolymer formed of two polymeric sequences (A) and (B) wherein sequence (A) is obtained by polymerization of one or more conjugated diolefins such as 1,3-butadiene and isoprene and sequence (B) is obtained by polymerization of acrylonitrile or an alkylacrylonitrile such as methacrylonitrile, said sequenced copolymer having an average molecular weight by number of from 1,000 to 20,000.

Abstract: Graft copolymer formed by reacting at least one polymerizable vinyl compound, in monomeric or polymerized form, with a hydrogenated polymer or copolymer selected from the hydrogenated homopolymers of conjugated dienes of 4-6 carbon atoms, the hydrogenated copolymers of at least 2 conjugated dienes and the hydrogenated copolymers of styrene and conjugated dienes of 4-6 carbon atoms, said hydrogenated polymer or copolymer having an average molecular weight ranging from 10,000 to 300,000 and a residual olefinic unsaturation lower than 15%.

Abstract: Graft copolymer formed by reacting at least one polymerizable vinyl compound in monomeric or polymerized form, with a hydrogenated polymer or copolymer selected from the hydrogenated homopolymers of conjugated dienes of 4-6 carbon atoms, the hydrogenated copolymers of at least 2 conjugated dienes and the hydrogenated copolymers of styrene and conjugated dienes of 4-6 carbon atoms, said hydrogenated polymer or copolymer having an average molecular weight ranging from 10.000 to 300.000 and a residual olefinic unsaturation lower than 15%.

Abstract: Epoxide resins of improved flexibility are obtained by partially substituting a conventional cross-linking agent with liquid polybutadiene containing carboxy groups. Specifically a liquid epoxide resin is reacted with a carboxylic compound and polybutadiene having carboxylic substitution.

Abstract: The behavior in the cold of crude oil or petroleum distillates may be improved by incorporation of polymeric substances such as a hydrogenated polybutadiene or a hydrogenated copolymer of butadiene with at least one conjugated aliphatic diolefin of 5-8 carbon atoms. The additive is active at concentrations of from 10 to 1,000 grams per m.sup.3 of oil.

Abstract: The behavior in the cold of crude oil or petroleum distillates may be improved by incorporation of polymeric substances such as a hydrogenated polybutadiene or a hydrogenated copolymer of butadiene with at least one conjugated aliphatic diolefin of 5-8 carbon atoms. The additive is active at concentrations of from 10 to 1,000 grams per m.sup.3 of oil.

Abstract: A lubricating oil composition having an improved viscosity index is manufactured by admixing lubricating oil in major proportion with a butadiene polymer in minor proportion, said polybutadiene having a molecular weight of at least 20,000 and a microstructure of from 65 to 85 % ##EQU1## units, from 2 to 35 % of -- CH.sub.2 --CH.sub.2 --CH.sub.2 --CH.sub.2 -- units and from 0 to 25 % of -- CH.sub.2 --CH = CH--CH.sub.2 -- units.

Abstract: An interferometric device is provided for measurement of the variations in length of a sample under the influence of temperature, the length of the sample being within a plane of reference and a plane of measurement defined by two plane terminal faces of the sample.