The present invention relates to a method for preparing superabsorbent polymer. The method for preparing superabsorbent polymer according to the present invention enables providing superabsorbent polymer having excellent absorption ratio, absorption speed and permeability.

The present disclosure relates to the technical field of oilfield chemicals, and discloses an acrylamide copolymer, wherein the acrylamide copolymer comprises a structural unit A, a structural unit B and a structural unit C, wherein the structural unit A has a structure shown in Formula (1), the structural unit B has a structure shown in Formula (2), and the structural unit C has a structure shown in Formula (3) and/or Formula (4);

##STR00001##

wherein R.sub.1 is methyl or H, R.sub.2 is —OH, —NH.sub.2, —COOH or C.sub.2-C.sub.12 alkyl, n is an integer between 0 and 6, and a, b and c are each independently selected from integers between 0 and 2.

The present disclosure relates to the technical field of oilfield chemicals, and discloses an acrylamide copolymer, wherein the acrylamide copolymer comprises a structural unit A, a structural unit B and a structural unit C, wherein the structural unit A has a structure shown in Formula (1), the structural unit B has a structure shown in Formula (2), and the structural unit C has a structure shown in Formula (3) and/or Formula (4);

##STR00001##

wherein R.sub.1 is methyl or H, R.sub.2 is —OH, —NH.sub.2, —COOH or C.sub.2-C.sub.12 alkyl, n is an integer between 0 and 6, and a, b and c are each independently selected from integers between 0 and 2.

A composition including a polytetrafluoroethylene and a polymer (I) containing a polymerization unit (I) based on a monomer represented by the following general formula (I), the composition having a standard specific gravity of 2.200 or less:

CX.sup.1X.sup.3═CX.sup.2R(—CZ.sup.1Z.sup.2-A.sup.0).sub.m   (I)

wherein X.sup.1 and X.sup.3 are each independently F, Cl, H, or CF.sub.3; A.sup.0 is an anionic group; X.sup.2 is H, F, an alkyl group, or a fluorine-containing alkyl group; R is a linking group; Z.sup.1 and Z.sup.2 are each independently H, F, an alkyl group, or a fluorine-containing alkyl group; and m is an integer of 1 or more.

The present invention relates to a method for preparing an aqueous dispersion of water-soluble polymers, which comprises a step (E) of radical polymerization, wherein the following are brought into contact in an aqueous medium (M) in which the synthesised polymer is not soluble: at least one ethylenically unsaturated monomer which is soluble in the aqueous medium (M); at least one source of free radicals; and a reactive stabiliser which comprises: a polymer chain (CP) which is soluble in the medium (M), a group (G) providing the radical polymerization of step (E) with a living and controlled nature, such as, for example, a group carrying a thiocarbonylthio —S(C═S)— group.

The present invention relates to a method for preparing an aqueous dispersion of water-soluble polymers, which comprises a step (E) of radical polymerization, wherein the following are brought into contact in an aqueous medium (M) in which the synthesised polymer is not soluble: at least one ethylenically unsaturated monomer which is soluble in the aqueous medium (M); at least one source of free radicals; and a reactive stabiliser which comprises: a polymer chain (CP) which is soluble in the medium (M), a group (G) providing the radical polymerization of step (E) with a living and controlled nature, such as, for example, a group carrying a thiocarbonylthio —S(C═S)— group.

The present invention provides a novel metal corrosion inhibitor containing a compound having a specific structure. The present invention relates to a metal corrosion inhibitor including a compound (X) including one molecule of a mercaptocarboxylic acid or a mercaptocarboxylic acid salt; one molecule of acrylic acid, an acrylic acid salt, or an acrylic acid ester; and one molecule of a monomer (B) represented by the following formula (1), which are bonded to each other: ##STR00001##

The present invention provides a novel metal corrosion inhibitor containing a compound having a specific structure. The present invention relates to a metal corrosion inhibitor including a compound (X) including one molecule of a mercaptocarboxylic acid or a mercaptocarboxylic acid salt; one molecule of acrylic acid, an acrylic acid salt, or an acrylic acid ester; and one molecule of a monomer (B) represented by the following formula (1), which are bonded to each other: ##STR00001##

To provide a method for producing modified polytetrafluoroethylene, in which formation of a fluorinated oligomer as a by-product is little. A method for producing modified polytetrafluoroethylene which contains substantially no C.sub.6-34 fluorinated oligomer containing hydrophilic functional groups and which contains substantially no fluorinated surfactant, the method comprising conducting copolymerization of tetrafluoroethylene and a monomer having a polar group, in a liquid dispersion 1 comprising a polymer containing units derived from a non-fluorinated monomer and an aqueous medium, or in a solution 2 obtainable by mixing at least one member selected from the group consisting of a polyalkylene oxide compound and a hydrocarbon-containing surfactant, with an oxidizing agent, in an aqueous medium, under such a condition that the amount of the monomer having a polar group to be used, is at most 0.150 mass % to the whole amount of tetrafluoroethylene, to obtain modified polytetrafluoroethylene.

To provide a method for producing modified polytetrafluoroethylene, in which formation of a fluorinated oligomer as a by-product is little. A method for producing modified polytetrafluoroethylene which contains substantially no C.sub.6-34 fluorinated oligomer containing hydrophilic functional groups and which contains substantially no fluorinated surfactant, the method comprising conducting copolymerization of tetrafluoroethylene and a monomer having a polar group, in a liquid dispersion 1 comprising a polymer containing units derived from a non-fluorinated monomer and an aqueous medium, or in a solution 2 obtainable by mixing at least one member selected from the group consisting of a polyalkylene oxide compound and a hydrocarbon-containing surfactant, with an oxidizing agent, in an aqueous medium, under such a condition that the amount of the monomer having a polar group to be used, is at most 0.150 mass % to the whole amount of tetrafluoroethylene, to obtain modified polytetrafluoroethylene.