A method for the preparation of a sulfur-free copolymer proceeds by solution polymerization in the presence of a radical initiator, wherein the copolymer contains at least one alkyl methacrylate and maleic anhydride having a number average molecular weight of 3000 to 9000 g/mol.

The instant invention concerns the use of polymers obtained by radical copolymerization of a mixture of (1) acrylic acid; (2) methacrylic acid; and (3) at least one allylcatechol selected from 4-allylbenzene-1,2-diol, 3-allylbenzene-1,2-diol; methylated forms thereof (eugenols); and mixtures thereof, for treating a metallic surface intended to be adhesive-bonded to another surface, in order to impart a resistance to the adhesive failure to the resulting bonding.

The instant invention concerns the use of polymers obtained by radical copolymerization of a mixture of (1) acrylic acid; (2) methacrylic acid; and (3) at least one allylcatechol selected from 4-allylbenzene-1,2-diol, 3-allylbenzene-1,2-diol; methylated forms thereof (eugenols); and mixtures thereof, for treating a metallic surface intended to be adhesive-bonded to another surface, in order to impart a resistance to the adhesive failure to the resulting bonding.

The present invention relates to a manufacturing method of a super absorbent polymer. The manufacturing method of a super absorbent polymer according to the present invention may include: carrying out a thermal polymerization or a photopolymerization of a monomer composition including a water-soluble ethylene-based unsaturated monomer and a polymerization initiator to form a hydrogel polymer; drying the hydrogel polymer; pulverizing the dried polymer; classifying the pulverized polymer into a fine powder having a particle diameter of less than 150 μm and a polymer having a particle diameter of 150 to 850 μm according to the particle diameter; performing reassembly by mixing and wetting the fine powder with 5 to 30° C. water in a content of 50 to 200 parts by weight with respect to 100 parts by weight of the fine powder having a particle size of 150 μm or less, to form a fine powder reassembly; and mixing the polymer having a particle diameter of 150 to 850 μm with the fine powder reassembly, followed by surface cross-linking, and may obtain a super absorbent polymer having a high fine aggregation strength.

The present invention relates to the novel method for the preparation of a polymer of (meth)acrylic acid in aqueous solution, said polymer having a molecular mass of less than 6,500 g/mol, as measured by SEC, using a compound of copper carbonate type or one of its derivatives and a compound of formula (I):

##STR00001## according to which: X represents Na, K or H and R represents an alkyl chain comprising from 1 to 5 carbon atoms.

When a polymer gel has excellent mechanical strength and an ability to maintain surface wetness for a longer time, the polymer gel may be very widely applied to a variety of fields. The present disclosure provides example embodiments of a polymer gel having excellent mechanical strength and an ability to maintain surface wetness for a longer time. Further, the present disclosure provides example embodiments of a method of preparing the polymer gel.

When a polymer gel has excellent mechanical strength and an ability to maintain surface wetness for a longer time, the polymer gel may be very widely applied to a variety of fields. The present disclosure provides example embodiments of a polymer gel having excellent mechanical strength and an ability to maintain surface wetness for a longer time. Further, the present disclosure provides example embodiments of a method of preparing the polymer gel.

The super absorbent polymer according to the present invention has reduced 3-hour saline solution re-wet while having a high absorption rate and absorption against pulp, and thus can be used for hygienic materials such as diapers, thereby exhibiting excellent performance.

The copolymer includes divalent units represented by formula —[CF.sub.2—CF.sub.2]—, divalent units represented by formula; and one or more divalent units independently represented by formula: The copolymer has an —SO.sub.2X equivalent weight in a range from 300 to 2000. A polymer electrolyte membrane that includes the copolymer and a membrane electrode assembly that includes such a polymer electrolyte membrane are also provided.

The copolymer includes divalent units represented by formula —[CF.sub.2—CF.sub.2]—, divalent units represented by formula; and one or more divalent units independently represented by formula: The copolymer has an —SO.sub.2X equivalent weight in a range from 300 to 2000. A polymer electrolyte membrane that includes the copolymer and a membrane electrode assembly that includes such a polymer electrolyte membrane are also provided.