A curable composition can comprise a polymerizable material and a photo-initiator, wherein the polymerizable material can comprise a first monomer including at least one bismaleimide-monomer and at least one second monomer. The curable composition can have a viscosity of not greater than 30 mPa.Math.s, and a cured layer of the curable composition can have a high thermal stability up to 350° C.

The present invention relates to a polymer obtained at least from a quantity A of 2-acrylamido-2-methylpropane sulfonic acid, in acid and/or salified form, characterized in that the quantity A of 2-acrylamido-2-methylpropane sulfonic acid contains 250 to 20,000 ppm by weight of 2-methyl-2-propenyl-sulfonic acid, in acid and/or salified form. The present invention also relates to the use of this polymer as a flocculant, viscosity reducing agent, thickener, absorbent, friction reducing agent or plasticizer or superplasticizer, in particular in a field chosen from among oil and gas recovery, water treatment, sludge treatment, paper manufacture, construction, mining, cosmetic product formulation, detergent formulation, textile manufacture and agriculture.

The present invention relates to a polymer obtained at least from a quantity A of 2-acrylamido-2-methylpropane sulfonic acid, in acid and/or salified form, characterized in that the quantity A of 2-acrylamido-2-methylpropane sulfonic acid contains 250 to 20,000 ppm by weight of 2-methyl-2-propenyl-sulfonic acid, in acid and/or salified form. The present invention also relates to the use of this polymer as a flocculant, viscosity reducing agent, thickener, absorbent, friction reducing agent or plasticizer or superplasticizer, in particular in a field chosen from among oil and gas recovery, water treatment, sludge treatment, paper manufacture, construction, mining, cosmetic product formulation, detergent formulation, textile manufacture and agriculture.

A process for enhanced oil recovery comprising the following steps: a) Preparation of an injection fluid comprising at least one water-soluble (co)polymer prepared at least from 2-acrylamido-2-methylpropane sulfonic acid (ATBS) or from at least one of its salts, with water or with brine, where the 2-acrylamido-2-methylpropane sulfonic acid is a hydrated crystalline form of 2-acrylamido-2-methylpropane sulfonic acid having a 2-theta powder X-ray diffraction diagram comprising peaks at 10.58°, 11.2°, 12.65°, 13.66°, 16.28°, 18.45°, 20°, 20.4°, 22.5°, 25.5°, 25.88°, 26.47°, 28.52°, 30.28°, 30.8°, 34.09°, 38.19°, 40.69°, 41.82°, 43.74°, 46.04° degrees. b) Injection of injection fluid into an underground formation, c) Flushing of the underground formation using the fluid injected, d) Recovery of an aqueous and hydrocarbon mixture.

A process for enhanced oil recovery comprising the following steps: a) Preparation of an injection fluid comprising at least one water-soluble (co)polymer prepared at least from 2-acrylamido-2-methylpropane sulfonic acid (ATBS) or from at least one of its salts, with water or with brine, where the 2-acrylamido-2-methylpropane sulfonic acid is a hydrated crystalline form of 2-acrylamido-2-methylpropane sulfonic acid having a 2-theta powder X-ray diffraction diagram comprising peaks at 10.58°, 11.2°, 12.65°, 13.66°, 16.28°, 18.45°, 20°, 20.4°, 22.5°, 25.5°, 25.88°, 26.47°, 28.52°, 30.28°, 30.8°, 34.09°, 38.19°, 40.69°, 41.82°, 43.74°, 46.04° degrees. b) Injection of injection fluid into an underground formation, c) Flushing of the underground formation using the fluid injected, d) Recovery of an aqueous and hydrocarbon mixture.

Provided is a zwitterionic polymer that has a zwitterion that includes an effect of improving the stability of proteins. This zwitterionic polymer is a polymeric protein stabilizer that exhibits a protein stabilizing effect even at a small addition amount of addition, and at the same time has an antioxidant capability. Also provided is a method for producing this zwitterionic polymer. This problem is solved by a zwitterionic polymer containing a repeating unit represented by formula (1) and having a number-average molecular weight of 1,000 to 1,000,000. On formula (1), R.sup.1 and R.sup.2 are each independently selected from a hydrogen atom; linear, branched or cyclic alkyl groups having 1 to 6 carbons; aromatic groups having 6 to 20 carbons; or alkylene groups having 1 to 6 carbons and formed by linking R.sup.1 to R.sup.2. R.sup.3 represents a hydrogen atom or a methyl group).

Provided is a zwitterionic polymer that has a zwitterion that includes an effect of improving the stability of proteins. This zwitterionic polymer is a polymeric protein stabilizer that exhibits a protein stabilizing effect even at a small addition amount of addition, and at the same time has an antioxidant capability. Also provided is a method for producing this zwitterionic polymer. This problem is solved by a zwitterionic polymer containing a repeating unit represented by formula (1) and having a number-average molecular weight of 1,000 to 1,000,000. On formula (1), R.sup.1 and R.sup.2 are each independently selected from a hydrogen atom; linear, branched or cyclic alkyl groups having 1 to 6 carbons; aromatic groups having 6 to 20 carbons; or alkylene groups having 1 to 6 carbons and formed by linking R.sup.1 to R.sup.2. R.sup.3 represents a hydrogen atom or a methyl group).

The present invention relates to a hydrated crystalline form of 2-acrylamido-2-methylpropane sulfonic acid having a 2-theta powder X-ray diffraction diagram comprising peaks at 10.58°, 11.2°, 12.65°, 13.66°, 16.28°, 18.45°, 20°, 20.4°, 22.5°, 25.5°, 25.88°, 26.47°, 28.52°, 30.28°, 30.8°, 34.09°, 38.19°, 40.69°, 41.82°, 43.74°, 46.04° degrees (+/−0.1°). The present invention also relates to a production method for this form of 2-acrylamido-2-methylpropane sulfonic acid and a preparation method for an aqueous solution A of a salt of this form of 2-acrylamido-2-methylpropane sulfonic acid, and the (co)polymer of this form of -acrylamido-2-methylpropane sulfonic acid.

The present invention relates to a hydrated crystalline form of 2-acrylamido-2-methylpropane sulfonic acid having a 2-theta powder X-ray diffraction diagram comprising peaks at 10.58°, 11.2°, 12.65°, 13.66°, 16.28°, 18.45°, 20°, 20.4°, 22.5°, 25.5°, 25.88°, 26.47°, 28.52°, 30.28°, 30.8°, 34.09°, 38.19°, 40.69°, 41.82°, 43.74°, 46.04° degrees (+/−0.1°). The present invention also relates to a production method for this form of 2-acrylamido-2-methylpropane sulfonic acid and a preparation method for an aqueous solution A of a salt of this form of 2-acrylamido-2-methylpropane sulfonic acid, and the (co)polymer of this form of -acrylamido-2-methylpropane sulfonic acid.

The invention relates to a method for the purification of acrylamido-2-methyl-2-propanesulphonic acid comprising the following successive steps: 1) preparation of a suspension of acrylamido-2-methyl-2-propanesulphonic acid crystals by distillation of an aqueous solution of acrylamido-2-methyl-2-propanesulphonic acid in order to obtain a suspension of acrylamido-2-methyl-2-propanesulphonic acid crystals, 2) isolation of the acrylamido-2-methyl-2-propanesulphonic acid crystals generally by solid/liquid separation from said suspension in order to isolate said acrylamido-2-methyl-2-propanesulphonic acid crystals, characterised in that the distillation step is carried out continuously and at a pressure below atmospheric pressure. The invention also relates to a polymer obtained from acrylamido-2-methyl-2-propanesulphonic acid crystals or its salts, obtained according to such a method, and to the use of said polymer in oil and gas recovery, in water treatment, in sludge treatment, in manufacturing paper, in construction, in mining, in cosmetic formulation, in detergent formulation, in textile making, or in agriculture.