A method for producing an aqueous dispersion of a fluorine-containing elastomer, which includes polymerizing a fluorine-containing monomer in the presence of a fluorine-free compound (1) represented by general formula (1): CR.sup.1X.sup.1═CX.sup.2—R.sup.2—COOM and an aqueous medium, to produce an aqueous dispersion of the fluorine-containing elastomer containing —CH.sub.2— in a main chain. Also disclosed is an aqueous dispersion of the fluorine-containing elastomer and a composition containing the fluorine-containing elastomer.

Provided is a method for producing an aqueous dispersion of a fluorine-containing elastomer, comprising polymerizing a fluorine-containing monomer in the presence of a compound (1) having a triple bond and a hydrophilic group and an aqueous medium to produce an aqueous dispersion of a fluorine-containing elastomer.

Provided is a method for producing an aqueous dispersion of a fluorine-containing elastomer, comprising polymerizing a fluorine-containing monomer in the presence of a compound (1) having a triple bond and a hydrophilic group and an aqueous medium to produce an aqueous dispersion of a fluorine-containing elastomer.

The invention relates to an organic peroxide emulsion comprising at least one organic peroxide comprising di-sec-butyl peroxydicarbonate, at least one emulsifier, at least one antifreeze, and water; said emulsion being free of methanol and ethanol.

The invention also relates to a process for preparing such an emulsion, to the use of such an emulsion for the polymerization or copolymerization of one or more ethylenically unsaturated monomers, and also to a halogenated vinyl polymer obtained by using such an emulsion.

The invention relates to an organic peroxide emulsion comprising at least one organic peroxide comprising di-sec-butyl peroxydicarbonate, at least one emulsifier, at least one antifreeze, and water; said emulsion being free of methanol and ethanol.

The invention also relates to a process for preparing such an emulsion, to the use of such an emulsion for the polymerization or copolymerization of one or more ethylenically unsaturated monomers, and also to a halogenated vinyl polymer obtained by using such an emulsion.

A vinyl alcohol-based polymer according to one embodiment of the present invention has an integral value (e) of 0.8 to 20 in the case when a sum of the following integral value (a) to (e) is 100 in a .sup.1H-NMR spectrum.

(a) integral value of peak confirmed at 5.70 to 5.96 ppm
(b) integral value of peak confirmed at 5.97 to 6.63 ppm
(c) integral value of peak confirmed at 6.64 to 7.55 ppm
(d) integral value of peak confirmed at 7.56 to 7.81 ppm
(e) integral value of peak confirmed at 7.82 to 8.04 ppm

A vinyl alcohol-based polymer according to one embodiment of the present invention has an integral value (e) of 0.8 to 20 in the case when a sum of the following integral value (a) to (e) is 100 in a .sup.1H-NMR spectrum.

(a) integral value of peak confirmed at 5.70 to 5.96 ppm
(b) integral value of peak confirmed at 5.97 to 6.63 ppm
(c) integral value of peak confirmed at 6.64 to 7.55 ppm
(d) integral value of peak confirmed at 7.56 to 7.81 ppm
(e) integral value of peak confirmed at 7.82 to 8.04 ppm

The invention relates to synthetic nanocompounds in the form of microparticles that allow major deformations before breaking and are especially useful for preparing low-density synthetic propping agents to be used in non-conventional oil and gas extraction processes (fracking). The invention also describes the process for obtaining said nanocompounds, propping agents and fracturing fluids for oil and gas extraction processes.

The present disclosure relates to a method for producing polymer microparticles, this method including a step for polymerizing vinyl monomers in a hydrophilic solvent, which dissolves the vinyl monomers and a dispersion stabilizer but does not dissolve a polymer formed, in the presence of the dispersion stabilizer. The present disclosure is a method for producing these polymer microparticles, wherein the dispersion stabilizer contains a macromonomer having carboxyl groups and ethylenically unsaturated groups at an intermediate location in a molecular chain thereof, the macromonomer has, on average, 1.4 to 2.5 ethylenically unsaturated groups per molecule, and an average value of a carboxyl group content in the macromonomer is 0.5 meq/g to 2.5 meq/g.

A process comprises polymerizing an olefin monomer in a loop reactor in the presence of a catalyst and a diluent, and producing a slurry comprising solid particulate olefin polymer and diluent. The Biot number is maintained at or below about 3.0 within the loop reactor during the polymerizing process. The slurry in the loop reactor forms a slurry film having a film coefficient along an inner surface of the reactor wall, and the film coefficient is less than about 500 BTU.Math.hr.sup.−1.Math.ft.sup.−2.Math.° F..sup.−1.