A method of preparing a fluoroelastomer capable of being vulcanized by using peroxide, the method comprising: in the presence of an initiator and a chain transfer agent, conducting emulsion polymerization reaction on comonomers to obtain a fluoroelastomer. The preparation method utilizes alkyl iodide RI.sub.x as the chain transfer agent, and introduces the atom I into the molecular structure of the polymer during the reaction, the atom I acting as a crosslinking point during peroxide vulcanization. The fluoroelastomer obtained via the preparation method greatly improves the performance after being vulcanized; in addition, due to the low cost and extensive sources of alkyl iodide, the preparation method also simplifies the manufacturing process, reduces cost, and has wide application prospects.

A method of preparing a fluoroelastomer capable of being vulcanized by using peroxide, the method comprising: in the presence of an initiator and a chain transfer agent, conducting emulsion polymerization reaction on comonomers to obtain a fluoroelastomer. The preparation method utilizes alkyl iodide RI.sub.x as the chain transfer agent, and introduces the atom I into the molecular structure of the polymer during the reaction, the atom I acting as a crosslinking point during peroxide vulcanization. The fluoroelastomer obtained via the preparation method greatly improves the performance after being vulcanized; in addition, due to the low cost and extensive sources of alkyl iodide, the preparation method also simplifies the manufacturing process, reduces cost, and has wide application prospects.

A process for producing a water-absorbing polymer composition, comprising the process steps of (i) mixing (α1) 0.1 to 99.999% by weight of ethylenically unsaturated monomers containing acid groups or salts thereof (α2) 0 to 70% by weight of polymerized, ethylenically unsaturated monomers copolymerizable with (α1), (α3) 0.001 to 10% by weight of one or more crosslinkers, (α4) 0 to 30% by weight of water-soluble polymers, and (α5) 0 to 20% by weight of one or more assistants, where the sum of their weights (α1) to (α5) is 100% by weight, (ii) free-radical polymerization with crosslinking to form a water-insoluble aqueous untreated hydrogel polymer, and surface postcrosslinking the ground hydrogel polymer wherein blowing agents having a particle size of 100 μm to 900 μm are added to the aqueous monomer solution prior to the addition of the initiator and the start of the free-radical polymerization.

A process for producing a water-absorbing polymer composition, comprising the process steps of (i) mixing (α1) 0.1 to 99.999% by weight of ethylenically unsaturated monomers containing acid groups or salts thereof (α2) 0 to 70% by weight of polymerized, ethylenically unsaturated monomers copolymerizable with (α1), (α3) 0.001 to 10% by weight of one or more crosslinkers, (α4) 0 to 30% by weight of water-soluble polymers, and (α5) 0 to 20% by weight of one or more assistants, where the sum of their weights (α1) to (α5) is 100% by weight, (ii) free-radical polymerization with crosslinking to form a water-insoluble aqueous untreated hydrogel polymer, and surface postcrosslinking the ground hydrogel polymer wherein blowing agents having a particle size of 100 μm to 900 μm are added to the aqueous monomer solution prior to the addition of the initiator and the start of the free-radical polymerization.

Provided is a method of forming a polymer, comprising (a) providing a reaction mixture comprising (i) one or more vinyl monomers, (ii) one or more pH-sensitive inhibition systems, (iii) one or more initiators, and (iv) water; (b) establishing conditions in said reaction mixture such that a free radical polymerization of said vinyl monomer occurs at a location, and (c) after steps (a) and (b) and prior to completion of said free radical polymerization, changing the pH of said reaction mixture to increase the rate of generation of said free radical polymerization at the location of said free radical polymerization.

Provided is a method of forming a polymer, comprising (a) providing a reaction mixture comprising (i) one or more vinyl monomers, (ii) one or more pH-sensitive inhibition systems, (iii) one or more initiators, and (iv) water; (b) establishing conditions in said reaction mixture such that a free radical polymerization of said vinyl monomer occurs at a location, and (c) after steps (a) and (b) and prior to completion of said free radical polymerization, changing the pH of said reaction mixture to increase the rate of generation of said free radical polymerization at the location of said free radical polymerization.

A composition comprising a mixture of fluoropolyether acids or salts having a number average value of about 800 to about 2500 g/mol. The amount of fluoropolyether acids or salt in the mixture having a molecular weight of not more than 500 g/mol is not more than 50 ppm by weight of the total amount of fluoropolyether acids or salts in the mixture. The amount of fluoropolyether acids or salts in the mixture having a molecular weight of 2500 g/mol or greater is not more than 40% by weight of the total amount of fluoropolyether acids or salts in the mixture. Preferably the fluoropolyether acids or salts comprise an anionic group selected from the group consisting of carboxylate, sulfonate, sulfonamide anion and phosphonate. Also disclosed is an aqueous dispersion polymerization process for fluoropolymer manufacture employing polymerization agent comprising the specified mixture of fluoropolyether acids or salts.

A composition comprising a mixture of fluoropolyether acids or salts having a number average value of about 800 to about 2500 g/mol. The amount of fluoropolyether acids or salt in the mixture having a molecular weight of not more than 500 g/mol is not more than 50 ppm by weight of the total amount of fluoropolyether acids or salts in the mixture. The amount of fluoropolyether acids or salts in the mixture having a molecular weight of 2500 g/mol or greater is not more than 40% by weight of the total amount of fluoropolyether acids or salts in the mixture. Preferably the fluoropolyether acids or salts comprise an anionic group selected from the group consisting of carboxylate, sulfonate, sulfonamide anion and phosphonate. Also disclosed is an aqueous dispersion polymerization process for fluoropolymer manufacture employing polymerization agent comprising the specified mixture of fluoropolyether acids or salts.

The present invention provides an aqueous polyurethane (PU)-polyacrylate hybrid dispersion obtainable by free radical polymerization of at least one acrylate polymer (A1) in the presence of at least one polyurethane (P1), a process for preparing these aqueous polyurethane-polyacrylate hybrid dispersions, wherein said process comprises a) preparing an aqueous polyurethane dispersion and b) using the polyurethane dispersion thus prepared as raw material for the further synthesis of a polyacrylate dispersion, and the use of the hybrid dispersion thus obtained as binder in filled coating materials, particularly as a binder for flexible roof coatings.

In one embodiment the invention relates to a method of preparing a polyrotaxane, said method comprising: performing a radical copolymerization of at least (a) a first polymerizable monomer having a stopper group, and of at least (b) a second polymerizable hydrophobic monomer, wherein said second monomer is complexed by a ring-shaped molecule, and of at least (c) a third polymerizable hydrophilic monomer; wherein during said copolymerization a copolymer threading said ring-shaped molecule is formed, wherein during said copolymerization said first monomer having a stopper group is incorporated into the chain of said copolymer at least partially between the ends thereof, and wherein said stopper groups prevent said ring-shaped molecule from disassembling from the copolymer; and wherein the amount of said first monomer having a stopper group is of from 0.1 mol % to 20 mol % based on 100 mol % of the total amount of polymerizable monomers. In another embodiment the invention relates to a method of preparing a polyrotaxane, said method comprising: performing a radical copolymerization of at least (a) a first polymerizable monomer having a stopper group, and of at least (b) a second polymerizable partially hydrophilic monomer, wherein said second monomer is complexed by a ring-shaped molecule, and wherein said second monomer has a solubility in water at 20° C. of from 5 g/L to 40 g/L; wherein during said copolymerization a copolymer threading said ring-shaped molecule is formed, wherein during said copolymerization said first monomer having a stopper group is incorporated into the chain of said copolymer at least partially between the ends thereof, and wherein said stopper groups prevent said ring-shaped molecule from disassembling from the copolymer; and wherein the amount of said first monomer having a stopper group is of from 0.1 mol % to 20 mol % based on 100 mol % of the total amount of polymerizable monomers. Furthermore, the present invention relates to methods of preparing cross-linked polyrotaxanes and cross-linked polyrotaxanes which can be prepared using such methods. Thus, the present invention also relates to polyrotaxane and crosslinked polyrotaxanes. The invention also relates to products which contain the polyrotaxanes or cross-linked polyrotaxanes or which can be prepared from the polyrotaxanes or the cross-linked polyrotaxanes. The present invention further relates to the use of polyrotaxanes or cross-linked polyrotaxanes in various applications, such as the use as a self-healing material.