A dispersion stabilizer for suspension polymerization of vinyl compounds comprising a vinyl alcohol polymer (A) which has a saponification degree of 30 mol % or more and less than 60 mol % and a viscosity-average polymerization degree (P) of more than 200 and less than 600, and has a terminal alkyl group having 6 to 18 carbon atoms, and in which a content of monomer units having an oxyalkylene group is 0.3 mol % or less and the relationship between the viscosity-average polymerization degree (P) and a modification rate (S) (mol %) of the alkyl group satisfies Formula (1). Thus, there can be provided a dispersion stabilizer for suspension polymerization with which, during suspension polymerization of vinyl compounds including vinyl chloride, even when it is used in a small amount, the absorbency of a plasticizer is high, resulting in easy processing and formation of coarse particles is little and the remaining monomer components can be easily removed.
50≦S×P/1.880<100  (1)

Disclosed are methods for upcycling polyvinyl chloride (PVC) that involve the dissolving of PVC in an organic solvent; and contacting the PVC with a base, thereby providing a partially dehydrochlorinated PVC. Polymers made by the disclosed, and articles therefore, are also disclosed.

Disclosed are methods for upcycling polyvinyl chloride (PVC) that involve the dissolving of PVC in an organic solvent; and contacting the PVC with a base, thereby providing a partially dehydrochlorinated PVC. Polymers made by the disclosed, and articles therefore, are also disclosed.

Method of making a composite material by paste polymerization, by forming an emulsion of at least one polymerizable monomer in an aqueous material, polymerizing the emulsion to provide a latex containing particles of polymer, in which the polymer has a glass transition temperature above 65° C., adding nanoparticles to the latex, the nanoparticles having at least one dimension in the range 0.5 to 200 nm, and spray-drying the latex. The at least one polymerizable monomer contains vinyl chloride.

Method of making a composite material by paste polymerization, by forming an emulsion of at least one polymerizable monomer in an aqueous material, polymerizing the emulsion to provide a latex containing particles of polymer, in which the polymer has a glass transition temperature above 65° C., adding nanoparticles to the latex, the nanoparticles having at least one dimension in the range 0.5 to 200 nm, and spray-drying the latex. The at least one polymerizable monomer contains vinyl chloride.

Disclosed is a method of preparing a vinyl chloride based resin by suspension polymerization to prevent foaming by slowly elevating reaction temperature such that pressure is maintained when pressure drops in a late stage of reaction. According to the method, the vinyl chloride based resin is prepared using suspension polymerizing vinyl chloride based monomers so as to reduce foaming and improve a protrusion, thermal stability and the like.

Disclosed is a method of preparing a vinyl chloride based resin by suspension polymerization to prevent foaming by slowly elevating reaction temperature such that pressure is maintained when pressure drops in a late stage of reaction. According to the method, the vinyl chloride based resin is prepared using suspension polymerizing vinyl chloride based monomers so as to reduce foaming and improve a protrusion, thermal stability and the like.

A method for producing a vinyl chloride type polymer is to produce the vinyl chloride type polymer by polymerizing a vinyl chloride monomer, or a mixture of a vinyl chloride monomer with a monomer copolymerizable with the vinyl chloride monomer in an aqueous medium by using a polymerization reactor. An aqueous solution of a copolymerized polyether having a weight-average molecular weight of 1,000 to 3,500 with a mole ratio of ethylene oxide to propylene oxide in the range of 10/90 to 60/40 and having an alkyl group or an aryl group at both the terminals thereof is charged into the polymerization reactor with an amount of 0.005 to 0.050 parts by weight as the copolymerized polyether relative to 100 parts by weight of the vinyl chloride monomer.

A method for producing a vinyl chloride type polymer is to produce the vinyl chloride type polymer by polymerizing a vinyl chloride monomer, or a mixture of a vinyl chloride monomer with a monomer copolymerizable with the vinyl chloride monomer in an aqueous medium by using a polymerization reactor. An aqueous solution of a copolymerized polyether having a weight-average molecular weight of 1,000 to 3,500 with a mole ratio of ethylene oxide to propylene oxide in the range of 10/90 to 60/40 and having an alkyl group or an aryl group at both the terminals thereof is charged into the polymerization reactor with an amount of 0.005 to 0.050 parts by weight as the copolymerized polyether relative to 100 parts by weight of the vinyl chloride monomer.

A method for producing a vinyl chloride-based polymer, wherein the vinyl chloride-based polymer is produced by sequentially adding a first emulsifier and a second emulsifier, which are different from each other, during polymerization and using a succinate compound as a first emulsifier. The method provides improved processability by achieving low-viscosity properties when plastisol is mixed using the produced polymer, and improved fogging properties by suppressing generation of volatile organic compounds.