A method for producing a vinyl polymer including a polymerization step of using a composition including a microcapsule and polymerizing a vinyl monomer by radical reaction to produce a vinyl polymer, in which the microcapsule has a core/shell structure, and the shell includes a water-soluble polymer and the core includes an organic peroxide. The water-soluble polymer is preferably at least one water-soluble polymer selected from the group consisting of polyvinyl alcohol, cellulose derivatives, gelatin, poly(meth)acrylic acid derivatives, polyvinylpyrrolidone, and polyethylene oxide.

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.

The present invention provides a production method of polyvinyl chloride by suspension polymerization and a feeding apparatus. This method comprises: Step 1: injecting a vinyl chloride monomer and water at 25-98° C. into a reaction vessel to obtain a water suspension, closing the reaction kettle, repeatedly and cyclically performing vacuum-pumping and cleansing with nitrogen, stirring and evacuating oxygen in the reaction kettle; Step 2: adding a first suspension agent and a second suspension agent into the reaction kettle, and then adding a nanopowder and an initiator composite, to carry out the polymerization reaction; Step 3: adding cold water to terminate the polymerization reaction upon the pressure in the reaction kettle is reduced to 3.5 bar or less; Step 4: evacuating and vacuumizing the reaction kettle, and then filtering, washing and drying the resulted polymer, to obtain polyvinyl chloride. The present invention also provides a feeding apparatus used for the above production method. Polyvinyl chloride produced by the method of this invention has good performance and can meet the requirements of physical and chemical properties and applicability for most applications.

The present invention provides a production method of polyvinyl chloride by suspension polymerization and a feeding apparatus. This method comprises: Step 1: injecting a vinyl chloride monomer and water at 25-98° C. into a reaction vessel to obtain a water suspension, closing the reaction kettle, repeatedly and cyclically performing vacuum-pumping and cleansing with nitrogen, stirring and evacuating oxygen in the reaction kettle; Step 2: adding a first suspension agent and a second suspension agent into the reaction kettle, and then adding a nanopowder and an initiator composite, to carry out the polymerization reaction; Step 3: adding cold water to terminate the polymerization reaction upon the pressure in the reaction kettle is reduced to 3.5 bar or less; Step 4: evacuating and vacuumizing the reaction kettle, and then filtering, washing and drying the resulted polymer, to obtain polyvinyl chloride. The present invention also provides a feeding apparatus used for the above production method. Polyvinyl chloride produced by the method of this invention has good performance and can meet the requirements of physical and chemical properties and applicability for most applications.

A dispersion stabilizer for suspension polymerization is provided that includes a vinyl alcohol-based polymer (A), wherein a 0.1 mass % concentration aqueous solution of the polymer (A) has an absorbance (a1) of less than 0.25 at a wavelength of 280 nm, the aqueous solution has an absorbance (a2) of less than 0.030 at a wavelength of 320 nm, the polymer (A) has a degree of saponification of not less than 68 mol % and not more than 98 mol %, the polymer (A) has a viscosity-average degree of polymerization of more than 1500 and less than 4500, and the polymer (A) in powder form has a YI value of not less than 5. The dispersion stabilizer is capable of producing a vinyl-based resin that is excellent in polymerization stability, has a small particle size, and has an improved bulk density.

A dispersion stabilizer for suspension polymerization is provided that includes a vinyl alcohol-based polymer (A), wherein a 0.1 mass % concentration aqueous solution of the polymer (A) has an absorbance (a1) of less than 0.25 at a wavelength of 280 nm, the aqueous solution has an absorbance (a2) of less than 0.030 at a wavelength of 320 nm, the polymer (A) has a degree of saponification of not less than 68 mol % and not more than 98 mol %, the polymer (A) has a viscosity-average degree of polymerization of more than 1500 and less than 4500, and the polymer (A) in powder form has a YI value of not less than 5. The dispersion stabilizer is capable of producing a vinyl-based resin that is excellent in polymerization stability, has a small particle size, and has an improved bulk density.

The present invention relates to a loop-route production method and system for polyvinyl chloride, and belongs to the intersecting fields of coal chemicals, polymer materials and chemical machinery. Limestone and carbon materials such as coal are reacted in an oxygen-enriched high temperature furnace to obtain calcium carbide and carbon monoxide, and then acetylene and carbon monoxide are respectively produced from calcium carbide and dichloroethane (obtaining ethylene, etc., through methanol or ethanol); both of the end products are combined to form a closed-loop; acetylene and dichloroethane are reacted to produce a vinyl chloride monomer, which is polymerized to obtain polyvinyl chloride. The system of the present invention mainly includes a device for pulverizing and mixing solid raw materials, a device for conveying solid materials, an oxygen-enriched calcium carbide furnace, an oxygen-enriched air-blowing device, a tube-shell thermostatic reactor, a fixed bed tubular reactor, a fluidized bed reactor, an acetylene generator having a heat exchanger, a fixed bed reactor and a polymerization reactor. The present invention has the advantages of not only removing the dependence on oil resources during the production of polyvinyl chlorides, but also totally eliminating the mercury pollution.

The present invention relates to a loop-route production method and system for polyvinyl chloride, and belongs to the intersecting fields of coal chemicals, polymer materials and chemical machinery. Limestone and carbon materials such as coal are reacted in an oxygen-enriched high temperature furnace to obtain calcium carbide and carbon monoxide, and then acetylene and carbon monoxide are respectively produced from calcium carbide and dichloroethane (obtaining ethylene, etc., through methanol or ethanol); both of the end products are combined to form a closed-loop; acetylene and dichloroethane are reacted to produce a vinyl chloride monomer, which is polymerized to obtain polyvinyl chloride. The system of the present invention mainly includes a device for pulverizing and mixing solid raw materials, a device for conveying solid materials, an oxygen-enriched calcium carbide furnace, an oxygen-enriched air-blowing device, a tube-shell thermostatic reactor, a fixed bed tubular reactor, a fluidized bed reactor, an acetylene generator having a heat exchanger, a fixed bed reactor and a polymerization reactor. The present invention has the advantages of not only removing the dependence on oil resources during the production of polyvinyl chlorides, but also totally eliminating the mercury pollution.

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)