A method of preparing an acrylonitrile-based copolymer for a carbon fiber. The method includes: preparing a reaction solution including a (meth)acrylonitrile-based monomer and a first reaction solvent; adding a first portion of a radical polymerization initiator to the reaction solution to initiate polymerization; and adding a second portion of the radical polymerization initiator to the reaction solution when a polymerization conversion ratio is between 70 to 80%.

A separator for electricity storage devices which comprises: a base comprising a porous film; and a thermoplastic polymer arranged on at least one surface of the base. The thermoplastic polymer has a dispersion (σ.sup.2), defined by the following numerical equation using the areas (Si) of Voronoi polygons obtained by Voronoi tessellation, of 0.01-0.7. (In the equation, Si is the measured area of each Voronoi polygon, m is an average of the measured areas of the Voronoi polygons, and n is the total number of the Voronoi polygons.)

A separator for electricity storage devices which comprises: a base comprising a porous film; and a thermoplastic polymer arranged on at least one surface of the base. The thermoplastic polymer has a dispersion (σ.sup.2), defined by the following numerical equation using the areas (Si) of Voronoi polygons obtained by Voronoi tessellation, of 0.01-0.7. (In the equation, Si is the measured area of each Voronoi polygon, m is an average of the measured areas of the Voronoi polygons, and n is the total number of the Voronoi polygons.)

The present disclosure relates to the production of polyacrylonitrile-based polymers with high conversion by a process comprising reacting acrylonitrile with at least one comonomer in the presence of a radical initiator in a liquid medium, wherein the radical initiator is present in an amount of from about 0.6 wt % to about 1.8 wt %, relative to the amount of acrylonitrile, and wherein no chain transfer agent is present. The polyacrylonitrile-based polymers produced may be used for producing carbon fiber, typically carbon fiber used in manufacturing composite materials.

The present disclosure relates to the production of polyacrylonitrile-based polymers with high conversion by a process comprising reacting acrylonitrile with at least one comonomer in the presence of a radical initiator in a liquid medium, wherein the radical initiator is present in an amount of from about 0.6 wt % to about 1.8 wt %, relative to the amount of acrylonitrile, and wherein no chain transfer agent is present. The polyacrylonitrile-based polymers produced may be used for producing carbon fiber, typically carbon fiber used in manufacturing composite materials.

A latex composition for dip molding includes a carboxylic acid-modified nitrile-based copolymer latex and a cholate-based emulsifier, wherein the cholate-based emulsifier is included in an amount of 0.02 to 3 parts by weight based on a solid content with respect to a solid content of 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer latex. A method of preparing the latex composition for dip molding and a molded article produced using the same are also provided.

A latex composition for dip molding includes a carboxylic acid-modified nitrile-based copolymer latex and a cholate-based emulsifier, wherein the cholate-based emulsifier is included in an amount of 0.02 to 3 parts by weight based on a solid content with respect to a solid content of 100 parts by weight of the carboxylic acid-modified nitrile-based copolymer latex. A method of preparing the latex composition for dip molding and a molded article produced using the same are also provided.

The present invention addresses the problem of providing: a dispersant which enables the production of a dispersed material having excellent dispersibility and storage stability even when the dispersant is used in a small amount; a dispersed material having excellent dispersibility and storage stability; an electrode film having excellent adhesiveness and electrical conductivity; and a non-aqueous electrolyte secondary battery having excellent rate properties and cycle properties. The problem can be solved by a dispersant which is a polymer containing 40 to 100% by mass of a (meth)acrylonitrile-derived unit and having a weight average molecular weight of 5,000 to 400,000.

The present invention addresses the problem of providing: a dispersant which enables the production of a dispersed material having excellent dispersibility and storage stability even when the dispersant is used in a small amount; a dispersed material having excellent dispersibility and storage stability; an electrode film having excellent adhesiveness and electrical conductivity; and a non-aqueous electrolyte secondary battery having excellent rate properties and cycle properties. The problem can be solved by a dispersant which is a polymer containing 40 to 100% by mass of a (meth)acrylonitrile-derived unit and having a weight average molecular weight of 5,000 to 400,000.

An optimized process for the preparation of a spinning solution for the production of acrylic fiber precursors (PAN) of carbon fibers and an optimized process for the production of carbon fibers from said acrylic precursor (PAN), are described.