Kuraray Co., Ltd.

Universitéde Liége

Takumi Takayama

Kazuhiko Maekawa

Yusuke Amano

Christophe Detrembleur

Antoine Debuigne

Christine Jerome

Naoki Fujiwara

Keisuke Morikawa

Hiroyuki Konishi

Naoyuki Iwachido

Christine Jérôme

Kazutoshi Mishima

Disclosed is a vinyl alcohol-based block copolymer that is a block copolymer composed of a vinyl alcohol-based polymer block (B-b) and a copolymer block (B-c) comprising a vinyl alcohol-based monomer unit and an acrylic acid-based monomer unit, wherein a content (Z) of the acrylic acid-based monomer unit relative to all monomer units is 0.05 to 20.0 mol %, the block copolymer has a saponification degree of 80 to 99.99 mol %, the block copolymer has a number-average molecular weight (Mn) of 20,000 to 440,000, the block copolymer has a molecular weight distribution (Mw/Mn) of 1.05 to 1.95, and a ratio (DP/DP) of a number-average polymerization degree (DP) of the vinyl alcohol-based polymer block (B-b) to the number-average polymerization degree (DP) of the block copolymer is 0.010 to 0.999. The copolymer has a fine balance derived from the copolymer block (B-c) of having a superior solubility in water while being unlikely to undergo thickening or gelation due to pH fluctuation, and also has high mechanic strength derived from the vinyl alcohol-based polymer block (B-b).

Vinyl alcohol-based block copolymer and method for producing same

A polyvinyl alcohol has a number-average molecular weight (Mn) from 4,400 to 440,000, a molecular weight distribution (Mw/Mn) from 1.05 to 1.70, a degree of saponification from 80 to 99.99 mol %, wherein the polyvinyl alcohol contains an end group represented by a formula (I) below, and a molar ratio (X) of the end group based on total monomer units and the number-average molecular weight (Mn) satisfy a formula (1) below. Such a polyvinyl alcohol has a narrow molecular weight distribution and a high number-average molecular weight with hue good. (In the formula, Rdenotes an optionally substituted aromatic group having a carbon number from 6 to 20, and Rdenotes a hydrogen atom, an alkyl group having a carbon number from 1 to 20, or an optionally substituted aromatic group having a carbon number from 6 to 20.)X&#xb7;Mn/44&#x2265;0.5&#x2003;&#x2003;(1)

Polyvinyl alcohol and method for producing polyvinyl alcohol

A polyvinyl alcohol has a number-average molecular weight (Mn) from 4,400 to 440,000, a molecular weight distribution (Mw/Mn) from 1.05 to 1.70, a degree of saponification from 80 to 99.99 mol %, and a carbon-carbon double bond content (X) of 0.1 mol % or less based on total monomer units, and satisfying a formula (1) below. A polyvinyl alcohol, having a narrow molecular weight distribution and a high number-average molecular weight with good hue, and a method for producing the same are thus provided.X&#xb7;Mn&#x2264;1000&#x2003;&#x2003;(1)

Polyvinyl alcohol

A polyvinyl alcohol is produced in a method comprising: a polymerization step comprising polymerizing vinyl ester monomers by controlled radical polymerization in the presence of a radical initiator and an organic cobalt complex to obtain a polymer solution containing a polyvinyl ester; an extraction step comprising extracting a cobalt complex from the polymer solution by contacting an aqueous solution containing a water-soluble ligand with the polymer solution; and a saponification step comprising saponifying the polyvinyl ester after the extraction step to obtain a polyvinyl alcohol. A method for producing a polyvinyl alcohol is thus provided that has a narrow molecular weight distribution and a high number-average molecular weight with good hue and further good solubility in water.

Polyvinyl alcohol and method for producing same

Provided are graft copolymer particles enabling introduction of adsorptive functional groups adsorbing metals and others, a method for producing same, and an adsorbent using same. (1) Porous graft copolymer particles containing graft chains introduced into porous particles (particle surface having an average pore diameter of 0.01-50 &#x3bc;m) including at least one resin selected from olefin resins, water-insoluble modified polyvinyl alcohol resins, amide resins, cellulosic resins, chitosan resins and (meth)acrylate resins. (2) A method for producing porous graft copolymer particles including (I) melt-kneading a polymer A and a polymer B other than the polymer A to obtain a compound material, (II) extracting and removing the polymer B from the compound material to obtain a porous material of the polymer A, (III) granulating the porous material, and (IV) introducing graft chains into the porous particles. (3) An adsorbent of porous graft copolymer particles.

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Kurashiki, Japan

Takumi Takayama