A block copolymer consists mainly of structural units each derived from an ethylenically unsaturated monomer and has at least one mercapto group. The block copolymer has an Mn of 5,000-500,000 and has a block structure, which is an A-B-A triblock structure or a star-shaped block structure of [A-B]qX. The q is an integer of 2-6. The polymer block (A) has a glass transition temperature of 20° C. or higher. The polymer block (B) of the triblock structure has a glass transition temperature lower than 20° C., and the [polymer block (B)]qX of the star-shaped block structure has a glass transition temperature lower than 20° C. The X is an initiator residue or/and a coupling-agent residue or is a derivative thereof.

Provided is a block copolymer with an acid group that, when used as a dispersant, can provide a dispersion composition having excellent dispersion stability, a dispersant containing the block copolymer, and a pigment dispersion composition using the dispersant. The block copolymer is an ABA block copolymer including an A block and a B block and has the feature that its acid value is 30 to 250 mgKOH/g and the B block contains a structural unit derived from a vinyl monomer with an acid group.

The present invention addresses the problem of providing a fluorine-containing aromatic polymer; a method for producing the fluorine-containing aromatic polymer; etc. The problem can be solved by: a polymer having a monomer unit represented by formula (1) (wherein R.sup.1 in each occurrence is independently a halogen atom, NR.sup.11R.sup.12 (wherein R.sup.11 and R.sup.12 are independently a hydrogen atom or an organic group), or an organic group; n1 is an integer of 0 to 4; two R.sup.1s that can be present in the ortho-positions may form a ring together with two carbon atoms on the adjacent benzene ring, wherein the formed ring may have an organic group as a substituent; and L.sup.1 is a single bond, an oxygen atom, a sulfur atom, -L.sup.11-O—, —O-L.sup.12-O—, -L.sup.13-S—, or —S-L.sup.14-S— (wherein L.sup.11 to L.sup.14 are each independently an alkylene group optionally having one or more substituents); etc.

The present invention relates to a method for the preparation of a synthetic rubber blend, wherein the blend comprises a high molecular weight polydiene (A) and a low molecular weight polydiene (B). The present invention further relates to a synthetic rubber blend obtainable according to the method described herein; as well as to rubber compositions comprising the blend; and articles, such as tires.

The invention provides a method for producing photochromic silicone hydrogel (SiHy) contact lenses based on thermal cast-molding technology in a relatively efficient and consistent manner. The method is characterized by selecting a high radical-reactive hydrophilic acrylic monomer while eliminating any low radical-reactive hydrophilic N-vinyl amide monomer in a lens formulation (polymerizable composition), by selecting a weight ratio of low-radical-reactive hydrophilic N-vinyl amide monomer to a high radical-reactive hydrophilic acrylic monomer in a lens formulation if the low radical-reactive hydrophilic N-vinyl amide monomer is needed, and/or by using a relatively high temperature thermal initiator in a lens formulation, to control the lens properties (e.g., water content, elastic modulus, etc.) and lens processability (capability of dry-delensing from molds) of thermally cast-molded SiHy contact lenses while minimizing loss in photochromic ability of resultant SiHy contact lenses.

A polyHIPE-based substance-releasing system capable of releasably encapsulating a highly concentrated solution and/or a room temperature solid while minimizing or avoiding burst release from the closed-cell microstructure of an elastic polyHIPE.

An ethylenically unsaturated polymer includes at a terminus the radical of an allylic compound that includes a functional group free of active hydrogen atoms that is bonded to the allylic C atom through a S, P, Si or Sn atom and a vinyl aromatic compound. The polymer can be used as a component of a variety of elastomeric compounds used in the production of vulcanizates.

The invention relates to a method for preparing a vinyl ether polymer by photo-initiated polymerization, which comprises the step of: under a protective atmosphere, performing photo-initiated polymerization on a vinyl ether monomer in the presence of an organic halogenated hydrocarbon and manganese carbonyl under irradiation of light having a wavelength of 365-550 nm at −25° C. to 25° C., to obtain a vinyl ether polymer after the reaction is completed. In the method, a vinyl ether monomer is subjected to cationic polymerization in the presence of manganese carbonyl and an organic halogenated hydrocarbon under visible light, to prepare a vinyl ether polymer with controlled molecular weight and narrow molecular weight distribution.

The present disclosure relates to a capped dual-headed organoaluminum composition having the formula (I) and processes to prepare the same. In at least one aspect, the capped dual-headed organoaluminum compositions can be used in olefin polymerization.

The block copolymer intermediate represented by the following general formula (1) or (2) is used. In the formulae, R.sup.1 and R.sup.7 each independently represent a polymerization initiator residue, R.sup.2 and R.sup.8 each independently represent an aromatic group or an alkyl group, Y.sup.1 represents a polymer block of (meth)acrylic ester: Y.sup.2 represents a polymer block of styrene or a derivative thereof, and m and n each independently represent in an integer from 1 to 5. In the formulae, R.sup.3 represents an alkylene group having 1 to 6 carbon atoms, L represents a linking group, R.sup.4 represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aromatic group, and R.sup.5 and R.sup.6 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

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