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.

A chloroprene-based block copolymer latex, including a chloroprene-based block copolymer, wherein: the chloroprene-based block copolymer contains 5 to 30% by mass of a polymer block (A) and 70 to 95% by mass of a chloroprene-based polymer block (B); the polymer block (A) is derived from a monomer; when the monomer is polymerized alone, a polymer with a glass transition temperature of 80° C. or higher can be obtained; the chloroprene-based polymer block (B) includes a chloroprene monomer unit; and when the chloroprene-based block copolymer latex is molded by immersion molding to obtain a film and then the film is heat-treated at 130° C. for 30 minutes, a tensile strength at break measured in accordance with JIS K6251 of the film is 17 MPa or more is provided.

The invention relates to the technical field of oil and gas drilling, and discloses an amphiphilic block polymer ultralow-permeability agent and an intelligent temporary plugging type water-based drilling fluid. The ultralow-permeability agent contains a structural unit provided by styryl hydrophobic monomer, maleic anhydride and acrylamide; the drilling fluid contains two or more of water, sodium bentonite, Pac-Lv, the ultralow-permeability agent, calcium carbonate, one-way plugging agent, white asphalt and barite which are stored in a mixed manner or independently stored. When the amphiphilic block polymer provided by the invention is used as the ultralow-permeability agent of the intelligent temporary plugging type water-based drilling fluid, the self-adaptive characteristic is realized; according to the amphiphilic block polymer, temporary plugging layer gaps formed in pore and throats by plugging materials in drilling fluid can be fully filled under the condition that the sizes and the distribution of the pore and throats of reservoirs are not required to be clear, so that the permeability of temporary plugging layer is greatly reduced, ultralow-permeability is realized, and the amphiphilic block polymer is weak in tackifying effect, has gel-improving effect and can improve the rheological property of the drilling fluid.

Disclosed herein is a composite material comprising a substrate coated with a block copolymer brush, where the block copolymer brush comprises a first block of a hydrophobic polymer conjugated to a nitric oxide source, where the first block of the hydrophobic polymer is covalently bonded to a surface of the substrate or a first block of a cationic polymer covalently bonded to a surface of the substrate and a second block of a hydrophilic polymer, extending from the first block to form an outer surface of the block copolymer brush.

A composition comprises: a base oil; an additive comprising a copolymer comprising hydrophobic and hydrophilic units; and a drug. The copolymer may for example have a comb structure in which the hydrophobic units and hydrophilic units are pendant chains on a backbone of the copolymer. The hydrophobic units and hydrophilic units may for example comprise polydimethylsiloxane moieties and ethylene glycol residues respectively. The composition may for example be used as a tamponade or as a component for a tamponade administered to the eye. The invention is useful for solubilising and/or releasing drugs.

The present invention provides polymers and methods of preparing the same. In certain embodiments, the polymers comprise acrylate repeating units that have been derivatized (e.g., reduced and/or substituted) to form new polymeric structures. In certain embodiments, the polymers described herein self-assemble to form well-defined nanostructures. In some instances, the nanostructures exhibit relatively small d-spacing (e.g., a d-spacing value of 10 nm or less). Due to their properties, the polymers described herein are useful in a variety of applications including functional materials and biomedical applications.

In an embodiment, the present disclosure pertains to a method of changing the glass transition temperature of a polymer. In some embodiments, the polymer includes at least one hydrazone-containing compound. In general, the methods of the present disclosure include one or more of the following steps of: (1) applying light to the polymer; and (2) thereby changing the glass transition temperature of the polymer. In another embodiment, the present disclosure pertains to a polymer having a light-adjustable glass transition temperature. In some embodiments, the polymer includes at least one hydrazone-containing compound.

The invention relates to a polyacrylate-based graft copolymer comprising a polyacrylate backbone and polyolefin side chains grafted thereon, wherein the graft copolymer is prepared by reacting a first polymer and a second polymer, wherein the first polymer comprises recurring units having the structure (I) and optionally further recurring units having the structures (II): Formulae (I), (II) wherein R.sup.1, R.sup.3 is H or CH.sub.3 and R.sup.2 is a hydrocarbon moiety comprising 1 to 6 carbon atoms, one of R.sup.4 and R.sup.5 is H and the other one of R.sup.5 and R.sup.4 is COOR.sup.2, C═N, Cl, or an aliphatic or aromatic hydrocarbon moiety optionally containing one or multiple hetero atom functionalities, wherein R.sup.2 in (I) is different from R.sup.2 in (II) and the second polymer is a functionalized polyolefin having one or multiple hydroxyl functional groups, wherein the graft copolymer is formed by transesterification of the COOR.sup.2 group of (1) or (II) with the hydroxyl functional group of the functionalized polyolefin.

A block copolymer is provided that includes a first block having pendant phosphorus-containing groups and a second block having fluorinated groups. Compositions containing the block copolymer as well as articles that include the block copolymer are also provided. The block copolymer can be used to provide a lower surface energy to a surface, particularly a metal-containing surface.

An immersion-molded body, wherein: the immersion-molded body is obtained using a latex; the latex comprises a chloroprene-based block copolymer; the chloroprene-based block copolymer contains 5 to 30% by mass of a polymer block (A) and 70 to 95% by mass of a chloroprene-based polymer block (B); the polymer block (A) is derived from a monomer; when the monomer is polymerized alone, a polymer with a glass transition temperature of 80° C. or higher can be obtained; the chloroprene-based polymer block (B) includes a chloroprene monomer unit; and when the immersion-molded body is heat-treated at 130° C. for 30 minutes, a tensile strength at break of the heat-treated immersion-molded body measured in accordance with JIS K6251 is 17 MPa or more.