144 results about "Lower critical solution temperature" patented technology

The present invention relates to novel polymeric compositions that exhibit Reverse Thermal Gelation (RTG) properties for use as Support Materials (SM) in the manufacture of three-dimensional objects. These polymers are Temperature Sensitive Polymers that respond with a significant change of properties to a small change in temperature. Temperature Sensitive Polymers exhibit cloud point (CP) or lower critical solution temperature (LCST) in aqueous solutions. Water-soluble Temperature Sensitive Polymers are chosen to give low viscosity liquid at low temperature when dissolved in water and by that to permit easy dispensing at low temperature. Raising the temperature above their gelation temperature (T_gel) will result in solidification of the composition. At its gel position the material has favorable characteristics as a support and building material. The gel layers have the appropriate toughness and dimensional stability to support the model layers during the building process. After the building process is completed the gel can be cooled down to a temperature below its T_gel so the gel can liquefy and be removed easily by rinsing with water.

A thermoviscoelastic system (TVE) fluid useful in a well treatment method can include a hydrophobically-modified polymer and a viscoelastic surfactant (VES) in an aqueous medium, wherein the polymer has a lower critical solution temperature (LCST). The polymer can have water solubility for preparation below the LCST, and the TVE has a low viscosity for pumping down a well bore in communication with a subterranean formation. When the TVE is heated above the LCST, interaction between the hydrophobic groups of the polymer and the VES form a cross-linked network to increase the viscosity to transport proppant into a fracture. The thickened TVE can have a low leak-off rate, optionally including colloidal particles or other fluid loss control agent, and can be broken by contact with hydrocarbons as during flowback from the reservoir.

An object of the present invention is to provide a method for forming a coating film that is capable of forming a coating film having excellent smoothness, distinctness of image and luster using an aqueous coating composition. The present invention provides a method for forming a coating film comprising:

Step (1): forming an uncured coating film by applying to a substrate an aqueous coating composition that contains a copolymer of monomer components comprising one or more N-substituted (meth)acrylamide compounds, the copolymer being a graft copolymer comprising (A) a main chain having a lower critical solution temperature T₁ in water within the range of 30 to 95° C., and (B) at least one hydrophobic side chain;

Step (2): preheating the uncured coating film formed in Step (1) under heating conditions such that a preheating temperature T₂ falls within the range of 60 to 100° C., and the preheating temperature T₂ and the lower critical solution temperature T₁ have a relationship represented by the formula T₂−T₁=−30 to 30° C.; and

Step (3): curing the uncured coating film formed in Step (2) by heating.

An intelligent tissue mimicking ultrasonic phantom, which is a temperature-sensitive polymer gel having the following acoustic properties and other physical characteristics: acoustic velocity: 1500-1550 m/s; acoustic impedance: (1.50−1.60)×10⁶ Pa·s/m; density: 1.01-1.06 g/cm³; and a denaturation temperature, namely, a Lower Critical Solution Temperature (LCST) or a Volume Phase Transition Temperature at which the volume of the phantom changes, adjustable by changing the ratio of raw materials, around which there is a reversible phase transformation between the opaque phase and the transparent phase. Said gel can be a polymer of isopropylacrylamide (NIPA). Said ultrasonic phantom has a transparent appearance, and an adjustable thermal denaturation temperature; the thermal denaturation region of the ultrasonic phantom is distinct and has a well-defined boundary; the material of the phantom is stable and deterioration-resistant, and can ensure the consistency of the quality; the phantom is thermal denaturable with the appearance thereof turning white, while the phantom recovers when the heat is removed, such that it can be used repeatedly.

The present invention is directed to separate a physiologically active agent accurately. Then, the present invention provides a structure for separation of a physiologically active agent, comprising a substrate, a substance exhibiting affinity for the physiologically active agent, and a block polymer composed of a segment having a lower critical solution temperature (LCST) and a hydrophilic segment, in which the substance exhibiting affinity and the block polymer are bound to the substrate.

The invention provides a preparation method and application of a temperature and oxidant dual stimuli responsive nano-aggregate. According to the invention, the redox inclusion principle of beta-cyclodextrin (beta-CD) and ferrocene (Fc) and the temperature sensitive properties of the polymer poly(N-isopropylacrylamide) (PNIPAM) are utilized to connect PNIPAM-beta-CD with the end containing a beta-CD host group to hydrophilic polyethylene glycol (mPEG-Fc) with the end modified by an Fc guest group in a water solution through a host-guest recognized noncovalent bond, thus forming a supramolecular complex mPEG-Fc/PNIPAM-beta-CD. When the temperature is higher than the LCST (lower critical solution temperature) of PNIPAM, the macromolecular adduct can further gather in water to form a micellar structure. Micelle formation and disintegration can be realized by adjusting the solution temperature and adding an oxidant. cytotoxicity assessment experiments find that the supramolecular complex has very good biocompatibility. The supramolecular micelle packing the anticancer drug doxorubicin has very good effect in inhibiting A549 tumor cell growth. The preparation method of the nano-aggregate is simple, environment-friendly and economical, and the nano-aggregate has great application value in the field of biological medicine.

The present invention is directed to a copolymer comprising: a polymeric backbone chain derived from a monomer comprising at least one conjugated diene monomer and optionally at least one vinyl aromatic monomer; and polymeric sidechains bonded to the backbone chain, the sidechains comprising a polymer capable of exhibiting a lower critical solution temperature (LCST).

The present invention is directed to a single stage free radical precipitation polymerization process for producing a copolymer involving admixing a solvent, a free-radical-forming agent, (meth)acrylic acid, and at least one monomer selected from the group consisting of styrene, vinyl acetate, methylmethacrylate, butyl acrylate, methyl acrylate, acrylonitrile, and isopropylacrylamide; initiating a free-radical precipitation polymerization to form a plurality of polymer radicals; precipitating a polymer from said polymer radicals; maintaining the admixture of reactants at a temperature above the lower critical solution temperature of said admixture; and controlling the temperature of said admixture to control the rate of propagation of the polymer. The process is useful for producing random copolymers of vinyl acetate or styrene with more than 4 percent and up to greater than 20 percent by weight of (meth)acrylic acid.

The invention relates to a method for preparing temperature-sensitive graphene/polymer hybrid material. The preparation method comprises the steps of reacting by hydroxyl and halogenated substances at the surface of oxidized graphene, converting hydroxyl into halogen atoms, taking the halogen atoms as a macroinitiator, polymerizing atom transfer radical of methacrylic acid-N,N-dimethylamino ethyl monomer to form an oxidized graphene/polymer hybrid material under the protection of an inert gas nitrogen or argon; and then carrying out quaternization on the polymer grafted at the surface of the oxidized graphene, so that the polymer has the property of converting into the highest critical solution temperature from the lowest critical solution temperature. The graphene/polymer hybrid material prepared by the method not only greatly improves the solubility of the graphene, but also has thermo-sensibility, and achieves transformation from the lowest critical solution temperature to the highest critical solution temperature by quaternization of the polymer. The method disclosed by the invention is simple and convenient to operate and easy to control, and expands the development and application of the graphene.

The invention provides a multi-responsive intelligent nano fiber functional material and a preparation method and application thereof. The method utilizes two temperature sensitive monomers of N-isopropyl acrylamide and N-vinyl caprolactam to simultaneously modify polyethyleneimine, and re-grafts the polyethyleneimine onto cellulose nanofibers to prepare the multi-responsive intelligent nanofiberfunctional material with good pH responsiveness and temperature responsiveness. The material can achieve the intelligent transformation of super-hydrophilic and super-hydrophobic and super-lipophilicand super-oleophobic under a temperature and pH stimulus responsiveness condition, and the low critical solution temperature of the material can be controllably adjusted in the range of 30.5-31.5 DEGC. The multi-responsive intelligent nano fiber functional material can be widely applied to the fields of drug sustained release, oil-water separation and the like.

The invention discloses a preparation method of L-proline-loaded temperature/magnetism double responsive functional hybrid microspheres. The technical point is as follows: a temperature-sensitive amphipathic block polymer is obtained by polymerizing functional L-proline ProlA, a temperature-sensitive monomer N-isopropylacrylamide NIPAM and a hydrophilic monomer oligomeric ethylene glycol acrylate OEGA by virtue of a reversible addition fragmentation chain transfer (RAFT) polymerization method and is loaded to magnetic Fe3O4 nanoparticles by virtue of a ''click chemistry'' method so as to obtain the temperature/magnetism double responsive hybrid microspheres. The hybrid microspheres can be used for catalyzing direct asymmetric Aldol reaction in a water phase, and the temperature of a reaction system is higher than a lower critical solution temperature (LCST) of the block polymer, so that the improvement of the catalytic efficiency of the Aldol reaction and the release of organic products are benefited; and by virtue of the magnetism, the hybrid microspheres can be efficiently separated and recycled and repeatedly used.

Hollow fiber membranes having a skinned surface on one diameter, and a porous surface on the opposite diameter arm produced from perfluorinated thermoplastic polymers by extruding a heated solution of the polymer having a lower critical solution temperature directly into a cooling bath to form the porous membrane by liquid-liquid phase separation. Extrusion can be conducted either vertically or horizontally. The hollow fiber membranes are useful as ultrafiltration membranes and as membrane contactors.

The invention discloses double-magnetic-response temperature-sensitive microcapsules and a preparation method thereof. A temperature-sensitive polymer is coated on the surface of magnetic nanoparticles and filled into the wall material of the microcapsules; under the action of an alternating magnetic field, the magnetic particles generates heat due to a magnetic lag effect the temperature of the magnetic particles thus rises, and when the temperature T is higher than the lowest critical solution temperature (LCST), the wall material forms lots of pores due to the shrinkage of the temperature-sensitive nanoparticles, the diffusion resistance to the medicine molecules passing through the wall material of the microcapluses is small and the release speed is high; and when the temperature T reaches the LCST, the temperature-sensitive magnetic nanoparticles expand to fully fill the pores in the wall material of the microcapsules, the diffusion resistance to the medicine molecules passing through the wall material of the microcapsules is big, and the release speed is low. Therefore, by regulating the synergetic effect between the temperature-sensitive structure of the temperature-sensitive polymer on the surfaces of the magnetic nanoparticles and the magnetothermal effect of the alternating magnetic field, the controlled release of the embedded medicine is realized. The microcapsulesprepared by the invention have double magnetic response and a temperature-sensitive controlled-release property.

The present invention is directed to a pneumatic tire having a tread, the tread comprising a rubber composition comprising:

• • a copolymer comprising a polymeric backbone chain derived from a monomer comprising at least one conjugated diene monomer and optionally at least one vinyl aromatic monomer; and polymeric sidechains bonded to the backbone chain, the sidechains comprising a polymer capable of exhibiting a lower critical solution temperature (LCST);
  • optionally, at least one additional diene based elastomer; and
  • a filler selected from the group consisting of carbon black and silica.

An absorption refrigeration system (ARS), includes a sorbent-refrigerant pair that has an ionic liquid (IL) sorbent and a refrigerant that displays a lower critical lower critical solution temperature (LCST) at a temperature of 50 to 100° C., wherein the separation of the sorbent from the refrigerant occurs upon heating the sorbent-refrigerant pair to a temperature above the LCST. This liquid-liquid phase separation requires significantly less energy to desorb the refrigerant from the sorbent than vapor-liquid phase separation in traditional ABSs.

The invention relates to a thermal response core-shell structure fire extinguishing agent applicable to a lithium ion battery and a preparation method of the thermal response core-shell structure fireextinguishing agent. The thermal response core-shell structure fire extinguishing agent comprises a shell and a core, wherein the shell comprises a thermal response polymer; the core comprises a fireextinguishing agent or a flame retardant; the core is wrapped by the shell to form a microcapsule; and the shell has a state that the conformation is converted into extension from collapse and the fire extinguishing agent or the flame retardant inside is released when a set temperature is met outside. The invention discloses that the thermal response polymer is adopted as a shell material for wrapping the fire extinguishing agent in the core. The thermal response polymer self is capable of sensing ambient temperatures and takes effective response effects into play, and at an LCST (lower critical solution temperature), the conformation of the conformation can be changed. The LCST of the thermal response polymer is adjusted to be approximately equal to the upper limit of a safe window temperature, and when the temperature of electrolyte is higher than the LCST, the thermal response polymer is turned into an expansion state from collapse, and then the fire extinguishing agent in the corecan be released.

A non-specific adsorption inhibitor includes a water-soluble polymer obtained by polymerizing a monomer unit that includes a monomer (A) that forms a polymer that has a lower critical solution temperature (LCST) of 80° C. or less in an aqueous solution under normal pressure when subjected to homopolymerization, and a monomer (B) that forms a polymer that does not have the LCST in an aqueous solution under normal pressure when subjected to homopolymerization.

The invention discloses a temperature-sensitive type polymer and a preparation method thereof. According to the preparation method of the polymer, reaction temperature is controlled and salt concentration, pH (Potential of Hydrogen) value and polymer concentration of a polymerization reaction solution are controlled to prepare the temperature-sensitive type polymer with different lower critical solution temperatures (LCST). The temperature-sensitive type polymer is used as a drilling fluid additive and can improve the low-temperature rheological property of water-based drilling fluid; the changes of the plastic viscosity and the apparent viscosity within a range of 0 to 60 DEG C are reduced by 50 percent. A preparation process of the temperature-sensitive type polymer is simple and feasible and the preparation efficiency is high; the temperature-sensitive type polymer has an excellent temperature-sensitive behavior in the deep-water water-based drilling fluid; the low-temperature rheological property of the water-based drilling fluid can be extremely improved, so that the preparation method of the temperature-sensitive type polymer and the temperature-sensitive type polymer prepared by the preparation method have actual application value in a petroleum industry, especially a deep-water well drilling field.