31 results about "Strand transfer reaction" patented technology

A method for synthesizing cyclic polymers using transition metal alkylidene complexes as reaction catalysts is provided, wherein the complexes contain a cyclic group. Polymerization is carried out on the catalyst, using cyclic olefin monomers that undergo ring insertion polymerization, and no linear intermediates are generated. Following completion of polymerization, the cyclic polymer detaches from the complex via an intramolecular chain transfer reaction and the catalytic complex is regenerated. The invention also provides novel transition metal alkylidene complexes useful as catalysts in the aforementioned process, as well as novel cyclic hydrocarbons.

Before hexafluoropropene oxide (HFPO) is polymerized in a polymerization initiator solution of a polymerization initiator of the formula: CSOCF2-Rf-CF2OCs wherein Rf is a perfluoroalkylene group which may have an ether bond in an aprotic polar solvent, the initiator solution is treated by adding a perfluoroolefin thereto at a sufficient temperature for the removal of protonic substances, cesium fluoride and hydrogen fluoride. This simple treatment restrains chain transfer reaction, and the process is successful in producing a difunctional HFPO polymer having a high degree of polymerization while suppressing formation of a monofunctional HFPO polymer.

The invention discloses a chain transfer near infrared dye and a high-molecular polymerization emulsion preparation method and application thereof. The chain transfer near infrared dye is prepared by reaction of a near infrared dye and a double functional group sulfhydryl group. The near infrared dye, a chain transfer functional reagent and a promoter are mixed in an organic solvent according to the mole ratio of 1:1-20:1-4 for reaction, the dosage of dye to solvent is 1g: 10ml to 50ml, in the reaction step, the temperature is 0-50 DEG C, and the time is 10 to 72h, after the reaction, the reaction product is separated and washed with ether, and is centrifuged at high speed of 8000-12000 revolutions per minute, and the chain transfer near infrared dye can be collected. In the process of emulsion polymerization, the chain transfer reaction can be occurred, and the high-molecular thermosensitive polymerization emulsion can be prepared. The high-molecular thermosensitive polymerization emulsion can not only improve the stability of the near infrared dye, but also can be used as a thermosensitive precursor in the field of infrared laser imaging.

A process for making hyperbranched polymers from An-Lz(XY)m type monomers wherein A is a polymerizable group moiety, XY is a telogen group moiety in which Y is a transferable atom or group which can participate in a transfer reaction with the formation of reactive X*, L is a linkage between A and XY, z is 0 or 1, and n and m are integers of at least 1, comprising: (a) initiating reaction by forming activated species from reaction between either an A or an XY group of the An-Lz(XY)m type monomer and an external stimulus to form activated monomer species with an activated polymerizable group moiety A* or an activated moiety X* derived from the telogen group moiety XY; and (b) polymer segment chain growth by (i) propagation reaction between the polymerizable group A moieties of the An-Lz(XY)m type monomers with the activated moieties A* and X* of activated species, and further reaction between the polymerizable group moieties with the activated moieties of the reaction products thereof, and (ii) chain transfer reaction between the activated A* polymerizable group moieties of activated species or of polymer segments formed in (b)(i) with XY telogen group moieties of the An-Lz(XY)m type monomers or of polymer segments formed in (b)(i), whereby activated X* moieties and inactive A-Y moieties are formed by transfer of transferable atom or group Y of the telogen group moiety XY to the activated A* moiety.

The invention provides a rare-earth catalyst of a nitrogen-containing heterocyclic carbene ligand and an olefin polymerization catalyzing method of the rare-earth catalyst. The rare-earth catalyst comprises a part A and a part B, wherein the part A is nitrogen-containing heterocyclic carbene coordinated rare-earth complex LMR2X, L is a cyclopentadienyl ligand selected from a cyclopentadienyl ligand, an indenyl ligand and a fluorenyl ligand, X is the nitrogen-containing heterocyclic carbene ligand selected from imidazolyl carbene, imidazolinyl carbene, triazolyl carbene and thiazolyl carbene, M is rare-earth metal selected from Sc, Y, Lu, Gd, Sm and Nd, and R is alkyl directly connected with the rare-earth metal; the part B is organoboron reagents. By using the rare-earth catalyst of the nitrogen-containing heterocyclic carbene ligand, the chain transfer reaction of propylene monomers can be effectively inhibited so as to prepare the homopolymer and copolymer, with higher molecular weight and narrower molecular distribution, of the propylene monomers.

The invention relates to the field of oil deposit fracturing, and particularly discloses a cyclodextrin star polymer, a preparation method and application of the cyclodextrin star polymer, and a fracturing fluid. The preparation method of the cyclodextrin star polymer includes the following steps: (1) subjecting a monofunctional acrylamide monomer and a carboxyl-terminal disulfide ester compound to a first reversible addition-chain transfer reaction to obtain a macromolecular chain transfer agent; (2) subjecting the macromolecular chain transfer agent and a bifunctional acrylamide monomer to asecond reversible addition-chain transfer reaction to obtain a star polymer; (3) subjecting the star polymer and amino cyclodextrin to an amidation reaction. The novel cyclodextrin polymer prepared by the method has an obvious thickening effect in brine, and can fully develop the suspended sand-carrying ability, so that the solubility of salt layers by the hydraulic fracturing fluid can be greatly reduced, oil layer collapse and casing deformation can be avoided, and effective fracturing transformation of inter-salt shale oil reservoirs is realized; the cyclodextrin star polymer has a great industrial application prospect.

The present invention provides a dinuclear metallocene compound, its preparation method and application. By introducing a bridging group with high steric hindrance and high rigidity, the chain transfer reaction in the polymerization process is restricted by steric effect. The compound is used to catalyze olefin polymerization , have higher reactivity, and at the same time, polymers with higher molecular weight distribution and molecular weight can be obtained, which has broad application prospects.

The invention belongs to the technical field of concrete superplasticizer, and discloses a polycarboxylic acid superplasticizer based on a lignin based polyether monomer as well as a preparation method thereof and an application thereof to concrete. The polycarboxylic acid superplasticizer based on the lignin based polyether monomer comprises the following components in parts by mass: 1-40 parts of an unsaturated lignin polyether monomer, 99-60 parts of nonsaturated polyoxyethylene ether, and 9-16 parts of unsaturated carboxylic acids; the superplasticizer is obtained by a chain transfer reaction of the components. The unsaturated lignin polyether monomer is prepared by reaction of the following components in parts by mass: 100 parts of nonsaturated polyoxyethylene ether, and 30-120 partsof lignin. The polycarboxylic acid superplasticizer based on a lignin based polyether monomer has good water retention, and the product has a certain reducing effect for viscosity of a cement system;under the same condition that initial fluidity of concrete is controlled, the more amount of lignin polyether, the more obvious reducing effects of viscosity; the product is good for reducing energy consumption, and can be applied to concrete.

The invention provides a bridged metallocene compound catalyst, and a preparation method and an application thereof. The chain transfer reaction in a polymerization process is restricted through the space effect by introducing a bridging group with large steric hindrance and high rigidity. The catalyst is used for catalyzing olefin polymerization, has high reaction activity, allows polymers with high molecular weight distribution and high molecular weight to be obtained, and has wide application prospect.

The invention relates to an in-situ hybridization photoreaction system of mercaptan-alkene / siloxane catalyzed by photoacid / photobase. Specifically, a mercapto compound, a polyfunctional siloxane compound with mercapto groups, a double-bond compound, photoacid / photobase and other photosensitizers and a solvent are mixed in a certain ratio and subjected to ultrasonic dissolution, a mercapto-double bond polymerization reaction and a hydrolytic condensation reaction of siloxane are carried out under ultraviolet light irradiation in air with a certain humidity, and then a uniform organic / inorganichybrid network structure can be produced with a one-step method. According to the photoreaction system, the chain transfer reaction between double bonds and mercapto groups reduces the volume shrinkage of a polymer; oxygen inhibition is avoided; gelation is retarded; the crosslinking degree and reaction velocity can be controlled by adjusting different mercapto compound proportions and double-bondcompound types; the hydrolytic condensation process between siloxane functional groups can increase the glass transition temperature of the reaction system and improve the crosslinking density.

A process for making hyperbranched polymers from An-Lz(XY)m type monomers wherein A is a polymerizable group moiety, XY is a telogen group moiety in which Y is a transferable atom or group which can participate in a transfer reaction with the formation of reactive X*, L is a linkage between A and XY, z is 0 or 1, and n and m are integers of at least 1, comprising: (a) initiating reaction by forming activated species from reaction between either an A or an XY group of the An-Lz(XY)m type monomer and an external stimulus to form activated monomer species with an activated polymerizable group moiety A* or an activated moiety X* derived from the telogen group moiety XY; and (b) polymer segment chain growth by (i) propagation reaction between the polymerizable group A moieties of the An-Lz(XY)m type monomers with the activated moieties A* and X* of activated species, and further reaction between the polymerizable group moieties with the activated moieties of the reaction products thereof, and (ii) chain transfer reaction between the activated A* polymerizable group moieties of activated species or of polymer segments formed in (b)(i) with XY telogen group moieties of the An-Lz(XY)m type monomers or of polymer segments formed in (b)(i), whereby activated X* moieties and inactive A-Y moieties are formed by transfer of transferable atom or group Y of the telogen group moiety XY to the activated A* moiety; wherein the reaction rates of the (b)(i) propagation reaction and of the (b)(ii) chain transfer reaction are within 2 orders of magnitude of each other, more preferably within one order of magnitude of each other, such that the combination of propagation reaction and chain transfer reaction results in formation of a highly branched polymer from the An-Lz(XY)m type monomer.

The invention provides a late transition metal catalyst for olefin polymerization with a structural formula (I), which is characterized by introducing a wedge-shaped dendritic molecule having certain space volume and more symmetrical spatial position of substituent into a ligand structure, successfully avoiding chain transfer reaction of propylene and effectively preventing the propylene from attacking the active site from the side chain. When the catalyst for the olefin polymerization is used for propylene polymerization together with an aluminium alkyl compound, the polymerization activity is remarkably improved, the activity of the catalyst can reach 105g polypropylene / mol Fe*h, and in particular, the number-average molecular weight and degree of isotacticity of the polymerization product are enhanced. The number-average molecular weight is far more than 15000g / mol, and the degree of isotacticity is close to 85%. M is a transition metal selected from Fe, Co or Ni.

The invention relates to a catalyst preparation technology and aims at providing a metal hydrides coordination catalyst and preparation and application thereof. The structural formula of an active component of the catalyst is Zn2[Co(CN)6](OR)mXn, wherein R is alkyl, aryl or acyl, X is a single valence anion, m and n are positive numbers, and m plus n is 1. The divalent Zn ions in the activated component are coordinated with inner metal trivalent cobalt ions through cyanide ions and surrounding anions OR and X at the same time to form a Co-CN-Zn-OR structure and a Zn-X structure. The activated triggering center structure of the catalyst is a definite Zn-OR bond; when the catalyst catalyzes a reaction in which epoxyalkane takes participate, due to the fact that one end of the generated polymer is an R group, the chain transfer reaction degree is reduced, and the degradation property of a product is improved; one end of the obtained polymerisate is an OR group, due to the diversity of the R group, functionalization of the end group of the polymer is achieved, and only polymer with the two ends being hydroxyls can be obtained through reported DMCC containing the Zn-OH bond.

A one-pot polymerization process of preparing long chain branching polymers is provided. Also described is a “T” reagent that serves as a link between main and side chains of an inventive long chain branching polymer. A “T” reagent has at least two functionalities, serving as both co-monomer and chain transfer reaction agent. Optionally, a copolymerization reaction between an alpha-olefin and “T” reagent takes place initially to incorporate some “T” molecules in the polyolefin main chain, and the incorporated “T” units then behave as chain transfer agents for reacting with the propagating polyolefin chains to form side chains. In a particular embodiment, a polymerization process for preparing long chain branching polyethylene (LCBPE) and long chain branching polypropylene (LCBPP) is detailed.

The invention relates to an in vitro screening method of HIV-1 integrase chain transfer reaction inhibitor and belongs to the field of biotechnology. The method includes using a FITC (fluorescein isothiocyanate) group to mark target DNA (deoxyribonucleic acid), detecting fluorescent signals of the FITC group to estimate chain transfer reaction activity of integrase or inhibitory activity of a sample to be tested. The process of the existing in vitro screening method of HIV-1 integrase chain transfer reaction inhibitor takes at least about 4h. The whole screening process of the in vitro screening method of HIV-1 integrase chain transfer reaction inhibitor is shortened to be within 2h, and the screening cost is reduced greatly.

The invention relates to a tetrahydrofuran-glycidol random hyperbranched copolyether and a preparation method of the tetrahydrofuran-glycidol random hyperbranched copolyether. The preparation method comprises the steps of selecting tetrahydrofuran as the linear monomer, and carrying out cationic ring opening polymerization to glycidol and tetrahydrofuran, so as to obtain the random hyperbranched copolyether, wherein ternary cyclic ether in the glycidol structure is to form ternary cyclic oxonium ion first in the chain initiation process during polymerizing; the highly-active ternary cyclic oxonium ion can synchronously initiate ring opening polymerization between the tetrahydrofuran and the glycidol, so as to achieve random copolymerization; once the ternary cycle of the glycidol is opened and enters the molecular chain, the contained alcoholic hydroxyl group is subjected to chain transfer reaction to generate new active points which initiate the lengthening of the chain, so that novel random hyperbranched copolyether is prepared. The preparation method provided by the invention is simple, convenient and easy to implement; the raw materials are easy to obtain; and initiating agents are available.

The invention discloses an itaconic acid bonded silica gel based hydrophilic chromatography stationary phase and a preparation method of the itaconic acid bonded silica gel based hydrophilic chromatography stationary phase. The invention provides the high performance liquid chromatography stationary phase and the preparation method of the high performance liquid chromatography stationary phase, the stationary phase is a reversed phase liquid chromatography stationary phase taking itaconic acid as a bonded phase; a mercaptopropyl silica gel and the itaconic acid are polymerized through the radical chain transfer reaction, a polymer monomer comprises two carboxyl, then the hydrophilic performance of the stationary phase is stronger, and the stationary phase is better separated; the preparation process of the stationary phase is simple and reliable, the raw materials are easy to get, the preparation method is favorable for implementing quantity production; the provided stationary phase isa universal hydrophilic chromatography stationary phase, has an excellent performance of separating most of polar compounds, and has an excellent market application prospect.

The invention relates to the field of medical research, especially to a preparation method for a medical MIP microsphere applied to clinical immunoassay. The method is simple and easily practicable and prepares the MIP microsphere with hydrophilic polymer brushes on its surface through a coupling reaction of a hydrophilic macromolecular chain transfer agent and a MIP microsphere with C-C double bonds on its surface; and the hydrophilic macromolecular chain transfer agent firstly undergoes a chain transfer reaction with free radicals produced by a common radical initiator so as to produce hydrophilic macromolecule free radicals, and then the hydrophilic macromolecule free radicals react with the C-C double bonds on the MIP microsphere so as to obtain the MIP microsphere with the hydrophilic polymer brushes on its surface. The surface of the magnetic MIP microsphere has a great number of hydroxyl groups, so the MIP microsphere is applicable to water-phase treatment, and has great adsorption capacity and selectivity; and the MIP microsphere has good application prospects in fields like biological medicine and clinical medicine.

The invention provides ultrahigh molecular weight functional polyethylene and a preparation method thereof. In the preparation process of the ultrahigh molecular weight polyethylene, polymerized monomer ethylene is copolymerized with trialkylaluminium-protected polar comonomer in a catalyst system composed of a catalyst and a promoter to obtain the ultrahigh molecular weight functional polyethylene, the catalyst is fluorenylamine titanium complex, and the promoter is methylaluminoxane, modified methylaluminoxane or trityl tetrakis(pentafluorophenyl)borate. By polymerizing ethylene and a polar comonomer, the ultrahigh molecular weight functional polyethylene that has a controllable content of polar functional groups is acquired; the catalyst system used herein has high copolymerizing capacity for trialkylaluminium-protected polar comonomer, good chain-extending speed is kept, chain transfer reaction is overcome, and the ultrahigh molecular weight functional polyethylene is effectively acquired.

The invention provides a late transition metal catalyst for olefin polymerization with a structural formula (I), which is characterized by introducing a wedge-shaped dendritic molecule having certain space volume and more symmetrical spatial position of substituent into a ligand structure, successfully avoiding chain transfer reaction of propylene and effectively preventing the propylene from attacking the active site from the side chain. When the catalyst for the olefin polymerization is used for propylene polymerization together with an aluminium alkyl compound, the polymerization activity is remarkably improved, the activity of the catalyst can reach 105g polypropylene / mol Fe*h, and in particular, the number-average molecular weight and degree of isotacticity of the polymerization product are enhanced. The number-average molecular weight is far more than 15000g / mol, and the degree of isotacticity is close to 85%. M is a transition metal selected from Fe, Co or Ni.

The invention discloses a water emulsion polymerization method for preparing a meltable fluorine-containing polymer. The method includes: using all-fluorine alkyl acetate as a chain transfer agent to adjust polymerization, wherein a general formula of all-fluorine alkyl acetate is CF3(CF2)nCH2COOX, n is an integer between 0 and 6, X is metal or nonmetal ion, and the chain transfer reaction process is CF3(CF2)nCH2COO-+R-CF2-CF2 to R-CF2-CF2H+CF3(CF2)nCH COO-.The meltable fluorine-containing polymer prepared by the method is excellent in mechanical performance and molecular weight distribution and has the advantages of low volatile and no color change.

The invention provides a rare-earth catalyst of a nitrogen-containing heterocyclic carbene ligand and an olefin polymerization catalyzing method of the rare-earth catalyst. The rare-earth catalyst comprises a part A and a part B, wherein the part A is nitrogen-containing heterocyclic carbene coordinated rare-earth complex LMR2X, L is a cyclopentadienyl ligand selected from a cyclopentadienyl ligand, an indenyl ligand and a fluorenyl ligand, X is the nitrogen-containing heterocyclic carbene ligand selected from imidazolyl carbene, imidazolinyl carbene, triazolyl carbene and thiazolyl carbene, M is rare-earth metal selected from Sc, Y, Lu, Gd, Sm and Nd, and R is alkyl directly connected with the rare-earth metal; the part B is organoboron reagents. By using the rare-earth catalyst of the nitrogen-containing heterocyclic carbene ligand, the chain transfer reaction of propylene monomers can be effectively inhibited so as to prepare the homopolymer and copolymer, with higher molecular weight and narrower molecular distribution, of the propylene monomers.

The invention relates to a preparation method of aromatic thermosetting resin containing polycarboxyl metal phthalocyanine. The method includes: employing a phthalic anhydride method to prepare polycarboxyl metal phthalocyanine, adding the metal phthalocyanine into an aromatic thermosetting resin prepolymer monomer and mixing them uniformly, leaving the mixture to undergo a high temperature reaction so as to obtain two prepolymers, i.e. Cx-MPc-COOH and Ax-MPc-COOH, mixing the two prepolymers uniformly, performing high temperature curing, thus obtaining an aromatic thermosetting resin composite material containing polycarboxyl metal phthalocyanine. The various monomers for synthesizing the aromatic thermosetting resin are terminated by carboxyl and ester groups, the polycarboxyl metal phthalocyanine can undergo chain transfer reaction with the monomers so as to be introduced into a molecular network structure of aromatic thermosetting resin. The method makes use of the excellent electron donating ability of metal phthalocyanine to perform coupling with the conjugated structure of aromatic thermosetting resin, thus reaching the purpose of improving dielectric properties of aromatic thermosetting resin. With the properties of high temperature resistance, ablation resistance, easy adhesion and the like, the aromatic thermosetting resin prepared by the invention has important applications in micro-electronics, semiconductors, electromagnetic materials, electrical smart materials and other fields.

A one-pot polymerization process of preparing long chain branching polymers is provided. Also described is a “T” reagent that serves as a link between main and side chains of an inventive long chain branching polymer. A “T” reagent has at least two functionalities, serving as both co-monomer and chain transfer reaction agent. Optionally, a copolymerization reaction between an alpha-olefin and “T” reagent takes place initially to incorporate some “T” molecules in the polyolefin main chain, and the incorporated “T” units then behave as chain transfer agents for reacting with the propagating polyolefin chains to form side chains. In a particular embodiment, a polymerization process for preparing long chain branching polyethylene (LCBPE) and long chain branching polypropylene (LCBPP) is detailed.

The invention provides ultrahigh molecular weight functional polyethylene and a preparation method thereof. In the preparation process of the ultrahigh molecular weight polyethylene, polymerized monomer ethylene is copolymerized with trialkylaluminium-protected polar comonomer in a catalyst system composed of a catalyst and a promoter to obtain the ultrahigh molecular weight functional polyethylene, the catalyst is fluorenylamine titanium complex, and the promoter is methylaluminoxane, modified methylaluminoxane or trityl tetrakis(pentafluorophenyl)borate. By polymerizing ethylene and a polar comonomer, the ultrahigh molecular weight functional polyethylene that has a controllable content of polar functional groups is acquired; the catalyst system used herein has high copolymerizing capacity for trialkylaluminium-protected polar comonomer, good chain-extending speed is kept, chain transfer reaction is overcome, and the ultrahigh molecular weight functional polyethylene is effectively acquired.

The invention relates to a method for preparing poly(VDF-CTFE-TrFE) or poly(VDF-TrFE) by using poly(VDF-CTFE) which adopts N-methylpyrrolidone as solvent, uses low-valent transition metal halide and corresponding coordination compound containing N-containing ligand as initiator, adopts hydrogen-donating compound as chain transfer agent and uses poly(VDF-CTFE) as raw material to perform one-step chain transfer reaction under the protection of nitrogen and synthesize poly(VDF-CTFE-TrFE) or poly(VDF-TrFE). The method of the invention is characterized by low cost, safe operation, good stability and low toxicity, and the proportioning of the product can be precisely controlled by adjusting the reactant ratio.