73 results about "Chain termination" patented technology

The invention belongs to the technical field of resin polymerization additives, and particularly relates to an antioxidant type suspended emulsion terminator for PVC (polyvinyl chloride) and a preparation method thereof, the antioxidant type suspended emulsion terminator comprises the following raw material components in parts by mass: 5-30 parts of phenolic antioxidant; 5 to 20 parts of a thioester antioxidant; 0.1-5 parts of an ultraviolet light absorber; 0.1 to 5 parts of a chain terminator; 1-10 parts of a heat stabilizer; 0.1 to 7 parts of a stabilizer; 0.1 to 5 parts of an emulsifier; 0.1-5 parts of a wetting dispersant; according to the invention, through the combination of the selected main and auxiliary antioxidants and the combination of the ultraviolet light absorber and the heat stabilizer, the defect structure of PVC is improved at the end of PVC polymerization, and meanwhile, the combination of the main and auxiliary antioxidants can quickly decompose peroxide and hydroperoxide at the later stage of processing; compared with the prior art, the whiteness and thermal stability of PVC in the early stage are good, the anti-yellowing effect and the long-term aging resistance of PVC in the later processing are more emphasized, the performance of PVC in the dynamic thermal stability is improved, and the volume impedance and the initial coloring are low.

Provided herein are products and processes for primer extension reactions using chain terminating reagents and enzymes having 3′ to 5′ exonuclease activity, whereby unextended oligonucleotides are digested and extended oligonucleotides are not digested. Also provided herein are products and processes for the detection of the presence, absence or amount of one or more variants of a target nucleic acid species or a plurality of target nucleic acid species comprising primer extension reactions using chain terminating reagents and enzymes having 3′ to 5′ exonuclease activity, whereby unextended oligonucleotides are digested and extended oligonucleotides are not digested.

The invention relates to a chemically modified high-strength high-temperature-resistant polyurethane fiber and a preparation method thereof.The preparation method comprises the following steps that 1, oligomer mixed polyol and diisocyanate are subjected to a full prepolymerization reaction, a solvent is added for full dissolution, and a-NCO-terminated prepolymer polyurethane formate solution is obtained; 2) adding hydroxyalkyl silane and a catalyst into the prepared prepolymer, and fully reacting to obtain a modified prepolymer; (3) carrying out chain extension reaction and chain termination reaction on the prepared modified prepolymer to obtain a polyurethane urea solution; (4) adding an antioxidant, an ultraviolet light absorber, an anti-yellowing agent, a delustering agent and a lubricating and releasing agent into the polyurethane urea solution to prepare a polyurethane spinning solution; and (5) preparing the high-strength high-temperature-resistant polyurethane from the prepared polyurethane spinning solution by virtue of a dry spinning system. According to the invention, a polyurethane molecular chain is subjected to functional chemical modification, so that the product has the characteristics of high temperature resistance and high strength.

The invention relates to a process for the manufacture of polyetherketoneketones, comprising:-reacting an aromatic ether or a mixture of aromatic ethers, which comprises at least 50 mol% of 1, 3-bis (4-phenoxybenzoyl) benzene, 1, 4-bis (4-phenoxybenzoyl) benzene, or a mixture thereof, and-reacting the aromatic ether or the mixture of aromatic ethers, which comprises at least 50 mol% of 1, 3-bis (4-phenoxybenzoyl) benzene, 1, 4-bis (4-phenoxybenzoyl) benzene, or a mixture thereof; in some embodiments, 1, 3-bis (4-phenoxybenzoyl) benzene and / or 1, 3-bis (4-phenoxybenzoyl) benzene are contacted with acyl chloride or a mixture of acyl chloride and a Lewis acid in all or a portion of a reaction solvent, with respect to the total moles of aromatic ether (s), to form a reaction mixture, 1, 3-bis (4-phenoxybenzoyl) benzene and / or 1, 3-bis (4-phenoxybenzoyl) benzene and / or 1, 3-bis (4-phenoxybenzoyl) benzene. The 1, 4-bis (4-phenoxybenzoyl) benzene is substantially insoluble in the reaction solvent at the end of the contacting step; and-polymerizing the reaction mixture, the polymerization being carried out at least partially at a temperature Tp greater than or equal to 50 DEG C; said method is characterized in that it comprises a step-by-step heating of the reaction mixture until an acceleration of the polymerization reaction is achieved, the step-by-step heating step being carried out at an average heating rate selected from the range from 0.65 DEG C / min to 2.5 DEG C / min; one or more chain terminators are optionally added during the process.

The present invention relates to a process for preparing polycarbonates from at least one dihydroxydiarylalkane, phosgene, at least one catalyst and at least one chain terminator by the phase interface process, wherein the process enables a reduced phosgene excess with a given energy input for dispersing the aqueous and organic phases. In addition, the process provides polycarbonates with a low oligomer fraction and a low di-chain terminator carbonate fraction.

The invention discloses the field of organic electronic materials, and particularly discloses a chain terminating molecule for straight-chain polyphosphocarbazole and a polymerization terminating method. The chain termination molecule is a carbazole derivative containing boronic acid pinacol ester, the core structure is'carbazole matrix-linking group-diethyl phosphate group ', and the linking group can be a butyl chain or a benzene ring; after a chain termination molecule is synthesized through a three-step reaction, a Suzuki coupling reaction is utilized to completely replace a residual Br site of straight-chain polyphosphocarbazole, and polymerization termination is realized. The bromine residual quantity of the product is less than or equal to 0.01 wt%, the molecular weight is stabilized at 6-7 monomeric units, and the molecular weight change rate is less than or equal to 5% after the product is dried and stored at 25 DEG C for 6 months; when the material is used as a hole transport layer, the laboratory small-area film thickness deviation is less than or equal to 10%, the corresponding perovskite assembly efficiency is greater than or equal to 23%, the 1000-hour attenuation rate is less than or equal to 15%, the defects of self-agglutination, poor stability and device performance fluctuation of the existing material are solved, the process is simple, and industrialization is easy.

The invention relates to a process for preparing a star copolymer of 1,3-diene and ethylene, the copolymer containing more than 50 mole percent ethylene units. The process comprises the polymerization of a monomeric mixture of 1,3-diene and ethylene in the presence of a catalytic system based on at least one neodymocene borohydride metallocene and an organomagnesium cocatalyst, followed by the reaction of tin tetrachloride with the polymerization reaction product, and then a chain-terminating reaction. The invention also relates to a star copolymer obtainable by the process according to the invention.

The present invention pertains to a polycarbonate resin which contains a structural unit (A) derived from a monomer represented by formula (1) and a structural unit (B) derived from a monomer represented by formula (2), and which has a terminal structure containing a structure derived from a chain terminator represented by formula (Z-1), the molar ratio (A: B) of the structural unit (A) to the structural unit (B) being 35: 65-75: 25, and the number of moles a of the structural unit (A), the number of moles b of the structural unit (B), and the number of moles z of the chain terminator represented by formula (Z-1) satisfy the relationship represented by formula (I). 45 < = 2 * (a + b) / z < 80 (I)

The invention relates to the technical field of silicone oil production, in particular to methyl phenyl high-boiling silicone oil and a preparation method thereof. The preparation method is used for solving the technical problem that in the prior art, the stability, the oxidation resistance and the antibacterial property of the methyl phenyl high-boiling silicone oil are not further improved by adding proper auxiliaries and improving the process. The preparation method comprises the following steps: by taking a methyl phenyl dichlorosilane high-boiling-point substance and a diphenyl dichlorosilane high-boiling-point substance as raw materials, adding a high-stability antibacterial agent to prepare methyl phenyl high-boiling-point silicone oil; the hydrolysis accelerant is added to promote the rearrangement reaction in the hydrolysis process of the high-boiling-point substance raw material, and a connecting ring of a polymer is destroyed through the chain terminator, so that the phenomena of gelling and curing do not occur in the subsequent copolymerization equilibrium reaction; calcium carbonate nanoparticles are used as a carrier, so that the calcium carbonate nanoparticles can exert oxidation resistance and antibacterial ability in the methyl phenyl high-boiling silicone oil for a long time, and the prepared methyl phenyl high-boiling silicone oil has more excellent stability and oxidation resistance and has a certain antibacterial effect.

Disclosed is a cDNA amplification method capable of comprehensively amplifying mRNA with a high efficiency and a low bias even from a very small amount of cell sample. The method of amplifying a complementary DNA strand of the present invention comprises steps of capturing a target RNA and synthesizing a complementary DNA strand using a reverse transcriptase having terminal transferase activity in a liquid-phase system or a solid-phase system such that bases such as CCC are added to an end of the complementary DNA strand, and thereafter carrying out homopolymer tailing by the TdT reaction in the presence of a chain-terminating nucleotide triphosphate. By combination with a template-switching reaction, the method enables amplification of the complementary DNA strand with a higher efficiency and a lower bias.

The invention discloses a high-performance metallocene floor heating pipe polyethylene resin and a preparation method thereof, the high-performance metallocene floor heating pipe polyethylene resin comprises the following components by mass: 100 parts of polyethylene powder, 0.2-0.4 part of a composite antioxidant, 0.01-0.02 part of a high-activity metallocene catalyst, ethylene as a main raw material, hydrogen as a chain terminator, hexene-1 as a comonomer, and isopentane as an induced condensing agent. The preparation method comprises the following steps: adding polyethylene powder and a compounding agent into a reactor through a material feeding line, metering the polyethylene powder and the compounding agent according to a certain ratio, fully mixing, and extruding and granulating through a twin-screw extruder, thereby realizing the efficient and stable production of metallocene polyethylene resin products, creating greater economic benefits for enterprises, meeting the requirements of market product processing users, and having wide application prospects. Provided is a metallocene material having excellent thermal conductivity and heat resistance required for manufacturing a floor heating pipe.

The invention discloses an IVB group metal alkyl complex of a monoanion polydentate ligand and application of the IVB group metal alkyl complex, and provides the IVB group metal alkyl complex of the monoanion polydentate ligand with a general formula structure as shown in a formula (I), a formula (II), a formula (III) and a formula (V). The catalyst can show excellent catalytic performance for homopolymerization and copolymerization of olefin, and especially has better catalytic performance for olefin copolymerization; and a polydentate ligand is adopted to stabilize the structure of the catalyst, increase steric hindrance and inhibit chain termination caused by beta-H elimination in the polymerization process, so that the high activity of the catalyst is realized, and a polymer with high molecular weight is obtained.

Methods for mitigation of methylation bias during preparation of sequencing libraries are described. The methods may comprise, e.g., extracting DNA fragments from a sample; performing at least one of: (i) a first end repair reaction, where the first end repair reaction comprises the use of a non-strand-displacing DNA polymerase; or (ii) a second end repair reaction, where the second end repair reaction comprises the use of a chain termination mechanism; performing at least one of: (iii) a tailing reaction to add an overhanging polynucleotide strand to the end-repaired DNA fragments, where the tailing reaction comprises the use of a single deoxynucleotide triphosphate (dNTP); or (iv) a nick / gap repair reaction using a DNA ligase to fill in single- stranded nicks or gaps in the end-repaired DNA fragments, to generate a plurality of modified DNA fragments; and performing methylation analysis of nucleic acid molecules derived from the plurality of modified DNA fragments.

The present disclosure relates to an antioxidant composition comprising component (a) and component (b), a process for preparing an aqueous dispersion comprising the antioxidant composition, the use of the antioxidant composition as a chain terminator and / or stabilizer, and a polymer composition comprising the antioxidant composition.

This invention provides the application of a class of nucleoside compounds that effectively inhibit CCHFV replication, particularly the application of 2'-α-fluoro-2'-β-methyl modified nucleoside compounds in the preparation of drugs for treating CCHF disease. Studies have found that 2'-α-fluoro-2'-β-methyl-CTP can specifically and efficiently inhibit CCHFV L protein polymerase through an immediate chain termination mechanism, but it cannot be incorporated into the L protein polymerases of Lassa virus (LASV) and Rift Valley fever virus (RVFV), which belong to the same order Arenavirales but different families as CCHFV. Further introduction of this modification into ATP, UTP, and GTP also exhibits good immediate chain termination activity. This invention provides a new direction for the preparation of anti-CCHFV nucleoside drugs and demonstrates its feasibility.

The present invention relates to a reactive hot-melt adhesive composition, containing, in relation to the total weight of the composition, a) 3 wt.% to 79.999 wt.% of at least one alpha-silane-terminated organic polymer; b) 20 wt.% to 96.999 wt.% of at least one silane-terminated polyurethane which is not an alpha-silane-terminated polyurethane; c) 0 wt.% to 70 wt.% of at least one filler; d) 0.001 wt.% to 3 wt.% of at least one silane which has a primary or secondary amino group or a blocked amino group which hydrolyses to form the primary or secondary amino group; wherein the at least one silane-terminated polyurethane b), which is not an alpha-silane-terminated polyurethane, can be obtained by a reaction in which at least one polyol (1) reacts with at least one polyisocyanate (2), optionally in the presence of at least one chain terminator (3), such that a polyurethane prepolymer is formed which, in a further reaction, is reacted with at least one secondary aminosilane (4), which is not an alpha-aminosilane, such that the content of free isocyanate is less than 0.1 wt.% in relation to the total weight of the silane-terminated polyurethane b), and wherein the following proportions result in relation to the sum of the reactants (1), (2), (3) and (4): 1) 40 wt.% to 85 wt.% of the at least one polyol; 2) 10 wt.% to 50 wt.% of the at least one polyisocyanate; 3) 0 wt.% to 25 wt.% of the at least one chain terminator; 4) 1 wt.% to 15 wt.% of the at least one secondary aminosilane, which is not an alpha-aminosilane. The invention also relates to methods for the preparation thereof and to a method for laminating surfaces using the composition.

The present application relates to naphthyl methylene quinone compounds, and preparation method and application thereof, the naphthyl methylene quinone compound has the structural formula of formula I, wherein R1 and R2 are each independently H, C 1‑18 Alkyl or C 1‑18 Cycloalkyl; R3 is H, C 1‑3 Alkyl, C 1‑3 Alkoxy, hydroxyl, nitro or carboxyl.The naphthyl methylene quinone compound of the present application has extended electronic delocalization, which is beneficial to disperse free radicals, makes the structure stable, and plays a role in the termination of free radical reaction chain.The polymerization inhibitor composition containing the naphthyl methylene quinone compound provided by the present application has excellent polymerization inhibition performance, and can be used in the industrial device for inhibiting the polymerization of double bond polymerization monomers.

The invention provides an electrolyte additive, an electrolyte and a battery, the electrolyte additive comprises alkynyl, ether bonds and bromine, the viscosity of ether is low, and the ether bonds are helpful for electrolyte flow, promote rapid movement of lithium ions and significantly improve the rate capability of the battery, so that the battery can still maintain good performance during high-rate charging and discharging; according to the present invention, the bromine group is adopted as the efficient flame retardant, such that the bromine group is rapidly dissociated and captures the free radical during the thermal runaway or short circuit of the battery by using the low bond energy of the carbon-bromine single bond and the high chain termination reaction equilibrium constant of the bromine so as to effectively prevent the flame chain reaction so as to substantially improve the safety of the battery; alkynyl groups are polymerized to form a film on the surfaces of a positive electrode and a negative electrode, the polymer film can well buffer volume expansion of the silicon negative electrode, active particle breakage, pole piece pulverization and active substance falling caused by volume change are reduced, and the cycle stability of the battery is improved; the electrolyte additive provided by the invention can obviously improve the safety performance and the high-temperature safety performance of the battery.

This invention relates to a light-blocking spandex and its preparation method. The light-blocking spandex comprises polyurethane-urea and a matting agent, wherein the matting agent accounts for 0.5% to 5% of the mass of the light-blocking spandex; the matting agent comprises a mixture of titanium dioxide, silicon dioxide, and acrylate. The preparation method is as follows: a polymeric polyol and a polyisocyanate are reacted to obtain a polyurethane prepolymer, which is then dissolved in a solvent to obtain a polyurethane prepolymer solution; the obtained polyurethane prepolymer solution, a diamine chain extender, and an amine chain terminator are reacted to obtain a polyurethane-urea solution; the polyurethane-urea solution and the matting agent are mixed in a certain proportion as raw materials; dry spinning is performed to obtain a light-blocking spandex with a cross-sectional shape including at least one of circular, trefoil, and cross-shaped. This product maintains conventional physical properties that are basically consistent with those of products of the same specification, making the fiber light-blocking, easy to dye, and solving the problem of light transmission and poor coverage of lightweight spandex-containing fabrics.

The invention discloses a preparation method of a high molecular weight polylactic acid-glycolic acid copolymer (PLGA). According to the method, PLGA (poly (lactic-co-glycolic acid)) with relatively low molecular weight is taken as a macromolecular initiator, and ring-opening polymerization of glycolide and lactide monomers is initiated under the action of a catalyst. In the preparation process, a programmed cooling control strategy is introduced by combining the kinetic characteristics of the polymerization reaction, so that the temperature field gradient in the reaction process is accurately regulated and controlled. The control strategy effectively inhibits chain termination and thermal degradation side reactions in the later stage of the reaction while ensuring rapid proceeding of the reaction in the initial stage. According to the method disclosed by the invention, the monomer conversion rate is remarkably improved, and the ultra-high molecular weight PLGA material with the intrinsic viscosity of 1.5 or above is successfully prepared.

The invention belongs to the field of advanced functional assistants, and discloses a macromolecular dispersant for digital printing glass ink and a preparation method and application thereof.The preparation method includes the following steps that unsaturated polyether monomers (including alkynediol polyether), unsaturated ester monomers, unsaturated acid monomers, water and a phosphorus-containing reducing agent are mixed, heated and stirred till solids are completely dissolved, and a mixture is obtained; dropwise adding a persulfate aqueous solution, and carrying out reflux reaction at 60-100 DEG C for 2-2.5 hours; and continuously carrying out heat preservation reaction at 90-100 DEG C, stopping heating, adding a chain terminator solution, terminating the reaction, cooling, adding alkali liquor, and carrying out neutralization reaction to obtain a polymer solution with the concentration of 42-48wt%, namely the macromolecular dispersing agent for the digital printing glass ink. The macromolecular dispersant can significantly improve the fluidity and stability of glass ink, has excellent thermal stability, mechanical properties and weather resistance, and also has good solubility, wettability and low-foam property in ink dispersion.

The present invention provides a method for preparing antibacterial and degradable spandex, specifically: polyether polyol and 4,4-diphenylmethane diisocyanate are mixed together in a ratio of 1:1.6 to 1.9 in terms of the amount of substance, and a polymerization reaction is performed to obtain a NCO-terminated prepolymer, and then N,N-dimethylacetamide solvent is added to fully dissolve the prepolymer to obtain a prepolymer solution; a quaternary ammonium salt chain extender, an amine chain extender, and a chain terminator are added to the prepolymer solution obtained in step 1 in order to perform a chain extension reaction and a termination reaction to obtain an antibacterial spandex spinning stock solution, and dry spinning is performed in a high-temperature tunnel after aging to obtain antibacterial spandex, and the temperature of the tunnel is set to 180°C to 270°C. The spandex prepared by the present invention not only has antibacterial properties, but also can be degraded in a humid environment. It is suitable for the fields of disposable diapers, bandages, wet wipes, disposable underwear, masks, etc.

The present application relates to natural gas hydrate inhibitor technical field, it is a kind of natural gas hydrate dynamics inhibitor containing polycyclic structure and its preparation method, the former raw material includes acryloyl morpholine, maleic anhydride, dimethylaminopropyl acrylamide, isohexyl glycol, initiator, chain transfer agent and chain terminator, obtain as follows: acryloyl morpholine, maleic anhydride and dimethylaminopropyl acrylamide are dissolved in isohexyl glycol solution, occur radical polymerization under the action of initiator, chain transfer agent and chain terminator and get it.In the natural gas injection and gathering and transportation process, add the natural gas hydrate dynamics inhibitor containing polycyclic structure of the present application, it can participate in hydrate crystal structure generation through the unique polycyclic ring, effectively inhibit the growth of hydrate crystal, prevent the generation of large particle hydrate, with the advantages of good inhibiting effect, less dosage, low comprehensive cost.

The present invention generally relates to the reuse, reprocessing or recycling of silicone polymers. More precisely, the process of the present invention relates to a method for preparing organopolysiloxanes OR by a depolymerization reaction of at least one silicone S in the presence of an acid catalyst and at least one chain blocker Bc having at least one siloxane function. These organopolysiloxanes OR can subsequently be used in polymerization reactions or directly in various formulations.

The application discloses a strong and tough synergic composite modified asphalt for hydraulic panel leveling layer and a preparation method thereof. Raw materials of the composite modified asphalt include base asphalt, composite modifier, rubber oil and vulcanizing agent. Raw materials of the composite modifier include epoxidized castor oil, HDI (hexamethylene diisocyanate), polymerization inhibitor, phthalic anhydride, inhibitor and chain termination agent. The application drops HDI into the epoxidized castor oil with the polymerization inhibitor to generate epoxidized polyurethane. The epoxidized polyurethane, phthalic anhydride and inhibitor are formed into composite glue particles with a certain size by a granulator. The crosslinking network of the long chain of the epoxidized castor oil and the HDI can effectively help the modified asphalt to realize strong and tough synergy, and the control of the crosslinking density can effectively reduce the viscosity of the modified asphalt, so that the material is more suitable for preparing the asphalt concrete for the strong and tough synergic, long service life hydraulic asphalt concrete panel leveling and cementing layer.

The invention discloses a 2 '-alpha-ethynyl-beta-fluoronucleoside compound which has a structure as shown in a formula I, and pharmaceutically acceptable salts or various optical isomers, solvates or prodrugs thereof, and is a compound targeting a new structure of RNA (Ribonucleic Acid) virus polymerase. The invention also discloses a preparation method of the compound, a composition containing the compound and application of the compound in preparation of drugs for treating virus infection diseases. The 2 '-alpha-ethynyl-beta-fluoronucleoside compound obtained by the invention shows a remarkable chain termination intervention effect in a CCHFV polymerase system, an SARS-CoV-2 polymerase system and an EV71 polymerase system. The result of a cellular level inhibition experiment shows that the 2 '-alpha-ethynyl-beta-fluoronucleoside compound has an obvious inhibition effect on CCHFV on an HUVEC cell.

The present disclosure relates to an antioxidant composition comprising component (a) and component (b), a process for preparing an aqueous dispersion comprising the antioxidant composition, the use of the antioxidant composition as a chain terminator and / or stabilizer, and a polymer composition comprising the antioxidant composition.

The invention provides a functional cycloolefin copolymer and a preparation method thereof, and particularly relates to a functional cycloolefin copolymer with controllable glass transition temperature and controllable polar group content and a preparation method thereof. The functionalized cycloolefin copolymer comprises a structural unit as shown in a formula I, a structural unit as shown in a formula II and a structural unit as shown in a formula III, the preparation method of the functionalized cycloolefin copolymer comprises the following steps: in the presence of a main catalyst and a cocatalyst, carrying out polymerization reaction on functionalized cycloolefin, unmodified cycloolefin and alpha-olefin, and then adding a chain terminator to terminate the polymerization reaction to obtain the functionalized cycloolefin copolymer. By designing the structure of the functional cycloolefin copolymer, the functional cycloolefin copolymer with excellent comprehensive performance, controllable glass transition temperature and controllable polar group content is prepared, and the preparation method of the functional cycloolefin copolymer is simple and suitable for industrial production.

The invention discloses a process for continuously producing multifunctional modified film material polyethylene, which belongs to the technical field of chemical production and comprises a first reaction system, a second reaction system, a third reaction system and a slurry mixing tank, the first reaction system, the second reaction system and the third reaction system are connected in parallel through pipelines and then are connected with the slurry mixing tank through pipelines, and raw materials of the first reaction system comprise a main catalyst I, a catalyst promoter I, a solvent, a chain terminator and an ethylene monomer; the raw materials comprise a main catalyst II, a cocatalyst II, a solvent, a chain terminator, a comonomer and an ethylene monomer, and the third reaction system comprises a main catalyst III, a cocatalyst III, a solvent, a chain terminator, a comonomer and an ethylene monomer.