27 results about "Chain termination" patented technology

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.

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.

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 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 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 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 invention belongs to the technical field of environmental analytical chemistry and detection, discloses a soil and water polychlorinated naphthalene environment rapid detection method, and aims to solve the problems that an existing polychlorinated naphthalene detection method is complex in sample pretreatment, long in detection period and high in cost, and a rapid detection technology is insufficient in sensitivity, weak in anti-interference capability and the like. The method comprises the following steps: constructing a free radical chain reaction kinetics system consisting of a chain initiator, a signal report molecule, a chain transfer and regeneration bifunctional reagent and a pH buffer system, taking polychlorinated naphthalene as a chain terminator, and determining the fluorescence quenching rate change of the signal report molecule after the polychlorinated naphthalene is introduced by measuring the fluorescence quenching rate change of the signal report molecule. The ultrasensitive quantitative detection of polychlorinated naphthalene in soil and water is realized. By adopting the technical scheme, the method has the advantages of high sensitivity and signal amplification effect, no need of complex sample pretreatment, environment friendliness, quick response, excellent anti-interference performance and the like.

The invention discloses a preparation method of grafted polypropylene wax. The preparation method comprises the following steps: step 1, raw material pretreatment and performance characterization; 2, preparing a pre-activation system; 3, melting and pre-activating polypropylene wax; 4, preparing a composite initiation system; step 5, carrying out segmented grafting reaction; step 6, chain termination and by-product inhibition; 7, purifying a grafted product; and 8, regulating and controlling performance and preparing a finished product. Ninthly, quality detection and finished product acceptance are conducted; according to the preparation method, pre-activation system preparation and high-speed shearing dispersion are combined, so that the dispersion uniformity of a grafting monomer in a polypropylene wax melting system is remarkably improved; the main initiator and the auxiliary initiator are compounded, so that the initiation temperature interval can be widened, monomer self-polymerization is reduced in the low-temperature initiation period, grafting chain growth is promoted in the medium-temperature growth period, the grafting rate is effectively increased, meanwhile, side reactions such as cross-linking and degradation are inhibited, and the performance stability of the product is remarkably enhanced.

The invention relates to the technical field of TPU materials, in particular to a water-based foaming TPU high and low temperature film and a preparation method thereof.The high and low temperature film comprises a water-based PU coating, a carrier layer and a hot melt adhesive layer, and the water-based PU coating is formed by coating a water-based PU material; the water-based PU material is prepared from the following raw materials in parts by weight: 100 to 150 parts of isocyanate, 200 to 300 parts of polyether polyol, 5 to 10 parts of a compound chain extender, 0.5 to 2 parts of a hydrophobic modifier, 0.2 to 0.5 part of an antioxidant, 0.02 to 0.05 part of a catalyst, 2 to 3 parts of a salt-forming agent and 0.2 to 0.5 part of a chain terminator, wherein the compound chain extender comprises a dihydric alcohol chain extender and a disulfide bond chain extender. By adding the compound chain extender and the hydrophobic modifier, the film has excellent tensile strength, elongation at break, water resistance, air permeability and repair performance, and has the advantages of light weight, soft touch and the like.

The invention provides a temperature-sensitive gel plugging agent as well as a preparation method and application thereof. The temperature-sensitive gel plugging agent is prepared from the following raw materials in specific parts by weight: hydroxyethyl acrylamide, a cross-linking agent, a stabilizer, an initiator, a chain terminator, a cosolvent and water. According to the temperature-sensitive gel plugging agent, the gelling time can be adjusted according to the temperature change, the water invasion resistance and the salt and gypsum invasion resistance are high after gelling, the high pressure-bearing strength of gel after gelling can be guaranteed, and the pressure-bearing capacity of a low-pressure stratum is greatly improved; meanwhile, degradation can be carried out through gel breaking according to needs, the plugging removal effect is achieved, the plugging agent is suitable for high-permeability, fissure and karst cave malignant leakage plugging, and oil, gas and water layers can be effectively separated to meet the site construction requirement.

Modified antisense mucleic acid molecules ending with or without chain terminating bases targeting the HIV-1 viral genomic RNA 3′ LTR region, and uses thereof for inhibiting HIV-1 replication and infection, are disclosed. The antisense mucleic acid molecules more specifically target a sequence corresponding to about nucleotide 9628 to about nucleotide 9642 of HIV-1 clone pNL4-3.

The invention relates to the technical field of preparation of diesel engine oil antioxidants, and particularly discloses a preparation process of a diesel engine oil composite antioxidant with a long oil change period, which comprises the following steps: S1, pretreating a nano antioxidant, S2, microencapsulating a main antioxidant, S3, pre-dispersing base oil, S4, dispersing and mixing, S5, homogenizing and stabilizing, and S6, post-treating. According to the invention, the phenolic main antioxidant is released in stages under high temperature and shearing conditions after being microencapsulated, and free radical capture and chain termination effects can be continuously provided in the whole service cycle of the oil product. The amine auxiliary antioxidant participates in free radical capture at the initial stage of a linear oxidation chain, and forms a double insurance mechanism with phenol components, so that the initial oxidation rate is reduced. The metal chelating agent can effectively capture transition metal ions in engine oil and combustion products, inhibit generation of free radicals catalyzed by metal, and guarantee the cooperative work efficiency of antioxidants.

The invention discloses a preparation method of a tetrafluoroethylene-hexafluoropropylene copolymer with regular chain segments, and relates to the technical field of fluorine-containing polymer synthesis. According to the method, the conversion efficiency of hexafluoropropylene and tetrafluoroethylene is optimized through constant-pressure continuous feeding, and a low-temperature and low-dosage initiator is adopted to prolong the chain growth stage and reduce the chain termination frequency, so that the copolymer with higher molecular weight and narrower molecular weight distribution is obtained. And the chain segment regularity of the copolymer is effectively improved by using the chain segment regularity accelerant and the specific molecular weight regulator, so that the tensile strength and the thermal deformation temperature are improved. And the performance deviation of different batches is obviously improved. The method has relatively good industrial operability and is suitable for preparing the high-performance fluoropolymer.

The present invention relates to a method for the generation of a cDNA library from transfer RNA (tRNA) comprising (a) optionally ligating at least one DNA adapter to 3′-end of tRNA, wherein 3′-end of the DNA adapter is preferably a chain terminator dideoxycytidine, preferably under one or more of the following conditions: (i) crowding reagent at 5% to 35%, preferably 15% to 30%, and most preferably about 25%, (ii) MgCl2 concentration of 1 mM to 15 mM, preferably 3 to 12 mM and most preferably about 10 mM (iii) a temperature of 12° C. to 37° C., preferably of about 25° C. (iv) a pH of 6.0 to 9.0, preferably 6.5 to 8.0 and most preferably about 7.0, (v) reducing agent concentration of 0.1 mM to 10 mM, preferably 0.5 to 5 mM and most preferably about 1 mM, and (vi) a reaction time of at least 30 min, preferably at least 1.5 h and most preferably at least 3 h; and (b) reverse transcription in a primer-dependent reaction, in case step (a) is present, or in a template-switching reaction, in case step (a) is absent, of tRNAs into cDNA by a group II intron reverse transcriptase, under the following conditions: (i) KCl or NaCl at a concentration of 20 mM to 250 mM, preferably 50 to 100 mM and most preferably about 75 mM, (ii) MgCl2 at a concentration of 0.5 mM to 15 mM, preferably 1 to 5 mM and most preferably about 3 mM, (iii) a temperature of 30° C. to 65° C., preferably of about 42° C., and (iv) a reaction time of at least 2 h, preferably at least 8 h and most preferably at least 15 h, and preferably (v) a pH of 6.5 to 9.5, preferably 7.0 to 8.5 and most preferably about 8.0, and / or (vi) a reducing agent (DTT) at a concentration of 1 mM to 12.5 mM, preferably 3 to 8 mM and most preferably about 5 mM.

This invention discloses a method for synthesizing bio-based spandex, belonging to the field of polymer material preparation technology, and is particularly suitable for dry spinning of spandex fibers. The method includes the following steps: (1) In the prepolymer reaction stage, polyester polyol and diphenylmethyl diisocyanate are mixed and reacted to obtain isocyanate-terminated polyurethane prepolymer; (2) The polyurethane prepolymer is dissolved in an aprotic polar solvent to obtain a prepolymer solution; (3) After cooling the prepolymer solution, a mixed amine solution is added to carry out chain extension and chain termination reactions to form a polyurethane stock solution; (4) Various additives are added to the polyurethane stock solution, and after thorough mixing, a spandex spinning solution is prepared; (5) After aging the prepared spandex spinning solution, high-elongation spandex fibers are obtained by dry spinning. This invention uses a bio-based diamine chain extender to partially replace petroleum-based raw materials. The prepared spandex fibers not only meet the requirements of high spinning speed but also possess excellent high drawability, while also having the advantages of being environmentally friendly and having a low carbon footprint.

The invention discloses retention rate enhancing and low-temperature initiating polyacrylamide for papermaking, which is prepared from the following components in parts by weight: 85 to 95 parts of acrylamide, 15 to 20 parts of dimethyl diallyl ammonium chloride, 10 to 12 parts of acryloyloxyethyl trimethyl ammonium chloride, 2 to 5 parts of ammonium sulfate, 4 to 8 parts of adipic acid, 0.03 to 0.06 part of EDTA-5Na (Ethylene Diamine Tetraacetic Acid), 0.02 to 0.05 part of initiator VA-044 and 0.02 to 0.03 part of sodium hypophosphite. The cleaning agent is prepared from the following components in parts by weight: 0.02-0.03 part of ammonium persulfate, 0.02-0.03 part of ammonium ferrous sulfate and 372-380 parts of deionized water. The invention also provides a preparation method of the polyacrylamide and application of the polyacrylamide as a papermaking retention aid. Polyacrylamide polymerization reaction is carried out at low temperature, external heating is not needed, energy consumption is reduced, in addition, chain termination reaction is effectively inhibited by low temperature, high-activity free radical concentration is ensured by synergistic initiation of the initiator VA-044, and the product is high in molecular weight, narrow in distribution, high in bridging efficiency and not prone to excessive flocculation. And high retention efficiency and good paper sheet uniformity are achieved.

The utility model provides an accurate control device for adding desalted water. The accurate control device comprises a metering tank, a screw pump, a first storage tank, a second storage tank, a mixing tank, a delivery pump, a filter, a metering pump, a polymerization tower, a chain terminator input port, a main raw material caprolactam inlet, a meter, a controller and an electromagnetic valve, the metering tank is connected with the first storage tank and connected to the mixing tank through the screw pump, the metering device is arranged in the mixing tank, and the controller is connected with the mixing tank; the mixing tank is connected with the filter, the second storage tank, the metering pump and the polymerization tower through the delivery pump; the chain terminator input port is connected with the metering tank, and the main raw material caprolactam inlet is connected with the mixing tank; the first electromagnetic valve is arranged between the metering tank and the first storage tank; the second electromagnetic valve is arranged between the screw pump and the mixing tank; the third electromagnetic valve is arranged between the mixing tank and the conveying pump; the fourth electromagnetic valve is arranged between the mixing tank and the main raw material caprolactam inlet; and the fifth electromagnetic valve is arranged between the controller and the mixing tank.

This invention relates to an aqueous polyurethane-urea dispersion comprising water and a polyurethane-urea, wherein the polyurethane-urea is obtained by at least partial deprotonation of the reaction products of at least components (A)-(F): (A) 60.0 to 80.0 wt% of one or more polyether polyols having a number average molecular weight of 500 to 4000 g / mol and a hydroxyl functionality of 1.9 to 2.1, wherein the polyether polyol comprises at least 65.0 wt% of one or more polytetrahydrofuran polyols based on the total weight of polyether polyol (A), (B) 5.0 to 12.0 wt% of one or more polyethers having a hydroxyl functionality of 0.9 to 1.1 and a number average molecular weight of 1500 to 2500 g / mol, (C) 0.5 to 2.0 wt% of one or more isocyanate reactive compounds containing at least one carboxylic acid group that can be converted into a salt group capable of dispersing the polyurethane-urea in water, (D) (A) 0.4 to 2.0 wt% of one or more branching agents (D1) having a hydroxyl functionality of 3.0 and / or 1.0 to 5.0 wt% of one or more branching agents (D2) having an isocyanate functionality of 3.0 to 4.0, (E) 10.0 to 30.0 wt% of one or more diisocyanates, (F) 0.1 to 5.0 wt% of one or more amine-functionalized chain extenders and / or one or more amine-functionalized chain terminators, wherein the amounts of (A) to (F) are given based on the weight of the polyurethane-urea, and wherein the deprotonation is achieved by reacting the reaction product with one or more amines and / or ammonia.

This invention discloses a method for synthesizing polyarylene ether nitrile using 2,6-dichlorobenzonitrile and diphenol, belonging to the field of polymer synthesis technology. The key to this method lies in: firstly, subjecting the 2,6-dichlorobenzonitrile and diphenol obtained by gas-phase ammonia oxidation to deep dehydration, degassing, and adsorption pretreatment, reducing moisture and trace amounts of ammonia / chloride to below 50 ppm; then, in a composite phase transfer catalytic system and an aprotic polar solvent, undergoing a programmed temperature-increased nucleophilic substitution polymerization reaction at a specific molar ratio; after the reaction, employing multi-stage washing precipitation and solid-liquid separation technology to efficiently remove inorganic salt byproducts, and achieving the recycling of solvent and catalyst residues. This invention effectively suppresses nitrile hydrolysis and chain termination side reactions, significantly improving the polymer molecular weight and purity.

This application relates to multiplexed methods for the identification and quantification of minor alleles and polymorphisms. Products and methods are provided for detecting the presence of minor nucleic acid substances in a sample containing a mixture of minor nucleic acid substances and one or more major nucleic acid substances, wherein the amount (frequency or copy number) of the minor nucleic acid substances is less than the amount of the major nucleic acid substances. Some methods involve amplifying the mixture and extending the resulting amplicons with a chain terminator and an extension primer that hybridizes specifically to the amplicons, wherein the chain terminator specific to the major nucleic acid substances has a lower concentration than the chain terminator specific to the minor nucleic acid substances. A higher concentration of the chain terminator specific to the minor nucleic acid substances, relative to the chain terminator specific to the major nucleic acid substances, improves the detection limit (sensitivity) for detecting minor nucleic acid substances present in the mixture at low frequency or copy number. Additionally, the signal generated from the extension product of the major nucleic acid substance amplicons can be used as a positive control and allows for the quantification of the minor nucleic acid substances relative to the major nucleic acid substances in the mixture.

The application relates to the technical field of UV protective film, in particular to a UV protective film and a preparation method thereof.A UV protective film comprises a PET base material and an adhesive layer coated on the base material; the combined material of the adhesive layer comprises raw materials with the following weight components: vinyl silicone oil, methyl MQ resin, vinyl MQ resin, hydrogen-containing silicone oil, hydroxyl-terminated silicone oil, inhibitor, tackifier and photocatalyst; the tackifier is prepared by taking tetramethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane and 2, 4, 6, 8-tetramethyl-2, 4, 6, 8-tetrakis[3-(oxiranylmethyloxy)propyl]cyclotetrasiloxane as monomers, trimethylmethoxysilane as a chain terminator and tetrabutyl titanate as a catalyst.The UV protective film prepared by the application has the advantage of good adhesion to a glass base material.

The invention relates to the technical field of UV protective films, in particular to a UV protective film and a preparation method thereof. The UV protective film comprises a PET (Polyethylene Terephthalate) base material and a bonding layer coated on the base material, the combined material of the bonding layer comprises the following raw materials in parts by weight: vinyl silicone oil, methyl MQ resin, vinyl MQ resin, hydrogen-containing silicone oil, hydroxyl-terminated silicone oil, an inhibitor, a tackifier and a photocatalyst; the tackifier is prepared by taking tetramethyl cyclotetrasiloxane, tetramethyl tetraphenyl cyclotetrasiloxane, tetramethyl tetravinyl cyclotetrasiloxane and 2, 4, 6, 8-tetramethyl-2, 4, 6, 8-tetra [3-(oxirane methoxy) propyl] cyclotetrasiloxane as monomers, trimethyl methoxy silane as a chain terminator and tetrabutyl titanate as a catalyst. The UV protective film prepared by the invention has the advantage of good adhesive property with a glass substrate.

The invention discloses a molding process and device of a polylactic acid composite material, and relates to the technical field of polylactic acid composite materials. The method specifically comprises a multi-stage temperature control and dynamic pressure maintaining crystallization stage which specifically comprises the following steps: a high-temperature crystallization stage: maintaining the temperature of a mold at 100-120 DEG C, and applying first-stage pressure maintaining pressure for 10-60 seconds; in a medium-temperature shaping period, the temperature of the mold is reduced to 80-95 DEG C; and a low-temperature cooling period. According to the preparation method, sufficient activity is provided for a PLA molecular chain segment in a high-temperature environment in the first-stage heat preservation stage, crystal nucleuses are rapidly formed and start to grow under the action of a nucleating agent, the crystallization process in the second-stage heat preservation stage continues to be carried out, but the movement ability of the molecular chain is weakened, and the crystallization rate is slowed down after reaching a peak value; the main effect is to stabilize the formed crystal structure and prevent the product from excessive shrinkage, the molecular chain is quickly frozen at the three-stage stage, the crystallization process is terminated, and the heat resistance of the product is improved.

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