109results about How to "Narrow molecular weight" patented technology

A method for preparing polymer for PAN precursor, by copolymerizing the water phase suspend using ammonium persulphate-ammonium sulfite or ammonium bisulfite as a primosome, is disclosed. The polyacrylonitrile powder material is obtained by adding the first monomer acrylonitrile, the second monomer crylic acid, methyl acrylate or acrylamide, and the third itaconic acid, or the first monomer crylic acid, the second monomer methyl acrylate or itaconic acid, and inorganic oxidation-reduction primosome without any metallic ion which comprises ammonium persulphate, ammonium sulfite or ammonium bisulfite and acidified deionized water into the polymerization kettle in defined proportions, controlling the temperature and stirring to react for a time, and discharging by removing the residual monomer, washing and drying. The average molecular weight is from 17.5 myriads to 26.1 myriads, and the distribution index of molecular weight is from 2.70 to 2.91; the intension of polyacrylonitrile precursor tested by spinning sample is from 4.58 to 6.61 CN/dtex; and the carbon fiber strength is 3.61-5.06MPa.

The invention relates to a preparation method of polypropylene wax. The method is characterized in that a liquid phase bulk polymerization technology is used, a supported metallocene catalyst is used, hydrogen is adopted as a molecular weight regulator, and a granular polypropylene wax product is directly obtained through catalyzing liquid propylene polymerization. The propylene polymerization reaction activity is not lower than 1000 times/h. The method has the characteristics of simple operation and high polymerization reaction activity, and the molecular weight of the polypropylene wax product obtained in the invention is adjustable and has narrow distribution.

The invention discloses a method for preparing crystal II-type ammonium polyphosphate with distribution of high polymerization degree and narrow molecular weight. The method comprises the following steps: putting phosphorus pentoxide and diammonium phosphate which have equal molar ratio into a malaxator which can accurately control a temperature and heated by conducting oil for mixing; under the protection of inert gas, heating the materials in the malaxator to between 100 and 250 DEG C through the circulatory conducting oil; stopping introducing the inert gas; performing ammonification on the materials and heating the materials under an atmosphere of ammonia gas till the materials are totally molten down; stopping introducing the ammonia gas; after homogenization, introducing the ammonia gas again and heating the materials; throwing a surface treating agent into the malaxator; after material throwing is completed, continuously introducing the ammonia gas, keeping warm and mixing the materials; after reaction is finished, transferring the materials to a closed vessel and reducing the temperature; simultaneously, continuously introducing the ammonia gas till the temperature of the materials is below 100 DEG C; and obtaining a finished product. The method can prepare the crystal II -type ammonium polyphosphate with the distribution of the high polymerization degree and the narrow molecular weight; and the product has the characteristics of uniform granularity shape, small water-solubility, good heat resistance, high polymerization degree, narrow distribution of molecular weight and high crystal II-type purity.

The invention discloses a cyclic azobenzene amphiphilic segmented copolymer and its preparation method. The preparation method is concretely characterized in that the cyclic azobenzene amphiphilic segmented copolymer with controllable molecular weight, molecular weight distribution and ratio of a hydrophilic segment to a hydrophobic segment is obtained by combining through controllable atom transfer radical polymerization (ATRP) and an efficient CuAAC reaction. Compared with linear polymers having a same molecular weight, the cyclic polymer disclosed in the invention has the advantages of high Tg, fast photo-isomerization, sensitive light and pH response performances in an alkaline medium, and wide application potential in medicine release, surfactants, coatings, adhesives and separation films.

The invention relates to a transition metal living free radical and/or atom transfer polymerisation process comprising the steps of: (a) mixing (i) a transition metal living free radical and/or atom transfer radical catalyst, (ii) a plurality of polymerisable monomers, and (iii) an initiator comprising a transferable atom or group a to an amide group to form a mixture; (b) incubating the mixture at a first temperature; and then (c) raising the temperature of the mixture to a second temperature to allow polymerisation of the monomers to proceed to produce polymer. Products and initiators are also provided.

The invention discloses a novel cold rolling extreme thin plate rolling oil composition. Synthesized ester and an alkylphenol epoxypropane compound are compounded to be used as an oily agent and can form a layer of quite dense protective film on the surface of metal to form favorable annealing detergency and heat stability. A nonionic compounded emulsifying agent can increase the diameter of the elaioplast of emulsion and shows better lubricity by matching with the interaction of a metal passivator, a sulfur-containing extreme pressure antiwear agent, and the like.

The invention relates to a method for preparing a high-performance polyacrylonitrile solution for carbon fibers, and especially relates to a method for preparing the polyacrylonitrile solution through adopting a new initiator to mainly solve a problem of difficult process control caused by wide molecular weight distribution or abundant gel generation of solutions prepared through a single initiator used for preparing an acrylonitrile solution in the prior art. According to the invention, the initiator comprises 70-100 parts by weight of azodiisobutyronitrile and 1-30 parts by weight of azobisisoheptonitrile. The method well solves the problem through above technical scheme, and can be used for the industrial production of the acrylonitrile solution polymerization

A modified polyolefin resin which is obtained by graft modifying a propylene-based random copolymer having a melting point of 50 to 130° C. obtainable by polymerization in the presence of a metallocene catalyst, with an unsaturated carboxylic acid and/or its derivative, and has a weight average molecular weight of 15,000 to 200,000, the graft weight of the unsaturated carboxylic acid and/or its derivative therein being in the range of 0.2 to 50% by weight, is suited as a binder, a primer, an adhesive and the like against a base to which a coating or the like is difficult to adhere in a stable manner. The polyolefin resin of the present invention is superior in adhesive strength, gasohol resistance, blocking resistance and the like. The polyolefin resin of the present invention is also superior in adhesive strength even when low temperature baking is conducted.

The invention discloses a block polymer, a drug carrier containing the same, and a preparation method and application of the block polymer. According to the block polymer, a copolymer with controllable copolymerization components, controllable molecular weight and narrow molecular weight distribution (the molecular weight distribution d<1.2) are obtained by adopting ring-opening polymerization (ROP) and reversible addition fragmentation chain transfer (RAFT) or atom transfer radical polymerization (ATRP) method. The drug carrier prepared from the polymer has relatively good slow release and tumor passive targeting effects, so that the polymer can be applied to targeting transportation of anti-tumor drugs; and the polymer has a high targeting property and good biocompatibility and is an anti-tumor targeting drug carrier with good performance.

The invention discloses a preparation method of an Al-SBA-15 mesoporous molecular sieve, application of the Al-SBA-15 mesoporous molecular sieve as a catalyst, and a method for catalyzing ethoxylationreactions of fatty alcohol. The fatty alcohol ethoxylation reaction method comprises the following steps: dispersing the Al-SBA-15 mesoporous molecular sieve into a certain amount of fatty alcohol, putting a dispersion liquid into a high-pressures kettle, performing nitrogen replacement, after the reaction temperature is 110-130 DEG C, adding ethylene oxide in batches, adding the ethylene oxide till the initial reaction pressure is 0.6-1.0 MPa each time, and cooling and discharging materials after reactions are completed. The Al-SBA-15 mesoporous molecular sieve catalyst prepared by using themethod has a relatively large specific surface area and an ordered microstructure, is good in catalysis activity, is narrow in catalyst product molecular weight distribution and can be repeatedly used.

The invention discloses a preparation system and a preparation method for polyisobutylene. The system comprises an isobutylene storage tank, a catalyst storage tank, a termination agent storage tank, a rapid mixer, a static mixing tube type polymerization reactor and a rapid reaction termination mixer. The isobutylene storage tank is connected to an isobutylene cooler through a pipeline and a raw material delivery pump. The isobutylene cooler is in pipeline connection with a raw material inlet of the rapid mixer. The catalyst storage tank is connected to the catalyst inlet of the rapid mixer through a pipeline and a catalyst metering pump. The outlet of the rapid mixer is communicated with the inlet of the static mixing tube type polymerization reactor, the outlet of which is communicated with the reaction feed inlet of the rapid reaction termination mixer. The termination agent storage tank is connected to the termination agent inlet of the rapid reaction termination mixer through a pipeline and a termination agent delivery pump. The static mixing tube type polymerization reactor is located in a constant temperature brine bath groove. The system provided by the invention has the advantages of uniform reaction temperature, narrow molecular weight distribution of polyisobutylene, and controllable molecular weight, etc.

The invention relates to a continuous long glass fiber reinforced PBT composite material. The composite material is prepared from, by mass, 40-80 parts of PBT resin, 20-50 parts of long glass fiber, 1-4 parts of a flow modifier, 2-6 parts of a flexibilizer, 1-3 parts of a nucleating agent, 0.3-0.6 parts of an antioxidant, 0.3-1 part of a lubricant, 0.1-1 part of diisocyanate or polyisocyanate and 0-5 parts of POE. The long glass fiber reinforced PBT composite material prepared in the invention has the advantages of excellent mechanical performances and good temperature tolerance, and the corresponding preparation method has the advantages of simplicity, no obvious increase of the production cost, and substantial economic benefit, and is worth to be popularized and applied.

To provide a process for producing a polyester ether poly- or mono-ol having a narrow molecular weight distribution, which is obtained by copolymerizing an initiator having hydroxyl groups with a cyclic ester compound and an alkylene oxide.

It is possible to produce a polyester ether poly- or mono-ol having a molecular distribution (Mw/Mn) of from 1.02 to 1.4 by copolymerizing a cyclic ester compound which carbon number is from 3 to 9 and an alkylene oxide which carbon number is from 2 to 20 with an initiator having from 1 to 12 hydroxyl groups and having a number average molecular weight (Mn) of from 18 to 20,000 in the presence of a double-metal cyanide complex catalyst is having tert-butyl alcohol as at least a part of an organic ligand.

The invention relates to a synthetic method of a saccharide-containing copolymer with biological specific recognition performance. The synthetic method comprises following steps: in an inert atmosphere, alpha-D-mannose monomer M1 and Grubbs third-generation catalyst are reacted in a solvent; beta-D-galactose monomer M2 is added for reaction; ethyl vinyl ether is added to stop polymerization, and post-treatment is carried out so as to obtain a segmented copolymer containing alpha-D-mannose and beta-D-galactose. Compared with the prior art, the polymer monomer synthetic method is simple and reliable; the obtained polymer structure is linear; the molecular weight is controllable; and the synthetic method can be applied in the fields such as high molecular material and biological medicine engineering.

The invention discloses a nitrogen-bridged bis(phenolate) yttrium dibenzyl oxygen compound and preparation and application thereof. A bridged bis(phenolate) lanthanide complex is the nitrogen-bridged bis(phenolate) yttrium dibenzyl oxygen compound, of which the chemical formula is p-C6H4[CH2OYL(THF)]2, wherein Y refers to lanthanide yttrium; and L refers to a nitrogen-bridged bis(phenolate) complex; L=Me2NCH2CH2N{CH2-(2-O-C6H2-R-3,5)}2, wherein 3 position and 5 position of an aromatic ring are provided with alkyl group substituents R, and R is selected from C1-C4 saturated alkyl. The double active center type nitrogen-bridged bis(phenolate) yttrium dibenzyl oxygen compound is synthesized simply and conveniently, not only can be used as a single-component catalyst under a mild condition to catalyze ring opening polymerization of epsilon-Hexalactone and L-lactide controllably with high activity, but also can initiates copolymerization of the two monomers to generate ABA type block copolymer.

The invention discloses water-based organic silicon modified cationic acrylic resin and a synthesis method. The water-based organic silicon modified cationic acrylic resin is prepared from the following raw materials: a monomer, a functional monomer, a solvent, acid, a chain transfer agent and an initiator, wherein the monomer comprises, by weight, 100-400 parts of methyl methacrylate, 5-50 partsof butyl acrylate and 20-200 parts of styrene, the functional monomer comprises, by weight, 10-100 parts of vinyltriethoxysilane, 20-200 parts of dimethylaminoethyl methacrylate and 30-250 parts of hydroxyethyl acrylate, the solvent comprises, by weight, 100-400 parts of propylene glycol monomethyl ether, 50-400 parts of absolute ethyl alcohol and 20-200 parts of N, N-dimethylformamide, the acid is 5-60 parts by weight of lactic acid, the chain transfer agent is 1-50 parts by weight of a methyl styrene linear dimer, and the initiator is 1-50 parts by weight of azodiisobutyronitrile. The invention solves the fundamental problems of unsatisfactory hardness, transparency, solvent resistance and other properties, high cost and the like of the traditional water-based wood paint, can completelyreplace the oil-based PU wood paint, and can generate great advantages for environmental beautification without losing the properties under the large situation of environmental protection.

The invention relates to a method for a preparing polyacrylonitrile spinning solution for a high-performance carbon fiber in an ionic liquid. The method comprises the following steps: sequentially adding a monomer in an acrylonitrile binary copolymerization system or a monomer in an acrylonitrile ternary polymerization system into the ionic liquid, dissolving at the room temperature, adding an evocating agent, and charging inactive gas for free radical polyreaction, stopping the polyreaction with ice-bath after reaction, solidifying the polymerisate with water and obtaining the polyacrylonitrile material after repeated water rinsing, oven drying and purification, and mixing to dissolve the obtained polyacrylonitrile powder material with dimethyl sulfoxide as the solution, thereby obtaining the polyacrylonitrile spinning solution with high-performance carbon fiber. In the method, the ionic liquid is used as the reaction solvent, with a wide melting point range, thereby facilitating the control of the polymerization temperature, and greatly speeding up the polymerization; and the obtained polyacrylonitrile has high molecular weight and narrow molecular weight distribution, thereby facilitating the preparation of the polyacrylonitrile precursor with stable performance for carbon fiber, improving the productivity and reducing the cost.

The present invention discloses polyethylene powder, a composition, a cross-linked polyethylene pipe and preparation methods of the polyethylene powder and the cross-linked polyethylene pipe. The polyethylene powder preparation method comprises that under the co-effect of a supported non-metallocene olefin polymerization catalyst and a co-catalyst, in the presence or absence of hydrogen, ethylene and alpha-olefin are subjected to slurry polymerization in an organic solvent, wherein the co-catalyst is one or a plurality of materials slected from an alkyl aluminum compound, a halogenated alkyl aluminum compound and alkyl aluminoxane. According to the present invention, the cross-linking degree of the obtained cross-linked polyethylene pipe can achieve more than or equal to 90%, the compression resistance can achieve and exceed the national standard related requirements, and the test results through the experiment examples show that the polyethylene powder prepared of the present invention has good environmental stress cracking resistance compared to the ethylene copolymer raw material prepared by using the existing technology.

The invention relates to the technical field of deep processing of ginseng, and in particular discloses a preparation method of ginseng chelating peptide. The preparation method at least comprises thefollowing steps: a. slicing ginseng, adding water and boiling, cooling to 55-58 DEG C, then adding amylase and saccharifying enzyme for carrying out desaccharification and enzymatic hydrolysis; b. adding bacillus subtilis neutral protease and bromelain into enzymatic hydrolysate for carrying out enzymolysis; after the enzymolysis is finished, carrying out enzyme deactivation to obtain hydrolysate, wherein the enzymatic hydrolysis conditions are as follows: the enzymatic hydrolysis temperature is 55-58 DEG C, and the enzymatic hydrolysis time is 3-4h; c. separating and purifying the hydrolyzate, then adding soybean peptide, and carrying out chelation at 45-50 DEG C to obtain a chelating solution; d. concentrating and drying the chelating solution to obtain the ginseng chelating peptide. The extraction rate of the ginseng chelating peptide prepared by the method is high; the obtained ginseng chelating peptide is small in molecular weight, narrow in distribution and high in chelating yield with trace elements, vitamins and polysaccharides.