56results about How to "Molecular weight control" patented technology

The invention relates to a process method for preparing polyisobutene and a polymerization device. An integrated reactor consisting of a premixer, a supergravity reactor and a tubular reactor is used as a polymerization reactor; a mixed liquid containing a monomer and diluent and a mixed liquid containing initiator and diluent are introduced to the supergravity reactor after being premixed by thepremixer according to a ratio, and cationic polymerization reaction is initiated under the condition of supergravity, and the reaction liquid enters into the tubular reactor from an outlet of the supergravity reactor to continuously finish macroscopic polymerization reaction. The average molecular weight of the polyisobutene as the obtained product is controllable and ranges from 800 daltons to 5000 daltons, the molecular weight distribution index ranges from 1.8 to 2.5, and the content of a chain end alpha-double bond can be up to over 90%. By using the supergravity polymerization process provided by the invention, the microcosmic mixing, mass transferring and heat transferring processes of a reaction is greatly enhanced; compared with the traditional stirring polymerization method, the process method ensures that the average residence time of materials in the supergravity reactor is at least shortened to over 20-30 times; and in addition, the equipment volume is greatly reduced, andthe operating cost is reduced.

The invention relates to a method for preparing hydrolyzed collagen protein by fresh animal skin, which mainly comprises the following steps: animal skin processing; enzymolysis; solid particulate matter elimination; enzymolysis reaction-separation and coupling; nanofiltration concentration; spray drying; and the like. The invention has high finished product yield; in addition, the average molecular weight of a product is about 2000, the product is easier to absorb by human bodies and has no bitter taste.

The invention provides a preparation method for synthesizing brominated polycarbonate with dual catalysts. By using a dual catalyst system and capping with a monohydric phenol reagent, brominated polycarbonate with an average molecular weight of 2500-2800 can be obtained at normal temperature and normal pressure , has the characteristics of good thermal stability, high yield, controllable molecular weight, and low content of impurities such as chlorine.

The present invention relates to a preparation method of double-peak high-density polyethylene communication cable insulating material. It is characterized by that on the Mitsui chemical high-density polyethylene technological equipment a double-slurry polymerization reactors series-connected reaction process can be adopted. Said invention is an improvement of existent technological process, namely, the catalyst only is added into the first reactor, and in the first reactor the comonomer butylene-1 is not added, the added quantity of hydrogen is controlled, the molecular weight distribution and density of polymer produced by two reactors can be regulated so as to make first reactor polymer be low molecular weight high-density polyethylene, the second reactor polymer be high molecular weight high-density polyethylene so as to obtain polymer-grade polyethylene whose molecular weight is formed into double-peak distribution. After the adjuvant is added into the above-mentioned material and granulated, the communication cable insulating material product can be made up by utilizing large equipment.

The invention discloses a supported double-metal cyanide catalyst and a preparation method and application thereof. The supported double-metal cyanide catalyst uses hydrotalcite as the supporter, double-metal cyanide is supported on the supporter, and the supported double-metal cyanide catalyst uses polyethylene glycol as the chelating agent. The preparation method includes: using zinc chloride and metal cyanide as precursors, dripping the aqueous solution of central metal into a ligand substance solution for reaction, adding the supporter and the chelating agent at the same time, and performing centrifugal separating and drying to obtain the supported double-metal cyanide catalyst. The invention also provides a preparation method using the supported double-metal cyanide catalyst to prepare carbon dioxide-epoxide copolymer. Compared with same-type catalysts, the supported double-metal cyanide catalyst has the advantages that the catalyst is high in catalyzing activity and good in product selectivity; when the catalyst catalyzes carbon dioxide to have copolymerization reaction with epoxides, the carbonic ester unit content of the copolymerization product is high, the cyclic carbonate content of the copolymerization product is low, and the catalyst is high in actual application value and promising in market prospect.

The invention belongs to the technical field of polysiloxane, and discloses vinyl polysiloxane as well as a preparation method and application thereof. The method comprises the following steps: (1) mixing 100 to 200 parts of DMC (dimethylcyclosiloxane) with 20 to 60 parts of methyl vinyl cyclosiloxane, and performing vacuum dewatering treatment to obtain a dewatered mixed monomer; (2) mixing the dewatered mixed monomer with 1 to 20 parts of an end-capping reagent, heating to 100 to 110 DEG C, adding 0.1 to 5 parts of a temporary catalyst, heating to 110 to 115 DEG C, performing heat preservation reaction for 1 to 3 hours, heating to 120 to 125 DEG C, performing heat preservation reaction for 3 to 5 hours, and continuously heating to 130 to 135 DEG C for reaction for 1 to 3 hours, so as toobtain a reaction product; (3) performing subsequent treatment on the reaction product, so as to obtain the vinyl polysiloxane, wherein the part is weight part. The method disclosed by the invention is simple, low in cost and high in monomer conversion rate, and is applied to synthesis and modification of silicone rubber and silicon resin and preparation of a releasing agent.

The invention provides a method for preparing a sodium polyacrylate dispersant. The method comprises the following steps of mixing first acrylic waste liquid and a chain transfer agent, heating, dropwise adding an initiator and second acrylic waste liquid, and reacting for obtaining a reaction product; adjusting the pH value of the reaction product by adopting solid sodium hydroxide, thereby obtaining the sodium polyacrylate dispersant. According to the method, during the preparation of the sodium polyacrylate dispersant, the first acrylic waste liquid and the chain transfer agent serve as a base solution, the second acrylic waste liquid and the initiator are dropwise added to the base solution, and a manner that acrylic acid is dropwise added to part of the acrylic waste liquid is adopted, so that the phenomenon that molecular weights are unequal due to violent reaction is avoided; moreover, sodium polyacrylate is prepared from the acrylic waste liquid, so that the waste is recycled, and meanwhile, the production cost of the acrylic waste liquid is reduced.

The invention discloses a preparation method of controllable high-molecular-weight MQ silicon resin. The preparation method comprises the following steps: (1) uniformly mixing a component A, a solventI and a catalyst to form mixed liquid C, dissolving a component B in a solvent II, and uniformly stirring and mixing to form mixed liquid D; (2) stirring the mixed liquid C at any temperature between30 DEG C and 80 DEG C at constant temperature, slowly dropwise adding the mixed liquid D for 30 to 60 min, and carrying out constant temperature reaction for 2 to 10 h at the end of dropwise adding;(3) adding a reaction inhibitor, stirring for 10 to 50 min, and distilling the mixture in vacuum to remove the solvent, thus obtaining the controllable high-molecular-weight MQ silicon resin. Preparation of the high-molecular-weight MQ silicon resin and control of the molecular weight can be realized only by adjusting a mole ratio of an active group of the component A to an active group of the component B. According to the preparation method, a few of side products are produced, and recycling of acid, byproducts and the like is not considered; the preparation method is short in production period and high in efficiency and can completely realize industrialization. The product disclosed by the invention is completely dissolved into a polarity or low-polarity solvent, so no problems of sediments and gel which are produced by the system are considered.

The invention relates to a manufacturing method of beaded polytrifluorochloroethylene resins, which comprises the following steps of: taking trifluorochlor oethylene, high-purity water, an organic dispersant and an initiator under the condition that the mass ratio of the trifluorochlor oethylene, the high-purity water, the organic dispersant and the initiator is 100:(500-1000): (50-200): (0.1-1); placing the high-purity water, the organic dispersant and the initiator in a reaction kettle, and at a stirring speed of 400-500 rmp, feeding the trifluorochlor oethylene into the reaction kettle; carrying out reaction on the obtained mixture for 4-6 hours under the conditions of 0.2-1 Mpa and 20-30 DEG C; and then continuing to react for 2-4 hours at a temperature of 50 DEG C and at a stirring speed of 100-200 rmp; and carrying out washing and drying on the obtained product so as to obtain a beaded polytrifluorochloroethylene resin with a diameter of 0.5-5 mm. The method disclosed by the invention is stable in polymerization rate and narrow in molecular weight distribution, no dust flying occurs in the process of production, and no further granulation treatment is required; the obtained polytrifluorochloroethylene resin is excellent in performances, and can be prepared into tubes, bars and profiles with more complicated shapes through melt injection molding; and no yellowing phenomenon occurs, therefore, the method has good social, economic and environmental benefits.

The invention discloses a dispersion type liquid mildew inhibitor. The dispersion type liquid mildew inhibitor is composed of certain amounts of propionic acid, ammonium propionate, and guanidine polymers, and a water locking agent is preferably added. The combination of the guanidine polymers and propionic acid plays a role in protection of carboxyl groups in propionic acid molecules, and shows a synergic effect in mildew inhibition effect promotion. A preparation method of the liquid mildew inhibitor is simultaneously disclosed. The liquid mildew inhibitor of the invention has the advantages of long mildew inhibition time, small application amount, and possessing of high economic benefits and social benefits.

This invention discloses a method for preparing poly (lactic acid)-based plasticizer. The method comprises: (1) melt-polycondensing lactic acid and small molecular dicarboxylic acid at a mol. ratio of 1:(10-100) in the presence of catalyst at 100-120 deg.C and 1-2 kPa for 3-5 h, and then at 140-180 deg.C and below 300 Pa for 3-15 h to obtain carboxyl-terminated prepolymer; (2) melt-polycondensing the prepolymer and polyalkylidene ether diol at a mol. ratio of (1:3)-(3:1) in nitrogen atmosphere at 150-230 deg.C and below 300 Pa for 3-20 h to obtain lactic acid-alkylidene ether multi-block copolymer. The method has such advantages as simple process, and abundant raw materials, and is suitable for industrialization.

The invention relates to a biological extracting and purifying method for beer yeast soluble 1,3-beta-D-glucan. An existing process for extracting soluble 1,3-beta-D-glucan in yeast cell walls is short of continuity. According to the method, in the same reaction system, yeast cells are degraded by ultrasonic wave, neutral protease, mannose and beta-glucanase, and soluble 1,3-beta-D-glucan with the molecular weight of 10 to 50kD is extracted by an ultrafiltration film with molecular cutoff of 10 to 50kD, so as to obtain soluble 1,3-beta-D-glucan with the molecular weight of 10 to 50kD. The method has the advantages of short technological process, high safety in production and fixed range of the molecular weight of a product; the obtained product has the characteristics of high solubility, good stability and high safety, and is suitable for the fields of food, medicines, cosmetics, pesticides, new materials, electronics, environmental protection and the like.

The invention discloses a synthesis method of related polypeptide, and belongs to the technical field of high polymer materials. With alkyl primary amine or aromatic amine as an initiator and N-substituted glycine-N-carboxy anhydrides as a monomer, solution ring opening polymerization of the N-substituted glycine-N-carboxy anhydrides is initialized under the condition of nitrogen flow to prepare the related polypeptide. Carbon dioxide generated in the reaction process is rapidly discharged in a manner of nitrogen flow, so that the reaction rate is improved; the polymerization reaction is facilitated; and the related polypeptide generated by the polymerization according to the method is relatively narrow in molecular weight distribution.

The invention belongs to the field of synthesis of a high molecular material and particularly relates to a method for synthesizing polyacrylonitrile by a Lewis base. The method is characterized by comprising the following steps of: under the protection of nitrogen gas, mixing 1,4-N,N-dimethylamino pyridine DMAP and dimethylamino pyridine DMSO to prepare a solution; then adding acrylonitrile into the solution to carry out polymerization reaction; reacting at a polymerization temperature of 0-60 DEG C for 1-48 hours, wherein the mass ratio of the dimethylamino pyridine to an acrylonitrile monomer is (7-500): 100; and the mass ratio of the 1,4-N,N-dimethylamino pyridine DMAP to the acrylonitrile monomer is (1.5-25): 100. The method has the beneficial effects that: an anion polymerization condition of the system is moderate and the acrylonitrile can be polymerized at a room temperature and a normal pressure; less side reaction exists and a product is pure; the control on the composition, the molecular weight and the distribution of a polymer is realized; and the polyacrylonitrile has a wide application prospect in the fields of polyacrylonitrile fibers, carbon fiber precursor materials, porous carbon material precursors and the like.

The invention discloses a cellulose grafted polyacrylamide composition with controllable molecular weight and an application thereof. According to the invention, through bonding of carboxyl and hydroxyl functional groups in CMC with an olefin bond of polyacrylamide to regulate and control the flocculation performance of PAM, the molecular weight of the cellulose grafted polyacrylamide compositioncan be controlled, so the product requirements of the cellulose grafted polyacrylamide composition under different conditions are met; and when the cellulose grafted polyacrylamide composition is applied in wastewater treatment, the flocculation performance can be improved, and the actual usage amount of the cellulose grafted polyacrylamide composition is reduced.

The invention provides a low-molecular dermatan sulfate. The number-average molecular weight of the low-molecular dermatan sulfate is 2,000 to 5,000 Da, and the weight-average molecular weight of thelow-molecular dermatan sulfate is 2500 to 6500 Da. The refined low-molecular dermatan sulfate obtained by the invention has narrower weight-average molecular weight distribution and data molecular weight distribution, is more suitable for human body absorption, and has a wide application prospect in antithrombotic drugs. The invention provides a process for refining the low-molecular dermatan sulfate. The process is a process for refining the low-molecular dermatan sulfate by an enzyme-ultrafiltration method. Particularly, the heparin sodium byproduct rich in dermatan sulfate is used as a rawmaterial, a bi ological enzyme-chondroitin sulfate B enzymecapable of degrading dermatan sulfate is utilized, an ultrafiltration method is combined, the comprehensive refining process is obtained, thereaction is mild, stable and controllable, the process repeatability is high, certain economic benefits and environmental protection effects are achieved, and the comprehensive refining process is suitable for industrial application and promotion.

The invention discloses a chemical industry technical area preparing method to produce a low molecular weight rubber type modifier polymer, which comprises the following steps: 1. mixing polymeric monomer, modifier, trigger, emulsifier and agent in rightly weight percentage; 2. adding those into autoclave; 3. gauging conversion rate and discharging after eligible; wherein the modifier is unodor regular twelve carbon sulfhydrate and carbon tetrachloride composite modifier.

The invention provides a catalyst for synthesizing amide, especially N-mercaptoethyl-3-sulfydryl-propanamide, and a preparation method of the catalyst. The method comprises the following steps: mixing a titanium salt solution, a zinc salt solution and ammonia water, tetraborate and basic nickel carbonate, collecting precipitation, then roasting, dipping and roasting in sulfuric acid, and then mixing the roasted product with (triphenylphosphine) cobalt (I) nitro-hydride and a cyclopentadienyl iron solution. The invention further provides a method for synthesizing N-mercaptoethyl-3-sulfydryl-propanamide by using a mixed crystal solid acid carrier coordination catalyst, the synthesized N-mercaptoethyl-3-sulfydryl-propanamide can be used for the regulation of the molecular weight in polymerization, especially the addition polymerization, the molecular weight can be effectively controlled, and the production of the byproducts is reduced.

Disclosed are terpolymers and processes of terpolymerization, wherein the terpolymer comprises units derived from ethylene, 1-pentene and another alpha-olefin containing at least six carbon atoms.