38 results about "Medium molecular weight" patented technology

The invention discloses a method for producing multimodal polyethylene through series connection of multiple reactors, and belongs to the field of olefin polymerization. The low-molecular-weight or medium-molecular-weight ethylene polymer is produced through polymerization in the first reactor, the obtained product enters the intermediate treatment unit to remove hydrogen, and then part of the product is shunted to enter the second reactor to be mixed with the ultra-high-molecular-weight ethylene polymer produced through ethylene polymerization in the second reactor; all polymers of the second reactor are returned to the intermediate treatment unit, and the rest products after hydrogen removal enter a third reactor and are mixed with high-molecular-weight ethylene polymers generated by copolymerization of ethylene and comonomers in the third reactor to generate multimodal polyethylene. The multimodal polyethylene produced by the method is wide in molecular weight distribution, and the molecular weight of ultra-high molecular weight polyethylene is flexible to regulate and control. According to the invention, material circulation between the third reactor and the second reactor is adopted, molecular chain-level mixing among the components is achieved, the compatibility is good, and the mechanical property is more excellent.

The invention belongs to the field of biomass-based functional materials, relates to a difunctional coating based on enzymolysis modified cassava starch as well as a preparation method and application of the difunctional coating, and innovatively solves the technical problem that a single coating gives consideration to oil prevention and water absorption through a synergistic technical path of pretreatment and composite enzymolysis. The core mechanism is as follows: the starch particle structure is destroyed through pretreatment, and the degradation degree of starch is accurately controlled through the synergistic effect of alpha-amylase and saccharifying enzyme, so that an unexpected technical effect is achieved, and an enzymolysis product with a film-forming skeleton (medium molecular weight dextrin) and a hydrophilic unit (small molecular saccharide) is formed; meanwhile, a compact and continuous network structure can be formed by a film-forming framework, and grease permeation is blocked; and the hydrophilic unit endows the coating with a rapid capillary water absorption effect.

The present invention provides for the synthesis of intermediate molecular weight heparin.

The application provides a composite implant containing different molecular weight agarose and a preparation method and application thereof, and belongs to the technical field of biomedical materials. The composite implant comprises two or more than two combinations of high molecular weight medical grade agarose, medium-high molecular weight medical grade agarose, medium molecular weight medical grade agarose and low molecular weight medical grade agarose. The application combines medical grade agarose with different molecular weights, so that the composite material has good injectability, moderate gel strength and controllable degradation performance. The prepared composite implant containing different molecular weight agarose has good antioxidant and anti-wrinkle effects, and has a wide application prospect in the field of skin anti-aging.

A high-strength multimodal polyethylene composition useful for the manufacture of plastic articles therefrom; a process for making the above-mentioned composition; and a pipe article made from the above-mentioned composition, the composition comprising a mixture of: (a) at least one first polymeric resin comprising a high molecular weight copolymer resin having a molecular weight greater than 350,000 g / mol; (b) at least one second polymeric resin comprising a low molecular weight homopolymer resin having a molecular weight less than 30,000 g / mol; and (c) at least one third polymeric resin comprising a medium molecular weight copolymer resin having a molecular weight of from 50,000 g / mol to 150,000 g / mol; wherein the high-strength multimodal polyethylene composition has a minimum required strength greater than 11.3 MPa.

The invention belongs to the technical field of textile printing and dyeing, and discloses a color fixing agent for polyester and a preparation method thereof. Polyethyleneimine, glycidyl methacrylate, a cationic monomer and 1-allylimidazole are used as main raw materials, a novel cationic polymer is constructed through amido epoxy ring opening and free radical copolymerization, the cationic polymer has a medium molecular weight, and a molecular chain is rich in acting force anchor points, so that the cationic polymer can be used for preparing a polymer with high molecular weight. Strong electrostatic adsorption, hydrogen bonds, Van der Waals force and the like can be generated with polyester groups, carboxyl groups and dye molecules on the fibers at the same time, so that the affinity adsorption of the dye to the fibers is ensured. Moreover, the color fixing agent molecules with medium chain length can realize rapid permeation in the fiber, and can wrap the dye molecules sufficiently, so that the color fixing effect is improved.

The invention relates to a preparation method and application of food-grade medium-molecular-weight tremella polysaccharide, and belongs to the technical field of fungal polysaccharide preparation. The preparation method of the food-grade medium-molecular-weight tremella polysaccharide comprises the steps of pretreatment, tremella base fermentation, primary enzymolysis, solvent extraction, secondary enzymolysis, separation, purification and the like. The tremella polysaccharide extracted by the method disclosed by the invention is relatively high in extraction rate, relatively high in pharmacological activity and remarkable in antioxidant activity.

The application discloses a kind of metallocene catalyst system, polyisobutylene and preparation method thereof.The metallocene catalyst system includes A, B, C, D four components;Component A is metallocene complex;Component B is borate;Component C is alkyl aluminum;Component D is selected from alkyl ether of carbon atom number 2~8.The metallocene catalyst system used in the application has high catalytic activity and raw materials are cheap and easy to obtain, which can greatly reduce production cost.Compared with BF3 catalyst system, the catalyst system provided by the application is non-toxic, harmless, non-polluting, non-corrosive, which can effectively solve the technical problems of toxic, harmful, corrosion and pollution existing in traditional technical route, thereby improving the operating environment, and ensuring personal health.The application can synthesize narrow distribution, medium molecular weight polyisobutylene under mild conditions of 0~80 DEG C, i.e., using conventional cooling water to remove heat, which solves the low temperature reaction problem existing in traditional cationic polymerization.

The invention belongs to the field of polymer chemical recovery, and discloses a method for preparing high-molecular-weight and mechanical-property PCL (polycaprolactone) through efficient polycondensation of low / medium-molecular-weight PCL. The method comprises the following steps: heating dried low / medium molecular weight PCL and a catalyst to 140-270 DEG C under the pressure condition of 10-500KPa, carrying out polycondensation reaction for 3-24 hours, and separating water generated by the polycondensation reaction from a reaction system in the reaction process to obtain high molecular weight PCL. The method is simple, efficient chemical recycling of low / medium molecular weight PCL is achieved, and high molecular weight and mechanical property PCL is formed through polycondensation. The molecular weight of the product is as high as 5.08 * 10 < 4 > g / mol, and the tensile strength and the elongation at break of the product respectively reach 31.1 MPa and 1420%, which are superior to those of commercial PCL.

The present invention comprises (i) an amorphous polymer composition containing one or more polyisobutenes, each having a glass transition temperature of -40°C or lower, as determined by differential scanning calorimetry (DSC); (ii) one or more butyl rubbers; (iii) one or more antioxidants; and (iv) one or more filler materials, wherein the one or more polyisobutenes have an average molecular weight in the range of about 500 to about 20,000 M v Low molecular weight polyisobutene (LMW PIB) having a molecular weight in the range of approximately 20,000 to approximately 120,000 M v The present invention relates to a corrosion-preventive composition for protecting articles from corrosion, independently selected from the group consisting of medium molecular weight polyisobutenes (MMW PIBs) having the following properties.

The present invention relates to a composition for protecting an article from corrosion, in which the corrosion protection composition comprises: (i) an amorphous polymer composition comprising one or more polyisobutylene, each of which has a glass transition temperature of-40 DEG C or less as determined by differential scanning calorimetry (DSC); (ii) one or more butyl rubbers; (iii) one or more antioxidants; and (iv) one or more filler materials wherein the one or more polyisobutylene is independently selected from the group consisting of low molecular weight polyisobutylene (LMW PIB) having an average molecular weight Mv in the range of about 500 to about 20,000, and medium molecular weight polyisobutylene (MMW PIB) having an average molecular weight Mv in the range of about 20,000 to about 120,000.

The present application relates to the field of paint technology, and disclose a kind of high filling super-solidification intermediate coating in rail transit field, and intermediate coating composition includes nanometer titanium dioxide base end hydroxyl hyperbranched polyester, medium molecular weight acrylic resin, blocked high functionality polyisocyanate crosslinking agent, dispersant etc..The super-solidification system of nanometer titanium dioxide base end hydroxyl hyperbranched polyester and isocyanate crosslinking agent used in the present application obtains coating crosslinking density, and toughness is good, significantly improves the resistance of coating resistance, such as water resistance, moisture resistance, achieves higher level of protection effect to putty, especially water resistance can reach 48h, meanwhile, the intermediate coating of the present application is quick-drying, easy to construction, has higher gloss and fullness, leveling property, matched high-performance putty and finish, can be widely used in rail transit field, and realizes life cycle performance guarantee.

This invention discloses a method for preparing medium molecular weight bisphenol A propane glycidyl ether. The method involves etherifying bisphenol A propane with epichlorohydrin using a polyethylene glycol-modified ionic liquid as a phase transfer catalyst. The resulting etherification product then undergoes a ring-closure reaction under an alkaline catalyst to obtain the medium molecular weight bisphenol A propane glycidyl ether. Compared to the traditional one-step production process, this method offers advantages such as high yield, good selectivity, low wastewater generation, and concentrated molecular weight distribution, thus meeting the application needs of the coatings industry.

A method of synthesis of medium molecular weight heparin includes the steps of dissolving unfractionated heparin in an aqueous solvent to provide a first solution; adding an oxidising agent to the first solution to provide a second solution; and incubating the second solution at a temperature of from about 15 °C to about 30 °C to form a medium molecular weight heparin solution.

The scheme provides a cleavage method of low molecular weight aldehyde carboxyl rubber, which comprises the following steps: dissolving rubber in an organic solvent to obtain a rubber solution; heating the rubber solution, adding sodium metavanadate solution and mixing uniformly to obtain a mixed solution; adding hydrogen peroxide drop by drop into the mixed solution until the cleavage reaction is completed to obtain a reaction solution, wherein the molar ratio of the total amount of hydrogen peroxide to the carbon-carbon double bond in the rubber is (1.2-2.5):1; and treating the reaction solution to obtain low molecular weight aldehyde carboxyl rubber. The method can reduce the cost, improve the environmental protection, significantly improve the functional group content and reaction efficiency of the product, and provide a better choice for the large-scale production and application of low molecular weight aldehyde carboxyl rubber.

This invention discloses a composite cationic flocculant based on a dual gradient of molecular weight and charge density, along with its preparation and application methods. The flocculant is composed of a medium-molecular-weight, high-charge-density poly(diallylammonium chloride)-acrylamide copolymer (PDA) and a high-molecular-weight, medium-low-charge-density cationic polyacrylamide (CPAM), with an effective mass ratio of 10:1 to 20:1. The mass charge density of PDA is 2 to 3 times that of CPAM. A gradient shear mixing preparation process and a time-sequential synergistic flocculation application method based on differences in diffusion kinetics are employed. Through a relay effect of rapid charge neutralization (0-30 seconds) and slow bridging (30-180 seconds), the flocculant can form a skeleton-filled floc structure, achieving adaptive interception of dissolved organic matter and complexation-encapsulation and fixation of heavy metals. This invention can significantly shorten plate and frame filter press time and reduce the moisture content of the filter cake and the concentration of pollutants in the effluent.

A functionalised medium molecular weight heparin includes a linker and a functional group. The functional group may be a polar functional group, an apolar functional group, an acidic functional group, or a basic functional group. The functional group may be an aryl, a phenyl, a heteroaryl, an alkyl, a cycloalkyl, an alkenyl, an alkynyl, an alcohol, a thiol, an ether, a sulphide, an amine, a carboxylic acid, and / or a fluoroalkyl. The linker may be an oxime linker or an amine linker.

The invention provides a cracking method of medium-low molecular weight aldehyde-terminated carboxyl rubber. The cracking method comprises the following steps: dissolving rubber by adopting an organic solvent to obtain a rubber solution; heating the glue solution, adding a sodium metavanadate solution, and uniformly mixing to obtain a mixed solution; dropwise adding hydrogen peroxide into the mixed solution until the cracking reaction is finished to obtain a reaction solution, wherein the molar ratio of the total usage amount of the hydrogen peroxide to the carbon-carbon double bond in the rubber is (1.2-2.5): 1; the method has the advantages that the cost is reduced, the environmental protection property is improved, the functional group content and the reaction efficiency of the product are obviously improved, and a better choice is provided for the large-scale production and application of the medium-low molecular weight aldehyde-terminated carboxyl rubber.

This invention discloses an oral care composition comprising hyaluronic acid and polyphosphate and its application. The oral care composition includes: 1) hyaluronic acid; 2) polyphosphate; and 3) an orally acceptable carrier. The polyphosphate is one or a combination of two or more of pyrophosphate, tripolyphosphate, or hexametaphosphate. The hyaluronic acid comprises one or a combination of two or more of high molecular weight hyaluronic acid, medium molecular weight hyaluronic acid, and low molecular weight hyaluronic acid. The pH value of the oral care composition is 6-9. The hyaluronic acid in this oral care composition can improve the stability of the polyphosphate in the composition, and hyaluronic acid also has the effect of improving the stability of the polyphosphate in the oral care composition. Moreover, the oral care composition comprising hyaluronic acid and polyphosphate of this invention also has a good effect on teeth whitening.

The invention discloses a high-temperature-resistant well completion fluid viscosity-shear improving agent based on covalent bond-secondary bond double bond cooperation and a preparation method of the high-temperature-resistant well completion fluid viscosity-shear improving agent, and belongs to the technical field of oil and gas resource exploration. On one hand, the viscosity and shear improving agent can form a new methylene bridge covalent bond crosslinking point, and on the other hand, the viscosity and shear improving agent can form a supramolecular association system through intermolecular hydrogen-bond interaction, and a structural system of an effective suspension stable high-density solid phase weighting agent can be formed without ultra-high molecular weight. The improvement of the crosslinking degree can effectively counteract the thermal degradation effect of high temperature on the polymer, and the high-pressure environment of the deep well can obviously enhance the stability of hydrogen bonds, so that the polymer body and a supramolecular association system formed by the polymer body are not easily damaged by the high-temperature effect, and the viscosity and cutting improving performance of the polymer in the completion fluid is further ensured.

The present disclosure provides a novel bio-based terpolymer and a preparation method and use thereof. The novel bio-based terpolymer includes itaconic acid, monoethyl itaconate, and diethyl itaconate units. Through the above-mentioned monomers, the bio-based terpolymer with a medium molecular weight and excellent performance is synthesized under optimized synthetic conditions in the presence of substances such as a molecular modifier. Moreover, the bio-based terpolymer is used in dishwashing liquids, dishwasher pods, laundry powders, laundry liquids, etc. The terpolymer provided by the present disclosure has a remarkable effect in the resistance to hard water and the inhibition of various limescales. It is observed that a glass cup washed by a dishwashing powder prepared with the terpolymer of the present disclosure is transparent and bright, and does not have dirt, water stains, spots, or film marks.

The invention discloses a collagen nanosphere composite solution for injection and a preparation method and application thereof.The collagen nanosphere composite solution for injection is prepared from, by mass, 0.5 wt%-3.0 wt% of collagen nanospheres, 0.1 wt%-2.0 wt% of medium-molecular-weight sodium hyaluronate, 0.1 wt%-5.0 wt% of low-molecular-weight sodium hyaluronate, 0.05 wt%-5.0 wt% of glycerinum, 0.005 wt%-0.1 wt% of amino acid, 0.001 wt%-0.1 wt% of vitamin and the balance water. The balance is a phosphate buffer solution; the preparation method comprises the following steps: preparing collagen nanospheres with the particle size of 50-500 nm through a high-pressure microjet homogenization technology, freeze-drying, compounding with a buffer matrix containing sodium hyaluronate, and sterilizing to obtain a final product. Through the synergistic effect of various components, the composite solution has multiple effects of instant moisturizing, long-acting slow release, collagen regeneration promotion, oxidation resistance and the like, can be used for preparing medical beauty products such as hydro-optic needle, microneedle and mesoderm therapy preparations, and has the advantages of lasting effect and high safety.

The invention discloses organic silicon anti-doodling resin and a preparation method thereof. The organic silicon anti-doodling resin is prepared by hydrolyzing and concentrating phenyl trimethoxy silane, propyl trimethoxy silane, dimethyl dimethoxy silane and the like, and then mixing with raw materials such as medium molecular weight polyester resin, hydroxyl silicone oil, a catalyst and an organic solvent. The preparation method comprises the following steps: hydrolyzing and concentrating phenyl trimethoxy silane, propyl trimethoxy silane and dimethyl dimethoxy silane with preferable dosage to prepare a phenyl propyl methyl silicon resin prepolymer, and then carrying out graft copolymerization on the phenyl propyl methyl silicon resin prepolymer, medium molecular weight polyester resin and hydroxyl silicone oil to obtain the organic silicon anti-doodling resin with excellent performance. The organic silicon anti-doodling resin synthesized by the invention has good mechanical properties, good anti-doodling performance, good heat resistance, good weather resistance and the like, and has very good technical effects. The anti-doodling paint can be used for equipment needing anti-doodling, outer walls of public places and the like

The invention discloses silk fibroin nail polish for repairing damaged nail surfaces and a preparation method of the silk fibroin nail polish, and belongs to the technical field of cosmetic materials. The preparation method comprises the following steps: preparing degummed silk; degummed silk is dissolved in an ionic solvent, a silk fibroin dialysis solution is obtained through dialysis, the solution is diluted and then subjected to enzymolysis, and low-molecular-weight silk fibroin is obtained through dialysis, filtration and freeze drying treatment; the preparation method comprises the following steps: dissolving degummed silk in CaCl2-C2H6O-H2O, and carrying out dialysis, filtration and freeze drying treatment, so as to obtain medium molecular weight silk fibroin; uniformly mixing the low-molecular-weight silk fibroin aqueous solution, a penetration enhancer and a humectant to obtain a low-molecular-weight silk fibroin mixed solution; uniformly mixing the medium molecular weight silk fibroin aqueous solution, a film-forming agent and a thickening agent to obtain a medium molecular weight silk fibroin mixed solution; and mixing the two mixed solutions, and adding a preservative to obtain the silk fibroin nail polish. The nail polish disclosed by the invention has the functions of deep repairing, structure strengthening and surface protection.

The invention provides a tacrolimus multi-layer coated pellet capsule and a preparation method of the tacrolimus multi-layer coated pellet capsule. The tacrolimus multi-layer coated pellet capsule is characterized by comprising an inner core pellet, a middle coating layer and an outer coating layer, the core pellet is prepared from tacrolimus, high molecular weight ethyl cellulose with the molecular weight of 100000 to 300000Da, a disintegrating agent and a filling agent; the middle coating layer comprises medium molecular weight ethyl cellulose with the molecular weight of 30000 to 50000 Da; the outer coating layer comprises low molecular weight ethyl cellulose with the molecular weight of 1000 to 10000 Da and a release accelerator. Through the innovative design of a three-layer coating structure, the multi-stage release characteristic of tacrolimus is realized. The core pellet adopts high-molecular-weight ethyl cellulose as a base material to provide a drug sustained release basis; the middle coating layer is made of medium-molecular-weight ethyl cellulose, so that a stable membrane-controlled release layer is formed, and the drug release rate is accurately controlled; and the outer coating layer adopts low-molecular-weight ethyl cellulose to be matched with a release accelerator, so that the quick release of the medicine is realized.

The invention discloses a menthol-containing soft contact lens preserving fluid as well as a preparation process and application thereof. The soft contact lens preserving fluid is prepared by compounding menthol with low-molecular-weight polyethylene glycol (the molecular weight is 100-400), hydroxypropyl methyl cellulose and medium-molecular-weight polyethylene glycol (the molecular weight is 600-1000); the menthol is uniformly and stably dispersed in a preservation solution system by controlling the feeding sequence, the temperature and the stirring speed, so that the menthol-containing soft contact lens preservation solution with stable performance is obtained, and the problems that the menthol is low in dissolution degree, easy to separate out and easy to volatilize in an aqueous solution are fundamentally solved; the menthol can be prevented from being separated out of an aqueous solution, the wearing safety of the soaked lens is guaranteed, through the combined effect of multiple components, enough menthol is stably distributed in a hydration system of the lens surface and the ocular surface and is slowly released, the effect of lasting, cool and comfortable wearing experience is achieved, and the menthol-containing eye drops have extremely good application value and popularization prospects.

Poly (2, 6-dimethyl-1, 4-phenylate) may be prepared by a method that includes reacting 2, 6-dimethylphenol in the presence of a solvent, oxygen, a copper ion, a counter ion, and N, N '-di-tert-butylethylenediamine to form the poly (2, 6-dimethyl-1, 4-phenylate). The usage amount of the N, N '-di-tert-butyl ethylenediamine is 0.47-0.6 wt% of the weight of the 2, 6-dimethylphenol, and the molar ratio of the 2, 6-dimethylphenol to the copper ions is 900: 1-1300: 1. The method provides a poly (2, 6-dimethyl-1, 4-phenylene ether) having a medium molecular weight and intrinsic viscosity.

The present invention discloses a soluble solid-state battery negative electrode material, comprising 70-90 parts of graphite, 4-12 parts of polyvinyl alcohol, and a solid electrolyte Li7La3Zr2O 12 5 to 13 parts of polyvinyl alcohol and 1 to 5 parts of a conductive agent; the polyvinyl alcohol is a medium molecular weight polyvinyl alcohol with a molecular weight of 120,000 to 150,000, and the conductive agent is carbon black or carbon nanotubes; also disclosed are a negative electrode plate, a preparation method thereof, and a lithium battery; the PVA and LLZO of the present invention can form a composite network structure in the negative electrode material, tightly wrapping the active material graphite to form a stable interface layer, such a structure can further improve the wettability and stability of the electrode and the ionic conductivity, thereby improving the performance of the battery, and can also inhibit the volume expansion and contraction of the graphite negative electrode material during the charge and discharge process, reduce the shedding and pulverization of the material, and improve the cycle life of the battery.

The invention relates to a corrosion-resistant and heat-resistant temporary bonding adhesive, a preparation method and a bonding and de-bonding method wherein the corrosion-resistant and heat-resistant temporary bonding adhesive comprises the following components by weight: 40-60 parts of a non-polar solvent; 5-10 parts of a low-polarity solvent; 10-40 parts of medium molecular weight resin; 10-30 parts of low molecular weight resin; 0.5 to 1 part of an adhesion promoter; 0.1 to 1 part of layered double metal hydroxide; and 0.1-1 part of an antioxidant. The low-molecular-weight resin and the medium-molecular-weight resin are compounded, it is guaranteed that the bonding adhesive layer has low rheological viscosity in high-temperature bonding, meanwhile, the bonding adhesive layer has high initial adhesion, the bonding adhesive layer cooperates with the adhesion promoter, stable chemical bonds are formed between the low-polarity temporary bonding adhesive and the surface of a wafer through the bridging effect, the interfacial force is enhanced, and the bonding strength is improved. And the bonding of the bonding glue is more uniform and firm.

The invention discloses a method for controlling molecular weight distribution of meta-aramid resin through gradient extraction and elution and application. According to the method, N, N-dimethylacetamide aqueous solutions with different mass concentrations are used, multi-stage sequential extraction is carried out on resin powder according to the concentration from high to low, insoluble substances are separated, washed and dried after each stage of extraction, and a plurality of resin fractions with narrower molecular weight distribution and smaller PDI are obtained. The technology not only narrows the overall molecular weight distribution, but also can realize grading according to molecular sizes. The high molecular weight component is suitable for high-strength fibers and high-performance insulation paper, the middle molecular weight component can be used for conventional fibers and insulation paper, and the low molecular weight component is suitable for being used as a bonding layer or a functional additive, so that high-value utilization of the raw materials is realized. The obtained resin has better processing stability and product performance uniformity, and has important application value in the fields of preparation of high-strength and high-modulus fibers, high-performance insulation paper, films, composite materials and the like.