19 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.

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 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 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.

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 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 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 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.

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.

The invention discloses a porphyrin-quaternary phosphonium salt bifunctional synergistic super-crosslinked polymer catalyst, which is a three-dimensional super-crosslinked polymer skeleton constructed through Friedel-Crafts reaction under the catalysis of Lewis acid by taking metalloporphyrin and quaternary phosphonium salt as precursor monomers and taking a cross-linking agent as a cross-linking unit. And the metal center of the metalloporphyrin and the cation functional group of the quaternary phosphonium salt are distributed in the three-dimensional super-crosslinked polymer skeleton. The invention discloses a method for catalytically synthesizing carbon dioxide-based polyol, which comprises the following step: by taking a porphyrin-quaternary phosphonium salt bifunctional synergistic super-crosslinked polymer catalyst as a catalyst, carrying out copolymerization reaction on epoxide and carbon dioxide in the presence of a chain transfer agent to prepare the carbon dioxide-based polyol. The catalyst provided by the invention still has good catalytic stability and proton tolerance in the presence of various chain transfer agents, and is beneficial to preparation of carbon dioxide-based polyols with low to medium molecular weight and relatively high carbonic ester chain segment content.

The application belongs to the technical field of polymer synthesis, and relates to a cyclic polymer and a synthesis method thereof, wherein the method is to take a heterocyclic lactone of formula 1 as raw material, and to perform ring-opening polymerization under the catalysis of an organic base to obtain the cyclic polymer of formula 2. The method realizes the preparation of the cyclic polymer with ultrahigh molecular weight and medium molecular weight distribution for the first time. The raw material used in the preparation method has a wide source, the catalyst used has good catalytic activity, the preparation is simple, and the cost is low. The method can effectively alleviate the harm caused by the greenhouse effect. The application also discloses the application of the cyclic polymer. The prepared polymer film is colorless, transparent, and has good flexibility and viscoelasticity. The application also discloses a recycling method of the cyclic polymer. The recycling method has a wide spectrum of substrates, can effectively recycle the heterocyclic lactone monomer in the cyclic polymer, and has a wide application prospect.

The invention belongs to the technical field of sodium hyaluronate compounds, and particularly relates to a compound composition of sodium hyaluronates with different molecular weights, a preparation method and application. The compound composition comprises a gradient hyaluronic acid group, an interface compound group, a continuous phase adjusting group and an auxiliary stabilizing group, and the gradient hyaluronic acid group comprises high molecular weight sodium hyaluronate, medium molecular weight sodium hyaluronate, low molecular weight sodium hyaluronate and oligomeric sodium hyaluronate. The interface compounding group comprises a phospholipid component and an amphoteric small molecule component, and the continuous phase adjusting group comprises a saccharide component, a polyol component, a buffer salt component and water. According to the present invention, the compatibility relationship and the compounding path among the components are clearer through the grouping construction and the step-by-step compounding mode, and the obtained composition has characteristics of good system uniformity, good dispersion coordination and good stability, and can be used for gel preparations, spray preparations, emulsion preparations, cream preparations, application preparations, medical dressing compositions and external liquid preparations.

This invention discloses a multi-gradient hyaluronic acid intimate soothing and nourishing gel and its preparation method, belonging to the technical field of feminine intimate care products. The gel's raw materials include lactic acid, sodium lactate, at least five hyaluronic acid compounds covering the low, medium, and high molecular weight ranges (medium molecular weight hyaluronic acid containing acetylated sodium hyaluronate), ceramide NP, ectoine, etc., and a lactic acid-sodium lactate buffer system is used to stabilize the pH value at 3.8-4.5. This invention constructs a 7D hydrating gradient hyaluronic acid moisturizing system, achieving multi-layered hydration and nourishment of the intimate area from deep cellular layers to the surface through a complete gradient compounding of seven specific molecular weight hyaluronic acids (3000Da, 5000Da, 10,000Da, 100,000Da acetylated, 500,000Da, 1,000,000Da, and 3,000,000Da). A dual-core nourishing system is formed by a mass ratio of ceramide NP and ectoine of 1:3 to 1:20, synergistically achieving both barrier nourishment and cellular nourishment. The preparation employs a graded temperature-controlled swelling and homogenization-free low-temperature process. This product is suitable for women's daily intimate care, postpartum care, and intimate anti-aging.

The invention discloses a composite cationic flocculant based on double gradients of molecular weight and charge density as well as a preparation method and an application method of the composite cationic flocculant. The flocculant is prepared by compounding a medium-molecular-weight and high-charge-density poly-dimethyl diallyl ammonium chloride-acrylamide copolymer (PDA) and a high-molecular-weight and medium-low-charge-density cationic polyacrylamide (CPAM), the effective content mass ratio of the PDA to the CPAM is 10: 1-20: 1, and the mass charge density of the PDA is 2-3 times that of the CPAM. A gradient shear mixing preparation process and a time sequence collaborative flocculation application method based on diffusion kinetics difference are adopted. Through the relay action of 0-30-second rapid electric neutralization and 30-180-second slow bridging, the flocculant can form a framework-filling floc structure, and self-adaptive interception of soluble organic matters and complexing-embedding fixation of heavy metals are realized. The plate-and-frame filter pressing time can be greatly shortened, and the water content of a mud cake and the concentration of tail water pollutants are reduced.