149results about How to "Small molecular weight distribution" patented technology

The invention relates to an industrial production method for semi-crystal poly(aromatic ether nitrile), which belongs to the field of polymer material. The method comprises the following steps: 2, 6-dichloro benzonitrile and hydroquinone are taken as raw materials; anhydrous potassium carbonate is taken as a catalyst; in the presence of a solvent and a dehydrating agent, the raw materials and the catalyst react under atmospheric pressure to obtain the poly(aromatic ether nitrile) homopolymer with low molecular weight and regular chain segments; and then the molecular weight of polymer is increased through pressurization, so as to obtain the semi-crystal poly(aromatic ether nitrile) polymer with high molecular weight. Due to the increase of crystallinity and molecular weight, the mechanical properties and heat resistance of the semi-crystal poly(aromatic ether nitrile) polymer are obviously improved.

The invention relates to application of rare-earth complexes chelated by tridentate carbazolyl in a conjugated diene and polar monomer copolymerization catalyst system. The catalyst system comprises the rare-earth complexes chelated by the tridentate carbazolyl, organic boron salt and an alkylation agent by the molar ratio ranging from 1:1:0 to 1:1:100. The catalyst system catalyzes copolymerization between conjugated diene and polar monomer; chain segment compositions and molecular weight of obtained copolymers can be regulated and controlled by changing molar ratio between two monomers and the catalyst system and the molar ratio between the two monomers; the molar ratio between a conjugated diene monomer and the catalyst system is 500-10000:1; and the molar ratio between the polar monomer and the catalyst system is 100-10000:1.The content of segmental cis 1,4 of poly-conjugated-diene of the obtained copolymers ranges from 97% to 99.9%, number-average molecular weight is within the range from 5 to 2 million, and molecular weight distribution is smaller than 3.0.

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 discloses a cross-linked fluorine (methyl)-containing acrylic segmented copolymer and its preparation method and use, and belongs to the field of chemical materials. The preparation method comprises that various (methyl) acrylate functional monomers are copolymerized into the cross-linked fluorine (methyl)-containing acrylic segmented copolymer by an atom transfer radical polymerization (ATRP) method. A structure, molecular weight and molecular weight distribution of the cross-linked fluorine (methyl)-containing acrylic segmented copolymer can be controlled. The molecular weight of the cross-linked fluorine (methyl)-containing acrylic segmented copolymer is in a range of 10000 to 35000 and the molecular weight distribution is less than 1.4. The cross-linked fluorine (methyl)-containing acrylic segmented copolymer is mixed with a curing agent according to a certain ratio and the mixture self-assembles in a selective solvent so that a micellar solution having an average particle size of about 100 to 450nm is formed. Through a solvent evaporation film-forming method, the micellar solution is prepared into a super-hydrophobic coating film having a contact angle of more than 150 degrees, hardness H and second-level adhesion. The preparation method has simple and feasible operation processes, a low cost and a wide application prospect in the field of water-proofing and moisture-proofing coatings.

The invention belongs to the technical field of biomedical polymer material and nanobiomaterial, particularly relates to a magnetic nano-carrier with targeted hydrophobic drug delivery to tumor and a preparation method thereof. The magnetic nano-carrier is formed by encapsulating superparamagnetic nano-particles with amphiphilic segmented copolymer methoxy polye thylene glycol-poly(lactide- glycolide) (MePEG-PLGA) micelles. First, a large amount of MePEG-PLGA with good dispersion is synthesized by the improved solution polymerization process, and then the MePEG-PLGA is used as raw materials to encapsulate Fe3O4 nano-particles by the solvent evaporation process to obtain a magnetic nano drug carrier. The carrier is expected to solve the solubility problem of insoluble drugs, achieves slow release of drugs, and achieves the passive-targeting of the drugs by the EPR effect of tumor; Fe3O4 nano-particles are used in the active-targeting of the drugs to reduce the dosage and the side effect and improve the treatment efficiency; besides, the carrier can be used in the magnetic resonance imaging (MRI) of tumor.

The invention relates to a modified polyurethane spraying composite material for cold insulation of an ultralow temperature liquefied natural gas (LNG) storage tank and a preparation method of the composite material. The composite material consists of a component A and a component B at a weight ratio of 1: (1-1.05), wherein the component A includes polyether glycol A, polyether glycol B, modified polyether glycol, a foam stabilizer A, a foam stabilizer B, a chemical foaming agent, a physical foaming agent, a catalyst, a fire retardant and other auxiliaries, and the component B is polymethenyl polyphenyl polyisocyanate; the preparation method comprises the steps of sequentially adding the ingredients of the component A in a reaction kettle, stirring for 0.5-1 hour at a high temperature for completely mixing; and uniformly mixing the component A and the component B at weight ratio of 1: (1-1.05) through a high-pressure spraying machine, atomizing and foaming so that foam is rapidly formed and ripened, thus obtaining a finished product. The foam prepared by the invention is quite strong in low-temperature size stability, and is free from contraction crack in a cryogenic environment, so as to guarantee a perfect cryogenic cold insulation effect; and the composite material is specifically applicable to cold insulation construction of the LNG storage tank.

The invention discloses a method for preparing hexafluoropropylene oxide oligomer. Alkali-metal fluoride salt, aprotic inertia polarity organic solvents, fluorine-containing organic solvents and perfluoro(2-methyl-3-oxahexanoyl)fluoride are used for preparing a homogeneous activation initiator, the homogeneous activation initiator is used for initiating a hexafluoropropylene oxide monomer to have a polymerization reaction, and then the hexafluoropropylene oxide oligomer with a high molecular weight is obtained. Meanwhile, a part of products and related solvents are recycled, and an environment-friendly recycle production effect is achieved.

The invention provides a preparation method of a polyethyleneglycol monomethyl ether-polylactic acid block copolymer, which comprises the following steps: reacting raw materials polyethyleneglycol monomethyl ether and D,L-lactide by melt polycondensation by using stannous octoate as a catalyst; and after the reaction finishes, carrying out after-treatment by a 1-4-time dichloromethane dissolution-aether crystallization process, wherein the product to be purified is dissolved by the dichloromethane and washed with pure water in the first or second crystallization process to remove more low-molecular impurities, thereby obviously narrowing the molecular weight distribution of the product. The hydroscopic property of the product is obviously improved, and the flowability is higher and is more suitable for preservation and use of the product.

The invention relates to a polyacrylonitrile copolymer spinning solution and a preparation method thereof. In the invention, copolymerization reaction is performed on acrylonitrile in a tubular reactor containing a static mixer component; the tubular reactor, which contains the static mixer component and has the characteristics of mass transfer, efficient heat transfer, continuous and stable reaction and no mechanical stirring, is adopted to prepare the polyacrylonitrile copolymer spinning solution with high molecular weight and narrow molecular weight distribution. The polyacrylonitrile copolymer spinning solution is obtained after copolymerization reaction is performed on reaction liquid composed of monomers, a radical initiator and a solvent, wherein the percent concentration by weight of the monomers in the reaction liquid is 15% to 20%; the weight of the radical initiator is 0.4% to 1% of that of the monomers; the solvent is in balancing amount; the monomers are an acrylonitrile monomer and a comonomer. The dynamic viscosity of the polyacrylonitrile copolymer spinning solution provided by the invention is 200 to 800 Pa.S, and the molecular weight distribution is 1.5 to 2.6.

The invention belongs to the field of random copolymer preparation, and particularly relates to a method for preparing an amphiphilic random copolymer P(SMA-co-DM) in a micro-reactor through free radical polymerization. A hydrophobic monomer SMA in the P(SMA-co-DM) has a long chain pendant group, such that the polymer easily forms a vesicle-shaped micelle in the subsequent self-assembly, and the property can be used in drug slow-release carriers, biomolecules and other fields; and a hydrophilic monomer DM has pH sensitivity and temperature sensitivity, and a morphology of a micelle can be controlled in copolymer self-assembly by changing a pH value and a temperature so as to provide a good prospect. In the prior art, amphiphilic random copolymer preparation is simple, but a series of problems such as low conversion rate, wide molecular weight distribution and the like exist. The micro-reactor provides great advantages in amphiphilic random copolymer preparation. In addition, a linear size of the channel is reduced to a micron size, and the whole volume of the micro-reactor is small, such that the operation is controllable, the safety is strong, and the operation is flexible.

The invention particularly discloses an aqueous UV (ultraviolet)-curable fluorine-alcohol-modified epoxy resin coating and a preparation method thereof. The preparation method comprises the following steps of: firstly reacting a fluorine-containing terminal hydroxy compound with a diisocyanate monomer by utilizing a solution polymerization method so as to prepare mono-isocyanate terminated fluorine-containing isocyanate; carrying out a directed grafting reaction on epoxy resin containing hydroxy groups by utilizing the mono-isocyanate terminated fluorine-containing isocyanate so as to prepare fluorine-alcohol-modified epoxy resin Fn-EP, and further reacting maleic anhydride monomers with epoxy groups at two ends of the Fn-EP to prepare aqueous ultraviolet-curable fluorine-alcohol-modified epoxy resin Fn-EMA; and salifying the obtained Fn-EMA resin by adding a neutralizer, and uniformly mixing the obtained salt with water, so as to obtain the coating. The aqueous UV (ultraviolet)-curable fluorine-alcohol-modified epoxy resin coating has good photo-curing performance and excellent heat resistance, weather fastness and pollution resistance, is a high-performance environment-friendly coating and can be applied to the fields of household daily carpentry, building walls and steel components.

A toner prepared by a method comprising granulating while polymerizing a ring-opening polymerizable monomer with a catalyst under the presence of a surfactant and a colorant in a compressible fluid.

The invention relates to a preparation method of tert-alkynol polyether, and belongs to the field of fine chemical engineering. The preparation method comprises following steps: (1) adding a catalystand tert-alkynol into a reactor, carrying out degassing for 1 hour at a certain temperature under a certain pressure, controlling the reaction temperature and reaction pressure, slowly and evenly adding part of olefin oxide into the reactor within a certain period, and after addition, maintaining the temperature until the pressure becomes stable; and (2) keeping on adding olefin oxide at a certaintemperature until the reactions are finished, maintaining the temperature until the pressure becomes stable, cooling to remove a little of unreacted olefin oxide, adding an acid to carry out neutralization, and discharging obtained tert-alkynol polyether. The invention provides a preparation method of tert-alkynol polyether, which has the advantages of light color, high unsaturation degree, narrow distribution, low residual raw materials, and low PEG/PPG content.

The invention relates to an initiation system for preparation of high reaction activity polyisobutylene and application. The initiation system consists of SnCl4, water and an organic compound containing oxygen, nitrogen and/or sulphur. The initiation system is added into an isobutene-containing polymerization raw material to induce cationic polymerization. The polymerization temperature is controlled at -60-30DEG C, and the polymerization reaction is stable and easy to control. Optimally, the terminal group alpha-double bond content can reach 98%. And according to needs, the initiation system can be used to prepare high reaction activity polyisobutylene with a number average molecular weight of 500-5000, a molecular weight distribution index up to 1.3 and an alpha-double bond content greater than 80%mol, a low molecular weight and narrow molecular weight distribution, and high reaction activity polyisobutylene with a number average molecular weight of 8000-15000, a molecular weight distribution index up to 1.6, an alpha-double bond content over 80%mol, a medium molecular weight and narrow molecular weight distribution.

The invention provides a method for preparing cardanol polyoxyethylene ether. The method comprises the following steps of, in a pressure-resistant reactor, enabling raw materials cardanol and ethyleneoxide, under the action of an alkoxide catalyst, in heating and pressurizing conditions, to complete a polymerization reaction within 2h to 4h; afterwards, cooling reaction materials, and neutralizing by using lactic acid, so that the cardanol polyoxyethylene ether is prepared. As alkoxide is used as the catalyst to replace a conventional inorganic strong base (such as NaOH and KOH) and the lactic acid is used as a neutralizer to replace usually used acetic acid, the polymerization reaction is enabled to be stable and controllable; an obtained product is light in color and luster, narrower inmolecular weight distribution and good in rheological characteristic, and therefore, has favorable application performance. The method provided by the invention is high in adaptability to the raw materials. A commercially available unsaturated cardanol raw material can be directly used. According to application demand, the molecular number of the ethylene oxide needing to be added can be adjusted, and thus, the hydrophile-lipophile balance (an HLB value) of the product is regulated, so as to prepare functional products of an emulsifier, a wetting and dispersing agent, a washing agent, a leveling agent and the like, which are applicable to corresponding fields.