19results about How to "Improve copolymerization performance" patented technology

The invention relates to a microbial preparation for regulating oral flora and application of the microbial preparation. A bacterial strain in the microbial preparation for regulating the oral flora consists of a lactobacillus reuteri LR108 bacterial strain and a lactobacillus plantarum LP194 bacterial strain, and the bacterial strain in the microbial preparation for regulating the oral flora consists of a lactobacillus reuteri LR108 bacterial strain and a lactobacillus plantarum LP194 bacterial strain. The microbial preparation can regulate oral flora, has good copolymerization ability and inhibition effect on porphyromonas gingivalis bred in the oral cavity, reduces colonization of the porphyromonas gingivalis in the oral cavity, and reduces inflammatory factors, thereby promoting oral health. Wherein the LR108 strain and the LP194 strain have excellent self-agglutination and hydrophobicity, and have a positive effect on adhesion with intestinal tracts.

The invention discloses a catalyst, a preparation method and application of the catalyst in preparation of polyethylene and chlorinated polyethylene. The catalyst carrier is synthesized under a low-temperature mild condition, the catalyst has high polymerization activity, strong hydrogen regulation sensitivity and good copolymerization performance, and the ethylene polymer with narrow particle size distribution of polymerization powder, high bulk density and excellent fluidity is obtained.

In the invention, rigid anthracene is introduced as a framework of bridged binuclear metal, the quinoline amino binuclear metal titanium zirconium hafnium catalyst is constructed, and the molecular weight of the obtained polymer can be effectively improved through the synergistic effect between the binuclear metal and the steric hindrance and electronic effect on the catalyst structure; a polyolefin elastomer (POE) and an ultra-high molecular weight random propylene (UHMWaPP) elastomer are efficiently synthesized. The quinoline amino binuclear metal titanium zirconium hafnium catalyst has the advantages of simple synthesis, easily available raw materials and high product yield. In copolymerization of ethylene and alpha-olefin, the catalyst shows excellent activity (6.25 * 10 < 7 > g (POE). Mol <-1 > (M). H <-1 >) and alpha-olefin selectivity (the insertion rate reaches 29.2 mol%), and a high-molecular-weight polyolefin elastomer (POE) (the polymer molecular weight Mw reaches 925 kg.mol <-1 >) is prepared. In propylene polymerization, the regularity of the polypropylene chain segment can be effectively regulated and controlled by adjusting the steric hindrance and the electronic effect of the catalyst, and the atactic polypropylene elastomer with the ultra-high molecular weight (the molecular weight reaches 3250 kg.mol <-1 >) is prepared with the high activity (6.6 * 10 < 7 > g (PP). Mol <-1 > (M). H <-1 >). In addition, the quinoline amino binuclear metal titanium zirconium hafnium catalyst also shows excellent high temperature resistance (higher than 160 DEG C), is suitable for high-temperature solution polymerization, and can be used for preparing high-performance polyolefin elastomers. Therefore, the invention has original innovation, and provides a new direction for the development of the field of polyolefin materials.

The present invention relates to the field of olefin copolymerization, and discloses an ethylene-cycloolefin copolymer and a preparation method thereof, the method comprises the following steps: ethylene and cycloolefin are subjected to a copolymerization reaction by using a catalyst composition, and the catalyst composition comprises the following components: a) a metallocene compound having a structure represented by a formula (1); b) a cocatalyst component, in the formula (1), M is a tetravalent transition metal atom; x1 and X2 are respectively and independently a halogen atom, an alkyl group with a carbon atom number of 1-10, an aryl group with a carbon atom number of 6-12 or an N, N-dialkyl amino group with a carbon atom number of 2-8. The method provided by the invention has the advantages of high catalytic activity, good copolymerization performance and high molecular weight of the obtained copolymer, and the catalyst is easy to synthesize and low in synthesis cost. # imgabs0 #

The present invention provides a modified polyolefin resin that can form a coating that exhibits excellent adhesion to a low-polarity base material, especially a poorly adherable polyolefin base material with no surface treatment even when being dried at low temperatures and has flexibility (bendability). Provided is a modified polyolefin resin that is a modified product of a polyolefin resin having a melting point (Tm) by a differential scanning calorimeter (DSC) of 60 to 165°C with a modifier comprising the following (A): (A) a monomer mixture comprising Monomer Group (A-1) and Monomer Group (A-2) with a weight ratio of Monomer Group (A-1) to Monomer Group (A-2) ((A-1) / (A-2)) of 30 / 70 to 50 / 50.

The present application relates to the field of olefin polymerization catalyst, in particular to a kind of main catalyst for olefin polymerization and its preparation method, olefin polymerization catalyst and olefin polymerization catalyst system, the method for olefin polymerization and polyolefin, the main catalyst for olefin polymerization includes magnesium-containing composite carrier and organic titanium compound, inorganic titanium compound, electron donor A and electron donor B loaded on magnesium-containing composite carrier;Magnesium-containing composite carrier contains magnesium-containing component A and magnesium-containing component B;Wherein, in the main catalyst, organic titanium compound, electron donor A and magnesium-containing component A form chemical bond;Inorganic titanium compound, electron donor B and magnesium-containing component B form chemical bond;The main catalyst for olefin polymerization in the present application contains titanium active center of multiple components, combines organic titanium compound and inorganic titanium compound, and can exhibit different hydrogen regulation performance and copolymerization performance.

The present invention proposes a restricted configuration metallocene compound and a preparation method and application thereof, belonging to the technical field of polyolefin catalysts. The restricted configuration metallocene compound has a structure as shown in the following formula: #imgabs0# or #imgabs1# wherein R1, R2 are independently selected from hydrogen, methyl, ethyl, C3-C6 alkyl or aromatic group; R3 is independently selected from methyl, ethyl, C3-C6 alkyl, aromatic group or adamantyl group; R4-R7 are independently selected from hydrogen or methyl group; M is independently selected from titanium or zirconium. The CGC catalyst of the above-mentioned novel structure is mainly used for olefin polymerization and copolymerization. By adjusting the substituent, a functional group with weak coordination and steric effect is introduced on the bridge, which is convenient for controlling the spatial effect and electronic effect of the metal center, improving the stability of the catalyst and the insertion rate of α-olefins, and then better regulating the distribution of polymer molecular weight and copolymerization performance, improving the metallocene copolymerization ability and polymerization reaction temperature, and having important significance for producing high molecular weight copolymerized olefins.

The present invention relates to a method for preparing a Ziegler-Natta catalyst for polymerization of a low density copolymer, and specifically, to a method for preparing a Ziegler-Natta catalyst comprising preparing a magnesium support by reacting an alkyl aluminum compound in the presence of a branched alkyl alcohol or cycloalkyl alcohol solvent. Since the Ziegler-Natta catalyst prepared by the method for preparing the Ziegler-Natta catalyst according to one embodiment has excellent catalytic activity, a low-density copolymer which can have various physical properties and excellent copolymerization performance can be efficiently produced.

The present invention belongs to the technical field of polymer compounds, and specifically relates to a tetrahydroquinoline-amine metal catalyst and its preparation method and application. Under a nitrogen atmosphere, a metal salt is dissolved in an anhydrous solvent, and a methylmagnesium bromide solution is added for reaction; a tetrahydroquinoline-imine ligand is then added for light-avoiding reaction, and the reaction is continued after the light-avoiding reaction is completed, the solvent is removed under reduced pressure, a good solvent is added for extraction, and a tetrahydroquinoline-amine metal catalyst is obtained by filtration. The present invention has the advantages of simple synthesis, easy availability of raw materials, high activity, excellent high temperature resistance, and high product yield.

The invention relates to a preparation method of a Ziegler-Natta catalyst for polymerization of linear low density polyethylene (LLDPE). A method of preparing a Ziegler-Natta catalyst for polymerization of linear low density polyethylene according to one embodiment includes preparing a magnesium chloride support containing a magnesium chloride alcoholate obtained by mixing an excess amount of an alcohol with magnesium chloride. In the method for preparing a Ziegler-Natta catalyst according to one embodiment, the catalyst composition can be easily controlled, so that linear low density polyethylene having various physical properties and excellent copolymerization performance can be efficiently produced.

The invention relates to the technical field of acrylic resin modification, in particular to a preparation method of modified acrylic resin. The invention provides a preparation method of modified acrylic resin, which comprises the following steps: mixing an emulsifier, a modifier, a cross-linking agent, a polymeric monomer and a first initiator, and carrying out first copolymerization reaction to obtain a first copolymer; and mixing the first copolymer with a second initiator, and carrying out a second copolymerization reaction to obtain the modified acrylic resin. The cross-linking agent (AAEM) is added into a reaction system, so that the emulsifying effect of the emulsifying agent is improved, and the copolymerization effect among monomers is enhanced. In addition, according to the preparation method, after the first copolymerization reaction, the initiator is added again, and the second copolymerization reaction is added, so that the copolymerization effect and yield of the product are further enhanced.

This invention relates to the field of olefin polymerization and discloses an ethylene-enol copolymer and its preparation method. The preparation method of the ethylene-enol copolymer provided by this invention includes: using a catalyst composition to copolymerize ethylene and an enol, wherein the catalyst composition includes a) a monometallic compound and b) a cocatalyst component. According to the preparation method of the ethylene-enol copolymer of this invention, it exhibits excellent copolymerization catalytic activity and good copolymerization performance even at high temperatures, and has a high comonomer content, resulting in a high molecular weight ethylene-enol copolymer.

The invention relates to the technical field of preparation of functional regenerated polyester, and provides a preparation method of copolymerized flame-retardant regenerated polyester chips and fibers suitable for a regenerated polyester system, which comprises the following steps: by taking high-purity rBHET recovered by a chemical method as a raw material, introducing a reaction type organic phosphine flame retardant; reaction materials and reaction conditions in a temperature rise stage and a polycondensation stage of a polymerization process are regulated and controlled, a flame-retardant esterification liquid preparation process is not needed, flame-retardant regenerated polyester chips are prepared through direct copolymerization, and the flame-retardant regenerated polyester fibers are prepared through further melt spinning. The preparation process of the flame-retardant regenerated polyester chip is optimized, the thermal decomposition risk of the flame retardant in the preparation process is reduced, meanwhile, the hue, viscosity, flame retardance, processing stability and other properties of the flame-retardant regenerated polyester product are greatly improved, and the preparation method is suitable for industrial production of the flame-retardant regenerated polyester fiber.

The present invention belongs to the field of polymer material synthesis, and relates to an epoxy resin modified water-based acrylic resin dispersion and a preparation method. The epoxy resin modified water-based acrylic resin dispersion comprises the following raw materials: epoxy resin, diol, hydrophilic monomer, methacrylate glycidyl ether, tertiary amine catalyst, vinyl soft monomer, vinyl hard monomer, functional monomer, vinyl organosiloxane, solvent, initiator, neutralizer, chain transfer agent and deionized water. The water-based acrylic resin dispersion and its downstream product water-based acrylic industrial coating prepared by using the above monomers as raw materials and semi-continuous seed free radical polymerization process have the characteristics of good optical properties, fast drying speed, excellent water resistance and salt spray resistance, high hardness, etc. The product is green and environmentally friendly, with moderate cost, in line with the development trend of the industry, and has broad application prospects in the fields of electronic devices, optoelectronic materials, nano-composite materials, etc.

The invention belongs to the technical field of polymer materials and chromatographic separation, and discloses an efficient chiral separation chromatographic column and a preparation method thereof. The preparation method comprises the following steps: dissolving cyclodextrin or a derivative thereof in an alkaline aqueous solution, then adding allyl epoxy terminated polyether, heating to 30-80 DEG C, stirring for etherification reaction, separating and purifying a product to obtain an allyl polyether substituted cyclodextrin compound, then mixing the allyl polyether substituted cyclodextrin compound with an acrylate monomer, a cross-linking monomer, a pore-forming solvent and an initiator, and carrying out a polymerization reaction to obtain the polymer. The method comprises the following steps: adding a pore-forming solvent into a chromatographic column, ultrasonically dissolving, degassing, filling into the chromatographic column, heating in a water bath to 40-80 DEG C, carrying out polymerization reaction, and washing to remove unreacted monomers and the pore-forming solvent after the reaction is completed, thereby obtaining the high-efficiency chiral separation chromatographic column. The whole chromatographic column solid-phase filler is prepared by copolymerization of the allyl polyether substituted cyclodextrin compound and free radicals of the acrylate monomer and the crosslinking monomer, the preparation method is simple and controllable, and the obtained chromatographic column has the advantage of high separation efficiency.

The invention discloses a preparation method of a supported metallocene catalyst for ethylene polymerization. The preparation method comprises the following steps: carrying out thermal activation treatment on a silica gel carrier; modifying the thermally activated silica gel carrier by using alkyl tin chloride to obtain an alkyl tin chloride / silica gel carrier; modifying the alkyl tin chloride / silica gel carrier by using methylaluminoxane to obtain an alkyl tin chloride / methylaluminoxane / silica gel carrier; and then loading a metallocene compound to obtain the loaded metallocene catalyst. Alkyl tin chloride is used for modifying a silica gel carrier, the compound can react with hydroxyl, and a large amount of hydroxyl is eliminated; and the metallocene can be combined with MAO, so that certain space barrier exists between the MAO and the surface of the silica gel, the crowding effect is weakened, the loading capacity is improved, and metallocene combination sites are increased.

The invention relates to the field of polymers, and discloses an ethylene propylene diene monomer and a preparation method and application thereof, the content of a third monomer of the ethylene propylene diene monomer is greater than or equal to 7.9 wt%, and the third monomer is non-conjugated diene. The ethylene propylene diene monomer provided by the invention is relatively high in content of a third monomer, and the content of the third monomer can be up to 12.9 wt%.

This invention discloses a metallocene catalyst, its preparation method, and its application, belonging to the field of polyolefin catalyst technology. The catalyst consists of a coarse-porous silica support modified with norbornene / perfluoroalkyl dual-modification, a methylaluminoxane co-catalyst, and a diphenylmethylene(cyclopentadienyl)(2,7-di-tert-butylfluorenyl)zirconia dichloride metallocene compound. The silica support is chemically modified with norbornene triethoxysilane to introduce a norbornene functional group containing strained double bonds; then, through an olefin cross-metathesis reaction, perfluoroolefins are grafted onto the norbornene double bonds to form a "silica-norbornene-perfluoroalkyl" composite structure. This composite structure not only provides stronger physical confinement and chemical shielding effects, but its rigid norbornene bridging structure can also effectively suppress the structural collapse of mesoporous channels under high-temperature polymerization conditions, significantly improving the catalyst's activity lifetime and kinetic stability in the high-temperature environment of gas-phase polymerization.

The invention relates to the field of olefin polymerization, and discloses a metallocene compound, a catalyst composition using the metallocene compound, an olefin polymerization method using the catalyst composition, and an application of the metallocene compound or the catalyst composition in olefin polymerization. The metallocene compound has a structure as shown in a formula (1), and in the formula (1), M is a tetravalent transition metal atom; x1 and X2 are respectively and independently a halogen atom, an alkyl group with a carbon atom number of 1-10, an aryl group with a carbon atom number of 6-12 or an N, N-dialkyl amino group with a carbon atom number of 2-8. The catalyst composition provided by the invention has the advantages of high catalytic activity, good copolymerization performance and high molecular weight of the obtained polymer. # imgabs0 #