630 results about "Macromonomer" patented technology

The invention discloses a preparation method of an ester polycarboxylic acid water reducer, and belongs to the technical field of concrete admixtures. The preparation method of the ester polycarboxylic acid water reducing agent comprises the following steps: under an alkaline condition, carrying out free radical polymerization reaction on a polyether macromonomer and an unsaturated carboxylic acid monomer under the action of a chain transfer agent A, a chain transfer agent B and an initiator, continuously adding a catalyst, and carrying out dehydration esterification reaction under the action of the catalyst, so as to prepare the ester polycarboxylic acid water reducing agent, the polyether macromonomer is monohydroxy polyether of which the molecular weight is between 500 and 5000; the chain transfer agent A is one of acetone, isopropanol, sodium hydrogen sulfite, sodium hypophosphite, sodium formate and the like; the chain transfer agent B is one of mercaptoethanol, mercaptopropanol, mercaptoacetic acid, mercaptopropionic acid and the like; the catalyst is a phosphonic acid compound with hydroxyl or amino. The preparation method is simple in process and low in energy consumption, and the prepared ester polycarboxylic acid water reducer product is excellent in performance.

The invention discloses a novel modified starch-based polycarboxylate superplasticizer and a preparation method thereof, and belongs to the technical field of concrete admixtures. The preparation process comprises the following steps: (1) performing acidolysis treatment on starch to obtain acidolysis starch; (2) modifying the acidolysis starch and a double-bond modifier under the action of auxiliaries such as a polymerization inhibitor to prepare novel double-bond-containing modified starch (AS); (3) mixing AS and a polyether macromonomer in water to form a base solution; (4) dropwise adding an acrylic monomer and a chain transfer agent into the base solution, and carrying out a copolymerization reaction through an initiation system; and (5) insulating and neutralizing to obtain a finished product. In order to solve the problems of non-renewable petroleum-based raw materials, high production cost and the like of the traditional polycarboxylate superplasticizer (PCA), active double bonds are introduced into modified starch by a solvent-free semi-dry process to replace part of polyether macromonomers, so that the polymerization activity and grafting ratio of the modified starch are effectively improved, the water-reducing dispersion effect of the modified starch is enhanced, and the water-reducing property of the modified starch is improved. The water reducer has the advantages of low mixing amount, high water reduction and the like, and has economic and environmental benefits.

The invention relates to a preparation method of composite porous carbon beneficial to silicon deposition and a silicon-carbon composite negative electrode. The method comprises the following steps: (P1) carrying out surface oxidation treatment on porous carbon fine powder to obtain oxidized porous carbon fine powder; (P2) adding the oxidized porous carbon fine powder and ether polycarboxylic acid silanol into a solvent to obtain ether polycarboxylic acid silanol modified porous carbon fine powder; the ether polycarboxylic acid silanol is prepared by copolymerizing a polyether macromonomer, an acrylic monomer and an alkenyl silane coupling agent in water; (P3) soaking the ether polycarboxylic acid silanol modified porous carbon fine powder in a salt aqueous solution to obtain catalyst-loaded porous carbon; (P4) mixing the porous carbon loaded with the catalyst with a carbon source precursor solution, and performing spray drying to obtain a composite carbon precursor; and (P5) carbonizing and activating the composite carbon precursor to obtain the composite porous carbon beneficial to silicon deposition. The composite porous carbon prepared by the invention is beneficial to more uniform deposition of silicon in pores of the core porous carbon fine powder.

Light Adjustable Lenses (LALs) are described that suppress unintended optical power drift. These LALs comprise a polymer silicone network, infused with a mobile macromer, a non-switchable ultraviolet absorber, a photoinitiator, and a front protection layer, including a switchable ultraviolet absorber. The LAL is light adjustable by a shaped illumination activating the photoinitiator which induces a polymerization of the mobile macromer, thereby changing an optical power of the LAL. The LAL can accommodate an 0.5 - 20 ppm oxygen concentration; and a ratio of the oxygen concentration times an oxygen-driven photoinitiator quench rate over a mobile macromer concentration times a photoinitiator-driven polymerization add rate is greater than 10. Some of these LALs include a non-switchable ultraviolet absorber in the front protection layer; or a radical scavenger; or a monofunctional, or sterically hindered mobile macromer; or a switchable photoinitiator, or an anchored photoinitiator.

Light Adjustable Lenses (LALs) are described that suppress unintended optical power drift. These LALs comprise a polymer silicone network, infused with a mobile macromer, a non-switchable ultraviolet absorber, a photoinitiator, and a front protection layer, including a switchable ultraviolet absorber. The LAL is light adjustable by a shaped illumination activating the photoinitiator which induces a polymerization of the mobile macromer, thereby changing an optical power of the LAL. The LAL can accommodate an 0.5-20 ppm oxygen concentration; and a ratio of the oxygen concentration times an oxygen-driven photoinitiator quench rate over a mobile macromer concentration times a photoinitiator-driven polymerization add rate is greater than 10. Some of these LALs include a non-switchable ultraviolet absorber in the front protection layer; or a radical scavenger; or a monofunctional, or sterically hindered mobile macromer; or a switchable photoinitiator, or an anchored photoinitiator.

The invention relates to the field of concrete admixtures, and particularly discloses an air-entraining type polycarboxylic acid water reducer and a preparation method thereof. The air-entraining type polycarboxylate superplasticizer is prepared from the following raw materials in parts by weight: 320 to 380 parts of unsaturated polyether macromonomer, 10 to 30 parts of air-entraining type functional monomer, 26 to 50 parts of unsaturated carboxylic acid or unsaturated carboxylic acid derivative, 1 to 4 parts of oxidizing agent, 0.5 to 2 parts of reducing agent, 0.6 to 2.8 parts of chain transfer agent, 18 to 30 parts of neutralizing agent and 500 to 600 parts of water, the preparation method of the air-entraining type functional monomer comprises the following steps: crushing maleated rosin, mixing the crushed maleated rosin with 48% liquid caustic soda, heating to 100-125 DEG C, carrying out heat preservation reaction for 1-2 hours, and adding water for dilution after the reaction is finished. According to the polycarboxylate superplasticizer, the air-entraining type functional monomer is added, so that the dispersity of the superplasticizer is not influenced, the polycarboxylate superplasticizer has relatively low air-entraining property, and the polycarboxylate superplasticizer has the advantages of improving the workability of concrete and increasing the freezing resistance and durability of the concrete at the same time.

The invention relates to the technical field of concrete admixtures, in particular to a high-performance polycarboxylate superplasticizer and a preparation method thereof. The high-performance polycarboxylate superplasticizer comprises the following components: a polycarboxylate superplasticizer and modified cellulose ether, the polycarboxylate superplasticizer is prepared by polymerization reaction of vinyl polyether macromonomer, unsaturated carboxylic acid and functional monomer under the action of initiator and chain transfer agent. According to the high-performance polycarboxylic acid water reducing agent provided by the invention, the polycarboxylic acid water reducing agent and the modified cellulose ether are compounded and applied to concrete, the initial fluidity of the concrete is good, the slump retaining property is good, the water-retaining property, the wrapping property and the cohesiveness of the concrete are good, and the segregation and bleeding phenomena are avoided when the concrete is mixed with the high-performance polycarboxylic acid water reducing agent.

The invention discloses a viscosity-reducing fast-dispersing polycarboxylate superplasticizer for high-strength concrete and a preparation method thereof, and relates to the technical field of polycarboxylate superplasticizers. The viscosity-reducing fast-dispersing polycarboxylic acid water reducer for the high-strength concrete comprises the following components in parts by weight: 400 parts of unsaturated polyether macromonomer, 20-40 parts of unsaturated acid monomer and 10-20 parts of unsaturated functional monomer. The invention also provides a preparation method of the polycarboxylate superplasticizer. The water reducer can reduce the viscosity of high-strength concrete, improve the dispersing performance of the concrete and shorten the mixing time, so that the problems of high plastic viscosity and the like of the concrete are solved under the condition of not reducing other performances such as the strength of the concrete.

The invention discloses a C6 monomer polycarboxylate superplasticizer and a preparation method thereof. The C6 monomer polycarboxylate superplasticizer is prepared from the following raw materials in parts by mass: 300-380 parts of C6 ethylene glycol monovinyl polyglycol ether polyether macromonomer, 7.5-11.0 parts of acrylic acid, 0.3-1 part of chain transfer agent, 0.15-1.0 part of reducing agent and 0.6-1.2 parts of oxidizing agent. The water reducing agent prepared by the invention has the advantages of simple process, energy conservation, environmental protection, shortened synthesis time, improved production efficiency, high adaptability and better water reducing property.

The invention discloses a side-chain type amphiphilic organosiloxane macromonomer and a preparation method and application thereof, the side-chain type amphiphilic organosiloxane macromonomer can be well mixed with various hydrophilic monomers under the condition of no hydrotropy of a solvent, and a silicon hydrogel material with high oxygen permeability and high hydrophilicity can be prepared. The invention also discloses a silicon hydrogel which is prepared from the side chain type amphiphilic organosiloxane macromonomer and the following components through polymerization reaction: 5-45 parts of side chain type organosiloxane macromonomer, 0-30 parts of micromolecular silicon monomer, 25-70 parts of hydrophilic monomer, an initiator and a cross-linking agent. The silicon hydrogel has good hydrophilic performance, high light transmittance and high oxygen permeability. Meanwhile, the invention further discloses a corneal contact lens which is made of the silicone hydrogel material and has the advantages of being good in oxygen permeability, hydrophilicity, light transmission, wearing comfort and the like.

The invention belongs to the technical field of concrete, and particularly relates to a polycarboxylate superplasticizer and a preparation method thereof. The polycarboxylate superplasticizer is prepared from an unsaturated polyether macromonomer, an unsaturated acid monomer, an unsaturated carbonate monomer, an unsaturated amino monomer, an initiator, a reducing agent, a chain transfer agent, deionized water, a solubilizer and organic alcohol amine. Wherein the unsaturated carbonate monomer is allyl methyl carbonate, and the unsaturated amino monomer is 2-aminoethyl methacrylate hydrochloride. According to the invention, excellent water reducing effect and stable control capability on concrete slump are maintained, and micro-cracks can be effectively made up through a dual mechanism formed by carbonate release and CaCO3 precipitation in the early and later stages of concrete hardening.

Light Adjustable Lenses (LALs) are described that suppress unintended optical power drift. These LALs comprise a polymer silicone network, infused with a mobile macromer, a non-switchable ultraviolet absorber, a photoinitiator, and a front protection layer, including a switchable ultraviolet absorber. The LAL is light adjustable by a shaped illumination activating the photoinitiator which induces a polymerization of the mobile macromer, thereby changing an optical power of the LAL. The LAL can accommodate an 0.5 - 20 ppm oxygen concentration; and a ratio of the oxygen concentration times an oxygen-driven photoinitiator quench rate over a mobile macromer concentration times a photoinitiator-driven polymerization add rate is greater than 10. Some of these LALs include a non-switchable ultraviolet absorber in the front protection layer; or a radical scavenger; or a monofunctional, or sterically hindered mobile macromer; or a switchable photoinitiator, or an anchored photoinitiator.

The invention relates to the technical field of concrete admixtures in building materials, in particular to a viscosity reduction type polycarboxylic acid water reducer suitable for high-strength concrete and a preparation method of the viscosity reduction type polycarboxylic acid water reducer. The hydrophobic modified unsaturated double-chain polyether macromonomer is prepared from the following components in parts by mass: 20 to 30 parts of unsaturated acid, 200 to 300 parts of hydrophobic modified unsaturated double-chain polyether macromonomer, 10 to 15 parts of phosphate monomer, 2 to 4 parts of oxidizing agent, 1 to 2 parts of reducing agent, 1 to 2 parts of chain transfer agent, 5 to 10 parts of neutralizing agent and 120 to 180 parts of water. According to the invention, the polyether chain can unfold in a pore solution, the steric hindrance effect is further enhanced, cement particles are ensured to be effectively dispersed in a compact space, and meanwhile, the hydrophobic part of the side chain can effectively reduce the surface tension of the pore solution, so that the condition of overhigh viscosity is avoided, and the flowability and constructability of the concrete are improved.

Light Adjustable Lenses (LALs) are described that suppress unintended optical power drift. These LALs comprise a polymer silicone network, infused with a mobile macromer, a non-switchable ultraviolet absorber, a photoinitiator, and a front protection layer, including a switchable ultraviolet absorber. The LAL is light adjustable by a shaped illumination activating the photoinitiator which induces a polymerization of the mobile macromer, thereby changing an optical power of the LAL. The LAL can accommodate an 0.5-20 ppm oxygen concentration; and a ratio of the oxygen concentration times an oxygen-driven photoinitiator quench rate over a mobile macromer concentration times a photoinitiator-driven polymerization add rate is greater than 10. Some of these LALs include a non-switchable ultraviolet absorber in the front protection layer; or a radical scavenger; or a monofunctional, or sterically hindered mobile macromer; or a switchable photoinitiator, or an anchored photoinitiator.

The invention relates to the technical field of polycarboxylate superplasticizers, and discloses a durability-enhanced polycarboxylate superplasticizer and a preparation method thereof.The preparation method comprises the following steps that raw materials such as a polyether macromonomer are prepared, the polyether macromonomer and the like have the requirements for purity and dosage, deionized water and the polyether macromonomer are added into a reaction kettle to form a solution A, and the solution A is prepared; and preparing an initiator solution B with the mass concentration of 10-20% from ammonium persulfate, heating to 60-80 DEG C, stirring, firstly adding 1 / 3 of the initiator solution B to react, then preparing a mixed monomer solution from acrylic acid and the like, dropwise adding the mixed monomer solution and the residual initiator solution B within 2-3 hours, carrying out heat preservation reaction, cooling, and regulating the pH value to 6-8 by using sodium hydroxide to obtain a finished product. The sulfonic acid group of the introduced sodium methallyl sulfonate functional monomer can enhance the electrostatic repulsion between water reducer molecules and cement particles, so that the dispersing performance of the water reducer is improved, the agglomeration of the cement particles can be inhibited to a certain extent, and the fluidity of concrete can be maintained.

The invention relates to the field of oil exploitation, in particular to temperature-resistant and salt-resistant efficient gel as well as a preparation method and application thereof, which are used for solving the problems that the efficiency of the gel is influenced and the oil displacement effect is reduced due to poor high temperature resistance and salt resistance and easiness in failure of the existing polyacrylamide hydrogel. According to the preparation method, through a copolymerization technology, various monomers with excellent temperature resistance and salt resistance, such as acrylamide, methacryloyloxyethyl trimethyl ammonium chloride, 2-acrylamido-2-methylpropanesulfonic acid, a temperature-resistant monomer and a hydrophobic macromonomer, are integrated, so that the gel can bear a relatively high temperature without degradation or performance reduction; the prepared oil displacement gel has good stability in a high-salinity environment, does not lose an oil displacement effect due to the existence of salt, ensures the activity and stability of the gel in a high-temperature and high-salt-content oil reservoir environment, and obviously enhances the oil displacement efficiency of the gel in crude oil exploitation, thereby greatly improving the exploitation efficiency and recovery rate of crude oil.

The invention relates to the technical field of polycarboxylic acid water reducer macromonomers, in particular to preparation and application of a low-air-entraining type TPEG polyether macromonomer, and the low-air-entraining type TPEG polyether macromonomer mainly comprises the following components in parts by mass: 10-20 parts of organopolysiloxane, 1-5 parts of an emulsifier, 2-10 parts of a thickener and 60-80 parts of a solvent. The emulsifier is one or a combination of more of sorbitan monostearate, sodium lauryl sulfate, polyoxyethylene ether, polyvinyl alcohol and sorbitan monooleate; the thickening agent is one or a combination of several of carboxymethyl cellulose, sodium polyacrylate, tragacanth, sodium starch phosphate, hydroxypropyl methyl cellulose and sodium alginate; wherein the solvent is water, and the low-air-entraining type TPEG polyether macromonomer disclosed by the invention has the following beneficial effects that the low-air-entraining type TPEG polyether macromonomer researched by the invention is small in adding amount of a defoaming agent, stable, efficient, high in economic benefit, easy to meter and simple and convenient to operate; redundant large bubbles in the concrete can be eliminated, proper small bubbles are reserved, the strength of the concrete is enhanced, and the surface of the concrete is more attractive.

A method for preparing monodisperse nanoscale calcium fluoride, comprising the following steps: (S1) dispersing calcium long-chain alkylbenzenesulfonate and an acrylate copolymer in a mixed solution of water, n-hexane, and an alcohol to form a stable emulsion A, wherein monomers of the acrylate copolymer comprise (meth)acrylic acid, a polyether macromonomer, and a C1-4 alkyl (meth)acrylate; (S2) dissolving a fluoride salt in water, adding polyvinyl alcohol, and uniformly mixing these materials to obtain a solution B; and (S3) slowly dropwise adding the solution B to the emulsion A under stirring and ultrasonic conditions, and carrying out standing for aging, centrifugal separation, washing, and drying to obtain monodisperse nanoscale calcium fluoride. By using the calcium long-chain alkylbenzenesulfonate with surface activity as a calcium source in combination with homemade acrylate as a dispersing agent, an emulsion is formed in a specific combined solvent, and by dropwise adding a fluorine salt aqueous solution to the emulsion under an ultrasonic condition, nanoscale calcium fluoride with a uniform and controllable particle size can be prepared under the action of a microemulsion.

The invention provides a copolymer oil-displacing agent containing a modified polyether amine macromonomer and a preparation method thereof, and belongs to the field of oilfield chemistry, the preparation method comprises the following steps: adding p-chlorobenzaldehyde and polyether monoamine which are equimolar into ethanol, stirring at room temperature, and carrying out Schiff base reaction to obtain an intermediate product solution; adding N-(3-dimethylaminopropyl) methacrylamide of which the mole is equal to that of p-chlorobenzaldehyde into the intermediate product solution, carrying out quaternization reaction, and carrying out rotary evaporation on ethanol to remove the ethanol, so as to obtain a modified polyether amine macromonomer; and polymerizing the modified polyether amine macromonomer and acrylamide, and crushing, hydrolyzing and drying a polymerization product to obtain the hydrophobic modified polyacrylamide containing the polyether amine structural unit. The oil-displacing agent has good temperature resistance and salt resistance, and can be used for preparing a polymer solution by taking seawater as a solvent.

The present invention relates to a biodegradable polymer composition formed by waterborne radical emulsion polymerization of monomers selected from ethylenically unsaturated monomers characterized in that, the polymer composition is composed of at least two different populations of particles, said populations differing in average particle size value by at least a factor of 1.5, wherein (a) a population P1 is constituted by particles having an average particle size of greater than 250 nanometers, said particles being constituted of polymer chains predominantly built of ethylenically unsaturated monomers, further comprising 0.5 to 50% by C weight of oligomer lactide 2-hydroxyethyl, methacrylate terminated macromonomer, based on the total weight of the monomers, and (b) a population P2, distinctive of P1 by average particle size value, is constituted by particles having an average particle size of less than or equal to 250 nanometers, said particles being constituted of polymer chains predominantly built of ethylenically unsaturated monomers, further comprising 0.5 to 50% by weight of oligomer lactide 2-hydroxyethyl, methacrylate terminated macromonomer, based on the total weight of the monomers, wherein said two different populations jointly constitute at least 70% by weight, preferably 90% by weight, of the total polymeric content within said composition.

The invention relates to the technical field of concrete admixtures, in particular to an air-entraining type polycarboxylate superplasticizer and a preparation method thereof. The air-entraining type polycarboxylate superplasticizer is formed by polymerizing a polyether macromonomer, a modified active agent and first unsaturated acid through a free radical polymerization reaction, the preparation method comprises the following steps: carrying out condensation reaction on a surfactant, a condensing agent and second unsaturated acid at 60-80 DEG C for 2-3 hours, and removing water in the condensation reaction to obtain the modified active agent. According to the air-entraining type polycarboxylate superplasticizer prepared by the invention, the modified active agent is introduced into the molecules of the air-entraining type polycarboxylate superplasticizer, the adsorption capacity of the polycarboxylate superplasticizer and cement and the specific surface tension of a hydration film are adjusted by utilizing different HLB (Hydrophile-Lipophile Balance) values of the modified active agent, and meanwhile, the flowability of concrete and the air content of the concrete are improved; therefore, the concrete slump rewinding emptying time is shortened, and the concrete compressive strength is kept at a certain good level.

The invention belongs to the field of additives, and provides a polycarboxylate superplasticizer as well as a preparation method and application thereof. The preparation method of the polycarboxylic acid water reducer comprises the following steps: in the presence of water, an initiator and a chain transfer agent, comonomers including a polyether macromonomer, unsaturated carboxylic acid, unsaturated amide and a functional monomer are subjected to a polymerization reaction to form polycarboxylic acid, and the functional monomer is an esterification product of rhamnolipid and unsaturated alcohol. The polycarboxylate superplasticizer provided by the invention has improved workability while maintaining a relatively high water-reducing rate.

The invention belongs to the technical field of additives, and particularly relates to a low-sensitivity air-entraining type polycarboxylate superplasticizer and a preparation method thereof. The low-sensitivity air-entraining type polycarboxylate superplasticizer is prepared from the following components in parts by weight: 60 to 90 parts of polyacrylic acid, 0.5 to 1.5 parts of stabilizer, 60 to 90 parts of maleated rosin modified polyether macromonomer, 12 to 20 parts of air-entraining monomer, 270 to 320 parts of solvent and 0.5 to 0.8 part of sodium hydroxide. The maleated rosin modified polyether macromonomer comprises the following components in parts by weight: 40-50 parts of ethylene glycol monovinyl polyethylene glycol ether, 10-20 parts of an intermediate and 100-200 parts of absolute ethyl alcohol, the intermediate 1 comprises the following components in parts by weight: 10-20 parts of maleated rosin, 5-10 parts of epoxy chloropropane, 50-70 parts of an organic solvent and 0.1-0.5 part of a catalyst. According to the invention, a hydrophobic cyclic structure of rosin and a hydrophilic group of fatty alcohol-polyoxyethylene ether are introduced, so that the air entraining and foam stabilizing capabilities of the water reducing agent are optimized, meanwhile, the dispersity and compatibility in cement paste are improved through a structural complementary design, and the working performance and durability of the water reducing agent are remarkably improved.

The present invention relates to the technical field of concrete admixtures, and particularly relates to a hydroxyl-terminated polyether macromonomer and a preparation method therefor, and a low-temperature rapid-dispersion-type ether polycarboxylic acid superplasticizer and a preparation method therefor. The ether polycarboxylic acid superplasticizer is formed by copolymerizing the hydroxyl-terminated polyether macromonomer, acrylic acid and a functional monomer C by means of a copolymerization reaction. The ether polycarboxylic acid superplasticizer, which is prepared by using the specific hydroxyl-terminated polyether macromonomer in the present invention, has a significantly improved adsorption rate and early-stage adsorption capacity on the surfaces of cement particles; in addition, the adsorption capacity of the superplasticizer in the later stage can be kept at a relatively high level, the cement paste dispersion time of cement using the superplasticizer is short, and the requirements of the superplasticizer are less while satisfying the same initial cement paste fluidity requirement; and the superplasticizer has a high dispersion speed, good dispersion performance, and good slump-retaining performance at low temperatures.

The invention relates to the technical field of concrete admixtures, in particular to a polycarboxylate superplasticizer and a preparation method thereof. Through molecular structure design, glycidyl ether compounds and unsaturated acid are subjected to ring-opening addition, and unsaturated functional monomers with unsaturated functional groups such as carbon-carbon double bonds, carboxyl and ester groups are obtained; condensing the unsaturated functional monomer with ethylene oxide and epoxypropane to obtain a glycidyl ether macromonomer; and carrying out copolymerization on the glycidyl ether macromonomer and free radicals such as polyether and unsaturated acid to obtain the required polycarboxylate superplasticizer. Under the synergistic effect of various groups, the polycarboxylate superplasticizer disclosed by the invention has the characteristics of high water-reducing rate and good adaptability, and the workability of concrete can be remarkably improved.

The invention provides an ester-ether copolymerization type slump-retaining polycarboxylic acid water reducer and a preparation method of the ester-ether copolymerization type slump-retaining polycarboxylic acid water reducer. The water reducing agent is prepared from the following raw materials in parts by weight: 80 to 120 parts of main chain macromonomer, 20 to 35 parts of unsaturated carboxylic acid, 1.5 to 3.2 parts of initiator, 0.2 to 0.5 part of reducing agent, 0.3 to 0.8 part of chain transfer agent, 8 to 15 parts of neutralizer, 200 to 300 parts of solvent, 5 to 10 parts of diphosphonic polyether monomer, 3 to 6 parts of temperature-sensitive dynamic crosslinking monomer and 2 to 5 parts of amide-ether bond grafting monomer. The water reducer has the comprehensive performance of dispersion, slump loss resistance, mud resistance, high-temperature response and the like.

The invention relates to the technical field of admixtures for cement concrete, in particular to a polycarboxylic acid admixture for enhancing low-activity admixtures and a preparation method thereof, the polycarboxylic acid admixture is formed by polymerizing the following components: polyether macromonomer, unsaturated carboxylic acid I, exciting functional monomer A, slump retaining functional monomer B, rheological functional monomer C, oxidizing agent, reducing agent, chain transfer agent and water; the exciting functional monomer A, the slump retaining functional monomer B and the rheological functional monomer C are sequentially added, and the exciting functional monomer A is formed by polymerizing polyhydric alcohol, unsaturated carboxylic acid II, an initiator, phosphonic acid and an alcohol amine small monomer. Through molecular design, key functional groups such as phosphonic acid groups, amino groups and sulfonic acid groups are innovatively introduced into a polycarboxylic acid main chain, so that the polycarboxylic acid admixture has multiple synergistic functions of reducing the cement consumption, effectively activating a low-activity cementing material, stably improving the working performance of concrete and the like.

The invention provides a polyoxyalkylene ether macromonomer, a preparation method and application of the polyoxyalkylene ether macromonomer in preparation of a polycarboxylate superplasticizer, the polyoxyalkylene ether macromonomer is obtained by performing ring-opening polymerization reaction on an initiator and an alkylene oxide monomer under the action of a deprotonation reagent, and the initiator is allyl mercaptan or methyl and phenyl substituted allyl mercaptan. The polycarboxylate superplasticizer is obtained by free radical copolymerization reaction of an acid monomer and the polyoxyalkylene ether macromonomer under the action of an initiator and a reducing agent. Allyl sulfide is easy to generate uniform cracking of carbon-sulfur bonds in the polymerization process, polyoxyalkylene ether sulfydryl free radicals are generated, chain transfer is achieved, in the chain transfer process of the polyoxyalkylene ether macromonomer, a transferred chain still retains terminal double bonds and can participate in polymerization again, and the polyoxyalkylene ether macromonomer has a good polymerization effect. Therefore, polycarboxylic acid synthesized by using the polyoxyalkylene ether macromonomer has a certain branched topological structure, and cement paste dispersed by the polyoxyalkylene ether macromonomer has better workability.

Mixed metallocene catalyst systems may comprise an activator, a first metallocene having a structure represented by Formula 1, and a second metallocene different from the first metallocene.M is a Group 4 metal, T is a bridging group, X1 and X2 are each a univalent anionic ligand or optionally joined together to define a metallocycle ring or similar, J1 and J2 are each H or J1 and J2 are joined together to form a cyclic or polycyclic ring structure, and R1, R2, and R8 are preferably independently H, optionally substituted C1-C40 alkyl, or optionally substituted C6-C14 aryl. R3 is a bulky alkyl group, such as an optionally substituted cyclohexyl, norbornanyl, adamantyl, or t-butyl, or an optionally substituted aryl group, such as an optionally substituted phenyl group. The second metallocene may have C2 symmetry or pseudo-C2 symmetry. The catalyst systems may afford polyolefins having a high degree of vinyl termination.

The invention provides a retarding type polycarboxylate superplasticizer as well as a preparation method and application thereof, and belongs to the technical field of building material concrete admixtures. The retarding type polycarboxylic acid water reducing agent is prepared from the following raw materials in parts by weight: 300 to 400 parts of polyether macromonomer, 60 to 150 parts of unsaturated carboxylic acid micromonomer, 30 to 60 parts of unsaturated sulfonic acid monomer, 15 to 30 parts of alkylphenol polyoxyethylene ether phosphate, 1.5 to 12 parts of chain transfer agent, 2 to 15 parts of initiator, 15 to 50 parts of caustic soda liquid and 200 to 600 parts of solvent. The polycarboxylic acid water reducing agent product with the retarding characteristic is synthesized through an RAFT method, the binding force between phosphate radicals and calcium ions in a cement pore liquid of the preparation raw material alkylphenol polyoxyethylene ether phosphate is high, hydration of C3A and formation of ettringite are delayed, the retarding effect of the water reducing agent is enhanced, and the polycarboxylic acid water reducing agent has the anion characteristic and the nonionic characteristic and can be used as a water reducing agent. And the workability of the concrete is improved.