424 results about "Chain transfer" patented technology

Disclosed in the present invention is a composition for preparing a vinyl block copolymer, the composition comprising: a first monomer ethylene, a second monomer a C3-C20 α-olefin and at least one regulation monomer, the regulation monomer being an olefin or a substituted olefin with the C atom number greater than 3, or styrene / a styrene derivative, and in the same composition, the second monomer being different from the regulation monomer. The composition is catalyzed by a main catalyst and a co-catalyst to obtain the vinyl block copolymer, wherein the main catalyst is a complex L-MR1R2R3 that contains three substituents and that is formed by an IVB-group metal and a monoanionic ligand, and the co-catalyst includes alkyl aluminum, polymerized or oligomerized aluminoxane, a neutral Lewis acid, a non-polymer, a non-coordinated ionic compound, or a mixture of two or more described above. Provided in the present invention is a composition capable of obtaining a lower-olefin block copolymer, the composition can obtain a lower-olefin block copolymer without the need of replenishing monomers or adding a chain transfer reagent for polymerization during polymerization processes, so that a production process is simple and involves low cost.

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 discloses an ethylene-vinyl acetate copolymer, an ethylene-vinyl alcohol copolymer and a preparation method thereof, and belongs to the field of polymers. Comprising the following steps: putting a mixture containing an initiator, a chain transfer agent, a solvent and vinyl acetate into a closed container, introducing ethylene gas, and carrying out pressurized polymerization to obtain the ethylene-vinyl acetate copolymer, the initiator is selected from at least one of lauroyl peroxide, benzoyl peroxide, azodiisobutyronitrile and azobisisoheptonitrile; the chain transfer agent is selected from the group consisting of 2-dimethylaminoethyl acetate and / or 2-dimethylaminoethyl propionate. The preparation method of the low-branching-degree EVA has the characteristics of mild conditions, strong controllability, simplicity in operation and large-scale application prospect. The invention also provides an ethylene-vinyl alcohol copolymer prepared from the prepared EVA through alcoholysis reaction, and the ethylene-vinyl alcohol copolymer has the characteristics of high molecular weight, narrow distribution, good appearance and the like, and meets the application requirements of commercial EVOH.

The invention provides a preparation method and application of novel acrylic continuous pre-polymerized resin. The preparation method comprises the following steps: preheating an MMA solution containing azodiisobutyronitrile to 50-60 DEG C, and enabling the preheated MMA solution to flow into the microreactor main body; the pure MMA is preheated to 90-95 DEG C and then flows into the microreactor main body; and mixing the inflowing materials, controlling the reaction temperature to be 120-130 DEG C, the pressure to be 0.2-0.3 MPa and the retention time to be 5-15 minutes, and carrying out continuous polymerization reaction to prepare the PMMA prepolymer resin. According to the technology, accurate regulation and control of the molecular weight and distribution of the PMMA / MMA prepolymer are realized through a continuous process under high temperature and high pressure, and the goal can be achieved without depending on a chain transfer agent. The method is safe and controllable, the product of the method is perfectly compatible with a solid plane material curing system of'an initiator first and then an accelerant ', and the energy consumption and the safety risk are effectively reduced while the production efficiency and the productivity are remarkably improved.

The application relates to the technical field of C09D5 / 03, in particular to a high-transmittance acrylic powder resin and a preparation method thereof, raw materials for preparing the acrylic powder resin by weight percentage at least include: 80-100 parts of soft monomers, 400-600 parts of hard monomers, 0-10 parts of carboxyl functional monomers, 200-400 parts of ester functional monomers, 20-100 parts of hydroxyl functional monomers, 10-30 parts of initiators, 5-20 parts of chain transfer agents, 800-1200 parts of solvents and 1-10 parts of nano additives; the nano additives are added, and the synthesis process of the acrylic resin is optimized, so that the prepared acrylic powder resin has high transmittance and good weather resistance, and can meet the actual use requirements in the fields of automobile hubs and photovoltaics.

A composition for printing a three-dimensional siloxane structure includes a siloxane monomer having at least one silane functional group, a chain transfer agent, a hydrosilylation catalyst, a radical initiator, and a photo-oxidizing agent.

The invention belongs to the field of special adhesives, and discloses an all-polymer super-water-resistant UV pressure-sensitive adhesive capable of being rapidly cured and a formed pressure-sensitive adhesive tape. The pressure-sensitive adhesive is prepared by polymerizing a free radical thermal initiator, a chain transfer agent, an inert organic solvent and 100 parts by mass of (methyl) acrylate at 75-85 DEG C, heating, and carrying out reduced pressure distillation to remove the solvent. The pressure-sensitive adhesive is coated on a PET (polyethylene terephthalate) or BOPP (biaxially-oriented polypropylene) film base material in a hot melting manner or a solution manner, and is irradiated by ultraviolet light to obtain the formed pressure-sensitive adhesive tape. The prepared pressure-sensitive adhesive can be rapidly cured, and the cured pressure-sensitive adhesive tape also has relatively high peel strength, high holding power and stability, has no adhesive residue, and has a wide application prospect in humid and water environments.

The present invention proposes a method and use for stabilizing a simple agglomerate for pH and salt and with adjustable size. In phosphoric acid buffer solutions with different salt concentrations and pH values, the polyacrylic acid hydroxypropyl group condensation body has specific stability; hydrophobic thermal response blocks are introduced into a hydroxypropyl acrylate monomer through reversible addition-fragmentation chain transfer polymerization to regulate and control the size of a condensation body, and a phase separation behavior is shown at different temperatures; a hydrophobic block without thermal response is introduced to regulate and control the size of the aggregate, and no thermal response behavior is shown. Continuous regulation and control of the size of the aggregate from the micron level to the nano level are achieved, and the requirements of different application scenes are met. The hydroxypropyl polyacrylate condensation body can be used for packaging various dyes and drugs; high-efficiency enzyme protection is achieved, formed aggregates can protect glucose oxidase, and the retention rate of enzyme activity reaches 85% or above after treatment is conducted for 3 hours at 60 DEG C; as a micro-reactor for the reaction of generating p-nitrobenzaldehyde phenylhydrazone from p-nitrobenzaldehyde and phenylhydrazine, the reaction rate is greatly improved.

The present application provides a narrow molecular weight distribution PVP copolymer, and a preparation method therefor and a use thereof. The PVP copolymer has the structure represented by formula I. In the present application, NVP monomer and allyl polyoxyethylene ether are subjected to a copolymerization reaction in a redox system, and a sulfonating agent is then added to the resulting copolymer reaction solution to perform sulfonation treatment of the terminal hydroxyl groups, thereby obtaining the PVP copolymer. The present application utilizes the chain transfer effect of allyl polyether to achieve effective control of the molecular weight distribution of the PVP copolymer, and performs strongly polar ionized end-group treatment to improve the segment uniformity of the PVP copolymer. The spatial steric hindrance of the polyether side chains and the charge repulsion of the ionic groups significantly improve the adequacy of chain extension of PVP in the casting solution, so as to increase the exchange rate of the casting solvent and precipitant, and obtain a membrane pore structure with uniform pore size, high porosity, and stable structure.

The present application relates to the technical field of concrete admixtures, in particular to a shrinkage-reducing admixture for concrete, a preparation method and application thereof.The preparation process of the present application overcomes the problems of poor alkali resistance of traditional admixtures and easy cracking of solidified concrete.The present application comprises the following steps: preparing a reducing initiator, a chain transfer agent, an unsaturated acid monomer, a shrinkage-reducing functional monomer and an amide functional monomer solution by step-by-step preparation, controlling the polymerization conditions under nitrogen protection, and obtaining a water reducing agent; using alkyl glycoside as a starter, step-by-step polymerizing propylene oxide and ethylene oxide to obtain a low-foaming polyether; mixing the water reducing agent and the low-foaming polyether with an alkali-resistant additive to obtain a shrinkage-reducing admixture; and significantly improving the water-reducing rate, flow retention and compressive strength of concrete, optimizing the setting time, reducing the dry shrinkage rate and the influence of alkali erosion, and improving the compactness and durability of concrete through hydrogen bond network, low surface tension and alkali resistance protection.The viscosity of the concrete admixture is moderate, which is suitable for concrete application, and the process is stable and easy to industrialize.

The application belongs to the technical field of chemical synthesis, and particularly relates to a preparation method of diisopropyl peroxydicarbonate and application of the diisopropyl peroxydicarbonate. The preparation method comprises the following steps: firstly, isopropyl chloroformate and an ester-soluble organic solution are added into a three-necked flask, stirring is started, hydrogen peroxide solution is added, when the temperature of the mixture in the flask is stabilized at-5 DEG C, sodium hydroxide solution is slowly added into the three-necked flask, and the time and temperature in the reaction process are controlled; finally, the organic phase is separated, washed with water, dried with anhydrous sodium sulfate, and obtained. The preparation method is safe and controllable, the yield of the diisopropyl peroxydicarbonate is high, the stability is good, the diisopropyl peroxydicarbonate can be directly used for the preparation of polyvinylidene fluoride, a chain transfer agent is not needed, polymerization can be carried out under low-temperature conditions, the molecular chain regularity of the polyvinylidene fluoride is improved, abnormal structures are few, the crystallinity is high, and the comprehensive performance is good.

The application discloses a preparation method and application of a composite catalyst for preparing carbon dioxide-based polycarbonate polyols, and belongs to the technical field of catalysts. The composite catalyst is prepared by compounding a double metal cyanide catalyst and a zinc gallate catalyst in a certain proportion. In the presence of a chain transfer agent, the two kinds of catalysts produce a synergistic effect in a polymerization process: the double metal cyanide catalyst serves as a main active center, initiates and promotes chain growth; and the zinc gallate catalyst serves as a selective regulation center, promotes carbon dioxide insertion and inhibits side reactions, so that the catalysts have high activity and high selectivity. The polycarbonate polyols prepared by using the composite catalyst have high carbon dioxide insertion rates and low number average molecular weights. Moreover, the composite catalyst has simple preparation process, is wide in raw material and low in cost, and is suitable for industrialized scale preparation.

This invention belongs to the field of battery materials technology, specifically relating to a liquid silicone rubber-type block copolymer binder, its preparation, and its application. The binder is composed of a topological block copolymer consisting of soft and hard segments, with a number-average molecular weight of 20,000–80,000 g / mol and a molecular weight distribution index (PDI) < 1.5. It contains 30%–60% functionalized polydimethylsiloxane segments as soft segments and 40%–70% acrylic acid-amide functionalized olefin units as hard segments. During preparation, a macromolecular RAFT chain transfer agent is used to control the monomers for controlled active radical copolymerization. This invention utilizes a spontaneously induced nanoscale microphase separation structure due to the thermodynamic incompatibility of the soft and hard phases. While providing high adhesion strength, this binder can efficiently dissipate the severe volume expansion stress of the silicon-based anode through dynamic bond dissociation, preventing the active material from pulverizing and detaching, and providing long-term stability of the SEI film, significantly improving the long cycle life and safety performance of high-capacity batteries.

The invention relates to the technical field of block copolymer materials, in particular to a preparation method of a polystyrene-vinylpyridine block copolymer composite membrane. The preparation method comprises the following steps: firstly, preparing a polyvinyl pyridine macromolecular chain transfer agent, then preparing a polystyrene-polyvinyl pyridine block copolymer, dissolving the synthesized polystyrene-polyvinyl pyridine block copolymer, spin-coating the surface of a microfiltration membrane with the dissolved polystyrene-polyvinyl pyridine block copolymer, and adjusting membrane-forming and pore-forming parameters, so that the block copolymer forms a continuous and uniform membrane layer on the surface of a base membrane; meanwhile, the interface is tightly combined with the base membrane. According to the method, high monomer conversion rate and narrow molecular weight distribution are achieved under the synergistic effect of the chain transfer agent and the free radical initiator, the polymerization activity is maintained by supplementing the initiator in different stages, and the polymerization efficiency is effectively improved.

The invention relates to a preparation method of a hyperbranched polymer containing phthalic dicarboxaldehyde, which comprises the following steps: dissolving a chain transfer agent, a monomer ADP containing a phthalic dicarboxaldehyde protecting group, dimethylacrylamide and azodiisobutyronitrile in tetrahydrofuran, and reacting for 8-24 hours at 70 DEG C in an inert atmosphere; cooling to normal temperature, adding trifluoroacetic acid, and continuously reacting for 1-3 hours; and stopping the reaction and precipitating, and then drying in vacuum to obtain the hyperbranched polymer containing o-phthalaldehyde. The hyperbranched polymer prepared by the invention can be efficiently cross-linked and fixed with sclera collagen, and is used for intervention treatment of myopia progress.

The invention belongs to the technical field of concrete, and discloses an anti-mud viscosity reduction type polycarboxylic acid water reducer as well as a preparation method and application thereof. The anti-mud viscosity reduction type polycarboxylic acid water reducer is prepared from the following raw materials in parts by weight: 150 to 300 parts of polyether monomer, 25 to 50 parts of unsaturated monomer, 5 to 15 parts of functional monomer, 3 to 8 parts of temperature-sensitive monomer, 0.8 to 1.5 parts of chain transfer agent, 0.5 to 5 parts of oxidant and 0.1 to 0.5 part of reducing agent. The functional monomer is a zwitterionic hybrid monomer with a boric acid group and a betaine group. According to the invention, the zwitterionic hybrid monomer with a boric acid group and a betaine group is added into the water reducing agent as a functional monomer, and N-isopropylacrylamide is added as a temperature-sensitive monomer, so that the mud resistance and viscosity reduction performance of the water reducing agent are realized.

The invention relates to the technical field of concrete admixtures, and particularly discloses a rapid dispersing type polycarboxylate superplasticizer and a preparation method thereof.The rapid dispersing type polycarboxylate superplasticizer is prepared from, by mass, 200-300 parts of polyether monomer, 1.5-3.5 parts of oxidizing agent, 0.2-0.5 part of reducing agent, 1.2-3 parts of chain transfer agent, 25-33 parts of unsaturated acid, 10-20 parts of self-made functional monomer modified alkyl glycoside, 5-10 parts of aconitic acid and 250-300 parts of tap water. The preparation method comprises the following steps: dissolving, preparing a solution A, preparing a solution B and synthesizing to prepare the quick dispersing type polycarboxylic acid water reducing agent. By introducing alkyl glycoside, wetting of cement particles is promoted, water-cement interfacial tension is rapidly reduced, meanwhile, cement particle aggregation is hindered through stereoisomerization of alkyl glycoside, the effect of rapid dispersion of cement particles is achieved, and modified alkyl glycoside provides adsorption points and electrostatic repulsion of cement particles to hinder cement particle aggregation, so that the cement particles are dispersed rapidly. The cement particles can be quickly dispersed in a low-temperature environment.

This invention discloses a low-cost, salt-resistant chemical viscosity reducer for cold oil recovery, relating to the field of oilfield production technology. The chemical viscosity reducer comprises a block copolymer and silica. The block copolymer is obtained by integrating monomer A containing sulfobetaine groups and monomer B containing tertiary amine groups onto a polystyrene backbone via a reversible addition-fragmentation chain transfer polymerization reaction. The chemical viscosity reducer prepared by this invention simplifies the composition of multi-component viscosity reducers, reduces costs, and also exhibits excellent salt resistance, meeting the needs of cold viscosity reduction in heavy oil recovery in high-salt reservoirs.

The invention discloses a preparation method of nitrile rubber, which comprises the following steps: (1) adding water, a vinyl nitrile monomer and an ionizable initiator into a polymerization kettle, stirring, heating, and cooling after the reaction is finished to obtain a reaction compound with an emulsification effect; (2) in the polymerization reaction, adding water, a cosolvent and the reaction compound obtained in the step (1), introducing nitrogen for replacement, then adding a deoxidant, a chain transfer agent with a surface activity function, conjugated diene and a vinyl nitrile monomer, heating, adding an ionizable initiator, and measuring the conversion rate of the reaction monomer in each period of time; and when the conversion rate is greater than 70%, adding a terminator and an anti-aging agent, stirring, degassing, adding a coagulant, flushing and drying to obtain the nitrile rubber. According to the preparation method, soap-free polymerization of nitrile rubber can be realized, the complexity of a post-treatment process is reduced, the environmental friendliness and economic benefits are improved, and the problem that the cleanliness of a product is difficult to improve is solved.

This invention provides a highly thermally stable, photoresponsive α-diimine nickel complex, its synthesis method, and its applications, aiming to develop novel olefin polymerization catalysts with both excellent thermal stability and photoresponsive properties. The core photoresponsive switch of this type of nickel complex is a rigid diphenylethylene derivative, which can achieve reversible photoisomerization of the E / Z configuration under 365 nm and 405 nm ultraviolet light irradiation: the E configuration has a relatively open coordination environment; after light irradiation, the Z configuration has a more compact spatial structure, which can form a dual regulatory mechanism: steric hindrance and potential metal-aryl π interactions. Due to this dual regulatory mechanism, the complex exhibits excellent thermal stability at 150 °C. o Even at high temperatures, it still maintains a high value of 0.8 × 10⁻⁶. 6 g·mol ‑1 ·h ‑1 The nickel complex of this invention exhibits enhanced catalytic activity and effectively inhibits chain transfer and chain walking reactions during high-temperature polymerization. By synergistically enhancing thermal stability through configurational tautomerism, and possessing both photoresponsive properties and high catalytic activity, it holds significant research value and broad application prospects in the precise synthesis of functionalized polyolefin materials.

This invention relates to the field of concrete admixtures, specifically to an anti-mud polycarboxylate superplasticizer, its preparation method, and its application. The anti-mud polycarboxylate superplasticizer provided by this invention comprises, by weight, the following raw materials: 100-180 parts of unsaturated polyether monomer, 5-10 parts of unsaturated carboxylic acid monomer, 2-5 parts of air-entraining monomer, 5-10 parts of anti-mud monomer, 10-20 parts of oxidant, 0.4-0.6 parts of reducing agent, 5-7 parts of chain transfer agent, and 150-300 parts of water; the air-entraining monomer and the anti-mud monomer have specific structures. The simultaneous introduction of specific anti-mud monomers and air-entraining monomers into the anti-mud polycarboxylate superplasticizer of this invention not only reduces clay adsorption but also provides better dispersibility and anti-mud effect at lower dosages, increasing the overall workability of concrete and improving concrete performance.

This invention relates to the field of catalyst synthesis technology, and more particularly to an alkoxytitanium non-metallocene catalyst for preparing polyethylene wax and its preparation method. The alkoxytitanium catalyst prepared by this invention can directly carry out ethylene polymerization. The polymerization process is simple, requires only a small amount of alkyl aluminum halides for impurity removal, and exhibits high catalytic activity. It requires no additional organoboron compounds or methylchlorooxyalkane, nor does it require chain transfer agents to adjust molecular weight. It has a novel structure, outstanding catalytic activity, and a simple synthesis process with diverse ligand designs. By designing different types of ligands, the molecular weight and activity of the polymer can be effectively improved, achieving precise control over catalyst activity and selectivity, thereby obtaining olefin polymers with specific structures and properties. This characteristic provides broad prospects for the preparation of polymer materials with specific properties and applications.

The purpose of the disclosure is to provide a resin composition for molding, said resin composition exhibiting good compatibility with polyolefins and containing an ultraviolet absorbing polymer that is able to be purified at a low cost, and said resin composition being capable of forming a molded body that exhibits good transparency. A resin composition for molding containing a thermoplastic resin and an ultraviolet absorbing polymer, wherein: the ultraviolet absorbing polymer has a monomer unit represented by general formula (1), a monomer unit represented by general formula (2) and a thiol-based chain transfer agent residue; and the thiol-based chain transfer agent that forms the thiol-based chain transfer agent residue has a thiol group and one or more moieties that are selected from the group consisting of a carboxyl group, a hydroxyl group and an ester bond.

The invention belongs to the technical field of water-based curing agents in the textile industry, and provides a water-based closed isocyanate curing agent, a preparation method thereof and application of the water-based closed isocyanate curing agent in fabric waterproof finishing. The preparation method comprises the following steps: mixing polyisocyanate, hydroxyl acrylate and a solvent, carrying out a polymerization reaction, adding a sealing agent into the obtained polymerization reaction system, and carrying out an end-capping reaction to obtain blocked isocyanate; the preparation method comprises the following steps: mixing blocked isocyanate, long-chain alkyl acrylate, a POSS (polyhedral oligomeric silsesquioxane) hydrophobic modifier, a chain transfer agent, an initiator and a solvent, and carrying out free radical addition reaction to obtain hydrophobic modified blocked isocyanate; and mixing the hydrophobic modified blocked isocyanate, an emulsifier, a pH regulator, water and a cosolvent, and carrying out high-pressure homogenization to obtain the water-based blocked isocyanate curing agent. The water-based closed isocyanate curing agent disclosed by the invention has waterproof synergism, and is compounded with a fluoride-free waterproof agent, so that the waterproofness and washability of the fluoride-free waterproof agent can be improved.

The application discloses a hydrophilic PVDF emulsion polymerization method, polyvinylidene fluoride prepared by the method and application, and relates to the technical field of lithium battery materials.The hydrophilic PVDF emulsion polymerization method comprises the following steps: S1, water and an emulsifier are added into a reaction device, vacuum is drawn, and inert gas is filled into the reaction device space until the oxygen content is less than or equal to 26 ppm; S2, vinylidene fluoride, an initiator and a chain transfer agent are added, and a polymerization reaction occurs at a temperature of 70-95 DEG C and a pressure of 3.5-5 MPa, wherein the chain transfer agent is a carboxyl functional group-containing thiocarbonic ester; and S3, the polymerization reaction is stopped, and the emulsion obtained through the polymerization reaction is subjected to coagulation, washing and drying to obtain the hydrophilic PVDF.Compared with traditional PVDF emulsion polymerization, more carboxyl groups can be introduced into the hydrophilic PVDF emulsion polymerization method, so that the PVDF product itself has good hydrophilicity.

The invention relates to the technical field of concrete admixtures, and particularly discloses a preparation method of an anti-freezing high-dispersion water reducing agent, which comprises the following steps: S1, preparing a base material: adding an allyl polyoxyethylene ether macromonomer and deionized water into a reaction container to form a macromonomer aqueous solution; then adding a sulfonic acid small monomer and a first part of initiator into the macromonomer aqueous solution; s2, preparation of a material A: dissolving acrylic acid, acrylamide, a hydroxyl-containing acrylate monomer or a hydroxyl-containing methacrylate monomer, a polyethylene glycol acrylate monomer or a polyethylene glycol methacrylate monomer and urea in deionized water to prepare the material A; s3, preparation of a material B: dissolving a chain transfer agent, a reducing agent and a second part of initiator in deionized water to prepare the material B; s4, dropwise adding and polymerizing: dropwise adding the material A and the material B into the reaction container at the same time; and S5, post-processing. The scheme is used for solving the problem that high dispersibility and anti-freezing property of concrete in a low-temperature environment cannot be effectively considered in the prior art.

The present application relates to the technical field of insulating base preparation, in particular to an easy crosslinking cable insulating base and a preparation method thereof.The preparation method of the easy crosslinking cable insulating base comprises the following steps: pressurizing ethylene and feeding it into a first-stage tubular reactor, adding end olefins, di-olefins and initiators in front of each stage of the tubular reactor respectively to initiate a reaction, and obtaining a high-pressure polyethylene base, which is the easy crosslinking cable insulating base.The present application increases the content of double bonds and branched chains by adding di-olefins and end olefins, preferably adding di-olefins and end olefins at a certain position, increasing the reaction temperature, reducing the reaction pressure, using a high-temperature initiator instead of a low-temperature initiator and other methods, enhances the chain transfer reaction and copolymerization reaction, increases the content of double bonds and branched chains, and prepares the easy crosslinking cable insulating base.Using the easy crosslinking cable insulating base to produce high-voltage cable insulating material can reduce the amount of crosslinking agents, antioxidants and other additives, and better meet the use requirements of high-voltage cables.

The present disclosure relates to a process for preparing an olefin-acrylate block copolymer, the process comprising: a) performing reversible addition-fragmentation chain-transfer (RAFT) polymerization by combining RAFT materials comprising an acrylate monomer, a radical initiator, and a RAFT agent, thereby forming a macroinitiator; and b) combining reaction materials comprising an alpha-substituted acrylate, a radical initiator, and the macroinitiator, thereby forming the olefin-acrylate block copolymer.

This invention relates to the field of polymer synthesis technology. This invention provides a controlled polymerization method for a high-alternation-degree ETFE copolymer, comprising the following steps: (1) adding a solvent to a high-pressure reactor, replacing the air, and then filling it with an initial monomer mixture to a total pressure of 1.5-2.5 MPa, wherein the monomer mixture is a mixture of tetrafluoroethylene and ethylene; (2) heating to 60-85°C, adding an initiator to initiate the polymerization reaction; (3) simultaneously adding the monomer mixture continuously or semi-continuously during the polymerization reaction; (4) adding a chain transfer agent, and discharging the product after the reaction, i.e., the high-alternation-degree ETFE copolymer. This invention also provides a controlled polymerization method for a high-alternation-degree ETFE copolymer. This invention also provides an application of the high-alternation-degree ETFE copolymer in new energy, aerospace, high-end equipment manufacturing, and photovoltaic fields. The high-alternation-degree ETFE copolymer of this invention has high alternation degree (>92%), high thermal stability, and excellent mechanical properties.

The application discloses a polycarboxylic acid water reducing agent and a preparation method and a fixed bed reaction device and a preparation system thereof. The fixed bed reaction device comprises a first feeding channel, a multi-layer plate structure and a discharging channel arranged in sequence along a specified direction, and the first feeding channel is used for conveying reaction monomers to the multi-layer plate structure; and a plurality of second feeding channels are further arranged and used for conveying reaction aids to the overflow surface of the laminar flow plate, wherein the reaction aids comprise an initiator and a chain transfer agent. The fixed bed reaction device, the system and the preparation method provided by the application avoid the polymerization explosion phenomenon in the preparation reaction process of the polycarboxylic acid water reducing agent by the specific feeding arrangement of the reaction aids, avoid the axial back mixing while retaining the beneficial effect of the radial mass transfer, and thus can improve the preparation efficiency of the polycarboxylic acid water reducing agent, save energy, and maintain the excellent use performance of the polycarboxylic acid water reducing agent.