50results about How to "Molecular weight regulation" patented technology

The invention discloses a preparation method for a polycarboxylic acid series comb-shaped surface active agent, which comprises the following steps of: mixing two comonomers, an initiator, a chain transfer agent and a solvent under the protection of nitrogen, heating to a reacting temperature for polymerization to obtain an intermediate polymer; adding a graft compound, a catalytic agent and a dissolvant into the intermediate polymer, carrying out graft reaction at graft temperature, decompressing and removing part of solvent in a reaction system after reaction, and then precipitating the product with a precipitator; dissolving filter cakes with the solvent; precipitating the dissolved solution with the precipitator again, dissolving repeatedly, precipitating again and then refining, and finally decompressing and drying the product to the constant weight. The preparation method has the advantages of reasonable technology, simple operation, low preparation cost, mild reacting conditions and good product quality.

A synthetic method of a styrene/maleic anhydride alternating copolymer with low molecular weight belongs to the field of macromolecular precipitation polymerization. Media and chain transfer agents used in the existing methods for preparing styrene/maleic anhydride copolymers by precipitation polymerization have disadvantages. In the synthetic method, the styrene/maleic anhydride alternating copolymer is prepared by taking a mixed solvent of organic acid alkyl ester and alkane as a reaction medium for the precipitation polymerization, alpha-methylstyrene or vinyl acetate as a molecular weight regulator and organic peroxide or an azo compound as an initiator for initiating a copolymerization reaction between styrene monomers and styrene. The synthetic method has simple process, the synthesized copolymer has good properties, and the method has the advantages of being economical, environment-friendly and the like.

The invention discloses a method for preparing a star-like waterborne polyurethane associated-type thickening agent. The method comprises the following steps of: in the presence of an inert gas, adding dehydrated polyethylene glycol to react with isocyanate so as to prepare a prepolymer, performing semi-blocking by using long-chain alkanol, performing chain extension by using a chain extension agent of a polyhydric alcohol structure, and drying after the opeation is completed, thereby obtaining the star-like waterborne polyurethane associated type thickening agent. The star-like waterborne polyurethane associated type thickening agent synthesized by using the method has multiple hydrophobic long chains, is relatively large in molecular weight, can form a relatively complete and stable hydrophobic associated network structure in a water phase or emulsion system, and is relatively good in thickening property and stability. The star-like waterborne polyurethane associated-type thickening agent synthesized by using the method is very good in thickening effect, is capable of effectively increasing the viscosity of an emulsion with a relatively small use amount, and moreover has the characteristics of being high in viscosity under the action of small shearing force and low in construction viscosity under the action of large shearing force.

The invention relates to a high-solid chrome-free acrylic polyurethane finish paint consisting of two components A and B which are mixed together according to a ratio of 100:25. The component A comprises the following components in parts by weight: 50-65 parts of self-made tert-carbonic glycidyl ester modified hydroxylated acrylic resin (with 75 mass percent of solids), 10-20 parts of a color filler, 10-20 parts of a chrome-free anticorrosive pigment, 0.5-1.5 parts of an anti-setting agent BE-828, 0.5-1.5 parts of a dispersant, 0.3-1.0 part of a defoaming agent, 0.5-2.5 parts of an anti-sagging agent, 0.3-0.5 part of a leveling agent and 5-10 parts of a solvent. The component B comprises the following components in parts by weight: 50-70 parts of fat diisocyanate and 30-50 parts of butyl acetate. The high-solid chrome-free acrylic polyurethane finish paint disclosed by the invention has relatively high requirements for overall properties including weather resistance, fullness, salt fog resistance, adhesive force, chemical resistance and the like.

The invention discloses a gas-phase bulk polymerization method of a polyolefin alloy, in particular a polybutene alloy material. The method is characterized by (1) adopting a continuous or batch polymerization process; (2) performing gas phase polymerization of the polybutene alloy material in a single gas phase reactor or two or more gas phase reactors which are connected in series; and (3) respectively implementing homopolymerization of two monomers in two stages. The method adopts a single heterogeneous Ziegler-Natta catalyst which has multiple active centers and good hydrogen sensitivity to catalyze stage-by-stage polymerization of butene-1 and propylene, so that the polybutene alloy material which is less in catalyst residue and good in particle shape, does not have agglomerates and has a core-shell structure can be obtained. The prepared polybutene alloy material comprises the following components in percentage by mass: 10-99% of polybutene-1, 1-80% of polypropylene and 0.01-10% of butene-1-propylene copolymer, and can be used for replacing part of polyethylene and polypropylene in use.

The invention provides a diphenylmethyl-containing asymmetric diimine pyridine complex with nitro-enhanced thermal stability and catalytic activity, and a preparation method and application thereof. The complex has a single catalytic activity center, the molecular weight of a polymer can be regulated and controlled by changing a ligand structure and polymerization conditions, and the complex has the advantages of high catalytic activity, low cost, stable performance and the like. The complex and intermediates thereof have the advantages of mild preparation conditions, short period, simple operation conditions and the like. The asymmetric complex can be applied to a catalyst for ethylene polymerization and has high catalytic activity, and high molecular weight (up to 599.5 kg/mol) linear polyethylene is obtained; especially, the provided iron complex is high in thermal stability, and even at a high temperature of 100 DEG C, the catalytic activity can still be kept at 3.86* 10<6> g*mol<-1>(Fe)*h<-1>. Compared with reported non-nitro substituents (CH3, Cl), the complex has the highest activity and molecular weight. Therefore, the complex can be used at a high environmental temperatureas engineering plastic, and has great industrial application potential.

The invention discloses a class of fluorine-containing alpha-diimine nickel coordination compounds for preparing a polyolefin elastomer, and an intermediate thereof, wherein the coordination compoundhas a single catalytic activity center, the molecular weight of a polymer can be regulated and controlled by changing a ligand structure and polymerization conditions, and the coordination compound has the advantages of high catalytic activity, low cost, stable performance and the like. The invention further provides preparation methods of an asymmetric alpha-diimine nickel coordination compound containing a difluoro group, and an intermediate thereof, wherein the two preparation methods have the advantages of mild reaction conditions, short period, simple operation conditions and the like. The invention also provides uses of a metal nickel coordination compound and a catalyst system thereof, wherein the metal nickel coordination compound is used for catalyzing ethylene polymerization, shows good catalytic activity and obtains a polyethylene elastomer material with narrow molecular weight distribution. The obtained polyethylene elastomer material is high in branching degree, has good tensile strength, elongation at break and elastic resilience, is a thermoplastic elastomer material and has great industrial application potential.

The invention relates to a low-molecular-weight polymer with functionally modified ends and a preparation method thereof. The preparation method comprises a step of subjecting a low-molecular-weight polymerization monomer and a RAFT chain transferring agent to a copolymerization reaction in the presence of an initiator through radical polymerization so as to obtain the low-molecular-weight polymerwith functionally modified ends, wherein the low-molecular-weight polymerization monomer is one or more selected from the group consisting of a betaine type amphiphilic polymer monomer, an acrylamidemonomer, a quaternary ammonium salt type long-carbon-chain association monomer and 2-acrylamide-2-methylpropanesulfonic acid; and two ends of the formed polymer are function groups as described in the specification, and in the function groups, m is in a range of 1-3 and n is in a range of 2-4, so the ends of the polymerization monomers can be connected with each other through the non-covalent interaction, i.e., host-guest clathration. The molecular weight of the polymer is controlled below 1 million Da, and the underground rapid recovery and thickening of a solution after shearing are realized.

The invention provides a class of asymmetric pyridineimine transition metal coordination compounds containing a large steric hindrance substituent, a preparation method and application thereof. According to the invention, the preparation method of the coordination compound is mild in condition, short in period and simple to operate; the coordination compound can be applied to a catalyst for ethylene polymerization, has a single catalytic active center, can regulate and control the molecular weight of a polymer by changing a ligand structure and polymerization conditions, and has the advantagesof low cost, high catalytic activity, good thermal stability and the like; And especially, compared with reported diphenylmethyl, the iron coordination compound provided by the invention has the advantages that the molecular weight of highly linear polyethylene obtained by catalyzing ethylene polymerization is high while high catalytic reaction activity and high thermal stability are maintained,wherein the molecular weight can reach 913.36 kg/mol, so that the coordination compound can be used as engineering plastic at a high environment temperature, is used for synthesizing high-molecular-weight linear polyethylene, and has great industrial application potential.

The invention provides a soluble linear conductive polymer and a preparation method thereof. The preparation method comprises the following steps: S1, taking S-dodecyl-S'-(R, R'-dimethyl-R''-(2-thienyl) ethyl acetate) trithiocarbonate as a chain transfer agent; carrying out a reversible addition-fragmentation chain transfer polymerization reaction on methyl acrylate, 2-(Dimethylamino)ethyl methacrylate and 1, 4-dioxane under the initiation of azodiisobutyronitrile to obtain polymethylacrylic acid N, N-dimethylaminoethyl ester-b-polymethyl acrylate; and S2, adding a 3, 4-ethylenedioxythiophenen-butyl alcohol solution into the polymethylacrylic acid N, N-dimethylaminoethyl ester-b-polymethyl acrylate hydrochloric acid solution, and carrying out interfacial polymerization reaction under theaction of a catalyst to obtain the soluble linear conductive polymer. The soluble linear conductive polymer is synthesized by adopting reversible addition-fragmentation chain transfer polymerization and interfacial polymerization methods, so that the length of a flexible chain segment of the soluble linear conductive polymer is controllable.

The invention provides a method for producing polymalic acid of different molecular weights. The method comprises the following steps: inoculating an aureobasidium pullulans seed solution to a fermentation medium, and fermenting to produce polymalic acid; controlling a content of asparaginic acid in the fermentation medium to be 0.25-0.45g/L; regulating the pH value of the fermentation liquor to 6.0-7.0 in the fermentation process; and producing the polymalic acid of different molecular weights. The fermentation process is regulated, and the polymalic acid of different molecular weights is obtained, so that the polymalic acid is widely and reasonably applied to the fields of foods, medicines, chemical industry and petroleum according to different polymerization degrees of the polymalic acid. Moreover, according to a synergistic effect between the asparaginic acid and the pH value, the fermentation medium is further optimized, and the molecular weight of the produced polymalic acid can be accurately oriented in a narrow range, so that the requirements of people for the polymalic acid with different polymerization degrees are met.

The invention provides a novel symmetrical seven-membered cyclopyridylimine metal complex containing a cycloalkane large-steric-hindrance substituent, a preparation method of the novel symmetrical seven-membered cyclopyridylimine metal complex and application to ethylene polymerization. A novel cycloalkane large-steric-hindrance structure enables the catalytic activity of the alpha,alpha'-dioxo-2,3:5,6-bis(pentamethylene)pyridine metal complex to be up to 10<7> g.mol<-1>.h<-1>, and the properties, especially thermal stability, are better. The catalytic active site of the complex provided is not limited to a single center, but the molecular weight of a polymer can still be regulated by changing the ligand structure and polymerization conditions. The complex provided can be used for catalyzing the ethylene polymerization together with a cocatalyst methylaluminoxane and modified methylaluminoxane to obtain highly linear polyethylene with high molecular weight (M<w> up to 272.0 kg.mol<-1>), and the shortcoming of low-molecular-weight polyethylene obtained by a previous catalyst is greatly overcome; and meanwhile, the linear polyethylene of different fine structures can be realized by regulating the temperature, and therefore, great industrial application value is achieved.

The invention discloses a polybutylene thermoplastic elastomer and a preparation method thereof. The polybutylene thermoplastic elastomer comprises: 10%-50% by mass of isotactic polybutylene, 45%-89.9% by mass of a block copolymerized elastomer, and 0.1%-5% by mass of atactic polybutene. The block copolymerized elastomer is a copolymer of butene and high-grade aliphatic alpha-olefin of 5-10 carbon atoms or aromatic olefin of 8-12 carbon atoms, and is a high isotactic polybutylene long block composed copolymer. According to the preparation method of the polybutylene thermoplastic elastomer, first a two-stage polymerization method is employed, butene firstly undergoes homopolymerization under the action of a loaded titanium catalyst, then butene and a comonomer copolymerize so as to obtain the polybutylene thermoplastic elastomer; and second, a multi-stage sequential polymerization method is employed, butene firstly undergoes homopolymerization under the action of the loaded titanium catalyst, then butene and the comonomer copolymerize, and homopolymerization and copolymerization are carried out in multiple cycles so as to obtain the polybutylene thermoplastic elastomer finally.