33results about How to "Molecular weight distribution index is small" patented technology

The invention relates to high-solid hydroxyl fluorine-containing acrylic resin and a preparation method thereof. The high-solid hydroxyl fluorine-containing acrylic resin comprises the following components in parts by weight: 10-25 parts of fluorine-containing acrylic ester monomer, 10-30 parts of hydroxyl group-containing acrylic ester monomer, 5-20 parts of methyl acrylic alkyl ester monomer, 5-15 parts of acrylic alkyl ester monomer, 0.3-6 parts of initiator, 0.2-4 parts of chain transfer and 30-50 parts of solvent. According to the hydroxyl fluorine-containing acrylic resin, the solid content reaches up to 75-90 percent, the viscosity is only 900-3,000 mPa.s, the number-average molecular weight is 1,200-6,000, and the molecular weight distribution index is 1.4-2.5; and the resin has the advantages of superior performance, high transparency, no odor of mercaptan, low VOC (Volatile Organic Compound) content, a fluorine carbon group included on a polymer chain and superior corrosion resistance of the resin and can be applied to the fields such as heavy anticorrosive coatings, marine antifouling coatings, aircraft surface coatings, anti-doodling coatings, exterior wall coatings of high weathering resistance and the like.

The invention relates to a monodisperse nano-polymer carrier with biological compatibility and a method for preparation and carrying drug thereof. Firstly, a reversible addition fragmentation chain transfer (RAFT) polymerization method is used for preparing amphiphilic block copolymers with smaller polydispersity index, wherein the hydrophilic segment is methylacryoyloxyethyl phosphorylcholine (MPC) and the hydrophobic segment is n-butyl methacrylate (BMA). Then through the method of solvent evaporation, the amphiphilic block copolymers are used for preparing nano-polymer micelle, drugs are encapsulated in the micelle through physical action, thus obtaining the monodisperse nano-polymer carrier system with good biological compatibility.

The invention discloses a preparation method of an acrylonitrile copolymer spinning solution with low molecular weight distribution. According to the invention, in a solution polymerization process between acrylonitrile monomers and comonomers, the weight-average molecular weight and number-average molecular weight of a copolymer are regulated in a continuous or intermittent cooling manner so as to reduce the molecular weight distribution index of the copolymer. Compared with other methods, the preparation method is simple and feasible and is stronger in process operability, the molecular weight distribution index of an acrylonitrile copolymer obtained according to the method can be controlled to be 2.3-2.8, and an acrylonitrile copolymer solution can be used as a high-performance polyacrylonitrile-based carbon fiber spinning solution after residual monomers and air bubbles are removed.

The invention discloses modified (methyl) acrylate resin. The resin contains a (methyl) acrylate chain link, an unsaturated double bond and carboxylic group, an unsaturated double bond and epoxy group and an organic silicon group containing double bonds. The modified (methyl) acrylate resin can be solidified through various methods, has the characteristics of high hardness, high toughness, no adhesion, strong adhering force, good wear resistance and the like, and can be applied to fields such as coating, ink and adhesive. The invention further relates to a preparation method of the material.

The invention relates to an imitated nylon differential fiber of dyeable polypropylene fiber for dyeing, which comprises: 80 to 90 percent of polypropylene, 9 to 11 percent of dyeable master batch, 0.3 to 0.7 percent of cooling auxiliary agent and 4.0 to 5.0 percent of polyethylene. The fiber has the advantages that: firstly, the polypropylene fiber has the flexibility, tensile property and elasticity as nylon through modifying the polypropylene fiber; and secondly, the dyeability of the modified polypropylene fiber is realized.

The invention discloses a preparation method of an acrylonitrile copolymer spinning solution with low molecular weight distribution. According to the preparation method, in a solution polymerization process of an acrylonitrile monomer and a comonomer, the acrylonitrile monomer is supplemented once or multiple times within certain reaction time to adjust a weight-average molecular weight and a number-average molecular weight of a copolymer so as to reduce a molecular weight distribution index of the copolymer. Compared with other methods, the preparation method is simple and easy to implement in process; the molecular weight distribution index of the acrylonitrile copolymer prepared by using the method can be controlled between 2.5 and 3.0; and after residual monomers and bubbles of an acrylonitrile copolymer solution are removed, the acrylonitrile copolymer solution can be used as a spinning solution of high-performance polyacrylonitrile-based carbon fibers.

A fractionators narrowing polyester polyol molecular weight distribution is disclosed. A wastewater collection tank (7) is installed adjacent to a polyester reaction vessel (2), also a reflux pipe is connected between the upper end of the polyester reaction vessel (2) and the lower end of a dephlegmator (4), the reflux-pipe segment is provided with a U-shaped pipe (5), the communication bottom end of the U-shaped pipe (5) is connected with the wastewater collection tank (7), and the bottom of a condenser is connected with the wastewater collection tank (7); the dephlegmator (4) is connected with the condenser (6), the polyester reaction vessel (2) is connected with the dephlegmator (4), a return valve is arranged at the pipeline connecting the U-shaped pipe (5) with the polyester reaction vessel (2). The product quality is improved, alcohol removal labor hour is saved, the processing time of 6 KL of the raw material is shortened within 1 h from original 3-5 h, micromolecule alcohols are rapidly efficiently removed, polyester polyol molecular weight distribution is properly narrowed, and the molecular weight distribution index is relatively small. The cobalt-platinum colour is relatively low, and the acid value is relatively low and is within 0.1 mg KOH/g.

The invention relates to a catalyst composition for preparing LLDPE by cascade catalysis, a catalytic polymerization system for preparing LLDPE by cascade catalysis comprising the catalyst composition, a method for preparing LLDPE by using the polymerization system, and LLDPE prepared by the method. The catalyst combination comprises a first catalyst, a second catalyst and a cocatalyst, wherein the first catalyst is a pyrrolophosphine metal complex represented by a formula I, the second catalyst is an arylamino ether metal complex represented by a formula II, and the cocatalyst is selected from at least one of alkylaluminoxane, alkylaluminium or modified alkylaluminoxane. The LLDPE prepared by using the catalyst composition is relatively high in molecular weight, narrow in molecular weightdistribution and excellent in performance.

The invention belongs to the technical field of organic synthesis, and particularly discloses a method for synthesizing polylactic acid by adopting a large-channel continuous flow microreactor, and the method comprises the following steps of: dissolving lactide in an organic solvent, then injecting a lactide solution and a non-metal organic catalyst into the large-channel continuous flow microreactor, and carrying out polymerization reaction to synthesize the polylactic acid. According to the method, the non-metal organic catalyst is combined with the continuous flow microreactor, so that the continuous material ratio, the reaction temperature and the reaction time can be precisely controlled, the reaction realizes rapid mixing and mass transfer, and the obtained product is good in reproducibility, stable in quality, high in monomer conversion rate, high in polymerization degree and low in molecular weight distribution index, and can be controlled to meet the high requirement of 1.1-1.3, the yellow index is low, expanded production in industrial reaction is facilitated, and the problems of high synthesis reaction temperature, many side reactions, long residence time, low production efficiency and the like of polylactic acid in the prior art can be effectively solved.