50results about How to "High number average molecular weight" patented technology

The invention relates to a polymerization method for preparing rare earth isoprene rubber, which adopts at least three reactors which are in series connection to conduct a solution polymerization reaction of an isoprene monomer, wherein a first reactor is an annular tube reactor which adopts isothermal operation, a following reactor is a continuous stirrer tank reactor which adopts heat insulation operation. By means of the method, the cis-form-1,4-configuration content of obtained gathering rare earth isoprene rubber can be high as 98wt%, the number-average molar mass can reach over 0.4 million, and molecular weight distribution coefficient is smaller than 3.

The invention discloses a polyester for 3D printing, and a preparation method thereof. According to the present invention, an aromatic dibasic acid or a dimethyl ester thereof, an aliphatic dibasic acid or a dimethyl ester thereof, and diol are used as monomers and are subjected to a normal pressure esterification reaction in the presence of a nucleation agent, a branching agent, a filler and a catalyst, heating pressure reducing is performed after the esterification reaction is completed, and a condensation polymerization reaction is performed to obtain the copolyester material, wherein the aromatic dibasic acid is an aromatic C6-C10 dibasic acid, the aliphatic dibasic acid is an aliphatic C2-C10 dibasic acid, the diol is a C2-C10 diol, and the branching agent is a polybasic acid or a polyol. According to the present invention, the obtained material has advantages of high elongation at break, large number average molecular weight, low melt index and degradability, and can be used as a3D printing material.

The invention relates to the technical field of organosilicon and provides a preparation method of polycarbosilane in order to solve the problems in polycarbosilane preparation at present. The preparation method is characterized by taking chloromethyl chlorosilane as a raw material, synthesizing a polycarbosilane intermediate in an organic solvent and then preparing the polycarbosilane by using a reducing agent. The preparation method provided by the invention has the advantages that the operation is convenient, and the time is shortened; meanwhile, the number-average molecular weight of the prepared polycarbosilane is higher, and the demands of preparing an organic functional material can be met.

The invention relates to the field of nylon materials, and discloses a method for preparing polyester-nylon composite fibers by melt direct spinning. The method comprises the following steps of 1) burdening, specifically, heating and mixing caprolactam, an end-capping reagent, water and a catalyst to obtain a mixture; 2) ring opening; 3) pre-polycondensation, specifically, carrying out a pre-polycondensation reaction and devolatilization; 4) final polycondensation, specifically, carrying out a final polycondensation reaction and devolatilization; 5) devolatilizing before spinning; and 6) spinning, specifically, directly conveying nylon melt and polyester melt which are devolatilized before spinning to a composite spinning assembly, performing extruding, cooling, oiling, stretching and winding to obtain the polyester-nylon composite fibers. By means of the method, direct spinning after nylon melt polymerization can be achieved, slices do not need to be prepared in advance, and the content of hot water extractables and cyclic dimers in the nylon melt can be effectively controlled; and composite spinning is carried out on the nylon melt and the polyester melt to obtain the polyester-nylon composite fibers in different composite forms.

The invention discloses a poly (cyclopentadiene-dicyclopentadiene) copolymer and a synthesis method thereof. Cyclopentadiene and dicyclopentadiene which are taken as polymerization monomers are subjected to ring-opening metathesis copolymerization to form a novel high polymer material. By adjusting the rate of the dicyclopentadiene in the comonomers, the content of a fat ring chain structure in the poly (cyclopentadiene-dicyclopentadiene) copolymer is adjusted, so that various high polymer materials with different properties and purposes are synthesized. Moreover, the dicyclopentadiene is used as one of the monomers and applied to preparing rubber materials, and a monomer ratio of the cyclopentadiene to the dicyclopentadiene is adjusted, so that the generated random copolymer has higher number-average molecular weight and proper Mooney viscosity.

The invention relates to a method for preparing a butyl rubber polymer. In the method, a mixture of C4-C8 monoolefine monomer and C4-C14 polyene monomer serving as a main material is subjected to polymerization at the temperature of between -90 and -70 DEG C and in absence of water and oxygen by taking the mixture of ionized water, hexane and monoalkyl aluminum dihalide as a catalyst and the mixture of methyl chloride and hexane as a solvent to form the butyl rubber polymer. The method has the advantages of simplicity, high polymerization temperature, low cost, high stability and initiation efficiency of the catalyst, high number average molecular weight of a product, high conversion rate and narrow molecular weigh distribution.

The invention relates to the field of nylon materials, and discloses a melt direct processing caprolactam polymerization method which comprises the following steps: (1) burdening: heating and mixing caprolactam, an end-capping reagent, water and a catalyst to obtain a mixture; (2) ring opening: heating the mixture to carry out a ring opening reaction; (3) pre-polycondensation: heating the productobtained through ring opening to conduct pre-polycondensation reaction and devolatilization; and (4) final polycondensation: heating the product obtained through pre-polycondensation to conduct finalpolycondensation reaction and devolatilization. By means of the method, direct processing of a nylon melt after polymerization can be achieved, and the content of hot water extractable substances andthe content of cyclic dimers in the nylon melt can be effectively controlled.

The invention provides a late transition metal catalyst for olefin polymerization with a structural formula (I), which is characterized by introducing a wedge-shaped dendritic molecule having certain space volume and more symmetrical spatial position of substituent into a ligand structure, successfully avoiding chain transfer reaction of propylene and effectively preventing the propylene from attacking the active site from the side chain. When the catalyst for the olefin polymerization is used for propylene polymerization together with an aluminium alkyl compound, the polymerization activity is remarkably improved, the activity of the catalyst can reach 105g polypropylene/mol Fe*h, and in particular, the number-average molecular weight and degree of isotacticity of the polymerization product are enhanced. The number-average molecular weight is far more than 15000g/mol, and the degree of isotacticity is close to 85%. M is a transition metal selected from Fe, Co or Ni.

The invention relates to a Ni-Pd metal complex as well as a preparation method, application and a product thereof and application of the product. The Ni-Pd complex is prepared through reaction of a phenylenediamine imidazolidine ligand and a metal precursor, and the structural formula of the prepared Ni-Pd metal complex is shown as follows: (the formula is shown in the description), wherein in theformula, R1-R12 are independently selected from hydrogen, alkyl, substituendum of alkyl, alkoxy, alkyl sulphanyl, halogen, nitryl, aryl and substituendum of aryl, M is Ni<2+> or Pd<2+>, and X and Y are independently selected from halogen and alkyl. The product of the Ni-Pd metal complex is mainly obtained by compounding the Ni-Pd metal complex and a promoter, and the Ni-Pd metal complex and the product thereof can both be used for catalyzing polymerization of olefine monomer. The method is easy to operate, the prepared Ni-Pd metal complex and the product thereof have high activity and good thermal stability, the number-average molecular weight and the insertion rate of the olefine polymer obtained through catalysis are high when the Ni-Pd metal complex is used for catalyzing the olefine monomer, and the Ni-Pd metal complex has very good popularization value.

The invention relates to the field of nylon materials, and discloses a method for preparing functional nylon 6 fiber based on the melt direct spinning technology. The method comprises the steps that firstly, burdening is conducted, caprolactam, an end-capping reagent, water and a catalyst are heated and mixed, and a mixture is obtained; secondly, ring opening is conducted; thirdly, pre-polycondensation is conducted, and the pre-polycondensation reaction and devolatilization are conducted; fourthly, final polycondensation is conducted, and the final polycondensation reaction and devolatilization are conducted; and fifthly, devolatilization is conducted before spinning; and sixthly, spinning is conducted, and the functional nylon 6 fiber is obtained. In the first step, functional componentsare added, or before devolatilization before spinning in the fifth step, functional nylon master batches containing functional components are added. The method can be divided into two parallel schemes, the functional components can be directly added in the first step, or the functional nylon master batches containing functional components are added before devolatilization in the fifth step. According to the method, fusion direct spinning is directly conducted after the functional components are added, devolatilization is conducted during pre-polycondensation and final polycondensation, and theproblem about poor functional component scattering can be solved.

The invention belongs to the technical field of thermoplastic polyurethane elastomers, and particularly relates to a soft segment cross-linked thermoplastic polyurethane elastomer and a preparation method thereof. The soft segment cross-linked thermoplastic polyurethane elastomer is prepared from the following raw materials in percentage by weight: 50 to 70 percent of dihydric alcohol, 22 to 38 percent of diisocyanate, 6 to 10 percent of chain extender, 0.1 to 0.8 percent of trihydric alcohol, 0.1 to 0.5 percent of bulking agent, 0.1 to 0.5 percent of antioxidant, 0.1 to 1 percent of light stabilizer, 0.5 to 1 percent of lubricating agent and 0.002 to 0.02 percent of catalyst. The synthesized polyurethane elastomer contains a certain amount of soft segment chemical crosslinking, the compression deformation of the product can reach 20-25%, the light transmittance can reach 91% or above, and the softening temperature is increased by 20-30 DEG C compared with a conventional system. The preparation method is simple and easy to implement, the melt viscosity is stable and controllable, and the method can be widely applied to the fields of oil seals, trundles, shoe materials, high-temperature oil pipes and the like.

The invention relates to a method for preparing a maleic rosin hydroxyethyl methacrylate polymer from rosin. The method comprises the following operation steps: 1) adding rosin into a reaction kettle,performing heating to complete melting of rosin, adding maleic acid and a catalyst, and carrying out a thermal reaction to generate maleic rosin; 2) carrying out a reaction of maleic rosin with hydroxyethyl methacrylate in butyl acetate to prepare maleic rosin hydroxyethyl methacrylate; and 3) carrying out a polymerization reaction of the maleic rosin hydroxyethyl methacrylate to prepare the maleic rosin hydroxyethyl methacrylate polymer. The method provided by the invention can eliminate a conjugate double bond to form a relatively stable six-membered ring internal double bond structure by using a D-A reaction under the premise of not destroying a structure of rosin, at the same time the occurrence of side reactions is effectively reduced, the subsequent processing is facilitated, a double bond structure of hydroxyethyl methacrylate is used for polymerization, the reactivity is high, the yield is effectively improved, and the needs of industrial large-scale production applications are met.