40results about How to "Raise the polymerization temperature" patented technology

The invention discloses a preparation method for acrylonitrile/methacrylic acid copolymer foamed plastic. The preparation method comprises the following steps: adding deionized water, a suspending agent and an aqueous phase inhibitor into a reactor, and uniformly agitating; uniformly mixing monosomic acrylonitrile, methacrylic acid and an initiator, adding the mixture into the reactor, agitating the mixture at the room temperature so as to obtain a stable suspension, rising the temperature to a reaction temperature, and performing free radical suspension polymerization under the condition of agitation; drying a slurry-shaped mixture obtained after the reaction; uniformly mixing copolymer powder, a carbamide foaming agent and a bismaleimide (BMI) crosslinking agent which are obtained after drying; performing hot-pressing foaming formation of the mixture, and otaining polymethacrylimide foamed plastic via heat treatment. The technical scheme provided by the invention is high in production efficiency and yield, can obtain a product with stable performance, is simple and convenient to operate and environmental-friendly, and realizes a beneficial implement effect.

The invention provides a load-type metallocene catalyst which comprises a carrier and an alkyl aluminoxane/magnesium chloride complex and a metallocene compound loaded on the carrier. The hollow ball mesoporous silica carrier has an average particle diameter of 3 to 20 micrometers, a specific surface area of 200 to 300 square meter per gram, a pore volume of 0.5 to 1.5 milliliter per gram, a most probable pore size of 3 to 20 nanometers and an average pore wall thickness of 1 to 2.9 micrometers. The metallocene compound has a structure as shown in formula 1. The load-type metallocene catalyst provided by the invention has a catalytic efficiency up to 3.8 * 10<8> gPE / (mol Zr * h) while homopolymerization and a catalytic efficiency up to 3.7 * 10<8> gPE / (mol Zr * h) while copolymerization under 70 DEG C, overcomes defects of sticking to kettles, is low in a polymerization temperature, and reduces energy consumption to some extent.

The invention relates to a new process for SG3 type PVC (polyvinyl chloride) resin production, which comprises the following steps of: adding a vinyl chloride monomer, pure water, a dispersant, an initiator and a conventional amount of thermal stabilizer and terminator into a reaction kettle, and meanwhile adding a chain extender of maleic acid di-allyl ester into the reaction kettle; wherein the reaction kettle is in a middle size, the mass proportion of the monomer, the pure water, the dispersant, the initiator and the chain extender is 20,000-25,000:30,000-33,000:490-530:120-140:4.5-5.5, and the temperature of polymerization reaction is 54-58 DEG C. Under the condition of no changing of traditional main production equipment, the invention adjusts the proportioning of relevant auxiliary agents, improves the temperature of the polymerization reaction, optimizes the control conditions of the production, and shortens the time of the polymerization reaction for about 60 minutes while adding a proper amount of the chain extender in a production formula, thereby saving power and energy consumption, improving production capacity of the equipment, and having safe and stable production system operation and better economic benefit.

The invention provides a supported metallocene catalyst which comprises a carrier, and an alkylaluminoxane/magnesium chloride complex and a metallocene compound which are supported on the carrier; the carrier is rodlike macroporous mesoporous silica which has a length of 2-20 microns, an aspect ratio of 2-8:1, a specific surface area of 320-380 square meter/g, and a pore volume of 0.5-1.5 ml/g. The metallocene compound has a structure as shown in formula 1. When the supported metallocene catalyst of the invention is used for catalyzing olefin polymerization, the catalytic efficiency for homopolymerization at 70 DEG C is up to 2.7*10<8> gPE/(mol Zr.h), and the catalytic efficiency for copolymerization at 70 DEG C is up to 4.2*10<8> gPE/(mol Zr.h); the supported metallocene catalyst overcomes the defect of kettle adhesion, has a low polymerization temperature, and thus reduces the energy consumption to some extent. Formula 1 is as follows.

The invention provides an aliphatic polycarbonate preparation method, which includes adopting a heterogeneous catalyst to polymerize carbon dioxide, propylene oxide and a comonomer to obtain aliphaticpolycarbonate, wherein the comonomer comprises a copolymer of one or more of styrene, acrylonitrile or vinyl acetate and glycidyl methacrylate or a glycidyl methacrylate homopolymer. According to themethod, the comonomer is introduced in the copolymerization process of carbon dioxide and propylene oxide to preform copolymerization, and thus the polymerization temperature is increased, and the generation amount of byproducts is reduced, so that the reaction time is reduced, and the utilization rate of equipment is improved. An experimental result shows that the method can improve the reactionrate by 2-4 times, improve the utilization rate of equipment and reduce the investment and production cost on the premise of ensuring low byproducts and high molecular weight.

The invention relates to a preparation method of composite microspheres, in particular to the preparation method of the composite microspheres which are obtained by using acrylamide as well as acrylic acids and derivatives thereof as monomers and carrying on multivariate copolymerization on the monomers by a distillation precipitation method. The preparation method of the composite microspheres, provided by the invention, can be widely used for the biological medical, medical immunology and cosmetic manufacturing fields, in particular the tertiary oil recovery field, and can be used for profile control and oil flooding of low-permeability reservoirs. Polymer microspheres are prepared by using the distillation precipitation method, an improvement is made on the basis of the precipitation method and stirring is replaced with distillation; and the preparation method comprises the following steps of: in a distilled state, copolymerizing a mixture of one or more of the acrylamide as well as the acrylic acids and the derivatives thereof in a reaction container in the presence of an oil-soluble initiator; after all solvents are distilled, dispersing and washing obtained solid polymer microspheres by ethanol; and centrifuging, drying and grinding the solid polymer microspheres so as to obtain dry microspheres. The preparation method of the composite microspheres, provided by the invention, has the advantages of simple process and convenience in implementation.

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 a preparation method of paclitaxel nano micelle, which comprises the following steps of: taking a block copolymer of polyether and polyester as a medicine supplementary material and paclitaxel as a medicine; and preparing the paclitaxel nano micelle by rotating an evaporation solvent, wherein the medicine supplementary material is prepared through body ring-opening polymerization, and the terminal hydroxyl group of the copolymer is modified into carboxylate so as to increase the stability of the micelle. According to the micelle disclosed by the invention, during the preparation process, no stabilizing agent is added, and the obtained medicine-carrying micelle can stably exist for over 48h under the body fluid environment, is a paclitaxel nano sustained-release carrier with a good application prospect, and has the characteristics of stability and tumour targeted effect.

The invention relates to a preparation method of a polymer carrier, particularly a preparation method of a macroporous penicillin acylase immobilized magnetic bead polymer carrier, which comprises the following steps: dissolving Fe<2+> and Fe<3+> salts used as magnetic source precursors in a polar organic solvent formamide while introducing nitrogen, regulating the pH value of the solution to 8-11 with concentrated ammonia water, curing at 60-90 DEG C for 30-60 minutes, and forming a magnetic fluid under alkaline conditions; by using a surfactant as a dispersant, a vinyl compound as a monomer and a nonpolar organic substance as a dispersion medium, carrying out cross-linking polymerization under the action of an initiator by an reversed phase suspension technique; and washing with acetone to separate the product in a magnetic field, washing with an organic solvent, and carrying out vacuum drying at room temperature to obtain the carrier. The invention has the advantages of unique method, low synthesis cost and simple process, omits the processes of Fe3O4 preparation and surface modification, is beneficial to industrialized application, and can obtain the magnetic macroporous bead penicillin acylase immobilized carrier. The carrier is used for preparing high-activity segregative immobilized enzymes by penicillin acylase immobilization.

The invention belongs to the technical field of rubber synthesis, and is a method for synthesizing butyl rubber with a narrow molecular weight distribution. The solvent used in the method is a solvent formed by mixing halogenated alkanes and saturated alkanes with carbon four to ten carbons, wherein the volume ratio of the content of halogenated alkanes is 1 %~55%; the composition of the main catalyst used is R-Al-Cl ₂ :R ₂ -Al-Cl ₁ : vanadyl trihalide, add a certain proportion of water in the catalyzer; Add benzopyrene and/or nitrosamine compound again in the prepared main catalyst, form co-initiator; Main initiator is R-Al-Cl ₂ and R ₂ -Al-Cl ₁ . The advantages of the present invention: the catalytic system is a homogeneous system, which is convenient for feeding; by adding a small amount of water, a stable complex initiation system is formed; the method can solve the problem that the molecular weight of butyl rubber decreases with the increase of temperature, and the obtained butyl The number average absolute molecular weight of the rubber is 2,000 to 550,000, and the molecular weight distribution is between 1.1 and 2.0.

The invention relates to the field of conjugated diene and monovinylarene random copolymers, and discloses a conjugated diene and monovinylarene random copolymer, and a preparation method thereof. Themethod is the continuous polymerization reaction conducted in each reactor, and includes the following steps that under the condition of anionic polymerization, reaction materials containing the first part of conjugated diene, monovinylarene, solvents, gel inhibitors and single organic lithium initiators are continuously introduced from the bottoms of reactors, the second part of conjugated dieneis introduced in the middles of the reactors, the third part of conjugated diene is continuously introduced on the upper parts of the reactors, and the polymerization temperature is controlled to be90-140 DEG C. According to the preparation method, under the conditions that any structural regulators or random agents are not added, the reaction temperature is high, and residence time is reasonable, the conjugated diene and monovinylarene random copolymer can be prepared with controllable basic molecular weight and low vinyl content.