阅读说明：本技术 一种聚偏氟乙烯（pvdf）合成工艺 (Polyvinylidene fluoride (PVDF) synthesis process ) 是由 施云云 倪志伟 江飞 曹娇 李红梅 于 2020-12-07 设计创作，主要内容包括：本发明公开了一种聚偏氟乙烯(PVDF)合成工艺,在配有搅拌的不锈钢高压釜内,加入一定量的去离子水和分散剂,密闭反应釜,抽真空,充氮气置换O-2后搅拌升温至,充入VDF使釜增压,加入引发剂和其他助剂,继续以一定速率加入单体和相应比例的引发剂及其他助剂,维持温度及压力,直到单体加完,然后降低反应釜内部的压力,停止搅拌,聚合反应结束,聚合产物进行离心、洗涤、干燥、得到聚偏氟乙烯(PVDF),该聚偏氟乙烯(PVDF)合成的粒子上吸附的分散剂量少,较容易脱除,产物纯度高,后处理工序简单,生产成本较低,粒状树脂可直接用来加工。(The invention discloses a synthetic process of polyvinylidene fluoride (PVDF). A certain amount of deionized water and dispersant are added into a stainless steel autoclave with stirring, the autoclave is sealed, vacuumized and filled with nitrogen to replace O 2 Then stirring and heating to raise the temperature, charging VDF to pressurize the kettle, adding initiator and other auxiliary agents, continuously adding monomer and initiator and other auxiliary agents in a corresponding proportion at a certain speed, maintaining the temperature and pressure until the monomer is added, then reducing the pressure in the reaction kettle, stopping stirring, finishing the polymerization reaction, centrifuging, washing and drying the polymerization product to obtain polyvinylidene fluoride (PVDF), wherein the polyvinylidene fluoride (PVDF) synthesized particles have less adsorbed dispersing agent, are easy to remove, have high product purity, have simple post-treatment process and lower production cost, and the granular resin can be directly used for processing.)

1. A synthetic process of polyvinylidene fluoride (PVDF), which is characterized in that: the method comprises the following steps:

A. adding a certain amount of deionized water and a dispersant into a stainless steel autoclave with stirring;

B. sealing the reaction kettle, vacuumizing, and filling nitrogen to replace O₂Then stirring and heating to raise the temperature, charging VDF to pressurize the kettle, adding the initiator and other additives, and continuously adding the monomer, the initiator and other additives in a corresponding proportion at a certain speed;

C. maintaining the temperature and pressure until the monomer addition is completed;

D. and reducing the pressure in the reaction kettle, stopping stirring, finishing the polymerization reaction, and centrifuging, washing and drying the polymerization product to obtain polyvinylidene fluoride (PVDF).

2. A process for the synthesis of polyvinylidene fluoride (PVDF) according to claim 1, wherein: according to step A

a. Adding 300ml of deionized water and 15ml of dispersing agent, 4 parts by weight of hydrogen peroxide and 5 parts by weight of inorganic alkali solution into a stainless steel autoclave with stirring, and uniformly stirring the deionized water and the dispersing agent by adopting a stirring paddle;

b. then 8 parts by weight of monofluorodichloroethane solvent and 1 part by weight of difluorobromoacetyl fluoride solution were added and stirred at-7 ℃ for reaction for 30 minutes.

3. A process for the synthesis of polyvinylidene fluoride (PVDF) according to claim 1, wherein: according to step B

a. Closing the reaction kettle, vacuumizing, and filling nitrogen to replace O₂Then stirring, heating to 50 ℃, charging VDF to ensure that the kettle pressure is 3.5 MPa;

b. initiator and other auxiliaries were added and the addition of monomer and phase was continued at a rate of 1ml/sd

Initiator and other auxiliary agent in the required proportion.

4. A process for the synthesis of polyvinylidene fluoride (PVDF) according to claim 1, wherein: according to the step C, the polymerization temperature is 30-60 ℃, the polymerization pressure is 21-70MPa, the polymerization time is 15-22h, and the product yield is more than or equal to 90%.

5. A process for the synthesis of polyvinylidene fluoride (PVDF) according to claim 1, wherein: said according to step D

a. The pressure inside the reaction kettle is reduced, the stirring is stopped after the pressure inside the reaction kettle is reduced to 28MPa,

b. and (4) centrifuging, washing and drying the polymerization product, and finishing the polyvinylidene fluoride polymerization reaction.

Technical Field

The invention relates to the technical field of polyvinylidene fluoride (PVDF) synthesis, in particular to a polyvinylidene fluoride (PVDF) synthesis process.

Background

PVDF, polyvinylidene fluoride, is a highly non-reactive thermoplastic fluoropolymer that can be synthesized by polymerization of 1, 1-difluoroethylene. Mainly refers to vinylidene fluoride homopolymer or copolymer of vinylidene fluoride and other small amount of fluorine-containing vinyl monomer, which has the characteristics of fluororesin and general resin, and has special performances of piezoelectricity, dielectricity, pyroelectricity and the like besides good chemical corrosion resistance, high temperature resistance, oxidation resistance, weather resistance and ray radiation resistance

In VDF suspension polymerization, VDF monomers are suspended in dispersion medium deionized water in a droplet form under the combined action of stirring and a dispersing agent, an oil-soluble initiator is used, the initiator enters the monomer droplets to initiate polymerization, and a polymerization product PVDF resin is precipitated in a solid particle form.

The VDF suspension polymerization system mainly comprises vDF monomers consisting of 5 components of DF monomer, dispersant, oil-soluble initiator, chain transfer agent and deionized water, and the critical temperature of the monomers is 30. WDF suspension polymerization is usually carried out at a relatively low temperature at 1 ℃, and high-activity peroxycarbonate compounds such as diisopropyl peroxydicarbonate (IPP) and di-2-ethylhexyl peroxydicarbonate (EHP) which are high-activity initiators are required to be the most important initiators for preparing PVDF by industrial suspension polymerization.

PVDF is a high strength, corrosion resistant material commonly used to make water pipes. PVDF membrane can bind protein and separate small-fragment protein, and is originally used for protein sequencing, because the nitrocellulose membrane can be degraded in Edman reagent, PVDF is searched as a substitute, and although the efficiency of PVDF membrane binding protein is not as high as that of nitrocellulose membrane, the PVDF membrane is an ideal product for protein sequencing due to its stability and corrosion resistance, and is used up to now. The PVDF membrane is the same as the nitrocellulose membrane, can be used for various dyeing and chemiluminescence detection, and has wide application range. The PVDF membrane has higher sensitivity, resolution and protein affinity than the conventional membrane under the fine process, is very suitable for detecting low molecular weight protein, and the technical scheme provides a method for synthesizing high-quality polyvinylidene fluoride.

Disclosure of Invention

The invention aims to provide a method for preparing a stainless steel autoclave with stirring, which comprises the steps of adding a certain amount of deionized water and a certain amount of dispersant into a stainless steel autoclave with stirring, sealing the autoclave, vacuumizing, filling nitrogen to replace O₂Then stirring and heating to raise the temperature, charging VDF to pressurize the kettle, adding initiator and other auxiliary agents, continuously adding monomer and initiator and other auxiliary agents in a corresponding proportion at a certain speed, maintaining the temperature and pressure until the monomer is added, then reducing the pressure in the reaction kettle, stopping stirring, finishing the polymerization reaction, centrifuging, washing and drying the polymerization product to obtain the polyvinylidene fluoride (PVDF) synthetic process of the PVDF, so as to solve the problems in the background technology.

In order to achieve the purpose, the invention provides a polyvinylidene fluoride (PVDF) synthesis process, which comprises the following steps:

A. adding a certain amount of deionized water and a dispersant into a stainless steel autoclave with stirring;

B. sealing the reaction kettle, vacuumizing, filling nitrogen for replacement, stirring, heating to the temperature, filling VDF to pressurize the kettle, adding the initiator and other additives, and continuously adding the monomer, the initiator and other additives in a corresponding proportion at a certain speed;

C. maintaining the temperature and pressure until the monomer addition is completed;

D. and reducing the pressure in the reaction kettle, stopping stirring, finishing the polymerization reaction, and centrifuging, washing and drying the polymerization product to obtain polyvinylidene fluoride (PVDF).

Preferably, said process is carried out according to step A

a. Adding 300ml of deionized water and 15ml of dispersing agent, 4 parts by weight of hydrogen peroxide and 5 parts by weight of inorganic alkali solution into a stainless steel autoclave with stirring, and uniformly stirring the deionized water and the dispersing agent by adopting a stirring paddle;

b. then 8 parts by weight of monofluorodichloroethane solvent and 1 part by weight of difluorobromoacetyl fluoride solution are added and stirred for reaction at the temperature of minus 7 ℃ for 30 minutes;

preferably, said step B is carried out according to

a. Closing the reaction kettle, vacuumizing, filling nitrogen for replacement, stirring, heating to 50 ℃, filling VDF to ensure that the kettle is pressurized to 3.5 MPa;

b. initiator and other auxiliaries were added and the addition of monomer and phase was continued at a rate of 1ml/sd

Initiator and other auxiliary agent in the required proportion.

Preferably, the polymerization temperature is 30-60 ℃, the polymerization pressure is 21-70MPa, the polymerization time is 15-22h, and the product yield is more than or equal to 90 percent according to the step C.

Preferably, said step D

a. The pressure inside the reaction kettle is reduced, the stirring is stopped after the pressure inside the reaction kettle is reduced to 28MPa,

b. and (4) centrifuging, washing and drying the polymerization product, and finishing the polyvinylidene fluoride polymerization reaction.

Compared with the prior art, the invention has the beneficial effects that:

the polyvinylidene fluoride (PVDF) synthesized particles have the advantages of less adsorbed dispersing agent amount, easy removal, high product purity, simple post-treatment process and lower production cost, and the granular resin can be directly used for processing.

Drawings

FIG. 1 is a flow chart of the synthetic process of polyvinylidene fluoride (PVDF) of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, the present invention provides a technical solution: a synthetic process of polyvinylidene fluoride (PVDF), which is characterized in that: the method comprises the following steps:

A. adding a certain amount of deionized water and a dispersant into a stainless steel autoclave with stirring;

B. secret keyClosing the reaction kettle, vacuumizing, and filling nitrogen to replace O₂Then stirring and heating to raise the temperature, charging VDF to pressurize the kettle, adding the initiator and other additives, and continuously adding the monomer, the initiator and other additives in a corresponding proportion at a certain speed;

C. maintaining the temperature and pressure until the monomer addition is completed;

D. and reducing the pressure in the reaction kettle, stopping stirring, finishing the polymerization reaction, and centrifuging, washing and drying the polymerization product to obtain polyvinylidene fluoride (PVDF).

Adding 300ml of deionized water and 15ml of dispersing agent, 4 parts of hydrogen peroxide and 5 parts of inorganic alkali solution into a stainless steel autoclave with stirring, uniformly stirring the deionized water and the dispersing agent by adopting a stirring paddle, adding 8 parts of monofluorodichloroethane solvent and 1 part of difluorobromoacetyl fluoride solution by weight, and stirring and reacting for 30 minutes at-7 ℃.

In the case of the example 1, the following examples are given,

adding 250ml of deionized water and 13ml of dispersing agent, 3.5 parts of hydrogen peroxide and 4.5 parts of inorganic alkali solution into a stainless steel autoclave with stirring, uniformly stirring the deionized water and the dispersing agent by adopting a stirring paddle, adding 6 parts of monofluoro-dichloroethane solvent and 1 part of difluorobromoacetyl fluoride solution by weight, and stirring and reacting for 30 minutes at-7 ℃.

In the case of the example 2, the following examples are given,

adding 280ml of deionized water and 16ml of dispersing agent, 5.5 parts of hydrogen peroxide and 5.5 parts of inorganic alkali solution into a stainless steel autoclave with stirring, uniformly stirring the deionized water and the dispersing agent by adopting a stirring paddle, adding 7 parts of monofluoro-dichloroethane solvent by weight, and stirring 1 part of difluorobromoacetyl fluoride solution by weight at the temperature of minus 7 ℃ for reaction for 30 minutes.

In the case of the example 3, the following examples are given,

adding 280ml of deionized water and 16ml of dispersing agent, 5.8 parts of hydrogen peroxide and 5.8 parts of inorganic alkali solution into a stainless steel autoclave with stirring, uniformly stirring the deionized water and the dispersing agent by adopting a stirring paddle, adding 9 parts of monofluoro-dichloroethane solvent by weight and 1 part of difluorobromoacetyl fluoride solution by weight, and stirring and reacting for 30 minutes at-7 ℃.

In the case of the example 4, the following examples are given,

adding 300ml of deionized water and 18ml of dispersing agent, 6.0 parts of hydrogen peroxide and 6.0 parts of inorganic alkali solution into a stainless steel autoclave with stirring, uniformly stirring the deionized water and the dispersing agent by adopting a stirring paddle, adding 10 parts of monofluoro-dichloroethane solvent by weight, and stirring 1 part of difluorobromoacetyl fluoride solution by weight at-7 ℃ for reaction for 30 minutes.

Closing the reaction kettle, vacuumizing, and filling nitrogen to replace O₂Then stirring, heating to 50 ℃, charging VDF to make the kettle pressure to 3.5MPa, adding initiator and other auxiliary agents, and continuing to add monomer and initiator and other auxiliary agents in corresponding proportion at the speed of 1 ml/sd.

Controlling the polymerization temperature at 30-60 ℃, the polymerization pressure at 21-70MPa, the polymerization time at 15-22h, the product yield at least equal to 90%, depressurizing the interior of the reaction kettle, stopping stirring after the pressure in the reaction kettle is reduced to 28MPa, centrifuging, washing and drying the polymerization product, and finishing the polymerization reaction of the polyvinylidene fluoride.

The polyvinylidene fluoride (PVDF) is prepared by adding 300ml of deionized water and 15ml of dispersing agent, 4 parts of hydrogen peroxide and 5 parts of inorganic alkali solution into polyvinylidene fluoride (PVDF) synthesized by different proportions, uniformly stirring the deionized water and the dispersing agent by adopting a stirring paddle, adding 8 parts of monofluoro-dichloroethane solvent and 1 part of difluorobromoacetyl fluoride solution by weight, and stirring and reacting for 30 minutes at-7 ℃.

The polyvinylidene fluoride (PVDF) synthesized particles have the advantages of less adsorbed dispersing agent amount, easy removal, high product purity, simple post-treatment process and lower production cost, and the granular resin can be directly used for processing.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.