A method for preparing a chloromethylated polymer-silane coupling agent crosslinked ultrafiltration membrane

Abstract

The application discloses a preparation method of a chloromethylated polymer-silane coupling agent crosslinking type ultrafiltration membrane, and the method comprises the following steps: (1) blending a chloromethylated polymer, a pore forming agent and N,N-dimethylformamide, slowly adding a small amount of an amino silane coupling agent, and performing crosslinking reaction of the chloromethylated polymer and the amino silane coupling agent, so as to obtain a polymer containing siloxane side chains through reaction between amino groups and chloromethyl groups, and form a three-dimensional network structure; (2) the amino silane coupling agent is subjected to a hydrolysis reaction in a phase inversion process in a coagulation bath, and then is subjected to dehydration condensation to form the chloromethylated polymer-silane coupling agent crosslinking type ultrafiltration membrane. The preparation method introduces siloxane groups with a self-crosslinking function into side chains of a film-forming polymer through reaction of the amino silane coupling agent and the chloromethylated polymer, performs self-crosslinking of the film-forming polymer through synchronous hydrolysis and condensation reaction of the siloxane side chain groups in a phase inversion process, and prepares the crosslinking type ultrafiltration membrane.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of membranes, and particularly relates to a preparation method of a chloromethylated polymer-silane coupling agent crosslinking type ultrafiltration membrane. BACKGROUND

[0002] Silane coupling agents are a kind of organosilicon compounds containing silane groups (-SiR3), in which R represents an alkyl group, an aryl group or other organic groups. They can connect two or more materials of different properties through chemical bonding, thereby improving the biocompatibility and bonding strength of the materials. Silane coupling agents are mainly used to enhance the bonding performance between organic materials (such as plastics and rubbers) and inorganic fillers (such as wollastonite and silicon dioxide), and in recent years, silane coupling agents have shown great application potential in many scientific fields such as medical materials, rubber industry and adhesive glass fibers.

[0003] Meanwhile, the combination of silane coupling agents and ultrafiltration membrane materials can greatly improve the viscosity of the casting solution and improve the structure and performance of the membrane. However, since general silane coupling agents cannot stably exist in the ultrafiltration membrane, the structural properties of the ultrafiltration membrane cannot be guaranteed, and therefore, it is very important to use silane coupling agents with special structures to enable them to stably integrate into the ultrafiltration membrane.

[0004] The modification of ultrafiltration membranes often uses interfacial polymerization or crosslinking reaction. Crosslinking reaction refers to the reaction in which two or more molecules (generally linear molecules) are crosslinked into a network structure of relatively stable molecules (bulk molecules). This reaction converts linear or lightly branched macromolecules into a three-dimensional network structure, thereby improving the strength, heat resistance, wear resistance, solvent resistance and other properties. The amino-containing silane coupling agent can easily crosslink with the chloromethylated polymer, and therefore, the use of crosslinking reaction can ensure the complete integration of the silane coupling agent, and a ultrafiltration membrane with excellent structure and performance can be obtained. SUMMARY

[0005] The purpose of the present application is to provide a preparation method of a chloromethylated polymer-silane coupling agent crosslinking type ultrafiltration membrane. The preparation method uses chloromethylated polymer as the membrane-forming polymer, introduces siloxane groups with self-crosslinking function into the side chain of the membrane-forming polymer through the reaction of amino-containing silane coupling agent and chloromethylated polymer, and performs self-crosslinking of the membrane-forming polymer through the synchronous hydrolysis and condensation reaction of the siloxane side chain groups during the phase inversion process, so as to prepare a crosslinking type ultrafiltration membrane with smaller pore size and higher rejection performance.

[0006] In order to achieve the above-mentioned purpose, the technical scheme created by the present application is implemented in the following manner:

[0007] The preparation method of the chloromethylated polymer-silane coupling agent crosslinking type ultrafiltration membrane comprises the following steps:

[0008] (1) blending chloromethylated polymer, pore-forming agent, N,N-dimethylformamide, slowly adding a small amount of amino silane coupling agent, cross-linking reaction of chloromethylated polymer and amino silane coupling agent, obtaining a polymer containing siloxane side chain through the reaction between amino and chloromethyl, forming a three-dimensional network structure;

[0009] (2) hydrolysis reaction of amino silane coupling agent occurs in the phase inversion process in the coagulation bath, and then dehydration condensation forms a chloromethylated polymer-silane coupling agent cross-linked ultrafiltration membrane.

[0010] Further, the chloromethylated polymer is used as a film-forming polymer, the siloxane groups with self-crosslinking function are introduced into the side chain of the film-forming polymer by the reaction of the amino silane coupling agent and the chloromethylated polymer, and the self-crosslinking of the film-forming polymer is carried out through the synchronous hydrolysis and condensation reaction of the siloxane side chain groups in the phase inversion process, so that the cross-linked ultrafiltration membrane is prepared.

[0011] Further, the chloromethylated polymer in step (1) includes one or more of chloromethylated polysulfone, chloromethylated polyether sulfone, chloromethylated polyether ketone, chloromethylated polyether ether ketone, and chloromethylated polyether ketone ketone, and the chloromethylation degree of the polymer is 55% to 95%.

[0012] Further, the mass fraction of the chloromethylated polymer in step (1) is 17% to 21%.

[0013] Further, the pore-forming agent in step (1) is polyvinylpyrrolidone with a molecular weight of 10,000 to 58,000 and a mass fraction of 1% to 3%.

[0014] Further, the amino silane coupling agent in step (1) includes one or more of 3-aminopropyl triethoxysilane, 3-aminopropyl trimethoxysilane, phenylaminomethyl triethoxysilane, and polyamino alkyl trialkoxysilane.

[0015] Further, the concentration of the amino silane coupling agent solution in step (1) is 0.1% to 5% of the chloromethylated polymer.

[0016] The present application adopts the cross-linking reaction between amino and chloromethyl to obtain a polymer containing siloxane side chain, then uses the phase inversion method in the film-forming process to complete the exchange of solvent-non-solvent (water), and the siloxane side chain rapidly undergoes hydrolysis and condensation reaction to form a cross-linked ultrafiltration membrane, the ultrafiltration membrane prepared by the method has strong mechanical properties and high density, and can realize high retention effect on BSA.

[0017] Compared with the prior art, the present application has the following advantages:

[0018] 1. The material used is easy to obtain, chloromethylated polymer and silane coupling agent, a wide variety of options.

[0019] 2. The silane coupling agent and chloromethylated cross-linking degree is good, the prepared membrane mechanical properties is good, not easy to deformation.

[0020] 3. The addition of silane coupling agent can greatly improve the viscosity of the casting solution, thereby improving the denseness of the membrane;

[0021] 4. The preparation process of the membrane is simple and easy to operate, and the manufacturing cost is low. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is the preparation method of the chloromethylated polymer-silane coupling agent cross-linked ultrafiltration membrane of the application;

[0023] Figures 2-6 is the cross-sectional scanning electron microscope comparison diagram of the ultrafiltration membrane of Comparative Example 1 and the silane coupling agent cross-linked ultrafiltration membranes of Example 1, Example 4, Example 5 and Example 6. DETAILED DESCRIPTION

[0024] The application will be further described below with reference to the drawings.

[0025] In order for the relevant personnel in the art to more clearly understand the application, the application will be further described in detail below in conjunction with examples, and the following selected examples are preferred embodiments of the application, and the scope of protection required by the application is not limited to this.

[0026] The application provides a preparation method of a chloromethylated polymer-silane coupling agent cross-linked ultrafiltration membrane, comprising the following steps: (1) blending chloromethylated polymer, pore-forming agent and N,N-dimethylformamide, slowly adding a small amount of amino silane coupling agent, the chloromethylated polymer and the amino silane coupling agent are cross-linked to form a three-dimensional network structure through the reaction between the amino group and the chloromethyl group; (2) the amino silane coupling agent is hydrolyzed in the phase inversion process in the coagulation bath, and then dehydrated and condensed to form a chloromethylated polymer-silane coupling agent cross-linked ultrafiltration membrane. The reaction process is selected, and chloromethylated polysulfone and 3-aminopropyl triethoxysilane are taken as examples, and the specific reaction process is shown in the following formula:

[0027]

[0028] Example 1

[0029] Chloromethylated polymer, polyvinylpyrrolidone, N,N-dimethylformamide were blended in a round bottom flask, the mass ratio of chloromethylated polymer, polyvinylpyrrolidone, N,N-dimethylformamide was 0.17:0.03:0.80, after being mixed uniformly, a small amount of silane coupling agent was slowly added dropwise, the mass of silane coupling agent was 0.5% of the mass of chloromethylated polymer, after the crosslinking reaction was completed, it was quickly put into a coagulation bath to form a film by phase inversion method.

[0030] Example 2

[0031] Chloromethylated polymer, polyvinylpyrrolidone, N,N-dimethylformamide were blended in a round bottom flask, the mass ratio of chloromethylated polymer, polyvinylpyrrolidone, N,N-dimethylformamide was 0.18:0.03:0.79, after being mixed uniformly, a small amount of silane coupling agent was slowly added dropwise, the mass of silane coupling agent was 0.5% of the mass of chloromethylated polymer, after the crosslinking reaction was completed, it was quickly put into a coagulation bath to form a film by phase inversion method.

[0032] Example 3

[0033] Chloromethylated polymer, polyvinylpyrrolidone, N,N-dimethylformamide were blended in a round bottom flask, the mass ratio of chloromethylated polymer, polyvinylpyrrolidone, N,N-dimethylformamide was (0.19:0.03:0.78), after being mixed uniformly, a small amount of silane coupling agent was slowly added dropwise, the mass of silane coupling agent was 0.5% of the mass of chloromethylated polymer, after the crosslinking reaction was completed, it was quickly put into a coagulation bath to form a film by phase inversion method.

[0034] Example 4

[0035] Chloromethylated polymer, polyvinylpyrrolidone, N,N-dimethylformamide were blended in a round bottom flask, the mass ratio of chloromethylated polymer, polyvinylpyrrolidone, N,N-dimethylformamide was 0.17:0.03:0.78, after being mixed uniformly, a small amount of silane coupling agent was slowly added dropwise, the mass of silane coupling agent was 1% of the mass of chloromethylated polymer, after the crosslinking reaction was completed, it was quickly put into a coagulation bath to form a film by phase inversion method.

[0036] Example 5

[0037] Chloromethylated polymer, polyvinylpyrrolidone, N,N-dimethylformamide were blended in a round bottom flask, the mass ratio of chloromethylated polymer, polyvinylpyrrolidone, N,N-dimethylformamide was 0.17:0.03:0.78, after being mixed uniformly, a small amount of silane coupling agent was slowly added dropwise, the mass of silane coupling agent was 2% of the mass of chloromethylated polymer, after the crosslinking reaction was completed, it was quickly put into a coagulation bath to form a film by phase inversion method.

[0038] Example 6

[0039] The chloromethylated polymer, polyvinylpyrrolidone, N,N-dimethylformamide were blended in a round bottom flask, the mass ratio of chloromethylated polymer, polyvinylpyrrolidone, N,N-dimethylformamide was 0.17:0.03:0.78, after being mixed uniformly, a small amount of silane coupling agent was slowly added, the mass of silane coupling agent was 3% of the mass of chloromethylated polymer, after the crosslinking reaction was completed, it was quickly put into a coagulation bath to form a film by phase inversion method.

[0040] Comparative Example 1

[0041] The chloromethylated polymer, polyvinylpyrrolidone, N,N-dimethylformamide were blended in a round bottom flask, the mass ratio of chloromethylated polymer, polyvinylpyrrolidone, N,N-dimethylformamide was 0.17:0.03:0.78, after being mixed uniformly, it was quickly put into a coagulation bath to form a film by phase inversion method.

[0042] The performance of the prepared chloromethylated polymer-silane coupling agent crosslinked ultrafiltration membrane is shown in Table 1:

[0043] Retention on BSA (%) Water flux (Lm -2 h -1 bar -1 )]]> Example 1 90.83 68.78 Example 2 92.47 59.67 Example 3 95.10 45.34 Example 4 90.83 68.78 Example 5 93.95 57.43 Example 6 95.26 50.26 Comparative Example 1 78.37 78.25

[0044] Table 1 Performance table of ultrafiltration membranes prepared in Examples 1-6 and Comparative Example.

[0045] It can be obtained in Examples 1-6 that with the increase of the mass fraction of chloromethylated polymer, the overall viscosity of the casting solution increases, the compactness of the membrane is enhanced, and the BSA rejection effect and water flux change significantly. With the addition of silane coupling agent, the crosslinking degree is significantly improved, and the condensation thickness gradually rises, which will lead to the increase of the thickness of the compact layer and the decrease of the thickness of the sponge layer, causing the phenomenon of the increase of the bovine serum rejection rate and the decrease of the water flux.

[0046] In Comparative Example 1, it can be obtained that the addition of silane coupling agent from nothing to something causes significant changes in the structure of the ultrafiltration membrane, resulting in the disappearance of the finger-like pores and the thickening of the compact layer, causing the high rejection performance of the ultrafiltration membrane. The above is a preferred embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for producing a chloromethylated polymer-silane coupling agent crosslinked ultrafiltration membrane, characterized by The method comprises the following steps: (1) blending chloromethylated polymer, pore-forming agent and N,N-dimethylformamide, slowly adding a small amount of amino silane coupling agent, cross-linking reaction between chloromethylated polymer and amino silane coupling agent, obtaining a polymer containing siloxane side chains through reaction between amino and chloromethyl, and forming a three-dimensional network structure; (2) after the cross-linking reaction is completed, quickly placing into a coagulation bath to form a film through phase inversion method, hydrolysis reaction of the amino silane coupling agent during phase inversion in the coagulation bath, and then dehydration condensation to form a chloromethylated polymer-silane coupling agent cross-linked ultrafiltration membrane.

2. The process for preparing a chloromethylated polymer-silane coupling agent crosslinked ultrafiltration membrane according to claim 1, characterized by: The chloromethylated polymer is used as a film-forming polymer, the siloxane groups with self-crosslinking function are introduced into the side chains of the film-forming polymer through reaction between the amino silane coupling agent and the chloromethylated polymer, and the self-crosslinking of the film-forming polymer is performed through synchronous hydrolysis and condensation reaction of the siloxane side chain groups during phase inversion to prepare the cross-linked ultrafiltration membrane.

3. The process for preparing a chloromethylated polymer-silane coupling agent crosslinked ultrafiltration membrane according to claim 1, characterized by: The chloromethylated polymer in step (1) comprises one or more of chloromethylated polysulfone, chloromethylated polyether sulfone, chloromethylated polyether ketone, chloromethylated polyether ether ketone and chloromethylated polyether ketone ketone, and the chloromethylation degree of the polymer is 55% to 95%.

4. The process for preparing a chloromethylated polymer-silane coupling agent crosslinked type ultrafiltration membrane according to claim 1, characterized by: The mass fraction of the chloromethylated polymer in step (1) is 17% to 21%.

5. The process for preparing a chloromethylated polymer-silane coupling agent crosslinked type ultrafiltration membrane according to claim 1, characterized by: The pore-forming agent in step (1) is polyvinylpyrrolidone with a molecular weight of 10000 to 58000 and a mass fraction of 1% to 3%.

6. The method for preparing a chloromethylated polymer-silane coupling agent crosslinked ultrafiltration membrane as described in claim 1, characterized in that: The amino silane coupling agent in step (1) comprises one or more of 3-aminopropyl triethoxysilane, 3-aminopropyl trimethoxysilane and phenylaminomethyl triethoxysilane.

7. The method for preparing a chloromethylated polymer-silane coupling agent crosslinked ultrafiltration membrane as described in claim 1, characterized in that: The concentration of the amino silane coupling agent solution in step (1) is 0.1% to 5% of the chloromethylated polymer.

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