CN104558453B - Method for preparing cationic fluorine-containing amphiphilic block copolymer micelles - Google Patents

Abstract

The invention discloses a method for preparing cationic fluorine-containing amphiphilic block copolymer micelles. The RAFT polymerization technology is used to prepare poly(N,N-dimethylaminoethyl methacrylate) macromolecular RAFT reagents, and then the polymethyl Mix N,N dimethylaminoethyl acrylate macromolecular RAFT reagent with deionized water and hexafluorobutyl acrylate to 65°C~75°C, then add the initiator aqueous solution dropwise, and keep the anaerobic environment for 3~4.5 h, that is. The present invention adopts hydrophilic macromolecular RAFT reagents to adjust the RAFT polymerization of fluorine-containing acrylate monomers, and prepares fluorine-containing amphiphilic block copolymer micelles in situ in water, which can be directly used in soap-free emulsion polymerization without the need for Dissolving the fluorine-containing amphiphilic block copolymer first solves the problem that the fluorine-containing amphiphilic block copolymer has low solubility in water and cannot form stable micelles because the fluorine-containing chain segment is too long.

Description

A kind of preparation method of cationic fluorine-containing amphiphilic block copolymer micelles

technical field

The invention belongs to the technical field of fluorine chemical industry, and in particular relates to a preparation method of cationic fluorine-containing amphiphilic block copolymer micelles.

Background technique

Cationic fluorine-containing polyacrylate not only has good film-forming properties, flexibility and adhesiveness of polyacrylate polymer, but also contains fluorine-containing side chain groups in the polymer, so the surface free energy is low. Due to the advantages of good thermal stability, strong chemical inertness, water repellency, oil repellency and stain resistance, fluoropolymers have been widely used in the waterproof finishing, oil repellent finishing and antifouling finishing of textiles. In addition, the cationic fluorine-containing emulsion is positively charged. Due to the electrostatic action, it can be combined with various negatively charged fabrics by ionic bonds. It has a good balance of negative charges and can be mixed with other cationic additives. Smooth effect.

In the cationic fluorine-containing polyacrylate emulsion prepared by traditional emulsion polymerization, the small molecule emulsifier is attached to the surface of the latex particles by physical adsorption, and it is easily desorbed by the influence of the external environment, causing the latex particles to collide and coagulate, thus making the emulsion stable. In the process of film formation, the small molecule emulsifier migrates to the surface of the film, which limits the enrichment of fluorine-containing components on the surface of the latex film, reduces the adhesion, water repellency, oil repellency and antifouling properties of the film, etc. And the waste liquid containing small molecule emulsifier will pollute the environment.

The use of cationic fluorine-containing amphiphilic block copolymers instead of small molecule emulsifiers can solve the adverse effects of small molecule emulsifiers on the performance of emulsions and membranes. However, the currently prepared fluorine-containing amphiphilic block copolymers generally need to be purified and dissolved in water when used, but too long fluorine-containing chain segments will reduce their solubility in water and cannot form stable micelles. If the segment is too short, it will affect its performance, so that the application of fluorine-containing amphiphilic block copolymer in soap-free emulsion is limited.

Contents of the invention

The purpose of the present invention is to provide a method for preparing cationic fluorine-containing amphiphilic block copolymer micelles, which solves the problem that the fluorine-containing amphiphilic block copolymer cannot form stable micelles due to too long fluorine-containing chain segments question.

The technical scheme adopted in the present invention is: a preparation method of cationic fluorine-containing amphiphilic block copolymer micelles, specifically comprising the following steps:

Step 1: using RAFT polymerization technology to prepare poly-N,N dimethylaminoethyl methacrylate macromolecular RAFT reagent;

Step 2: Mix the poly N,N dimethylaminoethyl methacrylate macromolecular RAFT reagent obtained in step 1 with deionized water and hexafluorobutyl acrylate according to the mass ratio of 1.5: 1500-11250: 75-450 to obtain mixed solution;

Step 3: Deoxygenate the mixed solution obtained in step 2 and heat it up to 65°C-75°C, then add the initiator aqueous solution dropwise, and keep the reaction in an oxygen-free environment for 3-4.5 hours after the dropwise addition to obtain a cationic fluorine-containing amphiphile Block copolymer micelles.

The present invention is also characterized in that,

Step 1 is specifically:

Step 1.1: At room temperature, add azobisisobutyronitrile:N,N dimethylaminoethyl methacrylate:1,4-dioxane:RAFT reagent according to the mass ratio of 4:350:630～1470:21 In the reactor, stir evenly to obtain a mixture containing N,N dimethylaminoethyl methacrylate;

Step 1.2: Pass argon into the mixture containing N,N dimethylaminoethyl methacrylate obtained in step 1.1 for 20-30 minutes, then heat to raise the temperature to 60°C-80°C, and react under the protection of argon for 6-30 minutes. After 10 hours, a macromolecular RAFT reagent of N,N dimethylaminoethyl methacrylate was obtained.

The RAFT reagents in step 1.1 are 2-{[(dodecylthio)thioformyl]sulfanyl}succinic acid, 2-(ethoxycarbonyl)isopropyl ester, cumene dithiobenzoate any of the esters.

The relative molecular mass of the macromolecular RAFT reagent of N,N dimethylaminoethyl methacrylate in step 1 is 1.7×10 ³ to 5.9×10 ³ , and the molecular weight distribution is 1.03 to 1.54.

The aqueous initiator solution in step 3 is an aqueous solution of azobisisobutylamidine hydrochloride.

The concentration of the aqueous solution of the initiator in step 3 is 0.2-1 mol/L, and the molar ratio of the initiator to the macromolecular RAFT reagent of N,N dimethylaminoethyl methacrylate is 1:1.

The dripping time of the initiator aqueous solution in step 3 is 10-30 minutes.

The cationic fluorine-containing amphiphilic block copolymer micelles obtained in step 3 have an average particle diameter of 15-200nm and a Zeta potential of +33.0mv-+36.3mv.

The beneficial effect of the present invention is: the preparation method of cationic fluorine-containing amphiphilic block copolymer micelles of the present invention, the RAFT polymerization of fluorine-containing acrylate monomer is adjusted by hydrophilic macromolecular RAFT reagent, and the original Fluorine-containing amphiphilic block copolymer micelles are prepared in one position, which can be directly used in soap-free emulsion polymerization without first dissolving the fluorine-containing amphiphilic block copolymer, which solves the problem of fluorine-containing amphiphilic block copolymers being too long Amphiphilic block copolymers have low solubility in water and cannot form stable micelles.

Description of drawings

Fig. 1 is the ¹ H-NMR spectrogram of the cationic fluorine-containing amphiphilic block copolymer micelles obtained in Example 1 of the present invention;

Fig. 2 is the particle size distribution diagram of the cationic fluorine-containing amphiphilic block copolymer micelles obtained in Example 3 of the present invention;

Fig. 3 is a TEM photo of the cationic fluorine-containing amphiphilic block copolymer micelles obtained in Example 3 of the present invention.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

A kind of preparation method of cationic fluorine-containing amphiphilic block copolymer micelle of the present invention, specifically comprises the following steps:

Step 1: Prepare poly-N,N-dimethylaminoethyl methacrylate macromolecular RAFT reagent by RAFT polymerization technology, specifically:

Step 1.1: At room temperature, add azobisisobutyronitrile:N,N dimethylaminoethyl methacrylate:1,4-dioxane:RAFT reagent according to the mass ratio of 4:350:630～1470:21 In the reactor, stir evenly to obtain a mixture containing N,N dimethylaminoethyl methacrylate; wherein, the RAFT reagent is 2-{[(dodecylthio)thioformyl]sulfanyl} Any one of succinic acid, 2-(ethoxycarbonyl) isopropyl ester, and cumyl dithiobenzoate;

Step 1.2: Pass argon into the mixture containing N,N dimethylaminoethyl methacrylate obtained in step 1.1 for 20-30 minutes, then heat to raise the temperature to 60°C-80°C, and react under the protection of argon for 6-30 minutes. After 10 hours, a poly N,N dimethylaminoethyl methacrylate macromolecular RAFT reagent (PDMAEMA-RAFT) with a relative molecular mass of 1.7×10 ³ to 5.9×10 ³ and a molecular weight distribution of 1.03 to 1.54 was obtained;

Step 2: The poly N, N dimethylaminoethyl methacrylate macromolecular RAFT reagent (PDMAEMA-RAFT) obtained in step 1, deionized water, and hexafluorobutyl acrylate are mixed according to the mass ratio of 1.5: 1500 ~ 11250: 75 ~450 mixed to obtain a mixed solution;

Step 3: Pass argon gas through the mixed solution obtained in step 2 for 20-30 minutes to remove oxygen, then heat up to 65°C-75°C, and then dropwise add azobisisobutylamidine hydrochloride ( AIBA) aqueous solution, the molar ratio of AIBA to PDMAEMA-RAFT is 1:1, the time for AIBA dropwise addition is 10-30min, after the dropwise addition, keep anaerobic environment for 3-4.5h, through dynamic light scattering (DLS) and transmission Characterized by electron microscopy (TEM), the cationic fluorine-containing amphiphilic block copolymer micelles with an average particle diameter of 15-200nm and a Zeta potential of +33.0mv-+36.3mv were obtained. The results show that the fluorine-containing block copolymers obtained by the reaction can form micelles in water under different fluorine-containing monomer ratios, that is, different fluorine-containing segment lengths, and the amount of fluorine-containing monomers is related to the obtained fluorine-containing copolymers. As the amount of fluorine-containing monomer increases, the fluorine-containing segment grows, and the particle size of fluorine-containing block copolymer micelles gradually increases, which solves the problem that the fluorine-containing segment is insoluble in water and cannot The problem of forming stable micelles. At the same time, the Zeta potential test results show that the formed micelles are positively charged, which can play a stabilizing role in the application of cationic fluorine-containing soap-free emulsion polymerization.

The beneficial effects of the present invention are: the present invention prepares stable fluorine-containing block copolymer micelles in situ in water, and the obtained fluorine-containing block copolymer micelles have a charge of more than +30, and its electrostatic effect can make The latex particles are more stable, which solves the problem that the fluorine-containing amphiphilic block copolymer has low solubility in water and cannot form stable micelles because the fluorine-containing chain segment is too long.

Example 1

Step 1: At room temperature, mix azobisisobutyronitrile: N,N dimethylaminoethyl methacrylate: 1,4-dioxane: 2-{[(dodecylthio)methylthio Acyl]sulfanyl}succinic acid was added into a four-necked flask equipped with a reflux condenser, air guide tube, and thermometer according to the mass ratio of 4:350:1050:21, wherein 1,4-dioxane was used as a solvent to obtain A mixture of N,N dimethylaminoethyl methacrylate;

Step 2: Pass argon into the mixture containing N,N dimethylaminoethyl methacrylate obtained in the above step 1 for 30 minutes, then heat to raise the temperature to 60°C, and react for 10 hours under the protection of argon to obtain a molecular weight of 4.5× 10 ³ . Poly(N,N)dimethylaminoethyl methacrylate (PDMAEMA-RAFT) with a molecular weight distribution of 1.23;

Step 3: Add PDMAEMA-RAFT: deionized water: hexafluorobutyl acrylate into a four-necked flask according to the mass ratio of 1.5:11250:75 and mix to obtain a mixture;

Step 4: Pass argon to the mixture obtained in the above step 3 for 30 minutes, then heat to raise the temperature to 65° C., and then add dropwise an aqueous solution of azobisisobutylamidine hydrochloride (AIBA) with a concentration of 0.6 mol/L, AIBA and The molar ratio of PDMAEMA-RAFT is 1:1, the dropping time is 20min, and the reaction is carried out under the protection of argon for 4h. Characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM), the average particle size is 15nm and the Zeta potential is +33.0mv cationic fluorinated amphiphilic block copolymer micelles.

The ¹ H-NMR spectrum of the fluorine-containing amphiphilic block copolymer micelles obtained in this example is shown in Figure 1. It can be seen from Figure 1 that the proton peak near the amino group in PDMAEMA-b-PHFBA- CH ₂ -N- and -N-( CH ₃ ) ₂ peak at 3.13ppm and 2.89ppm, and -CHF- and -CH ₂ CF ₂ - in the fluorine-containing segment are at 5.91ppm and 4.52ppm respectively The peaks appear, indicating that the cationic fluorine-containing amphiphilic block copolymer micelles have been successfully prepared.

Example 2

Step 1: At room temperature, azobisisobutyronitrile: N, N dimethylaminoethyl methacrylate: 1,4-dioxane: 2-(ethoxycarbonyl) isopropyl ester according to the mass ratio of 4 : 350: 1470: 21 was added to a four-neck flask equipped with a reflux condenser, an air guide tube, and a thermometer, in which 1,4-dioxane was used as a solvent to obtain N,N dimethylaminoethyl methacrylate mixture;

Step 2: Pass argon to the mixture containing N,N dimethylaminoethyl methacrylate obtained in the above step 1 for 20 minutes, then heat to raise the temperature to 70°C, and react for 8 hours under the protection of argon to obtain a molecular weight of 5.9× 10 ^3. Poly N,N dimethylaminoethyl methacrylate (PDMAEMA-RAFT) with a molecular weight distribution of 1.54;

Step 3: Mix PDMAEMA-RAFT: deionized water: hexafluorobutyl acrylate in a mass ratio of 1.5:1500:450 to obtain a mixture;

Step 4: Pass argon gas into the mixture obtained in the above step 3 for 20 minutes, then heat to raise the temperature to 70° C., and then add dropwise an aqueous solution of azobisisobutylamidine hydrochloride (AIBA) with a concentration of 0.2 mol/L, AIBA The molar ratio to PDMAEMA-RAFT is 1:1, the dropping time is 30min, and the reaction is carried out under the protection of argon for 4.5h. Characterized by dynamic light scattering (DLS) and transmission electron microscope (TEM), the average particle size is 200nm, Zeta Cationic fluorinated block copolymer micelles with a potential of +36.3mv.

Example 3

Step 1: At room temperature, mix azobisisobutyronitrile:N,N dimethylaminoethyl methacrylate:1,4-dioxane:cumyl dithiobenzoate according to the mass ratio of 4:350 :630:21 was added to a four-necked flask equipped with a reflux condenser, an air guide tube, and a thermometer, wherein 1,4-dioxane was used as a solvent to obtain a mixture containing N,N dimethylaminoethyl methacrylate;

Step 2: Pass argon to the mixture containing N,N dimethylaminoethyl methacrylate obtained in the above step 1 for 25 minutes, then heat to raise the temperature to 80°C, and react for 6 hours under the protection of argon to obtain a molecular weight of 1.7× 10 ^3. Poly N,N dimethylaminoethyl methacrylate (PDMAEMA-RAFT) with a molecular weight distribution of 1.03;

Step 3: Mix PDMAEMA-RAFT: deionized water: hexafluorobutyl acrylate in a mass ratio of 1.5:1500:450 to obtain a mixture;

Step 4: Pass argon to the mixture obtained in the above step 3 for 25 minutes, then heat to raise the temperature to 75° C., and then add dropwise an aqueous solution of azobisisobutylamidine hydrochloride (AIBA) with a concentration of 1 mol/L, AIBA and The molar ratio of PDMAEMA-RAFT is 1:1, the dropping time is 10min, and the reaction is carried out under the protection of argon for 3h. Characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS), the average particle size is 45nm and the Zeta potential is +34.4mv of cationic fluorinated block copolymer micelles.

Fig. 2 is the particle size distribution diagram of the cationic fluorine-containing block copolymer micelles obtained in embodiment 3 measured by dynamic light scattering (DLS). As can be seen from Fig. 2, the cationic fluorine-containing block copolymer micelles The particle size of the beam is about 60nm, and it is in a monodisperse state.

Fig. 3 is the transmission electron microscope (TEM) photograph of the cationic fluorine-containing block copolymer micelle that embodiment 3 obtains, as can be seen from Fig. 3, successfully prepared cationic fluorine-containing amphiphilic block copolymer micelle . In the test results, the average particle size of micelles measured by TEM is 45nm, which is smaller than the diameter of micelles tested by DLS, which is 60nm. This is because the samples tested by TEM need to be dried. size in solution.

Claims (5)

1. a preparation method of cationic fluorine-containing amphiphilic block copolymer micelle, is characterized in that, specifically comprises the following steps: Step 1: Prepare poly-N,N-dimethylaminoethyl methacrylate macromolecular RAFT reagent by RAFT polymerization technology, specifically: Step 1.1: At room temperature, add azobisisobutyronitrile:N,N dimethylaminoethyl methacrylate:1,4-dioxane:RAFT reagent according to the mass ratio of 4:350:630～1470:21 In the reactor, stir evenly to obtain a mixture containing N,N dimethylaminoethyl methacrylate; Step 1.2: Pass argon into the mixture containing N,N dimethylaminoethyl methacrylate obtained in step 1.1 for 20-30 minutes, then heat to raise the temperature to 60°C-80°C, and react under the protection of argon for 6-30 minutes. After 10 hours, a poly N,N dimethylaminoethyl methacrylate macromolecular RAFT reagent with a relative molecular mass of 1.7×10 ³ to 5.9×10 ³ and a molecular weight distribution of 1.03 to 1.54 was obtained; Step 2: Mix the poly N,N dimethylaminoethyl methacrylate macromolecular RAFT reagent obtained in step 1 with deionized water and hexafluorobutyl acrylate according to the mass ratio of 1.5: 1500-11250: 75-450 to obtain mixed solution; Step 3: Deoxygenate the mixed solution obtained in step 2 and heat it up to 65°C to 75°C, then add the initiator aqueous solution dropwise, and keep the reaction in an oxygen-free environment for 3 to 4.5 hours after the dropwise addition, to obtain an average particle size of 15~ Cationic fluorine-containing amphiphilic block copolymer micelles with 200nm and Zeta potential of +33.0mv～+36.3mv. 2. the preparation method of a kind of cationic fluorine-containing amphiphilic block copolymer micelle as claimed in claim 1, is characterized in that, in described step 1.1, RAFT reagent is 2-{[(dodecyl sulfide any one of thioformyl]sulfanyl}succinic acid, 2-(ethoxycarbonyl)isopropyl ester, and cumyl dithiobenzoate. 3. the preparation method of a kind of cationic fluorine-containing amphiphilic block copolymer micelle as claimed in claim 1, is characterized in that, the initiator aqueous solution in the described step 3 is azobisisobutylamidine salt salt solution. 4. The preparation method of a kind of cationic fluorine-containing amphiphilic block copolymer micelle as claimed in claim 1 or 3, is characterized in that, the concentration of the initiator aqueous solution in the described step 3 is 0.2～1mol/ L, the molar ratio of initiator to N,N dimethylaminoethyl methacrylate macromolecular RAFT reagent is 1:1. 5 . The preparation method of a cationic fluorine-containing amphiphilic block copolymer micelle according to claim 4 , characterized in that, the dripping time of the initiator aqueous solution in the step 3 is 10 to 30 minutes.