阅读说明：本技术 一种不含溶剂的本体凝胶及其制备方法 (Solvent-free body gel and preparation method thereof ) 是由 刘文广 刘博� 于 2019-09-20 设计创作，主要内容包括：本发明公开一种不含溶剂的本体凝胶及其制备方法,将聚乙二醇二甲基丙烯酸酯直接溶解在丙烯腈中,并通过自由基引发丙烯腈及聚乙二醇二甲基丙烯酸酯交联聚合,得到本体聚合凝胶,间断更换磷酸盐缓冲液直至水凝胶在缓冲液中达到平衡,最后得到高强度水凝胶。制备方法简单,且同时具备高强度与高韧性。(The invention discloses a solvent-free body gel and a preparation method thereof, wherein polyethylene glycol dimethacrylate is directly dissolved in acrylonitrile, the acrylonitrile and the polyethylene glycol dimethacrylate are initiated by free radicals to carry out cross-linking polymerization to obtain the body polymerized gel, and phosphate buffer solution is discontinuously replaced until hydrogel reaches balance in the buffer solution, so that the high-strength hydrogel is finally obtained. The preparation method is simple, and has high strength and high toughness.)

1. A solvent-free bulk gel, characterized by the following steps:

step 1, adding a crosslinking agent polyethylene glycol dimethacrylate into a monomer acrylonitrile, performing vortex centrifugation until a mixture becomes a clear solution, removing oxygen, and adding an initiator benzoyl peroxide and an initiator N, N-dimethylaniline to obtain a reaction solution; the mass ratio of the monomer acrylonitrile to the cross-linking agent polyethylene glycol dimethacrylate is (1-5):1, the benzoyl peroxide accounts for (1-5) wt% of the total mass of the monomer and the cross-linking agent, and the N, N-Dimethylaniline (DMA) accounts for (40-60) wt% of the mass of the benzoyl peroxide;

step 2, placing the reaction liquid prepared in the step 1 into a mold for polymerization, wherein the reaction temperature is 20-30 ℃, and the reaction time is 15-25h, so as to obtain a solvent-free body gel;

and 3, soaking the solvent-free body gel obtained in the step 2 in Phosphate Buffer Solution (PBS) at the temperature of 20-30 ℃ to obtain the high-strength hydrogel.

2. A solvent-free bulk gel according to claim 1, wherein in step 1 the polyethylene glycol dimethacrylate is PEGDMA2k, PEGDMA4k, PEGDMA8k, and has a number average molecular weight of 2000 to 8000.

3. A solvent-free bulk gel according to claim 1 or 2, wherein in step 1 the mass ratio of monomer acrylonitrile to cross-linker polyethylene glycol dimethacrylate is (3-5):1, benzoyl peroxide is (1-3) wt% of the total mass of monomer and cross-linker, and N, N-dimethylaniline is (50-60) wt% of the mass of benzoyl peroxide.

4. A solvent-free bulk gel according to claim 1 or 2, wherein the hydrogel has a high modulus and strength and is variable with the molecular weight of the cross-linking agent; the water content can be adjusted by varying the molecular weight of the crosslinker.

5. A solvent-free bulk gel according to claim 1 or 2, wherein in step 2, the temperature of the polymerization reaction is 25-30 ℃, the time of the polymerization reaction is 20-25h, the mold is composed of a PMMA plate and a silica gel spacer, the length and width of the PMMA plate are 8-12cm, the thickness is 1-3mm, and the thickness of the silica gel spacer is 0.5-2.5 mm.

6. A solvent-free bulk gel according to claim 1 or 2, wherein in step 3, the soaking process is performed by replacing phosphate buffer (pH 7-7.5) every (10-12) h for 5-10 days to remove residual monomers and initiator.

7. A method for preparing a solvent-free bulk gel, comprising the steps of:

step 1, adding a crosslinking agent polyethylene glycol dimethacrylate into a monomer acrylonitrile, performing vortex centrifugation until a mixture becomes a clear solution, removing oxygen, and adding an initiator benzoyl peroxide and an initiator N, N-dimethylaniline to obtain a reaction solution; the mass ratio of the monomer acrylonitrile to the cross-linking agent polyethylene glycol dimethacrylate is (1-5):1, the benzoyl peroxide accounts for (1-5) wt% of the total mass of the monomer and the cross-linking agent, and the N, N-Dimethylaniline (DMA) accounts for (40-60) wt% of the mass of the benzoyl peroxide;

step 2, placing the reaction liquid prepared in the step 1 into a mold for polymerization, wherein the reaction temperature is 20-30 ℃, and the reaction time is 15-25h, so as to obtain a solvent-free body gel;

and 3, soaking the solvent-free body gel obtained in the step 2 in Phosphate Buffer Solution (PBS) at the temperature of 20-30 ℃ to obtain the high-strength hydrogel.

8. The process for the preparation of a solvent-free bulk gel according to claim 7, wherein in step 1 the polyethylene glycol dimethacrylate is PEGDMA2k, PEGDMA4k, PEGDMA8k, and has a number average molecular weight of 2000 to 8000; the mass ratio of the monomer acrylonitrile to the cross-linking agent polyethylene glycol dimethacrylate is (3-5) to 1, the benzoyl peroxide accounts for (1-3) wt% of the total mass of the monomer and the cross-linking agent, and the N, N-dimethylaniline accounts for (50-60) wt% of the mass of the benzoyl peroxide; adding polyethylene glycol dimethacrylate serving as a crosslinking agent into acrylonitrile serving as a monomer, placing the acrylonitrile into a centrifugal tube to be dissolved, carrying out nitrogen bubbling on the solution at room temperature for 8-12min to remove oxygen so as to prevent polymerization inhibition, and finally adding an initiator and a promoter during the nitrogen bubbling.

9. The method of claim 7, wherein in step 2, the temperature of the polymerization reaction is 25-30 ℃, the time of the polymerization reaction is 20-25h, the mold comprises a PMMA plate and a silica gel pad, the PMMA plate has a length and a width of 8-12cm and a thickness of 1-3mm, and the silica gel pad has a thickness of 0.5-2.5 mm.

10. The method of claim 7, wherein the soaking step in step 3 is performed by replacing phosphate buffer (pH 7-7.5) every 10-12 h for 5-10 days to remove residual monomers and initiator.

Technical Field

The invention relates to the technical field of high-strength hydrogel, in particular to bulk gel without using a solvent and a preparation method thereof.

Background

The conventional artificial hydrogel usually has the microscopic defects of low molecular chain density, small acting force between molecular chains, arbitrary cross-linked network structure formed in the gelling process and the like of a molecular-level high-molecular polymer, so that the hydrogel macroscopically has the serious defects of poor mechanical property, poor stability, poor stimulus responsiveness and the like, and the practical application of the hydrogel is greatly hindered. The mechanical strength of the hydrogel is enhanced along with the increase of solid content, and the preparation of the hydrogel with high solid content can effectively improve the defect of poor mechanical property of the hydrogel.

Disclosure of Invention

The invention overcomes the defects of the prior art, namely the defect of weak mechanical property of the traditional hydrogel, acrylonitrile and polyethylene glycol dimethacrylate (PEGDMA2k, PEGDMA4k and PEGDMA8k) are directly subjected to bulk crosslinking polymerization by free radical initiation, and then the gel is immersed in phosphate buffer solution to exchange and remove small molecules which are not completely reacted, so that the bulk high-strength hydrogel without solvent is prepared, and the use of water or organic solvent (such as DMSO) is omitted.

The technical purpose of the invention is realized by the following technical scheme.

A solvent-free bulk gel and a preparation method thereof are carried out according to the following steps:

step 1, adding a crosslinking agent polyethylene glycol dimethacrylate into a monomer acrylonitrile, carrying out vortex centrifugation until a mixture becomes a clear solution, removing oxygen, and adding an initiator Benzoyl Peroxide (BPO) and an initiator N, N-Dimethylaniline (DMA) to obtain a reaction solution; the mass ratio of the monomer acrylonitrile to the cross-linking agent polyethylene glycol dimethacrylate is (1-5):1, the benzoyl peroxide accounts for (1-5) wt% of the total mass of the monomer and the cross-linking agent, and the N, N-Dimethylaniline (DMA) accounts for (40-60) wt% of the mass of the Benzoyl Peroxide (BPO);

in step 1, the polyethylene glycol dimethacrylate is PEGDMA2k, PEGDMA4k, PEGDMA8k, and has a number average molecular weight of 2000-8000.

In the step 1, adding a crosslinking agent polyethylene glycol dimethacrylate into monomer acrylonitrile, placing the monomer acrylonitrile into a centrifugal tube for dissolving, obtaining a mixture in the tube, carrying out nitrogen bubbling on the solution at room temperature for 8-12min to remove oxygen so as to prevent polymerization inhibition, and finally adding an initiator and a proinitiator when nitrogen bubbling is carried out.

In the step 1, the mass ratio of the monomer acrylonitrile to the crosslinking agent polyethylene glycol dimethacrylate is (3-5) to 1, the benzoyl peroxide accounts for (1-3) wt% of the total mass of the monomer and the crosslinking agent, and the N, N-dimethylaniline accounts for (50-60) wt% of the mass of the benzoyl peroxide.

Step 2, placing the reaction liquid prepared in the step 1 into a mould for polymerization, wherein the reaction temperature is 20-30 ℃, and the reaction time is 15-25h, so as to obtain the solvent-free body gel

In the step 2, the temperature of the polymerization reaction is 25-30 ℃, the time of the polymerization reaction is 20-25h, the mold consists of a PMMA plate and a silica gel gasket, the length and the width of the PMMA plate are 8-12cm, the thickness is 1-3mm, and the thickness of the silica gel gasket is 0.5-2.5 mm.

And 3, soaking the solvent-free body gel obtained in the step 2 in Phosphate Buffer Solution (PBS) at the temperature of 20-30 ℃ to obtain the high-strength hydrogel.

In step 3, the soaking process is to replace phosphate buffer solution (pH 7-7.5) every 10-12 h for 5-10 days to remove residual monomers and initiator.

Compared with the prior art, the technical scheme of the invention adopts the acrylonitrile monomer as the polymerization monomer and the reaction atmosphere, thereby saving the use of water or other organic solvents and avoiding the influence of the organic solvents on the environment. The preparation method is simple, and the defect of weak mechanical property of the traditional hydrogel is overcome; the modulus and the strength of the hydrogel are high and can be changed along with the molecular weight of the crosslinking agent; the water content can be adjusted by varying the molecular weight of the crosslinker.

Drawings

FIG. 1 is a tensile stress strain test graph of the hydrogel prepared by the present invention.

FIG. 2 is a bar graph showing the results of equilibrium water content testing of hydrogels prepared according to the present invention.

Detailed Description

The technical solution of the present invention is further illustrated by the following specific examples.

Example 1

Step 1, weighing 1g of polyethylene glycol dimethacrylate (PEGDMA2k) by using an analytical balance, putting the weighed materials into a 10ml centrifuge tube, adding 4ml of acrylonitrile, then adding 0.1g of BPO, uniformly mixing the materials, and introducing nitrogen for 10min to remove oxygen.

And 2, adding 40 mu L of DMA (direct memory access) into the mixture, uniformly mixing, immediately adding the solution in the centrifugal tube into a mold consisting of a PMMA (polymethyl methacrylate) plate and a silica gel gasket by using a plastic dropper, sealing the opening by using a preservative film, placing the sealed opening in a thermostat at 25 ℃ for 24 hours, and taking out the sealed opening.

Step 3, the mold was then opened, the gel sheet was taken out, and it was soaked in phosphate buffer solution (PBS ═ 7.5) at 25 ℃. In the soaking process, PBS is replaced every 12 hours for 7 days to remove residual monomers and initiators.

Example 2

Step 1, 0.8g of polyethylene glycol dimethacrylate (PEGDMA8k) is weighed by an analytical balance and placed in a 10ml centrifuge tube, 3ml of acrylonitrile is added, then 0.078g of BPO is added, the mixture is mixed uniformly again, and nitrogen is introduced for 10min to remove oxygen.

And 2, adding 39 mu L of DMA (direct memory access) and uniformly mixing, immediately adding the solution in the centrifugal tube into a mold consisting of a PMMA (polymethyl methacrylate) plate and a silica gel gasket by using a plastic dropper, sealing the opening by using a preservative film, placing in a thermostat at 25 ℃ for 24 hours, and taking out.

And 3, uncovering the mold, taking out the gel sheet, and soaking the gel sheet in Phosphate Buffered Saline (PBS) at 25 ℃. In the soaking process, PBS is replaced every 12 hours for 7 days to remove residual monomers and initiators.

Example 3

Step 1, 0.6g of polyethylene glycol dimethacrylate (PEGDMA4k) is weighed by an analytical balance and placed in a 10ml centrifuge tube, 2.4ml of acrylonitrile is added, then 0.06g of BPO is added, the mixture is mixed uniformly again, and nitrogen is introduced for 10min to remove oxygen.

And 2, adding 30 mu L of DMA (direct memory access) into the mixture, uniformly mixing, immediately adding the solution in the centrifugal tube into a mold consisting of a PMMA (polymethyl methacrylate) plate and a silica gel gasket by using a plastic dropper, sealing the opening by using a preservative film, placing the sealed opening in a thermostat at 25 ℃ for 24 hours, and taking out the sealed opening.

And 3, uncovering the mold, taking out the gel sheet, and soaking the gel sheet in Phosphate Buffered Saline (PBS) at 25 ℃. In the soaking process, PBS is replaced every 12 hours for 7 days to remove residual monomers and initiators.

The hydrogels prepared in examples were tested, and as shown in FIG. 1, after the gels were cut into dumbbell type test specimens (effective length 10mm, width 2mm, thickness 0.5mm), they were stretched using a strain rate of 100mm/min to obtain hydrogels having Young's modulus of 152-560MPa and breaking stress of 12.5-21.5MPa, which proved that the hydrogels obtained by bulk polymerization had much higher strength than the conventional gels. As shown in FIG. 2, the prepared gel was soaked in PBS, and the water content of the hydrogel after equilibration was 38-58%, which varied with the change of the molecular weight of the crosslinking agent.

The preparation of hydrosol can be realized by adjusting the process parameters according to the content of the invention, and the hydrosol shows the performance basically consistent with the invention through tests. The invention has been described in an illustrative manner, and it is to be understood that any simple variations, modifications or other equivalent changes which can be made by one skilled in the art without departing from the spirit of the invention fall within the scope of the invention.