CN1730515A - A kind of method for preparing hydrogel - Google Patents

Abstract

The invention provides a process for preparing aqueous gel comprising the following steps, mixing and dissolving alkene group monomer, cross linking agent and initiating agent by the ratio of 100:2-50:0.2-1:1-10, using microwave having a frequency of 2450MHz or frequency changed microwave of 300MHz-300GHz for radiation to the reaction system.

Description

A kind of method for preparing hydrogel

technical field

The invention belongs to the technical field of chemical materials, in particular to a method for preparing hydrogel

Background of the invention

Hydrogels can swell in water but cannot be dissolved, which is very similar to human tissue. Hydrogels have broad application prospects in the fields of biology, medicine and pharmaceutical preparations.

In the preparation of hydrogels, for example the preparation of poly(N-isopropylacrylamide) and poly(N-vinylcaprolactam), document J.Polym.Sci., PartA: Polym.Chem., 1992, 30 (10) , 2121-2129 and Macromol.Chem.Phys., 1996, 197, 1973-1982 using conventional oil bath heating. Conventional heating, such as oil bath, air bath and sand bath heating, etc., belongs to the traditional conduction heating. This kind of heating is not only complicated to operate, but also requires a long heating time, and the heating is uneven, and the temperature decreases from the outside to the inside, and there is a temperature gradient. What's more unfortunate is that conventional heating is inefficient and a lot of heat energy is wasted. However, microwave heating belongs to "body heating", which is a kind of internal heating, which not only heats evenly, but also has high efficiency and energy saving.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, to propose a new method for preparing hydrogel, adopting microwave heating reaction system, not only the heating speed is fast, but also the heating is uniform, the efficiency is high, and precious energy can be saved , can also improve the swelling properties of hydrogels.

The present invention proposes a kind of method for preparing hydrogel, is characterized in that:

1) After mixing vinyl monomers, crosslinking agents and initiators, dissolve them in a solvent to make a reaction system. The weight ratio of each component in the reaction system is: monomer: crosslinking agent: initiator: solvent=100: 2-50: 0.2-1: 1-10.

2) It is obtained by irradiating and heating the reaction system by using microwaves with a frequency of 2450MHz or microwaves with frequency conversion of 300MHz-300GHz.

Features and effects of the present invention

The traditional conduction heating of the present invention is changed to microwave heating, which not only can speed up the preparation of hydrogel, but also has uniform heating, high efficiency, and can save precious energy, which belongs to the category of green chemistry. More importantly, microwave heating can improve some properties of hydrogels, for example, hydrogels prepared by microwave heating tend to have higher swelling rate and faster swelling speed. These properties, such as swelling degree and swelling speed, are key indicators that determine the application of hydrogels.

Detailed ways

The method for preparing hydrogel of the present invention is described in detail as follows in conjunction with embodiment:

The method of the present invention comprises the following steps:

1) After mixing vinyl monomers, crosslinking agents and initiators, dissolve them in a solvent to make a reaction system. The weight ratio of each component in the reaction system is: monomer: crosslinking agent: initiator: solvent=100: 2-50: 0.2-1: 1-10;

2) It is obtained by irradiating and heating the reaction system by using microwaves with a frequency of 2450MHz or microwaves with frequency conversion of 300MHz-300GHz.

The power of the microwave or variable-frequency microwave can be 75 watts to 10,000 watts, and the irradiation heating takes 1-30 minutes.

The structural formula of the ethylenic monomer can be a or b:

Wherein R1=H, _CH3 ; R2=OR4, NR4R5; the structural formula of R3 is e, f or g:

in

R4, R5=H, CH ₃ , CH ₂ CH ₃ , CH ₂ CH ₂ OH, CH ₂ CH 2 CH ₃ , CH ₂ CH _{2 CH 2 OH} , CH(CH ₃ ) ₂ , CH ₂ CH ₂ CH ₂ CH ₃ , CH ₂ CH(CH ₃ ) ₂ , C(CH ₃ ) ₃ .

The structural formula of the crosslinking agent can be c and d:

For structural formula c, n=1-6; for structural formula d, n=1-30.

The solvent can be water, methanol, ethanol, acetone, tetrahydrofuran, acetonitrile, isopropanol, dioxane, DMSO, DMF, ethylene glycol, glycerol, polyethylene glycol, which have polar properties and effectively absorb microwaves 350-2000, and one of their mixed solvents.

Example 1

Dissolve 10g of acrylamide, 0.5g of N,N'-methylenebisacrylamide and 10mg of azobisisobutyronitrile in 40ml of water, blow in high-purity nitrogen, vacuumize, repeat degassing three times, and seal the tube under vacuum. Then put the sealed tube into a microwave oven with a frequency of 2450 MHz and select an output power of 340 watts to irradiate for 2 minutes. The obtained hydrogel was washed with water and dried. Yield 90%.

Example 2

Mix 10g acrylamide, 2g acrylic acid, 0.5g N,N'-methylenebisacrylamide and 10mg azobisisobutyronitrile, dissolve in 50ml water, degas three times with high-purity nitrogen, seal the tube under vacuum, and then Put the sealed tube into a microwave oven and irradiate it with 75W microwaves with a frequency in the range of 300MHz-300GHz for 20 minutes. Wash, tumble dry. Yield 88%.

Example 3

A mixture of 100g N-vinylpyrrolidone, 5g N, N'-methylenebisacrylamide and 0.1g azobisisobutyronitrile was dissolved in 400ml ethanol/water (1:1v/v), and argon gas was introduced to remove Gas three times, seal the tube under vacuum, then put the sealed tube into a microwave oven with a frequency of 2450NHz and irradiate it under 800W power microwave for 10 minutes. The obtained hydrogel was fully washed with water and dried. Yield 89%.

Example 4

5g N-isopropylacrylamide, 1g methyl hydroxyethyl acrylate, 0.25g N, N'-methylenebisacrylamide and 10mg azobisisobutyronitrile were dissolved in 20ml ethanol/water (1:1v/v), Degas with argon, seal the tube, irradiate with microwave at frequency 2450MHz170W for 3 minutes, wash with water, and dry in vacuum at 40°C until constant weight. Yield 96%.

Example 5

Dissolve 5g of N-vinylcaprolactam, 0.25g of N,N'-methylenebisacrylamide and 10mg of azobisisobutyronitrile in 20ml of ethanol/water (1:1v/v), bubble through high-purity nitrogen for 3min, and pump Vacuum for 5 minutes, repeat degassing three times, seal the tube under vacuum, and then switch to a microwave oven with a frequency of 2450MHz and irradiate with 1000W microwave for 1min. Wash thoroughly with water, and dry in vacuum at 40°C to constant weight. Yield 60%.

Example 6

Mix 10g N-isopropylacrylamide, 2g acrylamide, 0.5g O, O'-ethylene glycol diacrylate and 20mg azobisisobutyronitrile with 50ml ethylene glycol, put in a microwave oven, choose 340W Output power, irradiation 5min. Wash with water and dry in vacuum. Yield 92%.

Example 7

Mix 10g N-vinylcaprolactam, 2g N-vinylpyrrolidone, 0.5g O, O'-ethylene glycol diacrylate and 20mg azobisisobutyronitrile with 50ml glycerol, degas with high-purity nitrogen At least three times, seal the tube, place it in a frequency conversion microwave oven with a frequency in the range of 300MHz-300GHz at 340W and irradiate for 10min. The obtained hydrogel is fully washed with water and dried in vacuum. Yield 63%.

Example 8

Mix 100g N-isopropylacrylamide, 5g N,N'-methylenebisacrylamide and 0.1g azobisisobutyronitrile with 200ml polyethylene glycol-400 thoroughly, degas at least three times with high-purity nitrogen , seal the tube, place it in a frequency conversion microwave oven with a frequency in the range of 300MHz-300GHz, select an output power of 5000W, irradiate continuously for 2 minutes, wash with water, and dry. Yield 95%.

Claims (8)

1. method for preparing hydrogel is characterized in that:

1) make reaction system in the solvent with being dissolved in after vinyl monomer, linking agent and the initiator mixing, the weight ratio of each composition is in this reaction system: monomer: linking agent: initiator: solvent=100: 2-50: 0.2-1: 1-10;

2) utilize frequency reaction system to be carried out obtaining after the irradiated heat for microwave or the 300MHz-300GHz variable frequency microwave of 2450MHz.

2. as claims 1 described method for preparing hydrogel, it is characterized in that the power of described microwave or variable frequency microwave is 75 watts to 10,000 watts, irradiated heat 1-30 minute.

3. as claims 1 described method for preparing hydrogel, it is characterized in that described vinyl monomer structural formula is a or b:

R1=H wherein, CH ₃R2=OR4, NR4R5; The structural formula of R3 is e, f or g:

Wherein

R4，R5＝H，CH ₃，CH ₂CH ₃，CH ₂CH ₂OH，CH ₂CH ₂CH ₃，CH ₂CH ₂CH ₂OH，CH(CH ₃) ₂，CH ₂CH ₂CH ₂CH ₃，CH ₂CH(CH ₃) ₂，C(CH ₃) ₃。

4. as claims 1 described method for preparing hydrogel, it is characterized in that described linking agent structural formula is c and d:

For structural formula c, n=1-6; For structural formula d, n=1-30.

5. as claims 1 described method for preparing hydrogel, it is characterized in that described solvent is to have the water that polarity can effectively absorb microwave, methyl alcohol, ethanol, acetone, tetrahydrofuran (THF), acetonitrile, Virahol, dioxane, DMSO, DMF, ethylene glycol, glycerol, polyoxyethylene glycol 350-2000, and their mixed solvent is a kind of.

6. as claims 1 described method for preparing hydrogel, it is characterized in that described initiator adopts Diisopropyl azodicarboxylate.

7. as claims 3 described methods that prepare hydrogel, it is characterized in that described monomer is a vinylformic acid, methyl acrylate, ethyl propenoate, methyl methacrylate, Hydroxyethyl acrylate, Jia Jibingxisuanyizhi, hydroxyethyl methylacrylate, acrylamide, N,N-DMAA, the N-ethyl acrylamide, N-propyl group acrylamide, N-N-isopropylacrylamide, the N-vinyl pyrrolidone, any of N-caprolactam and composition thereof.

8. as claims 5 described methods that prepare hydrogel, it is characterized in that, described linking agent is N, N '-methylene diacrylamine, N, N '-ethylene group diacrylamine, O, O '-glycol diacrylate, among the different molecular weight polyethylene glycol diacrylate of 300-1000 any.