阅读说明：本技术 基于聚丙烯酰基甘氨酰胺和海藻酸钠的双网络水凝胶及其制备方法 (Double-network hydrogel based on polyacryl glycinamide and sodium alginate and preparation method thereof ) 是由 刘文广 范川川 于 2018-09-11 设计创作，主要内容包括：本发明提供基于聚丙烯酰基甘氨酰胺和海藻酸钠的双网络水凝胶及其制备方法,先将甘氨酰胺和丙烯酰氯制备丙烯酰基甘氨酰胺(NAGA),然后将丙烯酰基甘氨酰胺(NAGA)单体与海藻酸钠(alginate)溶液共混,加入热引发剂共聚反应后,将凝胶浸泡在Ca<Sup>2+</Sup>溶液中,得到基于聚丙烯酰基甘氨酰胺和海藻酸钠的双网络水凝胶。由氢键和离子键构成的基于聚丙烯酰基甘氨酰胺和海藻酸钠的双网络水凝胶,在这种水凝胶中,丙烯酰基甘氨酰胺(NAGA)强的氢键作用使得凝胶具有泡水稳定以及具有高强度的性能,而海藻酸钠(alginate)的引入可以通过离子交联使得凝胶的力学性能得到一定的延续。(The invention provides a double-network hydrogel based on polyacryl glycinamide and sodium alginate and a preparation method thereof 2+ In solution, obtaining a double network based on polyacryloyl glycinamide and sodium alginateA hydrogel. In the hydrogel, the strong hydrogen bonding action of acryloyl glycinamide (NAGA) enables the gel to have the properties of stable water soaking and high strength, and the introduction of sodium alginate (alginate) can enable the mechanical property of the gel to be continued to a certain extent through ionic crosslinking.)

1. The double-network hydrogel based on the polyacryl glycinamide and the sodium alginate is characterized in that: the method comprises the following steps:

step 1, placing glycinamide hydrochloride, deionized water, potassium carbonate and diethyl ether into a reaction container for mixing ice bath, mixing acryloyl chloride and diethyl ether, slowly dripping the mixture into the reaction solution for 0.5-1.5h, stirring the mixture for reaction for 3-5h in the ice bath after dripping is finished, adjusting the pH of the reaction solution to 1-3, washing the diethyl ether, adjusting the pH of the reaction solution to 6-7, freeze-drying the reaction solution, washing the ethanol/methanol mixed solvent, and performing rotary evaporation and drying to obtain acryloyl glycinamide (NAGA);

and 2, dissolving the obtained acryloyl glycinamide (NAGA) and sodium alginate (alginate) into water to obtain a mixed solution of the acryloyl glycinamide (NAGA) and the sodium alginate (alginate), wherein the mass ratio of the acryloyl glycinamide (NAGA) to the sodium alginate (alginate) is (5-12): 1, adding a thermal initiator into the mixed solution, wherein the dosage of the thermal initiator is 1-3% of the mass of acryloyl glycinamide (NAGA) monomer, removing oxygen in the solution, injecting the mixed solution into a mold, transferring the mold filled with the mixed solution into a 50-70 ℃ oven for crosslinking for 6-9h, and soaking the mold in 250-350mM Ca²⁺And taking out the solution to obtain the double-network hydrogel based on the polyacryl glycinamide and the sodium alginate.

2. The polyacryloyl glycinamide and sodium alginate-based double network hydrogel according to claim 1, characterized in that: in step 1, the addition amount of glycinamide hydrochloride is 6.0-7.0g, the addition amount of potassium carbonate solution is 32-35mL, the concentration of potassium carbonate solution is 2mol/L, the addition amount of diethyl ether is 16-20mL, and in the diethyl ether solution of acryloyl chloride: the addition amount of the acryloyl chloride is 5.0-6.5g, the addition amount of the diethyl ether is 20-30mL, and the reaction time is 3-4h under low-temperature stirring.

3. The polyacryloyl glycinamide and sodium alginate-based double network hydrogel according to claim 1, characterized in that: in step 2, the mass ratio of acryloyl glycinamide (NAGA) to sodium alginate (alginate) is (6-10): 1.

4. the polyacryloyl glycinamide and sodium alginate-based double network hydrogel according to claim 1, characterized in that: in step 2, the amount of the thermal initiator is 2-3% of the mass of the acryloyl glycinamide (NAGA) monomer, and the thermal initiator adopts Ammonium Persulfate (APS).

5. The polyacryloyl glycinamide and sodium alginate-based double network hydrogel according to claim 1, characterized in that: in step 2, the total solids content is 15-25%.

6. Method for preparing a double-network hydrogel based on polyacryloyl glycinamide and sodium alginate according to claim 1, characterized in that: the method comprises the following steps:

step 1, placing glycinamide hydrochloride, deionized water, potassium carbonate and diethyl ether into a reaction container for mixing ice bath, mixing acryloyl chloride and diethyl ether, slowly dripping the mixture into the reaction solution for 0.5-1.5h, stirring the mixture for reaction for 3-5h in the ice bath after dripping is finished, adjusting the pH of the reaction solution to 1-3, washing the diethyl ether, adjusting the pH of the reaction solution to 6-7, freeze-drying the reaction solution, washing the ethanol/methanol mixed solvent, and performing rotary evaporation and drying to obtain acryloyl glycinamide (NAGA);

and 2, dissolving the obtained acryloyl glycinamide (NAGA) and sodium alginate (alginate) into water to obtain a mixed solution of the acryloyl glycinamide (NAGA) and the sodium alginate (alginate), wherein the mass ratio of the acryloyl glycinamide (NAGA) to the sodium alginate (alginate) is (5-12): 1, adding heat to the mixed solutionInitiator and thermal initiator with the amount of 1-3% of the mass of acryloyl glycinamide (NAGA) monomer, removing oxygen in the solution, injecting the mixed solution into a mold, transferring the mold filled with the mixed solution into a 50-70 ℃ oven for crosslinking for 6-9h, and soaking in 250-350mM Ca²⁺And taking out the solution to obtain the double-network hydrogel based on the polyacryl glycinamide and the sodium alginate.

7. The method for preparing the polyacrylamide glycinamide and sodium alginate-based double-network hydrogel according to claim 6, which is characterized in that: in step 1, the addition amount of glycinamide hydrochloride is 6.0-7.0g, the addition amount of potassium carbonate solution is 32-35mL, the concentration of potassium carbonate solution is 2mol/L, the addition amount of diethyl ether is 16-20mL, and in the diethyl ether solution of acryloyl chloride: the addition amount of the acryloyl chloride is 5.0-6.5g, the addition amount of the diethyl ether is 20-30mL, and the reaction time is 3-4h under low-temperature stirring.

8. The method for preparing the polyacrylamide glycinamide and sodium alginate-based double-network hydrogel according to claim 6, which is characterized in that: in step 2, the mass ratio of acryloyl glycinamide (NAGA) to sodium alginate (alginate) is (6-10): 1.

9. the method for preparing the polyacrylamide glycinamide and sodium alginate-based double-network hydrogel according to claim 6, which is characterized in that: in step 2, the amount of the thermal initiator is 2-3% of the mass of the acryloyl glycinamide (NAGA) monomer, and the thermal initiator adopts Ammonium Persulfate (APS).

10. The method for preparing the polyacrylamide glycinamide and sodium alginate-based double-network hydrogel according to claim 6, which is characterized in that: in step 2, the total solids content is 15-25%.

Technical Field

The invention relates to the technical field of preparation of double-network high-strength hydrogel, in particular to double-network hydrogel based on polyacryl glycinamide and sodium alginate and a preparation method thereof.

Background

The polymer hydrogel is a three-dimensional network structure containing a large amount of water, has greater similarity with soft tissues in organisms in structural morphology, and generally has good biocompatibility, so the hydrogel is widely applied to various fields such as tissue engineering scaffolds, drug delivery carriers, wound dressings and the like. However, the hydrogel is a porous network structure, the interior of the hydrogel contains a large amount of water, and polymer segments in water are in a high swelling state, and during a stress process, the segments show larger brittleness and lower energy dissipation mechanism, so that the mechanical properties of the hydrogel are weaker, and the application of the hydrogel is greatly limited.

In order to overcome the defect of poor mechanical properties of the hydrogel, people adopt various strategies to improve the mechanical properties of the hydrogel: 1) the nano composite hydrogel uniformly introduces nano particles into a polymer matrix: on one hand, the high modulus of the nano particles can obviously improve the modulus of the hydrogel; on the other hand, the nano particles often have high specific surface area and rich active functional groups, and can form stronger interface action with a high molecular chain segment through physical adsorption or chemical bonding action, so that high-efficiency energy transmission is realized, and further high-performance composite hydrogel is obtained; in addition, the nanoparticles are used as the crosslinking units of the macromolecular chain segments, so that the energy can be dissipated in situ in the giant crosslinking units, and the functional hydrogel with high strength, high toughness and stimulus responsiveness is obtained. 2) The double-hydrogen bond hydrogel has low bond energy because hydrogen bonds are used as physical bonds, and particularly, single hydrogen bonds are easy to dissociate in a water-powered polar solvent, so that the hydrogel has the defects of poor mechanical properties and water soaking instability, but the double-hydrogen bonds can keep the gel stable in an aqueous solution, and the gel has high strength and toughness. 3) The double-network structure hydrogel improves the toughness and strength of the hydrogel by introducing the sacrificial bonds, and when external force is applied, the sacrificial bonds in the hydrogel break to play an energy dissipation role, so that the hydrogel is endowed with good mechanical properties. 4) The polymer chains form a nanofiber structure similar to structures such as tendons or ligaments of organisms through molecular chain orientation, so that the high-modulus hydrogel is obtained.

Disclosure of Invention

The invention overcomes the defects in the prior art and provides a polyacrylamide and sodium alginate-based double-network hydrogel and a preparation method thereof, the double-network hydrogel is composed of hydrogen bonds and ionic bonds and is based on polyacrylamide and sodium alginate, in the hydrogel, the strong hydrogen bonding action of acryloyl glycinamide (NAGA) ensures that the gel has stable water soaking and high strength, and the introduction of sodium alginate (alginate) can ensure that the mechanical property of the gel is continued to a certain extent through ionic crosslinking.

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

The double-network hydrogel based on the polyacryl glycinamide and the sodium alginate and the preparation method thereof are carried out according to the following steps:

step 1, placing glycinamide hydrochloride, deionized water, potassium carbonate and diethyl ether into a reaction container for mixing ice bath, mixing acryloyl chloride and diethyl ether, slowly dripping the mixture into the reaction solution for 0.5-1.5h, stirring the mixture for reaction for 3-5h in the ice bath after dripping is finished, adjusting the pH of the reaction solution to 1-3, washing the diethyl ether, adjusting the pH of the reaction solution to 6-7, freeze-drying the reaction solution, washing the ethanol/methanol mixed solvent, and performing rotary evaporation and drying to obtain acryloyl glycinamide (NAGA);

and 2, dissolving the obtained acryloyl glycinamide (NAGA) and sodium alginate (alginate) into water to obtain a mixed solution of the acryloyl glycinamide (NAGA) and the sodium alginate (alginate), wherein the mass ratio of the acryloyl glycinamide (NAGA) to the sodium alginate (alginate) is (5-12): adding a thermal initiator into the mixed solution, wherein the dosage of the thermal initiator is 1-3% of the mass of acryloyl glycinamide (NAGA) monomer, removing oxygen in the solution, injecting the mixed solution into a mold, and transferring the mold filled with the mixed solution into an oven at 50-70 ℃ for crosslinkingAfter 6-9h, the mixture is soaked in 350mM Ca at 250-²⁺And taking out the solution to obtain the double-network hydrogel based on the polyacryl glycinamide and the sodium alginate.

In step 1, the addition amount of glycinamide hydrochloride is 6.0-7.0g, the addition amount of potassium carbonate solution is 32-35mL, the concentration of potassium carbonate solution is 2mol/L, the addition amount of diethyl ether is 16-20mL, and in the diethyl ether solution of acryloyl chloride: the addition amount of acryloyl chloride is 5.0-6.5g, and the addition amount of diethyl ether is 20-30 mL.

In the step 1, the reaction time is 3-4h under low-temperature stirring.

In step 2, the mass ratio of acryloyl glycinamide (NAGA) to sodium alginate (alginate) is (6-10): 1.

in step 2, the amount of the thermal initiator is 2-3% of the mass of the acryloyl glycinamide (NAGA) monomer, and the thermal initiator adopts Ammonium Persulfate (APS).

In step 2, the total solids content is 15-25% (total solids content is the ratio of the total mass of all reactants to the total mass of all reactants and solvent).

The powder of the dried polyacrylamide and sodium alginate based double network hydrogel was determined using a fourier transform infrared Spectrometer (FTIR, Spectrum 100FTIR Spectrometer, PerkinElmer inc., USA). As shown in FIG. 1, the IR spectra of the double-network hydrogel and polyacryloyl glycinamide (PNAGA) were compared at 3424cm^-1The peak of stretching vibration of hydroxyl appears at 1702cm^-1The stretching vibration peak of carbonyl in carboxyl is shown, which indicates that the double-network structure has the sodium alginate high molecular structure, and further proves that the two high molecular structures of the polymer exist.

The mechanical properties of the hydrogel are tested by using a stretching instrument, as shown in fig. 2, acryloyl glycinamide (NAGA) and sodium alginate (alginate) are prepared into a double-network hydrogel according to the proportion of 6:1,8:1 and 10:1 respectively, and a stretching test is carried out, wherein when the tensile curve is shown in fig. 2, when acryloyl glycinamide (NAGA): when the ratio of sodium alginate (alginate) to sodium alginate (alginate) is 8:1, the tensile strength and the elongation at break of the gel are higher than those of gels with other proportions under the same solid content.

The invention has the beneficial effects that: the acryloyl glycinamide (NAGA) and the sodium alginate (alginate) with different proportions are added, so that the polyacrylic acryloyl glycinamide and sodium alginate-based double-network hydrogel with different tensile strengths can be prepared, a cross-linking agent is not added in the preparation process of the hydrogel, the purpose of polymerization is achieved only through a double network formed by hydrogen bonds and ionic bonds between monomers, meanwhile, the preparation method of the double-network hydrogel is widened, and the application prospect is wide.

Drawings

FIG. 1 is an infrared spectrum of a polyacrylamide and sodium alginate based dual network hydrogel and polyacryl glycinamide (PNAGA) prepared according to the present invention;

FIG. 2 is a stress-strain diagram of a double-network hydrogel based on polyacryloyl glycinamide and sodium alginate prepared according to the invention, wherein a is the hydrogel prepared in example 1, b is the hydrogel prepared in example 2, and c is the hydrogel prepared in example 3.

Detailed Description

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