Preparation method of low-temperature-resistant high-water-retention core-shell structure hydrogel

Abstract

The invention relates to the field of hydrogel, and discloses a preparation method of low-temperature-resistant high-water-retention core-shell structure hydrogel, which comprises the following steps: step 1, dissolving polysaccharide macromolecules in deionized water, and uniformly dispersing; step 2, transferring the uniformly dispersed polysaccharide polymer solution into a hydrothermal reaction kettle, tightening the hydrothermal reaction kettle, and heating the hydrothermal reaction kettle in a drying oven; step 3, cooling to room temperature to obtain polysaccharide polymer hydrogel; 4, the polysaccharide polymer hydrogel is soaked in a polyhydroxy alcohol solution for several hours, and the hydrogel is obtained. The preparation method is simple and convenient, tedious reaction conditions are avoided, the prepared hydrogel is green and pollution-free, and the raw materials are polysaccharide, alcohol and an aqueous solution; a layer of shell can be formed on the surface of the hydrogel due to the crosslinking effect, so that the hydrogel with a core-shell structure is constructed, and the water retention property and the mechanical property of the hydrogel are improved.

Description

Technical Field

[0001] The invention relates to the field of hydrogels, and more specifically, to a method for preparing a low-temperature-resistant, high-water-retention, core-shell structure hydrogel. Background Art

[0002] At present, the preparation of most tough hydrogels mainly uses the strategies of constructing double network systems, cross-linking, and entanglement; water-retaining hydrogels are mostly achieved by using non-volatile solvents such as ionic liquids and solvent exchange strategies.

[0003] Gel materials often have outstanding performance in a single field, but there are still problems such as complex network structure of tough hydrogels, poor self-healing properties, cumbersome preparation conditions, high cost, poor water retention, and poor biocompatibility. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for preparing a low-temperature-resistant, high-water-retention, core-shell structure hydrogel.

[0005] The present invention provides a method for preparing a low-temperature resistant, high water-retention, core-shell structure hydrogel, comprising the following steps:

[0006] Step 1: Dissolve the polysaccharide polymer in deionized water and disperse it evenly;

[0007] Step 2: Transfer the evenly dispersed polysaccharide polymer solution to the hydrothermal reactor, tighten it and place it in an oven for heating.

[0008] Step 3: After cooling to room temperature, a polysaccharide polymer hydrogel will be obtained.

[0009] Step 4: Soak the polysaccharide polymer hydrogel in a polyhydroxy alcohol solution, and after several hours, a hydrogel that is both tough and has high water retention is obtained.

[0010] Preferably: in step S2, after tightening, place in an oven and heat at 100°C.

[0011] Preferably: in step S2, the heating time is 20 min.

[0012] A low temperature resistant, high water retention, core-shell structure hydrogel is prepared by the above method. The raw materials of the hydrogel consist of: polysaccharide polymer, deionized water and polyhydroxy alcohol solution.

[0013] The beneficial effects of the present invention are as follows: the preparation method of the present invention is simple and convenient, and cumbersome reaction conditions are avoided; the hydrogel prepared by the present invention is green and pollution-free, and the raw materials are polysaccharides, alcohol and aqueous solution.

[0014] The hydroxyl groups on the alcohol and the sulfate groups on the polysaccharide polymer can be used as cross-linking points. By changing the immersion time, the mechanical properties of the hydrogel can be regulated, which broadens the application of the hydrogel.

[0015] Due to cross-linking, a shell can be formed on the surface of the hydrogel, constructing a core-shell structure of the hydrogel, thereby improving its water retention and mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is the infrared spectrum in Example 2 of the present invention;

[0017] Figure 2 It is a screenshot of the molecular structure formula of the cross-linked structure of 1,4-butanediol and carrageenan in Example 2 of the present invention;

[0018] Figure 3 is a stress-strain curve diagram in Example 2 of the present invention;

[0019] Figure 4 is a bar graph of Young's modulus in Example 2 of the present invention;

[0020] Figure 5 is a toughness bar graph in Example 2 of the present invention;

[0021] Figure 6 is a stress bar graph in Example 2 of the present invention;

[0022] Figure 7 is a strain bar graph in Example 2 of the present invention;

[0023] Figure 8 is a weight change curve diagram in Example 2 of the present invention;

[0024] Fig. 9 This is the appearance change diagram in Example 2 of the present invention

[0025] Fig.10 is the ethylene glycol stress diagram in Example 2 of the present invention;

[0026] Fig.11 is the stress diagram of 1,2-propylene glycol in Example 2 of the present invention;

[0027] Fig.12 is the stress diagram of 1,3-propylene glycol in Example 2 of the present invention;

[0028] Fig.13 1,4-butanediol stress diagram in Example 2 of the present invention. DETAILED DESCRIPTION

[0029] The subject matter described herein will now be discussed with reference to example embodiments. It should be understood that the discussion of these embodiments is only to enable those skilled in the art to better understand and implement the subject matter described herein, and the functions and arrangements of the elements discussed may be changed without departing from the scope of protection of the contents of this specification. Each example may omit, replace or add various processes or components as needed. In addition, the features described relative to some examples may also be combined in other examples.

[0030] Example 1

[0031] In this embodiment, a method for preparing a low-temperature resistant, high water-retention, core-shell structure hydrogel is proposed, comprising the following steps:

[0032] Step 1: Dissolve 0.2g polysaccharide polymer in 9.8ml deionized water and disperse evenly;

[0033] Step 2: Transfer the evenly dispersed polysaccharide polymer solution to the hydrothermal reactor, tighten it, and heat it in an oven at 100°C (higher than the glass transition temperature of the hydrogel) for 20 minutes.

[0034] Step 3: After cooling to room temperature, a polysaccharide polymer hydrogel will be obtained.

[0035] Step 4: Soak the polysaccharide polymer hydrogel in a polyhydroxy alcohol solution, and after several hours, a hydrogel that is both tough and has high water retention is obtained.

[0036] Example 2

[0037] In this embodiment, a low-temperature resistant, high water-retention, core-shell structure hydrogel is proposed, which is prepared by the method in Example 1. The raw materials of the hydrogel consist of: polysaccharide polymer, deionized water and polyhydroxy alcohol solution.

[0038] Example 3

[0039] This example is used to study the effect of immersing a polysaccharide polymer hydrogel in a polyhydroxy alcohol solution on the mechanical properties of the hydrogel.

[0040] The polyhydric alcohols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, and 1,4-butylene glycol.

[0041] Since carrageenan has sulfate groups, carboxyl groups and hydroxyl groups can undergo esterification reaction, and the sulfate groups on the carrageenan and the hydroxyl groups on the dihydroxy alcohol undergo cross-linking reaction, and a hydrogel with a core-shell structure is formed by soaking.

[0042] In addition, since the polyhydric alcohol solution has good water retention and antifreeze properties, it can be imparted to the hydrogel to make it have water retention and antifreeze properties.

[0043] After cross-linking, the mechanical properties of the hydrogel can also be improved.

[0044] Taking the sample obtained by soaking carrageenan in ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butylene glycol and propylene glycol solutions as an example, the research and analysis were carried out.

[0045] 1. Carry out infrared analysis on each sample, see attached Figure 1 Infrared spectrum of .

[0046] Infrared analysis:

[0047] 3300-3600cm -1 :-OH stretching vibration peak can prove the enhancement of hydrogen bonding interaction.

[0048] 2900-2950cm -1 : CH stretching vibration peaks of methyl and methylene, 2850-2960cm-1: symmetric and asymmetric stretching vibration peaks of CH, proving whether there are methyl groups inside the hydrogel, etc.

[0049] 1600-1680cm -1 :①The hydrogel has an ordered structure②It may be due to the water absorption peak generated during operation.

[0050] 1250-1260cm -1 :CO stretching vibration peak proves that alcohol has entered the hydrogel.

[0051] 2. Ethylene glycol, propylene glycol, and butylene glycol: As the carbon chains increase, they enter the hydrogel and form regions, providing the hydrogel with skeleton density, making the hydrogel more compact, and increasing the number of hydrogen bonds, thereby improving the mechanical properties.

[0052] Taking 1,4-butanediol as an example, polyhydroxy alcohol solution can cross-link the carrageenan hydrogel skeleton to form a cross-linked structure, see Figure 2 The molecular structure of .

[0053] The mechanical properties of each sample were tested. Figure 3 The stress-strain curve in Figure 4 Young's modulus bar graph, Figure 5 The resilience bar chart in Figure 6 The stress histogram and Figure 7 Strain bar graph in .

[0054] in:

[0055] Modulus: A measure of the strength of a hydrogel, the slope of the stress-strain curve.

[0056] Toughness: integrated area of ​​stress-strain curve.

[0057] Stress: Maximum fracture stress of the hydrogel, the maximum value on the y-axis.

[0058] Strain: maximum elongation at break of the hydrogel, the maximum value on the x-axis.

[0059] 3. Study on the soaking time of each sample

[0060] See attached Figure 8 Weight change curve and Fig. 9 Appearance change diagram. As the immersion time increases, the exterior of the hydrogel is cross-linked by the polyhydroxy alcohol solution to form a core-shell structure, which prevents the hydrogel from further solvent exchange and forms a protective shell.

[0061] 3. Study on cyclic loading and unloading stretching of each sample

[0062] See Fig.10 - Stress diagram of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, and 1,4-butanediol in 13.

[0063] In the 100-cycle loading and unloading stretching test, the hydrogel has good cyclic stability, proving that it has good water retention.

[0064] The above describes an embodiment of the present embodiment, but the present embodiment is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present embodiment, ordinary technicians in this field can also make many forms, all of which are within the protection of the present embodiment.

Claims

1. A method for preparing a low-temperature resistant, high water-retention, core-shell structure hydrogel, characterized in that: The steps include: Step 1: Dissolve the polysaccharide polymer in deionized water and disperse evenly; Step 2: Transfer the evenly dispersed polysaccharide polymer solution to the hydrothermal reactor, tighten it and place it in an oven for heating. Step 3: After cooling to room temperature, a polysaccharide polymer hydrogel will be obtained. Step 4: Soak the polysaccharide polymer hydrogel in a polyhydroxy alcohol solution, and after several hours, a hydrogel that is both tough and has high water retention is obtained.

2. The method for preparing a low-temperature-resistant, high-water-retention, core-shell structure hydrogel according to claim 1, characterized in that: In step S2, after tightening, place in an oven and heat at 100°C.

3. The method for preparing a low-temperature-resistant, high-water-retention, core-shell structure hydrogel according to claim 1, characterized in that: In step S2, the heating time is 20 minutes.

4. The method for preparing a low-temperature resistant, high water-retention, core-shell structure hydrogel according to claim 1, characterized in that: The raw materials of the hydrogel include polysaccharide polymer, deionized water and polyhydroxy alcohol solution.

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