Composite gel with high water-retaining property as well as preparation method and application of composite gel

Abstract

The invention relates to the technical field of gel, and particularly discloses composite gel with high water-retaining property as well as a preparation method and application of the composite gel. Comprising the following steps: (1) adding sodium alginate into a chitosan oligosaccharide solution to prepare chitosan oligosaccharide-sodium alginate gel; (2) soaking the chitosan oligosaccharide-sodium alginate gel in an inorganic salt solution to prepare composite gel; the inorganic salt solution comprises a magnesium chloride solution; the concentration of the inorganic salt solution is 0.5-1 mol / L. The prepared composite gel has relatively high water-retaining property, and the change of the water-retaining property has quantitative controllability and reversibility. The strength, the toughness and the flexibility of the gel can be changed by changing the water-retaining property of the composite gel, so that the controllability and the reversibility are changed. The method for changing the water-retaining property acts on the interior of the gel, the modified gel has uniformity, and the method is different from a traditional surface treatment water-retaining method. And the method for regulating and controlling the water-retaining property is simple, has low reaction requirements and can be used for batch production.

Description

Technical Field

[0001] The invention relates to the technical field of gel, and in particular to a composite gel with high water retention, a preparation method and application thereof. Background Art

[0002] Hydrogels are three-dimensional network structures formed by cross-linking of hydrophilic polymer chains in water. This structure enables hydrogels to absorb and retain large amounts of water while remaining insoluble in water. Since hydrogels contain a large amount of water, they generally have good biocompatibility, which makes hydrogels have a wide range of application potential in areas such as tissue engineering, drug delivery, and medical implants. The water content directly affects the physicochemical properties of hydrogels, such as elasticity, fracture behavior, and adhesion properties. For example, changes in water content can affect the mechanical strength and toughness of hydrogels, which in turn affects their performance in practical applications.

[0003] Since hydrogels contain a large amount of water, this water will inevitably evaporate, causing the hydrogels to gradually dehydrate in the air, resulting in the gradual loss of their flexibility, elasticity and other functions. The evaporation of water limits the practical application of hydrogels in some fields.

[0004] The water-retaining hydrogels currently on the market are mainly achieved through surface modification and encapsulation structure. Although this structure can achieve water retention in the hydrogel, it cannot effectively and accurately quantify the degree of water retention in the hydrogel to achieve changes in the hardness, volume, and toughness of the hydrogel. Moreover, most water retention properties do not have the corresponding reversibility to flexibly transform the performance of the hydrogel.

[0005] Therefore, it is necessary to provide a composite gel with high water retention and a preparation method and application thereof. The prepared composite gel can maintain good toughness and elasticity for a long time in a dry room temperature environment and has a good water retention effect. Summary of the invention

[0006] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention proposes a composite gel with high water retention and a preparation method and application thereof. The prepared composite gel can maintain good toughness and elasticity for a long time in a dry room temperature environment and has a good water retention effect.

[0007] A first aspect of the present invention provides a method for preparing a composite gel with high water retention.

[0008] Specifically, the preparation method of the composite gel with high water retention comprises the following steps:

[0009] (1) adding sodium alginate into a chitosan oligosaccharide solution to prepare a chitosan oligosaccharide-sodium alginate gel;

[0010] (2) soaking the chitosan oligosaccharide-sodium alginate gel in an inorganic salt solution to obtain a composite gel;

[0011] The inorganic salt solution includes a magnesium chloride solution;

[0012] The concentration of the inorganic salt solution is 0.5-1 mol / L.

[0013] Preferably, in step (1), the mass percentage of the sodium alginate is 4-6wt%.

[0014] Further preferably, in step (1), the mass percentage of the sodium alginate is 4.5-5.5 wt %.

[0015] More preferably, in step (1), the mass percentage of the sodium alginate is 5 wt %.

[0016] Preferably, in step (1), the viscosity of the sodium alginate is 180 to 900 mPa·s.

[0017] Preferably, in step (1), the mass percentage of the chitosan oligosaccharide solution is 4 to 6 wt %.

[0018] Further preferably, in step (1), the mass percentage of the chitosan oligosaccharide solution is 4.5-5.5wt%.

[0019] More preferably, in step (1), the mass percentage of the chitosan oligosaccharide solution is 5wt%.

[0020] Preferably, in step (2), the soaking time is 10 to 15 hours.

[0021] Further preferably, in step (2), the soaking time is 10 to 12 hours.

[0022] More preferably, in step (2), the soaking time is 12 hours.

[0023] Preferably, in step (2), the soaking temperature is 20-30°C.

[0024] Further preferably, in step (2), the soaking temperature is 24-26°C.

[0025] More preferably, in step (2), the soaking temperature is 25°C.

[0026] Preferably, in step (2), the inorganic salt solution also includes a magnesium sulfate solution.

[0027] A second aspect of the present invention provides a composite gel with high water retention capacity.

[0028] Specifically, the composite gel is prepared by the preparation method described in the first aspect.

[0029] The third aspect of the present invention provides an application of a composite gel with high water retention in the field of desiccants.

[0030] A fourth aspect of the present invention provides an application of a composite gel with high water retention in the field of hemostatic agents.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] The composite gel prepared by the present invention has high water retention, and the change of water retention is quantitatively controllable and reversible. The strength, toughness and flexibility of the gel can be changed by changing the water retention of the composite gel, and the change can be controllable and reversible. The method of changing the water retention of the present invention acts on the inside of the gel, and the modified gel has uniformity, which is different from the traditional surface treatment water retention method. In addition, the method for regulating water retention is simple, has low reaction requirements, and can be mass-produced, which is different from the traditional method of changing water retention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of competition between chitosan oligosaccharide-sodium alginate hydrogel and magnesium ions;

[0034] Figure 2 The sample pictures of each composite gel after drying;

[0035] Figure 3 is the SEM image of the composite gel of Comparative Example 4;

[0036] Figure 4 SEM image of the gel formed by 5wt% sodium alginate and 5wt% chitosan oligosaccharide solution;

[0037] Figure 5 This is a SEM image of the composite gel of Example 1 of the present invention;

[0038] Figure 6 This is a sample picture of the composite gel in Example 1 of the present invention that absorbs water again after being heated at high temperature. DETAILED DESCRIPTION

[0039] In order to make the technical scheme of the present invention more clearly understood by those skilled in the art, the following embodiments are listed for illustration. It should be pointed out that the following embodiments do not limit the protection scope of the present invention.

[0040] Unless otherwise specified, the raw materials, reagents or devices used in the following examples can be obtained from conventional commercial sources or by existing known methods.

[0041] Example 1

[0042] A composite gel with high water retention and a preparation method thereof.

[0043] The preparation method comprises the following steps:

[0044] (1) adding 0.5 mL of 5 wt % sodium alginate with a viscosity of 200 mPa·s to a 5 wt % chitosan oligosaccharide solution to prepare a chitosan oligosaccharide-sodium alginate gel;

[0045] (2) The chitosan oligosaccharide-sodium alginate gel was immersed in a 1 mol / L magnesium chloride solution at 25°C for 12 h to obtain a composite gel.

[0046] Example 2

[0047] A composite gel with high water retention and a preparation method thereof.

[0048] The difference from Example 1 is that the concentration of the magnesium chloride solution is 0.5 mol / L.

[0049] Comparative Example 1

[0050] A composite gel with high water retention and a preparation method thereof.

[0051] The difference from Example 1 is that the concentration of the magnesium chloride solution is 0.25 mol / L.

[0052] Comparative Example 2

[0053] A composite gel with high water retention and a preparation method thereof.

[0054] The difference from Example 1 is that the magnesium chloride solution is replaced by 1 mol / L calcium chloride.

[0055] Comparative Example 3

[0056] A composite gel with high water retention and a preparation method thereof.

[0057] The difference from Example 2 is that the magnesium chloride solution is replaced by 0.5 mol / L calcium chloride.

[0058] Comparative Example 4

[0059] A composite gel with high water retention and a preparation method thereof.

[0060] The difference from Example 1 is that the magnesium chloride solution is replaced by 1 mol / L sodium chloride.

[0061] Comparative Example 5

[0062] A composite gel with high water retention and a preparation method thereof.

[0063] The difference from Example 1 is that the magnesium chloride solution is replaced by 1 mol / L potassium chloride.

[0064] Comparative Example 6

[0065] A composite gel with high water retention and a preparation method thereof.

[0066] The difference from Example 1 is that the magnesium chloride solution is replaced by water.

[0067] Comparative Example 7

[0068] A composite gel with high water retention and a preparation method thereof.

[0069] The difference from Example 1 is that the magnesium chloride solution is replaced by 1 mol / L cesium chloride.

[0070] Comparative Example 8

[0071] A composite gel with high water retention and a preparation method thereof.

[0072] The difference from Example 1 is that the magnesium chloride solution is replaced by 1 mol / L magnesium acetate.

[0073] 1. Detect weight loss changes.

[0074] Each composite gel was taken out from the solution, and the surface moisture was dried with absorbent paper, and the wet weight of the composite gel prepared in Examples 1 to 2 and Comparative Examples 1 to 6 was measured respectively, and then dried at 50° C. for 3 h, and the dry weight was weighed, and the loss weight was calculated. The results are shown in Table 1.

[0075] Table 1 Weight loss variation results of composite gels obtained in Examples 1 to 2 and Comparative Examples 1 to 6

[0076]

[0077]

[0078] As can be seen from Table 1, the hydrogel with the addition of 0.5-1 mol / L magnesium chloride has a much higher water retention than other ion concentrations, and the water retention is better with the increase of magnesium ion concentration. Figure 2 (The left side of the figure shows the experimental mold) We can see that the hydrogel with magnesium ions added still maintains a good flexibility after drying, and has good water retention, which is much higher than the water retention effect of other ions, proving that magnesium ions play a key role in controlling water retention. In Comparative Example 8, magnesium chloride is replaced with magnesium acetate solution. Although the solution can still achieve a good water retention effect, the gel formed in the magnesium acetate solution will have viscosity due to the presence of acetate.

[0079] 2. SEM image characterization.

[0080] like Figure 3 As shown, it can be seen from the SEM image that although the sodium chloride in comparative example 4 cannot form a gel with chitosan oligosaccharide-sodium alginate by itself, its own crystallization will form a layer of crystals on the surface of the chitosan oligosaccharide-sodium alginate gel to prevent further precipitation of water, but the particles of the sodium chloride crystals are relatively large. Such large particle crystallization damages the strength and toughness of the gel, greatly reducing its application value.

[0081] like Figure 4 As shown, the surface of the unmodified chitosan oligosaccharide-sodium alginate gel is smoother and flatter due to the lack of water, making its arrangement more compact, but it also loses its elastic bonds and toughness.

[0082] like Figure 5 As shown, the surface of the chitosan oligosaccharide-sodium alginate gel modified by magnesium chloride, chitosan oligosaccharide and magnesium chloride compete with each other with sodium alginate, so that their combination presents a state of overlapping particles and sheets. In Example 1, the crystals generated by magnesium chloride on the surface are finer and arranged more closely, which effectively prevents water volatilization and also plays a role in fine crystal strengthening, so that the gel maintains good strength and toughness.

[0083] 3. Study on the changes in properties of composite gels under high temperature.

[0084] The composite gel prepared in Example 1 was heated at 300° C. for 0.5 h to obtain a black foamy solid, which absorbed water in the air and was allowed to stand for 12 h, and a black gel was observed.

[0085] like Figure 6 As shown, after high temperature heating, the composite gel prepared in Example 1 will undergo irreversible denaturation, the gel color changes from white to dark brown, and the original dense structure is generated into a porous foam structure, because the cross-linking state is lost due to the loss of water. The foam solid is placed indoors and found to have extremely strong water absorption in the air. After standing for 12 hours, it quickly absorbs water into an oily state and regenerates gel, but its strength will be reduced. The reason is that during the heating process, related chemical reactions occur, resulting in partial cleavage of the high molecular weight sodium alginate into small molecular compounds, which reduces the cross-linking effect of the gel. Therefore, this new composite gel is expected to be used in desiccants and hemostatic agents.

[0086] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution obtained by any modification, equivalent replacement, improvement, etc. made by a person skilled in the art based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art shall be within the scope of protection determined by the claims.

Claims

1. A method for preparing a composite gel with high water retention, characterized in that: The following steps are involved: (1) adding sodium alginate into a chitosan oligosaccharide solution to prepare a chitosan oligosaccharide-sodium alginate gel; (2) soaking the chitosan oligosaccharide-sodium alginate gel in an inorganic salt solution to obtain a composite gel; The inorganic salt solution includes a magnesium chloride solution; The concentration of the inorganic salt solution is 0.5-1 mol / L.

2. The preparation method according to claim 1, characterized in that: In step (1), the mass percentage of the sodium alginate is 4-6wt%.

3. The preparation method according to claim 1, characterized in that: In step (1), the viscosity of the sodium alginate is 180 to 900 mPa·s.

4. The preparation method according to claim 1, characterized in that: In step (1), the mass percentage of the chitosan oligosaccharide solution is 4-6wt%.

5. The preparation method according to claim 1, characterized in that: In step (2), the soaking time is 10 to 15 hours.

6. The preparation method according to claim 1, characterized in that: In step (2), the soaking temperature is 20-30°C.

7. The preparation method according to claim 1, characterized in that: In step (2), the inorganic salt solution also includes a magnesium sulfate solution.

8. A composite gel with high water retention, characterized in that: The composite gel is prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the composite gel with high water retention according to claim 8 in the field of desiccants.

10. Use of the composite gel with high water retention according to claim 8 in the field of hemostatic agents.

Images