A carboxymethyl cellulose / β-cyclodextrin temperature-sensitive hydrogel with high mechanical strength and high moisture retention, and its preparation method and application

Abstract

The present invention discloses a carboxymethyl cellulose / β-cyclodextrin thermosensitive hydrogel with high mechanical strength and high moisture retention, and a preparation method and application thereof. The present invention obtains a macromolecular chain A solution by cross-linking reaction of acryloylated β-cyclodextrin, ascorbic acid and a cross-linking agent system; the macromolecular chain A solution is mixed with carboxymethyl cellulose, N-isopropylacrylamide and a cross-linking agent system for cross-linking reaction to obtain a carboxymethyl cellulose / β-cyclodextrin thermosensitive hydrogel with high mechanical strength and high moisture retention. After freeze-drying, the hydrogel is added with a facial mask functional component solution to obtain a self-molding facial mask or a drug solution is added to obtain a wound dressing. The thermosensitive hydrogel of the present invention can respond quickly at low temperatures, and the phase state is repeatedly reversible. In addition, the hydrogel of the present invention has a large mechanical strength in a gel state, is suitable for being applied to the skin surface of any part of the human body and forming a gel film, and can be used as a facial mask, a lip mask, an eye mask, a hand mask, a foot mask, etc.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogel materials, and particularly relates to a carboxymethyl cellulose / β-cyclodextrin thermosensitive hydrogel with high mechanical strength and high moisture retention, and a preparation method and application thereof. Background Art

[0002] In order to endow facial masks with more functions, various natural active substances are added to facial masks to achieve effects such as cleansing, astringency, whitening, moisturizing, and anti-wrinkle. At present, the most common facial masks on the market mainly use silk, tencel, biocellulose, non-woven fabric, hydrogel, non-woven cloth, and cotton cloth as substrates, soak them in facial mask efficacy solutions, and then directly apply them to a certain part of the body. The penetration of the facial mask liquid into the human skin can achieve effects such as moisturizing the skin and improving skin quality. However, traditional facial mask substrates have poor adsorption to facial mask efficacy solutions, low liquid content in the facial masks, and poor adsorption of efficacy solutions that are prone to oxidation, hydrophobic, and unstable by traditional facial masks. These substrates have problems such as poor fit and discomfort with the skin, resulting in the need for further improvement of facial masks.

[0003] Therefore, scholars have turned their attention to hydrogels. It is a three-dimensional network structure semi-solid composed of hydrophilic macromolecular chains, with strong swelling ability but insoluble in water. Hydrogels have biocompatibility, a soft texture, and rubber elasticity, can reduce irritation to epidermal cells and tissues, increase comfort, and can be used as ideal raw materials for human skin care. In order to increase the adhesion of the hydrogel to the skin, a thermosensitive monomer N-isopropylacrylamide is introduced into the gel to increase the thermal response performance.

[0004] To improve the loading of thermosensitive gels with poorly stable efficacy components, β-cyclodextrin can be introduced into the gels. β-cyclodextrin (β-CD) is a special carbohydrate polymer derived from starch, and its structure is like a cavity site to bind or chelate certain chemical substances. The cavity of β-CD can be used to load or release hydrophobic drugs, such as drug molecules. When the hydroxyl groups of β-cyclodextrin are etherified, esterified, acylated, and crosslinked, the water solubility, surface activity, and water absorption rate of modified β-CD are improved, so it can be used to produce more functional materials. The copolymerization reaction of derivatives of β-CD with other monomers can form more stable chemical crosslinks to enhance the stability of the gel. In addition, carboxymethyl cellulose is added to increase the mechanical strength and hydrophilicity of the gel. Polysaccharides have excellent properties such as biocompatibility, environmental friendliness, wide sources, large-scale regeneration, biodegradability by bacteria, and low white pollution, so they are often used to manufacture medical, beauty, and packaging materials.

[0005] In summary, through a series of combinations of raw materials such as derivatives of β-CD, N-isopropylacrylamide, carboxymethyl cellulose, and facial mask efficacy solutions, a thermosensitive plastic facial mask with high mechanical strength and high moisture retention is obtained.

[0006] Arpita et al. (β-Cyclodextrin based pH and thermo-responsive biopolymeric hydrogel as a dual drug carrier) prepared a novel network gel with biocompatibility and stimulus responsiveness by grafting and crosslinking poly(N-isopropylacrylamide) and polymethacrylic acid. The copolymer had low viscoelasticity, yield stress, and compressive stress effects. In addition, the critical transition temperature of the thermosensitive gel did not shift, and the gel film-forming speed was slow at low room temperature in winter and required a high temperature. Summary of the Invention

[0007] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a carboxymethyl cellulose / β-cyclodextrin thermosensitive hydrogel based on high mechanical strength and high moisture retention, as well as its preparation method and application, to solve the problems in the existing technology.

[0008] To achieve the above purpose, the present invention provides the following technical solutions:

[0009] A preparation method of a carboxymethyl cellulose / β-cyclodextrin thermosensitive hydrogel with high mechanical strength and high moisture retention, comprising the following steps:

[0010] (1) Crosslinking reaction of acrylated β-cyclodextrin, ascorbic acid, and a crosslinking agent system to obtain a macromolecular chain A solution;

[0011] (2) Mixing the macromolecular chain A solution with carboxymethyl cellulose, N-isopropylacrylamide, and a crosslinking agent system for crosslinking reaction to obtain a carboxymethyl cellulose / β-cyclodextrin thermosensitive hydrogel with high mechanical strength and high moisture retention.

[0012] Preferably, in step (1), the preparation method of the acrylated β-cyclodextrin is: dissolving β-cyclodextrin in alkaline water, adding acryloyl chloride for reaction to obtain acrylated β-cyclodextrin.

[0013] More preferably, the mass ratio of β-cyclodextrin to acryloyl chloride is 10:1 to 1:10;

[0014] More preferably, the pH of the alkaline water is 10-14; the volume-mass ratio of the alkaline water to β-cyclodextrin is 5:1 ml / g to 20:1 ml / g; the dissolution temperature is 0-5°C, and the time is 0.5-5 h;

[0015] More preferably, the reaction temperature is 20-50°C, and the time is 2-12 h.

[0016] Preferably, in step (1), the crosslinking reaction is carried out in water, and the mass ratio of water to acryloylated β-cyclodextrin is 5:1 to 20:1;

[0017] Preferably, in step (1), the mass ratio of acryloylated β-cyclodextrin to ascorbic acid is 1:20 to 20:1;

[0018] Preferably, in step (1), the mass ratio of the crosslinking agent system to the total amount of acryloylated β-cyclodextrin and ascorbic acid is 1:(50 - 10 4 );

[0019] Preferably, in step (1), the crosslinking agent system is ammonium persulfate and ferric chloride hexahydrate; the mass ratio of ammonium persulfate to ferric chloride hexahydrate is 1:10 to 10:1;

[0020] Preferably, in step (1), the temperature of the crosslinking reaction is 90°C - 120°C, and the time is 0.5 - 4 h.

[0021] Preferably, in step (2), the carboxymethyl cellulose is a carboxymethyl cellulose suspension; the absolute dry mass percentage of the carboxymethyl cellulose suspension is 0.1% - 5%;

[0022] Preferably, in step (2), the absolute dry mass ratio of the macromolecular chain A solution, carboxymethyl cellulose and N-isopropylacrylamide is (1 - 100):(1 - 100):(10 - 1000);

[0023] Preferably, in step (2), the absolute dry mass ratio of the crosslinking agent system to the total amount of carboxymethyl cellulose, macromolecular chain A solution and N-isopropylacrylamide is 1:(50 - 10 4 );

[0024] Preferably, in step (2), the crosslinking agent system is ammonium persulfate and ferric chloride hexahydrate; the mass ratio of ammonium persulfate to ferric chloride hexahydrate is 1:10 to 10:1;

[0025] Preferably, in step (2), the temperature of the crosslinking reaction is 90°C - 120°C, and the time is 0.5 - 4 h.

[0026] The carboxymethyl cellulose / β-cyclodextrin thermosensitive hydrogel with high mechanical strength and high moisture retention prepared by the above preparation method.

[0027] The application of the above carboxymethyl cellulose / β-cyclodextrin thermosensitive hydrogel with high mechanical strength and high moisture retention in the preparation of self-shaping facial masks and wound dressings, including the following steps:

[0028] The high mechanical strength and high moisture-retaining carboxymethyl cellulose / β-cyclodextrin thermosensitive hydrogel is freeze-dried to obtain an aerogel; a mask liquid is added to the aerogel to obtain a self-shaping mask, and a drug solution is added to the aerogel to obtain a wound dressing. The mask and the dressing are in a liquid state and change from a sol to a gel when exposed to temperature.

[0029] Preferably, the temperature of the freeze-drying is below -120°C and the time is above 12 h; the mass ratio of the mask liquid to the aerogel is 1:1 to 10:1; the mass ratio of the drug solution to the aerogel is 1:1 to 10:1.

[0030] Preferably, the mask liquid contains active ingredients; the active ingredients include one or more of whitening, moisturizing, anti-inflammatory, soothing, repairing, anti-aging, antibacterial, and cleansing ingredients;

[0031] More preferably, the whitening ingredients include one or more of vitamin C, kojic acid, ellagic acid, tranexamic acid, niacinamide, ferulic acid, idebenone, arbutin, and centella asiatica; the moisturizing ingredients are selected from one or more of glycerol, lanolin, jojoba oil, ceramide, natural moisturizing factor, lactic acid, squalane, rice bran oil, and provitamin B5; the anti-inflammatory ingredients include one or more of licorice, bisabolol, niacinamide, ectoin, aloe vera gel, curcumin, allantoin, glycyrrhizic acid, and bisabolol; the repairing ingredients include one or more of aloe barbadensis miller gel extract, natural beeswax, resveratrol, aloe vera, chamomile, honeysuckle, candelilla wax, green tea, lithospermum erythrorhizon extract, chamomilla recutita extract, salvia miltiorrhiza, centella asiatica, hops extract, and oleanolic acid; the anti-aging ingredients include one or more of collagen, sweet almond oil, vitamin E, and osmanthus extract; the antibacterial ingredients include one or more of zanthoxylum piperitum fruit, rosemary, usnea barbata extract, viscum coloratum leaf extract, salicylic acid, and thyme; the cleansing ingredients include one or more of mint leaf extract, dipeptide-2, ulmus davidiana root extract, and grapefruit extract.

[0032] Preferably, the drug ingredients in the drug solution include one or more of anti-inflammatory, soothing, repairing, antibacterial, and cleansing ingredients;

[0033] Further preferably, the anti-inflammatory components include one or more of the following drugs: tetracycline, erythromycin, norfloxacin, curcumin, allantoin, mycin, ofloxacin, glycyrrhizic acid, and bisabolol; the sedative components include one or more of the following drugs: natural beeswax, resveratrol, aloe vera, chamomile, honeysuckle, candelilla oil, green tea, purple perilla extract, chamomile extract, salvia miltiorrhiza, asiatic pennywort, hops extract, dipotassium glycyrrhizinate, and dianthin; the repair components include one or more of the following drugs: recombinant human epidermal growth factor, ceramide, astaxanthin, and allantoin; the antibacterial components include one or more of the following: zanthoxylum fruit, rosemary, usnea barbata extract, viscum coloratum leaf extract, salicylic acid, and thyme; the cleansing components include one or more of the following: peppermint leaf extract, dipeptide-2, slippery elm root extract, and grapefruit.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] (1) The thermosensitive hydrogel of the present invention responds at low temperature (19°C), is suitable for being applied to any skin surface to form a facial mask paper, and can be used as a facial mask, lip mask, eye mask, hand mask, foot mask, etc.

[0036] (2) In an environment above 19°C, the hydrogel of the present invention can rapidly undergo a gelation transformation within 2 seconds, avoiding the loss of the sol on the skin surface.

[0037] (3) The two-phase sol and gel of the gel material of the present invention are reversibly repeated with the change of temperature (0 - 60°C).

[0038] (4) The hydrogel of the present invention can be removed from the skin surface and can be directly torn off from the skin surface.

[0039] (5) The cyclodextrin-based hydrogel of the present invention has excellent performance in containing hydrophobic drug molecules, and thus can load a variety of functional ingredients. The functional ingredients include one or more of whitening, moisturizing, anti-inflammatory, sedative, repair, anti-aging, antibacterial, and cleansing components, etc.

[0040] (6) The cyclodextrin-based hydrogel of the present invention has good biocompatibility and antioxidant properties, which are beneficial to the skin. After the antioxidant test, it reaches 80% - 95%.

[0041] (7) The hydrogel of the present invention has high mechanical strength: at 37°C, the tensile strength of the gel state is about 80 Pa, its elastic modulus ranges from 5000 to 40000 Pa, and the storage modulus ranges from 5000 to 25000 Pa; and high moisture retention performance: the hydrogel has hydrophilic properties and the water content reaches more than 80%.

[0042] (8) The catalyst and the remaining reagents used in the hydrogel of the present invention are harmless to the human body, and both cyclodextrin and carboxymethyl cellulose are renewable and degradable resources. Description of the Drawings

[0043] Figure 1 is the scanning electron microscope image of Example 1 of the present invention;

[0044] Figure 2 is the tensile data graph of Example 1 of the present invention;

[0045] Figure 3 is the macroscopic view of Example 1 of the present invention. Detailed Embodiments

[0046] The present invention will be specifically described below in conjunction with embodiments, but the embodiments and the scope of protection of the present invention are not limited to the following embodiments.

[0047] Example 1

[0048] A method for preparing a carboxymethyl cellulose / β-cyclodextrin-based hydrogel, comprising the following steps:

[0049] (1) β-cyclodextrin (30 g) is dissolved in alkaline water (420 mL) with pH = 13, the dissolution temperature is 4 °C, and the time is 2 h; acryloyl chloride (100 g) is added for acrylation reaction, the reaction temperature is 40 °C, and the time is 3 h, and after purification, a derivative of β-cyclodextrin is finally obtained.

[0050] (2) A derivative of β-cyclodextrin (0.1 g), ascorbic acid (50 μL), and water (1 mL) are mixed, and the mass ratio of the derivative of β-cyclodextrin to ascorbic acid is 2:1; ammonium persulfate (40 μL, 1 wt%) and ferric chloride hexahydrate (4 μL, 0.01 g / L) in the crosslinking agent system are added for crosslinking reaction, the mass ratio of ammonium persulfate to ferric chloride hexahydrate is 10:1, and the mass ratio of the crosslinking agent system to the reaction system (the derivative of β-cyclodextrin and ascorbic acid) is 22:7500. The temperature of the crosslinking reaction is 90 °C, and the time is 1 h to obtain a solution of crosslinked macromolecular chain A;

[0051] (3) Dissolve carboxymethyl cellulose in water to form a suspension; the absolute dry weight of the carboxymethyl cellulose suspension is 3 wt%; in step (2), the macromolecular chain A solution of the crosslinking agent is mixed with carboxymethyl cellulose (3 wt%, 4 mL) and N-isopropylacrylamide (1 g); then add the crosslinking agent system ammonium persulfate (40 μL, 1 wt%) and ferric chloride hexahydrate (4 μL, 0.01 g / L) for crosslinking reaction. The mass ratio of ammonium persulfate to ferric chloride hexahydrate is 10:1, and the absolute dry mass ratio of the crosslinking agent system to the reaction system (carboxymethyl cellulose, absolute dry macromolecular chain A solution of the crosslinking agent and N-isopropylacrylamide) is 22:63500. The temperature of the crosslinking reaction is 90 °C and the time is 1 h.

[0052] (4) Dry at -120 °C in a freeze dryer for 24 h;

[0053] (5) Select an aqueous salicylic acid solution (7 ml, 2 wt%) as the mask efficacy ingredient solution and add it to the aerogel (1.27 g) in (4). The aqueous salicylic acid solution has the functions of antibacterial and anti-inflammatory, effectively treating acne and pimples, and can also dissolve cutin and fade acne marks.

[0054] Figure 1 This is the electron microscope scanning image of the hydrogel in Example 1 of the present invention. After freeze-drying, the pore structure of the hydrogel prepared by the present invention has a pore size of about 10 μm, and has the function of loading and releasing the efficacy mask solution.

[0055] Figure 2 This is the tensile data graph of the hydrogel in Example 1 of the present invention. The tensile data of a thermosensitive hydrogel prepared by the present invention at 37 °C meets the use strength of daily masks.

[0056] Figure 3 This is the usage diagram of the hydrogel in Example 1 of the present invention. A thermosensitive hydrogel prepared by the present invention becomes a gel at 37 °C and has the characteristic of stretching into a film. As Figure 3 shown, the material is in a sol state at 4 °C. When the material is placed in an environment above 19 °C (near body temperature), a thermosensitive response occurs within 1-2 seconds. Macroscopically, the material changes from a sol to a gel phase state, the fluidity decreases, the material changes from a transparent sol to a white gel state, and the mechanical strength increases.

[0057] Example 2

[0058] A preparation method of a carboxymethyl cellulose / β-cyclodextrin-based hydrogel, comprising the following steps:

[0059] (1) β - Cyclodextrin (30 g) was dissolved in alkaline water (420 mL) with pH = 13 at a dissolution temperature of 4 °C for 2 h. Acryloyl chloride (200 g) was added for acylation reaction at a reaction temperature of 40 °C for 3 h, and after purification, a derivative of β - cyclodextrin was finally obtained.

[0060] (2) A derivative of β - cyclodextrin (0.15 g), ascorbic acid (50 μL), and water (1 mL) were mixed, and the mass ratio of the derivative of β - cyclodextrin to ascorbic acid was 3:1. Ammonium persulfate (50 μL, 1%) and ferric chloride hexahydrate (8 μL, 0.01 g / L) in the cross - linker system were added for cross - linking reaction. The mass ratio of ammonium persulfate to ferric chloride hexahydrate was 25:4, and the mass ratio of the cross - linker system to the reaction system (derivative of β - cyclodextrin and ascorbic acid) was 29:10000. The cross - linking reaction was carried out at a temperature of 90 °C for 1 h to obtain a solution of cross - linked macromolecular chain A.

[0061] (3) Carboxymethyl cellulose was dispersed in water to form a suspension. The absolute dry content of the carboxymethyl cellulose suspension was 3 wt%. The solution of cross - linked macromolecular chain A in step (2) was mixed with carboxymethyl cellulose (3 wt%, 5 mL) and N - isopropylacrylamide (1 g). Then, ammonium persulfate (50 μL, 1 wt%) and ferric chloride hexahydrate (8 μL, 0.01 g / L) in the cross - linker system were added for cross - linking reaction. The mass ratio of ammonium persulfate to ferric chloride hexahydrate was 25:4, and the absolute dry mass ratio of the cross - linker system to the reaction system (carboxymethyl cellulose, absolute dry solution of cross - linked macromolecular chain A, and N - isopropylacrylamide) was 29:67500. The cross - linking reaction was carried out at a temperature of 90 °C for 1 h.

[0062] (4) Drying was carried out in a freeze - dryer at a temperature below - 120 °C for 24 h.

[0063] (5) A nicotinamide aqueous solution (7 ml, 1 wt%) was selected as the mask efficacy ingredient solution and added to the aerogel in (4) (1.35 g). The nicotinamide aqueous solution has a whitening function.

[0064] Example 3

[0065] A preparation method of carboxymethyl cellulose / β - cyclodextrin - based hydrogel, comprising the following steps:

[0066] (1) β - Cyclodextrin (30 g) was dissolved in alkaline water (420 mL) with pH = 13 at a dissolution temperature of 4 °C for 2 h. Acryloyl chloride (150 g) was added for acylation reaction at a reaction temperature of 40 °C for 3 h, and after purification, a derivative of β - cyclodextrin was finally obtained.

[0067] (2) The derivative of β-cyclodextrin (0.10 g), ascorbic acid (80 μL), and water (1 mL) were mixed, and the mass ratio of the derivative of β-cyclodextrin to ascorbic acid was 5:4; ammonium persulfate (60 μL, 1%) and ferric chloride hexahydrate (4 μL, 0.01 g / L) in the crosslinking agent system were added for crosslinking reaction. The mass ratio of ammonium persulfate to ferric chloride hexahydrate was 15:1, and the mass ratio of the crosslinking agent system to the reaction system (the derivative of β-cyclodextrin and ascorbic acid) was 4:1125. The temperature of the crosslinking reaction was 90 °C and the time was 1 h to obtain the solution of crosslinked macromolecular chain A;

[0068] (3) Carboxymethyl cellulose was dispersed in water to form a suspension; the absolute dryness of the carboxymethyl cellulose suspension was 3 wt%; the solution of crosslinked macromolecular chain A in step (2) was mixed with carboxymethyl cellulose (3 wt%, 6 mL) and N-isopropylacrylamide (1 g); then ammonium persulfate (50 μL, 1 wt%) and ferric chloride hexahydrate (8 μL, 0.01 g / L) in the crosslinking agent system were added for crosslinking reaction. The mass ratio of ammonium persulfate to ferric chloride hexahydrate was 25:4, and the absolute dry mass ratio of the crosslinking agent system to the reaction system (carboxymethyl cellulose, absolute dry solution of crosslinked macromolecular chain A, and N-isopropylacrylamide) was 58:13600. The temperature of the crosslinking reaction was 90 °C and the time was 1 h.

[0069] (4) Drying was carried out in a freeze dryer at a temperature below -120 °C for 24 h;

[0070] (5) The aqueous centella asiatica solution (8 ml, 1 wt%) was selected as the mask efficacy component solution and added to the aerogel in (4) (1.36 g). Centella asiatica has the effects of whitening and removing freckles and acne marks.

[0071] Comparative Example 1

[0072] A preparation method of pure N-isopropylacrylamide-based hydrogel, comprising the following steps:

[0073] (1) N-isopropylacrylamide (1 g) was mixed with 1.5 mL of water;

[0074] (2) Ammonium persulfate (40 μL, 1%) and ferric chloride hexahydrate (4 μL, 0.01 g / L) in the crosslinking agent system were added for crosslinking reaction. The mass ratio of ammonium persulfate to ferric chloride hexahydrate was 10:1, and the mass ratio of the crosslinking agent system to the reaction system was 11:25000. The temperature of the crosslinking reaction was 90 °C and the time was 1 h.

[0075] (3) Drying was carried out in a freeze dryer at a temperature below -120 °C for 24 h;

[0076] (4) Select nicotinamide aqueous solution (7 ml, 1 wt%) as the mask efficacy component solution and add it to the aerogel (1 g) in (3). Nicotinamide has the effects of whitening and removing spots, and removing acne marks.

[0077] Comparative Example 2

[0078] Preparation method of carboxymethyl cellulose / β-cyclodextrin (unmodified) based hydrogel, including the following steps:

[0079] (1) Mix pure β-cyclodextrin (0.10 g), ascorbic acid (80 μL) and water (1 mL). The mass ratio of β-cyclodextrin to ascorbic acid is 5:4; add the crosslinking agent system ammonium persulfate (60 μL, 1%) and ferric chloride hexahydrate (4 μL, 0.01 g / L) for crosslinking reaction. The mass ratio of ammonium persulfate to ferric chloride hexahydrate is 15:1. The mass ratio of the crosslinking agent system to the reaction system (β-cyclodextrin and ascorbic acid) is 4:1125. The temperature of the crosslinking reaction is 90 °C and the time is 1 h to obtain the physical crosslinked product A solution;

[0080] (2) Disperse carboxymethyl cellulose in water to make a suspension; the absolute dryness of the carboxymethyl cellulose suspension is 3 wt%; mix the physical crosslinked product A solution in step (1) with carboxymethyl cellulose (3 wt%, 5 mL) and N-isopropylacrylamide (1 g); then add the crosslinking agent system ammonium persulfate (200 μL, 1 wt%) and ferric chloride hexahydrate (30 μL, 0.5 g / L) for crosslinking reaction. The mass ratio of ammonium persulfate to ferric chloride hexahydrate is 4:3. The absolute dry mass ratio of the crosslinking agent system to the reaction system (carboxymethyl cellulose, absolute dry physical crosslinked product A solution and N-isopropylacrylamide) is 7:2660. The temperature of the crosslinking reaction is 90 °C and the time is 1 h.

[0081] (3) Dry in a freeze dryer at a temperature below -120 °C for 24 h;

[0082] (4) Select nicotinamide aqueous solution (7 ml, 1 wt%) as the mask efficacy component solution and add it to the aerogel (1.33 g) in (3). Nicotinamide has the effects of whitening and removing spots, and removing acne marks.

[0083] Comparative Example 3

[0084] Preparation method of carboxymethyl cellulose / β-cyclodextrin based (without carboxymethyl cellulose) hydrogel, including the following steps:

[0085] (1) Dissolve β-cyclodextrin (30 g) in alkaline water (420 mL) with pH = 13. The dissolution temperature is 4 °C and the time is 2 h. Add acryloyl chloride (100 g) for acrylation reaction. The reaction temperature is 40 °C and the time is 3 h. Purify to finally obtain the derivative of β-cyclodextrin.

[0086] (2) The derivative of β-cyclodextrin (0.1 g), ascorbic acid (50 μL) and water (1 mL) were mixed, and the mass ratio of the derivative of β-cyclodextrin to ascorbic acid was 2:1; Ammonium persulfate (40 μL, 1%) and ferric chloride hexahydrate (4 μL, 0.01 g / L) in the cross-linking agent system were added for cross-linking reaction. The mass ratio of ammonium persulfate to ferric chloride hexahydrate was 10:1, and the mass ratio of the cross-linking agent system to the reaction system (the derivative of β-cyclodextrin and ascorbic acid) was 22:7500. The temperature of the cross-linking reaction was 90 °C and the time was 1 h to obtain the solution of cross-linked macromolecular chain A.

[0087] (3) The solution of cross-linked macromolecular chain A in step (2) and N-isopropylacrylamide (1 g) were mixed; Ammonium persulfate (40 μL, 1%) and ferric chloride hexahydrate (4 μL, 0.01 g / L) in the cross-linking agent system were added for cross-linking reaction. The mass ratio of ammonium persulfate to ferric chloride hexahydrate was 10:1, and the absolute dry mass ratio of the cross-linking agent system to the reaction system (the absolute dry solution of cross-linked macromolecular chain A and N-isopropylacrylamide) was 11:28750. The temperature of the cross-linking reaction was 90 °C and the time was 1 h.

[0088] (4) Drying was carried out in a freeze dryer at a temperature below -120 °C for 24 h;

[0089] (5) Aqueous nicotinamide solution (7 ml, 1 wt%) was selected as the mask efficacy component solution and added to the aerogel (1.15 g) in (4). Nicotinamide has the effects of whitening, removing spots and removing acne marks.

[0090] Performance comparison between Examples 1-3 and Comparative Examples 1, 2, 3:

[0091] Critical transition temperature test: The gel was placed in a water bath environment with high sensitivity. The water bath temperature was gradually increased from 4 °C at a rate of 1 °C / min. The appearance change of the gel was observed. When the gel changed from transparent to white and changed from the flowing sol state to the gel state, the temperature was the critical transition temperature, and the time used was the conversion time.

[0092] The rheological and tensile properties were tested by a rheometer and a tensile testing machine.

[0093] (1) The critical transition temperature of the material in Comparative Example 1 was 32 °C, and the reaction time was greater than 1 min. Compared with Example 1, the critical transition temperature in Comparative Example 1 was too high and the response time was too long. The tensile strength of Example 1 was 80 Pa, and the elastic modulus G' = 23500 Pa. The tensile strength of Comparative Example 1 was 15 Pa, and the elastic modulus G' = 900 - 3000 Pa. The mechanical strength of Comparative Example 1 was not high, and the tensile property was relatively poor.

[0094] (2) The critical transition temperature of the material in Comparative Example 2 is 19 °C, and the reaction time is greater than 2 s. The tensile strength of Comparative Example 2 is 20 Pa, and the elastic modulus G' = 2000 - 4000 Pa. In Comparative Example 2, only physical crosslinking exists in the cyclodextrin molecules. Therefore, the mechanical strength and tensile properties are poorer than those of Example 1.

[0095] (3) The critical transition temperature of the material in Comparative Example 3 is 23 °C, and the reaction time is about 30 s. The tensile strength of Comparative Example 3 is 10 Pa, and the elastic modulus G' = 200 - 1000 Pa. Compared with Example 1, the carboxymethyl cellulose is absent in Comparative Example 3. Therefore, the mechanical strength is low, and the tensile and film-forming properties are poor.

[0096] (4) Characteristics of Example 1: (1) The critical transition temperature is 19 °C, the reaction time is about 2 s, and it has high mechanical strength, tensile and film-forming properties. (2) Since cyclodextrin has an inner cavity, cyclodextrin can form inclusion compounds with functional molecules (hydrophobic, easily oxidized drugs or functional molecules), which is convenient for transporting and storing functional molecules. However, the cyclodextrin inclusion compounds are easily dispersed in water. After the derivatives of cyclodextrin are crosslinked with ascorbic acid and N-isopropylacrylamide, the strength of the gel is continuously enhanced, and cyclodextrin is not easily dispersed and free outside the gel.

[0097] (5) The main components in the gel are crosslinked macromolecular chain A, carboxymethyl cellulose, and N-isopropylacrylamide. Macroscopically, as the proportion of carboxymethyl cellulose in the total system increases, the critical transition temperature rises. When the ratio of crosslinked macromolecular chain A to carboxymethyl cellulose (the value of crosslinked macromolecular chain A / carboxymethyl cellulose) decreases, the phase transition rate of the gel slows down; and when the ratio of crosslinked macromolecular chain A to carboxymethyl cellulose reaches a certain value, the mechanical strength of the gel reaches the highest. After that, when the ratio of crosslinked macromolecular chain A to carboxymethyl cellulose increases, the mechanical strength of the gel decreases (as shown in Table 1). Therefore, in Examples 1 - 3 (Table 1), the critical transition temperature of Example 1 is the lowest (19 °C), and the tensile strength and elastic modulus are the highest; the tensile strength of Example 2 (75 Pa) is greater than that of Example 3 (61 Pa). The elastic modulus of Example 2 (6700 Pa) is greater than the elastic modulus of Example 3 (4700 Pa). The critical transition temperature (20 °C) and transition speed time (2 s) of Example 2 are better than those of Example 3 (critical transition temperature 23 °C, transition speed time 2 s).

[0098] Table 1

[0099]

[0100] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A method for preparing a carboxymethyl cellulose / β-cyclodextrin temperature-sensitive hydrogel with high mechanical strength and high moisture retention, characterized in that: The following steps are involved: (1) cross-linking reaction of acryloyl-β-cyclodextrin, ascorbic acid and a cross-linking agent system to obtain a macromolecular chain A solution; the cross-linking agent system is ammonium persulfate and ferric chloride hexahydrate; (2) The macromolecular chain A solution is mixed with carboxymethyl cellulose, N-isopropylacrylamide, and a crosslinking agent system to undergo a crosslinking reaction to obtain a carboxymethyl cellulose / β-cyclodextrin thermosensitive hydrogel with high mechanical strength and high moisture retention; the crosslinking agent system is ammonium persulfate and ferric chloride hexahydrate.

2. The preparation method according to claim 1, characterized in that: In step (1), the preparation method of the acryloylated β-cyclodextrin is as follows: β-cyclodextrin is dissolved in alkaline water, and acryloyl chloride is added to react to obtain the acryloylated β-cyclodextrin.

3. The preparation method according to claim 2, characterized in that: The mass ratio of β-cyclodextrin to acryloyl chloride is 10:1 to 1:10; The pH of the alkaline water is 10-14; the volume mass ratio of the alkaline water to β-cyclodextrin is 5:1 ml / g-20:1 ml / g; the dissolution temperature is 0-5°C and the dissolution time is 0.5-5h; The reaction temperature is 20-50°C and the reaction time is 2-12 h.

4. The preparation method according to claim 1, characterized in that: In step (1), the cross-linking reaction is carried out in water, and the mass ratio of water to acryloyl β-cyclodextrin is 5:1 to 20:1; The mass ratio of the acryloylated β-cyclodextrin to ascorbic acid is 1:20 to 20:1; The mass ratio of the crosslinking agent system to the total amount of acryloyl β-cyclodextrin and ascorbic acid is 1: (50-10 4 ); In step (1), the mass ratio of ammonium persulfate to ferric chloride hexahydrate is 1:10 to 10:1; In step (1), the temperature of the cross-linking reaction is 90°C-120°C, and the time is 0.5-4 h.

5. The preparation method according to claim 1, characterized in that: In step (2), the carboxymethyl cellulose is a carboxymethyl cellulose suspension; the absolute dry mass percentage of the carboxymethyl cellulose suspension is 0.1%-5%; In step (2), the absolute dry mass ratio of the macromolecular chain A solution, carboxymethyl cellulose and N-isopropyl acrylamide is (1-100): (1-100): (10-1000); In step (2), the absolute dry mass ratio of the crosslinking agent system to the total amount of carboxymethyl cellulose, macromolecular chain A solution and N-isopropyl acrylamide is 1: (50-10 4 ); The mass ratio of ammonium persulfate to ferric chloride hexahydrate is 1:10 to 10:1; In step (2), the temperature of the cross-linking reaction is 90°C-120°C, and the time is 0.5-4h.

6. The carboxymethyl cellulose / β-cyclodextrin temperature-sensitive hydrogel with high mechanical strength and high moisture retention prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the high mechanical strength and high moisture retention carboxymethyl cellulose / β-cyclodextrin temperature-sensitive hydrogel according to claim 6 in the preparation of self-molding facial masks or wound dressings, characterized in that: The following steps are involved: The carboxymethyl cellulose / β-cyclodextrin temperature-sensitive hydrogel with high mechanical strength and high moisture retention is freeze-dried to obtain an aerogel; a facial mask liquid is added to the aerogel to obtain a self-molding facial mask, or a drug solution is added to the aerogel to obtain a wound dressing.

8. The use according to claim 7, characterized in that: The freeze-drying temperature is below -120°C and the time is more than 12 hours; the mass ratio of the mask liquid to the aerogel is 1:1 to 10:1; the mass ratio of the drug solution to the aerogel is 1:1 to 10:

1.

9. The use according to claim 7, characterized in that: The facial mask liquid contains functional ingredients; the functional ingredients include one or more of whitening, hydrating, anti-inflammatory, calming, repairing, anti-aging, antibacterial and cleaning ingredients.

10. The use according to claim 7, characterized in that: The drug components in the drug solution include one or more of anti-inflammatory, sedative, repairing, antibacterial and cleaning components.

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