Cellulose hydrogel and method of preparing the same, device for preparing the same

Abstract

The application discloses a cellulose hydrogel and a preparation method and a preparation device thereof, wherein the preparation device comprises an ultralow-temperature preservation box, an inner container and a stirrer, and the preparation method comprises the following steps of synthesizing an ice-water mixed solution of urea alkali, adding polysaccharide biomaterials, synthesizing a pre-gel solution and obtaining polysaccharide biomaterial-based hydrogel through gelation. The cellulose hydrogel has a good rapid cooling effect, and does not have a temperature rising phenomenon after long-time use; the cellulose hydrogel can present different color changes at special temperatures of 36.5 DEG C, 37.5 DEG C, 38.5 DEG C and 39.5 DEG C, and has a good temperature indicating function. The cellulose hydrogel preparation method is simple, and the reaction conditions can be well controlled by combining the preparation device, and the cellulose hydrogel is suitable for industrial scale production and use.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of cooling materials, and particularly relates to a cellulose hydrogel and a preparation device and method thereof. BACKGROUND

[0002] Fever, also known as heat, is a condition caused by excessive heat production and reduced heat dissipation due to direct action of heat on the body temperature regulating center, dysfunction of the body temperature center or various reasons, resulting in body temperature rising above the normal range. Although fever can enhance the immune system, it may also be severe enough to affect physical health. Therefore, after fever, reasonable methods should be taken to lower the body temperature to the normal range as soon as possible, and physical cooling is the preferred cooling method.

[0003] Compared with traditional physical cooling methods such as room temperature control, warm water or ethanol bath, ice compress, etc., the high polymer gel cooling patch cooling method as a new type of physical cooling method is widely used due to its simple and convenient operation, and advantages such as not being limited by external conditions. However, most of the hydrogel patches on the market have the following shortcomings: (1) poor heat dissipation effect: although the hydrogel can take away the body heat through the evaporation of its own water, thereby achieving the purpose of local cooling, but due to the low thermal conductivity coefficient, the heat dissipation effect is poor; (2) no temperature indication function: when children have a fever, the body temperature cannot be directly observed after using the cooling patch to reduce the body temperature to the normal level, and parents need to measure the body temperature of infants for a long time, which not only consumes a lot of energy and effort, but also affects the rest of the infants when various instruments are used for body temperature testing; (3) no antibacterial property: the hydrogel contains a large amount of water, and the cooling patch usually contains a lining, which is easy to breed bacteria in a humid environment, causing skin allergy. The raw materials of the existing hydrogel of the cooling patch are mostly synthetic polymers (such as Chinese patent CN113842264A), or natural polymers without antibacterial property (such as Chinese patents CN111568631B, CN101879148B and CN114272434A). SUMMARY

[0004] To solve the above technical problems, the technical scheme adopted by the present application is: a cellulose hydrogel preparation device, comprising an ultra-low temperature preservation box, an inner container and a stirrer, the ultra-low temperature preservation box comprises a box body and a box cover covering the upper end of the box body, the inner container is arranged in the box body, a window hole communicating with the inside of the box body is arranged on the box cover, the stirrer comprises a cover plate, a rotating shaft and a motor, the motor is installed on the cover plate, the rotating shaft is rotatably connected to the cover plate, the motor drives the rotating shaft to rotate, the lower end of the rotating shaft extends into the inner container through the window hole, the cover plate is arranged on the box cover and covers the window hole, and a plurality of stirring blades are connected to the lower end of the rotating shaft.

[0005] As the preferred of the above scheme, the rotating shaft is provided with a plurality of process grooves and a plurality of hinged blocks, the sliding rod is fixedly connected in the process groove, the limiting block and the spring are movably sleeved on the sliding rod, the spring is located above the limiting block and abuts against the limiting block, the sliding rod is parallel to the rotating shaft, the hinged block corresponds to the process groove one by one, the hinged block is fixedly connected with the rotating shaft, the hinged block is located below the corresponding process groove, one end of the stirring blade is fixedly connected with the rotating block, the rotating block and the hinged block are rotatably connected through the hinge shaft, the upper surface of the rotating block is provided with the abutting surface for abutting with the lower surface of the limiting block, and the torsional spring is installed on the hinge shaft.

[0006] As the preferred of the above scheme, the stirring blades are sequentially arranged from bottom to top on the rotating shaft, and the stirring blades are staggered with each other.

[0007] The preparation method of the cellulose hydrogel uses the preparation device and comprises the following steps:

[0008] Step one, the inner container containing ultrapure water is placed in the box body of the ultra-low temperature preservation box, the alkali and urea are placed in the ultrapure water, the box cover is closed, the stirrer is installed, the temperature of the ultra-low temperature preservation box is set to-6℃-0℃, the stirrer is started to stir, and an ice water mixed solution of urea alkali is obtained;

[0009] Step two, the stirrer is lifted, the polysaccharide biomaterial is added into the ice water mixed solution of urea alkali from the window hole, the stirrer is installed back, the temperature of the ultra-low temperature preservation box is controlled to-60-0℃, the stirrer is started to stir for 5-48h, and then is placed for a period of time;

[0010] Step three, the box cover of the ultra-low temperature preservation box is opened, the supernatant in the inner container is taken as a polysaccharide biomaterial dissolution solution, the temperature-sensitive color-changing material and the crosslinking agent are sequentially added into the polysaccharide biomaterial dissolution solution, and the pre-gel solution is obtained after stirring uniformly.

[0011] Step four, the pre-gel solution is placed in the film device, irreversible gelation of the pre-gel solution is induced under room temperature, after the hydrogel is formed, the hydrogel is transferred to a flowing water bath for water washing and replacement, and finally the polysaccharide biomaterial-based hydrogel with precise temperature indication function is obtained.

[0012] As the preferred of the above scheme, the alkali is selected from one of lithium hydroxide, sodium hydroxide or potassium hydroxide, the mass amount of the alkali is 3-12wt% of the mass amount of water, and the mass amount of urea is 6-20wt% of the mass amount of water.

[0013] As the preferred of the above scheme, the polysaccharide biomaterial is one or more of cellulose powder, cotton, wood powder, hemp fiber, viscose, rice straw, sugarcane, chaff, corn cob, tree leaves, chitin and chitosan, and the mass amount of the polysaccharide biomaterial is 1.5-10wt% of the total mass of the ice water mixed solution of urea alkali.

[0014] As the preferred solution of the above-mentioned scheme, the crosslinking agent is any one or more of N,N'-methylenebisacrylamide, polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, N,N'-bis(acryloyl)cystamine, dimethacryloyloxyethyl disulfide, epichlorohydrin; the thermochromic material is a 33℃ thermochromic powder purchased from Shenzhen Fantasy Color Changing Technology; the mass amount of the crosslinking agent is 0.5-20wt% of the mass amount of cellulose; and the mass amount of the thermochromic material is 0.3-2wt% of the mass amount of cellulose.

[0015] The cellulose hydrogel is prepared by the above-mentioned preparation method, and the cellulose hydrogel with the temperature indicating function has obvious color differences at 36.5℃, 37.5℃, 38.5℃ and 39.5℃.

[0016] The cellulose hydrogel has good rapid cooling effect, and does not have temperature rise phenomenon after long-time use, can present different color changes at special temperatures of 36.5℃, 37.5℃, 38.5℃ and 39.5℃, and has good temperature indicating function. The preparation method of the cellulose hydrogel is simple, the reaction conditions can be well controlled by cooperating with the preparation device, and is suitable for industrial scale production and use. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a color development test diagram of the cellulose hydrogel in Example 1;

[0018] Figure 2 is a color development test diagram of the cellulose hydrogel in Example 2;

[0019] Figure 3 is a cooling effect fitting diagram of the cellulose hydrogel in Example 1;

[0020] Figure 4 is a preparation device schematic diagram of the cellulose hydrogel. DETAILED DESCRIPTION

[0021] The technical solutions of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0022] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] Apparatus for preparing cellulose hydrogels, such as Figure 4 As shown, the device includes an ultra-low temperature storage chamber, an inner liner 1, and a stirrer. The ultra-low temperature storage chamber includes a chamber body 2 and a lid covering the upper part of the chamber body 2. The inner liner 1 is placed inside the chamber body 2. The lid has a window hole 3 communicating with the interior of the chamber body 2. The stirrer includes a cover plate 4, a rotating shaft 5, and a motor 6. The motor 6 is mounted on the cover plate 4. The rotating shaft 5 is rotatably connected to the cover plate 4. The motor 6 drives the rotating shaft 5 to rotate. The lower end of the rotating shaft 5 passes through the window hole 3 and extends into the inner liner 1. The cover plate 4 is placed on the lid and covers the window hole 3. The lower end of the rotating shaft 5 is connected to several stirring blades 7, and the stirring blades 7 are hinged to the rotating shaft 5. Considering the requirement for ultra-low temperatures in the cellulose hydrogel reaction process, the designed preparation device can perform feeding and stirring without affecting the ultra-low temperature conditions, fully ensuring the effective conduction of the reaction under the designed conditions. The ultra-low temperature storage chamber is based on an existing ultra-low temperature storage chamber, but the orientation of the door has been changed; other components such as the refrigeration system and control system remain unchanged. This device can also be scaled up for industrial production of this cellulose hydrogel product.

[0025] Further, the rotating shaft 5 is provided with a plurality of process grooves 8 and a plurality of hinged blocks 9, the process grooves 8 are fixedly connected with sliding rods 10, the sliding rods 10 movably sheath limit blocks 11 and springs 12, the springs 12 are above the limit blocks 11 and abut against the limit blocks 11, the sliding rods 10 are parallel to the rotating shaft 5, the hinged blocks 9 correspond to the process grooves 8 one by one, the hinged blocks 9 are fixedly connected with the rotating shaft 5, the hinged blocks 9 are below the corresponding process grooves 8, one end of the stirring blade 7 is fixedly connected with a rotating block 13, the rotating block 13 and the hinged block 9 are rotatably connected through a hinged shaft 14, the upper surface of the rotating block 13 is provided with a fitting surface 15 for abutting against the lower surface of the limit block 11, and the hinged shaft 14 is provided with a torsion spring. When the stirrer is lifted upward, the stirring blade 7 can rotate after colliding with the box cover, so that the stirring blade 7 can be folded, and the whole stirrer can be separated from the box cover. The stirring blade 7 can automatically extend to a horizontal state in a natural state, and can form a good stirring effect after the motor 6 is started.

[0026] Further, the stirring blades 7 are sequentially arranged from bottom to top on the rotating shaft 5, and the stirring blades 7 are staggered with each other. The stirring blades 7 staggered with each other can improve the stirring effect, which is beneficial to the sufficient dissolution of cellulose powder and the acceleration of the reaction process and the improvement of the reaction efficiency.

[0027] Example 1

[0028] An inner container containing a certain amount of ultrapure water is placed in the box body 2 of the ultralow-temperature preservation box, lithium hydroxide and urea are dissolved in the ultrapure water to obtain an alkali / urea mixed solution, the amount of lithium hydroxide is 5wt% of the amount of water, and the amount of urea is 10wt% of the amount of water. Close the box cover, install the stirrer, set the temperature of the ultralow-temperature preservation box to-5℃, start the stirrer to stir, and obtain an ice water mixed solution of urea alkali. A certain amount of cellulose powder is dispersed in the ice water mixed solution of alkali / urea from the window hole, and low-temperature treatment is carried out at-60℃ for 6h, and the stirrer is started to stir for 24h. After the cellulose is fully dissolved, a clear and transparent cellulose alkali / urea aqueous solution is obtained, and the mass amount of cellulose powder is 5wt% of the total mass of the ice water mixed solution of urea alkali. Open the box cover of the ultralow-temperature preservation box, take the polysaccharide biomaterial solution in the inner container, dissolve the thermosensitive color-changing microcapsules and N,N'-methylene bisacrylamide in the cellulose alkali / urea aqueous solution to obtain a cellulose pre-gel solution, the mass amount of the thermosensitive color-changing microcapsules is 0.5wt% of the mass amount of cellulose, and the mass amount of N,N'-methylene bisacrylamide is 0.5wt% of the mass amount of cellulose; the cellulose pre-gel solution is transferred to a film device, and irreversible gelation of cellulose is induced at room temperature. After the hydrogel is formed, it is transferred to a flowing water bath for water replacement and washing, and finally the cellulose hydrogel is obtained.

[0029] Example 2

[0030] The inner container containing a certain amount of ultrapure water is placed in the box body 2 of the ultra-low temperature preservation box, lithium hydroxide and urea are dissolved in the ultrapure water to obtain an alkali / urea mixed solution, the amount of lithium hydroxide is 10 wt% of the amount of water, and the amount of urea is 20 wt% of the amount of water. Close the box cover, install the stirrer, set the temperature of the ultra-low temperature preservation box to -5 DEG C, start the stirrer to stir, and obtain an ice water mixed solution of urea alkali. A certain amount of cellulose powder is dispersed in the ice water mixed solution of alkali / urea from the window hole, and the cellulose is treated at a low temperature of -50 DEG C for 6 h, and the stirrer is started to stir for 24 h. After the cellulose is fully dissolved, a clear and transparent cellulose alkali / urea aqueous solution is obtained, and the mass amount of cellulose powder is 8 wt% of the total mass of the ice water mixed solution of urea alkali. Open the box cover of the ultra-low temperature preservation box, take the polysaccharide biomaterial solution in the inner container, dissolve the temperature-sensitive color-changing microcapsules and N,N'-methylene bisacrylamide in the cellulose alkali / urea aqueous solution to obtain a cellulose pre-gel solution, the mass amount of temperature-sensitive color-changing microcapsules is 1.5 wt% of the mass amount of cellulose, and the mass amount of N,N'-methylene bisacrylamide is 1.0 wt% of the mass amount of cellulose; the cellulose pre-gel solution is transferred to a film container, and the cellulose is induced to undergo irreversible gelation at room temperature. After the hydrogel is formed, it is transferred to a flowing water bath for water replacement, and finally a cellulose hydrogel is obtained.

[0031] The cellulose hydrogels obtained in Examples 1 and 2 are subjected to cooling tests, respectively. The test results of Example 1 are shown in Figure 1 , and the test results of Example 2 are shown in Figure 2 . Figure 3 is the cooling fitting line of the cellulose hydrogel in Example 1. It can be seen that the cellulose hydrogel prepared in the application has obvious color difference at 36.5 DEG C, 37.5 DEG C, 38.5 DEG C and 39.5 DEG C. When it is made into a cooling patch, not only can it utilize the evaporation of water in the hydrogel to take away the heat of the human body, thereby achieving the purpose of rapid local cooling, but also can display the temperature in real time and detect the real-time body temperature of the user.

[0032] It is worth mentioning that the motor and other technical features involved in the present patent application should be regarded as prior art. The specific structure, working principle and possible control method and spatial arrangement method of these technical features can be selected by using conventional methods in the art, and should not be regarded as the invention point of the present patent. The present patent will not be further expanded and described in detail.

[0033] The preferred embodiments of the present application have been described in detail heretofore, it should be understood that those skilled in the art can make many modifications and changes without departing from the spirit of the present application, therefore, any technical solutions obtained by logical analysis, reasoning or limited experiments based on the prior art according to the concept of the present application should be within the protection scope defined by the claims.

Claims

1. A device for the preparation of a polysaccharide bio-based hydrogel, characterized by, The utility model provides a kind of super low temperature preservation box, inner container and stirrer, the super low temperature preservation box includes box body and the box cover of covering on the upper end of box body, the inner container is placed in the inside of box body, the window hole that is connected with the inside of box body is equipped on the box cover, the stirrer includes cover, rotating shaft, motor, the motor is installed on cover, rotating shaft is rotatably connected cover, motor drives rotating shaft rotation, the lower end of rotating shaft is inserted into the inner container through window hole, cover is placed on the box cover and covers window hole, the lower end of rotating shaft is connected with several stirring blades, the stirring blade is hinged with rotating shaft, rotating shaft is equipped with several process grooves and several hinged blocks, sliding rod is fixedly connected in process groove, limit block and spring are movably sleeved on sliding rod, spring is located above limit block and pushes against limit block, sliding rod is parallel with rotating shaft, hinged block corresponds with process groove, hinged block is fixedly connected to rotating shaft, hinged block is located below corresponding process groove, one end of stirring blade is fixedly connected with rotating block, rotating block and hinged block are rotatably connected by hinged shaft, the upper surface of rotating block is equipped with the fit surface for and the lower surface of limit block is fitted, torsion spring is installed on hinged shaft.

2. The device for preparation of polysaccharide-based hydrogel according to claim 1, wherein, The stirring blades are sequentially arranged on the rotating shaft from bottom to top, and the stirring blades are staggered with each other.

3. Process for the preparation of a polysaccharide bio-based hydrogel, characterized in that, The preparation device according to any one of claims 1-2 is used, comprising the following steps: Step one, the inner container containing ultrapure water is placed in the box body of the super low temperature preservation box, the alkali and urea are placed in the ultrapure water, the box cover is closed, the stirrer is installed, the temperature of the super low temperature preservation box is set to -6-0°C, the stirrer is started to stir, and an ice-water mixed solution of urea alkali is obtained; Step two, the stirrer is lifted, the polysaccharide biomaterial is added into the ice-water mixed solution of urea alkali from the window hole, the stirrer is installed back, the temperature of the super low temperature preservation box is controlled to -60-0°C, the stirrer is started to stir for 5-48 h, and then is placed for a period of time; Step three, the box cover of the super low temperature preservation box is opened, the supernatant in the inner container is taken as a polysaccharide biomaterial dissolving solution, the temperature-sensitive color-changing material and the crosslinking agent are sequentially added into the polysaccharide biomaterial dissolving solution, and a pre-gel solution is obtained after stirring uniformly; Step four, the pre-gel solution is transferred to a mold, and is induced to occur irreversible gelation under room temperature conditions, after the hydrogel is formed, is transferred to a flowing water bath for water washing replacement, and finally a polysaccharide biomaterial-based hydrogel with precise temperature indication function is obtained.

4. The method for preparing a polysaccharide-based hydrogel according to claim 3, wherein The alkali is selected from one of lithium hydroxide, sodium hydroxide or potassium hydroxide, and the mass amount of the alkali is 3-12 wt% of the mass amount of water, and the mass amount of urea is 6-20 wt% of the mass amount of water.

5. The method for preparing a polysaccharide-based hydrogel according to claim 3, wherein The polysaccharide biomaterial is one or more of cellulose powder, cotton, wood powder, hemp fiber, viscose, rice straw, sugarcane, chaff, corn cob, tree leaves, chitin and chitosan, and the mass amount of the polysaccharide biomaterial is 1.5-10 wt% of the total mass of the ice-water mixed solution of urea alkali.

6. The method for preparing a polysaccharide-based hydrogel according to claim 3, wherein The crosslinking agent is any one or more of N,N'-methylenebisacrylamide, polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, N,N'-methylenebisacrylamide, dimethacryloyloxyethyldisulfide, epichlorohydrin; the thermochromic material is a 33℃ thermochromic powder; the polysaccharide biomaterial is cellulose powder; the mass amount of the crosslinking agent is 0.5-20 wt% of the mass amount of the cellulose powder; and the mass amount of the thermochromic material is 0.3-2 wt% of the mass amount of the cellulose powder.

7. A polysaccharide bio-based hydrogel, characterized in that, The polysaccharide biomaterial-based hydrogel with temperature indicating function prepared by the method of any one of claims 3-6 has obvious color difference at 36.5℃, 37.5℃, 38.5℃, and 39.5℃.

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