Aperture-controllable polysaccharide aerogel as well as preparation method and application thereof

Abstract

The invention relates to polysaccharide aerogel with a controllable pore size as well as a preparation method and application thereof, and relates to the technical field of filter materials. The polysaccharide aerogel comprises the following components in parts by weight: 5-20 parts of konjak, 10-40 parts of starch, 10-40 parts of fibers, 1-20 parts of a plasticizer, 1-5 parts of a preservative, 0.1-5 parts of syrup, 0.1-5 parts of salt and 1-10 parts of water-absorbent resin. Free water in the glue solution is adsorbed through the water-absorbent resin, the equilibrium condition is achieved, the viscosity of the glue solution is improved, it is avoided that too much free water affects generation of an ice crystal zone, in addition, hydrogel balls uniform in size are formed after the water-absorbent resin absorbs water, and the hydrogel balls occupy a certain space in the glue solution, so that the water absorption effect is improved, and the water absorption efficiency is improved. In the freeze-drying process, the moisture of the hydrogel balls sublimates, so that the space occupied by the hydrogel balls in the original gel liquid forms a uniform pore structure, and the uniformity of the pore structure of the polysaccharide aerogel is improved.

Description

Technical Field

[0001] The present application relates to the technical field of filter materials, and particularly relates to a polysaccharide aerogel with controllable pore size, a preparation method thereof, and an application thereof. Background Art

[0002] An aerogel is a highly dispersed solid material with a nano-porous network structure formed by the mutual aggregation of colloidal particles or polymer molecules, and a gaseous dispersion medium filling the pores. At present, due to its continuous three-dimensional spatial network structure and continuously adjustable density, aerogel materials can be applied to adsorption materials.

[0003] In related technologies, the pore size of the aerogel is mainly generated by removing the space occupied by ice crystals formed by solvent freezing in the aerogel colloidal solution, so as to obtain a porous structure. However, the pore structure generated in this way has uncontrollable size and uneven pore distribution, which affects the filtration performance and adsorption effect of the aerogel during use, and the stability of the prepared product is also poor. Summary of the Invention

[0004] The present application provides a polysaccharide aerogel with controllable pore size, a preparation method thereof, and an application thereof, so as to solve the problems in related technologies that the pore size of the aerogel is uncontrollable and the pore distribution is uneven.

[0005] In order to achieve the above object, in the first aspect of the present application, a polysaccharide aerogel with controllable pore size is provided. The polysaccharide aerogel includes, by weight:

[0006] 5-20 parts of konjac, 10-40 parts of starch, 10-40 parts of fiber, 1-20 parts of plasticizer, 1-5 parts of preservative, 0.1-5 parts of syrup, 0.1-5 parts of salt, and 1-10 parts of water-absorbing resin.

[0007] In some embodiments of the present application, the above water-absorbing resin is pre-treated by water absorption, and the water absorption amount of the pre-treatment of the water-absorbing resin is 50-100 g / g.

[0008] In some embodiments of the present application, the above water-absorbing resin is any one or a combination of several of sodium polyacrylate, polyacrylamide, konjac-modified water-absorbing resin, starch acrylate polymer, starch-acrylonitrile graft copolymer, acrylamide-acrylonitrile-acrylic acid terpolymer.

[0009] In some embodiments of the present application, the above water-absorbing resin is any one or a combination of several of sodium polyacrylate, polyacrylamide or konjac-modified water-absorbing resin, and the particle mesh number of the water-absorbing resin is 50-300 mesh.

[0010] In some embodiments of the present application, the above syrup is any one or a combination of several of malt syrup, golden syrup, fructose syrup, sucrose syrup;

[0011] The concentration of the above-mentioned syrup is 0.01 g / ml - 0.5 g / ml.

[0012] In some embodiments of the present application, the above-mentioned salt is any one or a combination of several of sodium chloride, calcium chloride, and magnesium chloride.

[0013] The second aspect of the present application provides a method for preparing the above-mentioned polysaccharide aerogel, which includes the steps:

[0014] Take 5 - 20 parts of konjac, 10 - 40 parts of starch, 10 - 40 parts of fiber, 1 - 20 parts of plasticizer, 1 - 5 parts of preservative, 0.1 - 5 parts of syrup, and 0.1 - 5 parts of salt, add them to water, mix and stir, and heat up to 80 - 90 °C to obtain a glue solution;

[0015] Take 1 - 10 parts of water-absorbing resin and add it to the above-mentioned glue solution, and stir evenly to obtain a mixture;

[0016] After cooling the above-mentioned mixture to 20 - 35 °C, carry out vacuum freeze-drying to obtain the above-mentioned polysaccharide aerogel.

[0017] In some embodiments of the present application, before adding to the above-mentioned glue solution, it further includes:

[0018] The above-mentioned water-absorbing resin is pre-treated by water absorption, and the water absorption amount of the pre-treatment of the water-absorbing resin is 50 - 100 g / g.

[0019] In some embodiments of the present application, when mixing and stirring and heating up to 80 - 90 °C, the rotation speed is 150 r / min, and the heating rate range is 1 - 2 °C / min;

[0020] Take 1 - 10 parts of water-absorbing resin and add it to the above-mentioned glue solution, and when stirring evenly, the rotation speed is 200 r / min.

[0021] The third aspect of the present application provides an application of the above-mentioned polysaccharide aerogel in a filtering material.

[0022] Compared with the prior art, the present application has at least the following beneficial effects:

[0023] The polysaccharide aerogel provided by the present application, its preparation method and application. The polysaccharide aerogel is prepared by blending a water-absorbing resin and a glue solution. The water-absorbing resin adsorbs the free water in the glue solution to reach an equilibrium condition and increases the viscosity of the glue solution, avoiding the excessive free water from affecting the formation of the ice crystal zone. In addition, the water-absorbing resin forms uniformly sized hydrogel spheres after absorbing water. The hydrogel spheres will occupy a certain space in the glue solution. During the freeze-drying process, the water in the hydrogel spheres sublimes, causing the space originally occupied by the hydrogel spheres in the glue solution to form a uniform pore structure, thereby improving the uniformity of the pore structure of the polysaccharide aerogel and solving the problems in the related art that the pore size of the aerogel cannot be controlled and the pore distribution is uneven. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0025] Figure 1 It is a flowchart of the preparation method of the polysaccharide aerogel in the embodiment of the present application;

[0026] Figure 2 It is a scanning electron microscope of the polysaccharide aerogel in Embodiment 2 of the present application;

[0027] Figure 3 It is a scanning electron microscope of the polysaccharide aerogel in Embodiment 3 of the present application;

[0028] Figure 4 It is a scanning electron microscope of the polysaccharide aerogel in Embodiment 4 of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] To make the objectives, technical solutions and advantages of the present application clearer, the following will clearly and completely describe the technical solutions of the present application in combination with the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0030] In some embodiments, when preparing the aerogel, the pore structure is controlled by controlling the ice crystal size. There are many influencing factors for the ice crystal size, such as the type of solute, the content of inorganic salts, the temperature during freezing, the direction of cold transfer during freezing, the flow rate of cold air during freezing, etc., all of which will affect the growth of ice crystals. From the analysis of the pore size results of the aerogel using the vacuum freeze-drying method, the pore size distribution of such aerogels is extremely uneven, thus affecting the filtration performance and adsorption effect of the aerogel during use, and the stability of the prepared product is also poor; in addition, during the freezing process, due to the high solvent content in the freeze-drying process, large ice crystal bands are likely to appear during the freezing process, which will cause cracks on the surface of the freeze-dried aerogel.

[0031] In view of this, the embodiments of the present application provide a polysaccharide aerogel with controllable pore size. The polysaccharide aerogel is prepared by blending a water-absorbing resin and a glue solution. The water-absorbing resin adsorbs the free water in the glue solution to reach an equilibrium condition, and increases the viscosity of the glue solution, avoiding the excessive free water from affecting the formation of ice crystal bands. In addition, the water-absorbing resin forms uniformly sized hydrogel spheres after absorbing water. The hydrogel spheres will occupy a certain space in the glue solution. During the freeze-drying process, the water in the hydrogel spheres sublimes, causing the space originally occupied by the hydrogel spheres in the glue solution to form a uniform pore structure, thereby improving the uniformity of the pore structure of the polysaccharide aerogel and solving the problems in the related art that the pore size of the aerogel cannot be controlled and the pore distribution is uneven.

[0032] The polysaccharide aerogel of this embodiment includes by weight:

[0033] 5-20 parts of konjac, 10-40 parts of starch, 10-40 parts of fiber, 1-20 parts of plasticizer, 1-5 parts of preservative, 0.1-5 parts of syrup, 0.1-5 parts of salt, and 1-10 parts of water-absorbing resin.

[0034] In this embodiment, the konjac is in powder form and serves as the base material of the polysaccharide aerogel. It can thicken the glue solution, enabling materials such as fibers to be better suspended in the glue solution; form a pre-occupation through the water-absorbing resin to improve the uniformity of the pore structure of the polysaccharide aerogel; by adding a certain amount of syrup and salt, the osmotic pressure of the solvent in the glue solution can be adjusted, thereby controlling the water absorption multiple of the water-absorbing resin and realizing the control of the size of the hydrogel spheres of the water-absorbing resin; in addition, the two can also be used as an antifreeze to regulate the growth of ice crystals, avoiding the appearance of large ice crystal bands during the vacuum freeze-drying process of the aerogel glue solution. Among them, the salt has a greater influence on the water absorption multiple of the water-absorbing resin than the syrup, and the syrup has a better antifreeze effect on the glue solution than the salt, effectively preventing the formation of large ice crystal bands.

[0035] In some embodiments provided by the present application, the above water-absorbing resin is pre-treated by water absorption, and the water absorption amount of the pre-treatment of the water-absorbing resin is 50-100 g / g.

[0036] In this embodiment, due to the relatively high viscosity of the glue solution, by pre-absorbing water with 1-10 parts of the water-absorbing resin, and the weight ratio of the water-absorbing resin to water being 1:50-100, the pre-absorbed water-absorbing resin can be better dispersed in the glue solution.

[0037] Preferably, the water absorption ratio of the above water-absorbing resin in pure water is 100-500 times its own weight.

[0038] In some embodiments provided by the present application, the above water-absorbing resin is any one or a combination of several of sodium polyacrylate, polyacrylamide, konjac-modified water-absorbing resin, starch acrylate polymer, starch-acrylonitrile graft copolymer, acrylamide-acrylonitrile-acrylic acid terpolymer.

[0039] Preferably, the above water-absorbing resin is any one or a combination of several of sodium polyacrylate, polyacrylamide, konjac-modified water-absorbing resin, and the particle mesh number of the water-absorbing resin is 50-300 mesh.

[0040] More preferably, the particle mesh number of the above water-absorbing resin is 100-150 mesh.

[0041] It can be understood that the above konjac-modified water-absorbing resin is a high water-absorbing resin material prepared by modifying konjac. Common modification methods include graft copolymerization, etherification, carboxymethylation, sulfonation, oxidation, cationization, etc.

[0042] In some embodiments provided by the present application, the above syrup is any one or a combination of several of malt syrup, golden syrup, fructose syrup, sucrose syrup.

[0043] The concentration of the above syrup is 0.01 g / ml - 0.5 g / ml.

[0044] In some embodiments provided by the present application, the above salt is any one or a combination of several of sodium chloride, calcium chloride, magnesium chloride.

[0045] The concentration of the above salt is 0.01 g / ml - 1 g / ml.

[0046] As Figure 1 shown, the embodiments of the present application also provide a method for preparing the above polysaccharide aerogel, including the following steps:

[0047] Step S101, add 5-20 parts of konjac, 10-40 parts of starch, 10-40 parts of fiber, 1-20 parts of plasticizer, 1-5 parts of preservative, 0.1-5 parts of syrup, and 0.1-5 parts of salt to water, mix and stir, and heat up to 80-90 °C to obtain a glue solution; where the water is 1000 parts;

[0048] Step S102, add 1-10 parts of the water-absorbing resin to the above glue solution, and stir evenly to obtain a mixture;

[0049] Step S103: After cooling the above mixture to 20 - 35°C, perform vacuum freeze-drying to obtain the above polysaccharide aerogel.

[0050] In this embodiment, uniformly sized water-absorbing resins are used to achieve pre-occupation. Through vacuum freeze-drying, the water in the hydrogel spheres of the mixture can be sublimated, thereby forming a uniform pore structure.

[0051] In some embodiments provided by the present application, in the above step S102, before adding 1 - 10 parts by weight of water-absorbing resin to the above glue solution, it further includes:

[0052] Subject the above 1 - 10 parts by weight of water-absorbing resin to pre-water absorption treatment, and the water absorption amount of the pre-water absorption treatment of the water-absorbing resin is 50 - 100 g / g.

[0053] In this embodiment, the hydrogel spheres formed after pre-water absorption of the water-absorbing resin are poured into the glue solution to occupy the space of the glue solution, which can increase the space occupation effect and the uniformity of occupation.

[0054] In some embodiments provided by the present application, in the above step S101, when mixing and stirring and heating to 80 - 90°C, the rotation speed is 150 r / min, and the heating rate range is 1 - 2°C / min, so as to obtain a glue solution with better mixing effect.

[0055] In the above step S102, when adding 1 - 10 parts by weight of water-absorbing resin to the above glue solution and stirring evenly, the rotation speed is 200 r / min. During this process, the temperature is maintained at 80 - 90°C, and the stirring rotation speed is higher than that in step S101, which can better disperse the water-absorbing resin, ensure full mixing of the materials, and achieve a uniform state.

[0056] The embodiment of the present application also provides an application of the above polysaccharide aerogel in a filter material.

[0057] The technical solutions provided by the present application will be described in detail below with reference to embodiments. If the manufacturer's brand or production method is not specified, the raw materials or equipment used are common raw materials or equipment on the market.

[0058] Example 1:

[0059] Example 1 of the present application provides a polysaccharide aerogel with controllable pore size, and the polysaccharide aerogel includes the following components by weight:

[0060] 5 parts of konjac, 20 parts of starch, 10 parts of fiber, 20 parts of plasticizer, 1 part of preservative, 0.1 part of syrup, 0.5 part of salt, 3 parts of water-absorbing resin, and the mesh number of the water-absorbing resin particles is 50 - 100 mesh.

[0061] Among them, the water-absorbing resin is sodium polyacrylate, the syrup is maltose syrup, the salt is sodium chloride, the plasticizer is glycerol, and the preservative is potassium sorbate.

[0062] Example 1 of the present application also provides a method for preparing the above polysaccharide aerogel, which specifically includes:

[0063] In the first step, take 5 parts of konjac, 20 parts of starch, 10 parts of fiber, 20 parts of plasticizer, 1 part of preservative, 0.1 part of syrup, and 0.5 part of salt, add them to 1000 parts of water, mix and stir, and heat up to 80 °C to obtain a glue solution.

[0064] In the second step, take 3 parts of the water-absorbing resin for pre-water absorption treatment, the weight ratio of the water-absorbing resin to water is 1:50, and then add the water-absorbed water-absorbing resin to the above glue solution and stir evenly to obtain a mixture.

[0065] In the third step, after cooling the above mixture to 25 °C, perform vacuum freeze-drying to obtain the polysaccharide aerogel.

[0066] Example 2

[0067] Example 2 of the present application provides a polysaccharide aerogel with controllable pore size, and the polysaccharide aerogel includes by weight:

[0068] 10 parts of konjac, 20 parts of starch, 10 parts of fiber, 20 parts of plasticizer, 1 part of preservative, 0.5 part of syrup, 1 part of salt, 3 parts of water-absorbing resin, and the mesh number of the water-absorbing resin particles is 100-150 mesh.

[0069] Among them, the water-absorbing resin is polyacrylamide, the syrup is fructose syrup, the salt is sodium chloride, the plasticizer is glycerol, and the preservative is potassium sorbate.

[0070] Example 2 of the present application also provides a method for preparing the above polysaccharide aerogel, which specifically includes:

[0071] In the first step, take 10 parts of konjac, 20 parts of starch, 10 parts of fiber, 20 parts of plasticizer, 1 part of preservative, 0.5 part of syrup, and 1 part of salt, add them to 1000 parts of water, mix and stir, and heat up to 85 °C to obtain a glue solution.

[0072] In the second step, take 3 parts of the water-absorbing resin for pre-water absorption treatment, the weight ratio of the water-absorbing resin to water is 1:50, and then add the water-absorbed water-absorbing resin to the above glue solution and stir evenly to obtain a mixture.

[0073] In the third step, after cooling the above mixture to 25 °C, perform vacuum freeze-drying to obtain the polysaccharide aerogel, and its scanning electron microscope photograph is as Figure 2 shown.

[0074] Example 3

[0075] Example 3 of this application provides a polysaccharide aerogel with controllable pore size. The polysaccharide aerogel includes the following components by weight:

[0076] 10 parts of konjac, 40 parts of starch, 10 parts of fiber, 10 parts of plasticizer, 2 parts of preservative, 0.5 part of syrup, 1 part of salt, 3 parts of water-absorbing resin, and the particle mesh number of the water-absorbing resin is 100 - 150 mesh.

[0077] Among them, the water-absorbing resin is polyacrylamide, the syrup is sucrose syrup, the salt is magnesium chloride, the plasticizer is glycerol, and the preservative is potassium sorbate.

[0078] Example 3 of this application also provides a preparation method of the above polysaccharide aerogel, which specifically includes:

[0079] First step, take 10 parts of konjac, 40 parts of starch, 10 parts of fiber, 10 parts of plasticizer, 2 parts of preservative, 0.5 part of syrup, 1 part of salt, add them to 1000 parts of water, mix and stir, and heat up to 85 °C to obtain a glue solution.

[0080] Second step, take 3 parts of water-absorbing resin for pre-water absorption treatment. The weight ratio of the water-absorbing resin to water is 1:50. Then add the water-absorbed water-absorbing resin to the above glue solution and stir evenly to obtain a mixture.

[0081] Third step, after cooling the above mixture to 20 °C, perform vacuum freeze-drying to obtain the polysaccharide aerogel, and its scanning electron microscope photo is as Figure 3 shown.

[0082] Example 4

[0083] Example 4 of this application provides a polysaccharide aerogel with controllable pore size. The polysaccharide aerogel includes the following components by weight:

[0084] 10 parts of konjac, 10 parts of starch, 40 parts of fiber, 1 part of plasticizer, 5 parts of preservative, 0.5 part of syrup, 5 parts of salt, 1 part of water-absorbing resin, and the particle mesh number of the water-absorbing resin is 50 - 100 mesh.

[0085] Among them, the water-absorbing resin is polyacrylamide, the syrup is malt syrup, the salt is magnesium chloride, the plasticizer is glycerol, and the preservative is potassium sorbate.

[0086] Example 4 of this application also provides a preparation method of the above polysaccharide aerogel, which specifically includes:

[0087] First step, take 10 parts of konjac, 10 parts of starch, 40 parts of fiber, 1 part of plasticizer, 5 parts of preservative, 0.5 part of syrup, 5 parts of salt, add them to 1000 parts of water, mix and stir, and heat up to 85 °C to obtain a glue solution.

[0088] In the second step, 1 part of the water-absorbing resin is taken for pre-water absorption treatment. The weight ratio of the water-absorbing resin to water is 1:50. Subsequently, the water-absorbed water-absorbing resin is added to the above-mentioned glue solution and stirred evenly to obtain a mixture.

[0089] In the third step, after cooling the above mixture to 25 °C, vacuum freeze-drying is carried out to obtain a polysaccharide aerogel, and the scanning electron microscope photograph thereof is as Figure 4 shown.

[0090] Example 5

[0091] Example 5 of the present application provides a polysaccharide aerogel with controllable pore size, and the polysaccharide aerogel includes by weight:

[0092] 20 parts of konjac, 20 parts of starch, 10 parts of fiber, 20 parts of plasticizer, 1 part of preservative, 1 part of syrup, 0.1 part of salt, 10 parts of water-absorbing resin, and the mesh number of the water-absorbing resin particles is 150-200 mesh.

[0093] Among them, the water-absorbing resin is a konjac-modified water-absorbing resin, the syrup is fructose syrup, the salt is calcium chloride, the plasticizer is glycerol, and the preservative is potassium sorbate.

[0094] Example 5 of the present application also provides a method for preparing the above polysaccharide aerogel, which specifically includes:

[0095] In the first step, 20 parts of konjac, 20 parts of starch, 10 parts of fiber, 20 parts of plasticizer, 1 part of preservative, 1 part of syrup, and 0.1 part of salt are taken, added to 1000 parts of water, mixed and stirred, and heated to 90 °C to obtain a glue solution.

[0096] In the second step, 10 parts of the water-absorbing resin are taken for pre-water absorption treatment. The weight ratio of the water-absorbing resin to water is 1:50. Subsequently, the water-absorbed water-absorbing resin is added to the above-mentioned glue solution and stirred evenly to obtain a mixture.

[0097] In the third step, after cooling the above mixture to 30 °C, vacuum freeze-drying is carried out to obtain a polysaccharide aerogel.

[0098] Example 6

[0099] Example 6 of the present application provides a polysaccharide aerogel with controllable pore size, and the polysaccharide aerogel includes by weight:

[0100] 15 parts of konjac, 20 parts of starch, 20 parts of fiber, 5 parts of plasticizer, 1 part of preservative, 5 parts of syrup, 1 part of salt, 3 parts of water-absorbing resin, and the mesh number of the water-absorbing resin particles is 250-300 mesh.

[0101] Among them, the water-absorbing resin is sodium polyacrylate, the syrup is fructose syrup, the salt is calcium chloride, the plasticizer is glycerol, and the preservative is potassium sorbate.

[0102] Example 6 of this application also provides a method for preparing the above polysaccharide aerogel, specifically including:

[0103] In the first step, take 15 parts of konjac, 20 parts of starch, 20 parts of fiber, 5 parts of plasticizer, 1 part of preservative, 5 parts of syrup, and 1 part of salt, add them to 1000 parts of water, mix and stir, and heat up to 90 °C to obtain a glue solution.

[0104] In the second step, take 3 parts of water-absorbing resin for pre-water absorption treatment, the weight ratio of the water-absorbing resin to water is 1:50, then add the water-absorbed water-absorbing resin to the above glue solution, and stir evenly to obtain a mixture.

[0105] In the third step, after cooling the above mixture to 35 °C, carry out vacuum freeze-drying to obtain a polysaccharide aerogel.

[0106] Comparative Example 1

[0107] Comparative Example 1 provides a polysaccharide aerogel with controllable pore size, and this polysaccharide aerogel includes by weight:

[0108] 25 parts of konjac, 45 parts of starch, 20 parts of fiber, 10 parts of plasticizer, 1 part of preservative, 1 part of syrup, and 1 part of salt.

[0109] Among them, the syrup is fructose syrup, the salt is sodium chloride, the plasticizer is glycerol, and the preservative is potassium sorbate.

[0110] Comparative Example 1 also provides a method for preparing the above polysaccharide aerogel, specifically including:

[0111] In the first step, take 25 parts of konjac, 45 parts of starch, 20 parts of fiber, 10 parts of plasticizer, 1 part of preservative, 1 part of syrup, and 1 part of salt, add them to 1000 parts of water, mix and stir, and heat up to 85 °C to obtain a glue solution.

[0112] In the second step, after cooling the above glue solution to 25 °C, carry out vacuum freeze-drying to obtain a polysaccharide aerogel.

[0113] Comparative Example 2

[0114] Comparative Example 2 provides a polysaccharide aerogel with controllable pore size, and this polysaccharide aerogel includes by weight:

[0115] 5 parts of konjac, 45 parts of starch, 45 parts of fiber, 10 parts of plasticizer, 1 part of preservative, 0.1 part of syrup, 0.1 part of salt, 0.5 part of water-absorbing resin, and the particle mesh number of the water-absorbing resin is 100 - 150 meshes.

[0116] Among them, the water-absorbing resin is polyacrylamide, the syrup is fructose syrup, the salt is sodium chloride, the plasticizer is glycerol, and the preservative is potassium sorbate.

[0117] Comparative Example 2 also provides the preparation method of the above polysaccharide aerogel, which specifically includes:

[0118] In the first step, take 5 parts of konjac, 45 parts of starch, 45 parts of fiber, 10 parts of plasticizer, 1 part of preservative, 0.1 part of syrup, and 0.1 part of salt, add them to 1000 parts of water, mix and stir, and heat up to 85 °C to obtain a glue solution.

[0119] In the second step, take 0.5 part of superabsorbent resin for pre-water absorption treatment, the weight ratio of the superabsorbent resin to water is 1:100, then add the water-absorbed superabsorbent resin to the above glue solution, and stir evenly to obtain a mixture.

[0120] In the third step, after cooling the above mixture to 25 °C, carry out vacuum freeze-drying to obtain the polysaccharide aerogel.

[0121] Comparative Example 3

[0122] Comparative Example 3 provides a polysaccharide aerogel with controllable pore size, and the polysaccharide aerogel includes by weight:

[0123] 10 parts of konjac, 20 parts of starch, 20 parts of fiber, 10 parts of plasticizer, 1 part of preservative, 6 parts of syrup, 6 parts of salt, 12 parts of superabsorbent resin, and the particle mesh number of the superabsorbent resin is 100-150 mesh.

[0124] Among them, the superabsorbent resin is polyacrylamide, the syrup is fructose syrup, the salt is sodium chloride, the plasticizer is glycerol, and the preservative is potassium sorbate.

[0125] Comparative Example 3 also provides the preparation method of the above polysaccharide aerogel, which specifically includes:

[0126] In the first step, take 10 parts of konjac, 20 parts of starch, 20 parts of fiber, 10 parts of plasticizer, 1 part of preservative, 6 parts of syrup, and 6 parts of salt, add them to 1000 parts of water, mix and stir, and heat up to 85 °C to obtain a glue solution.

[0127] In the second step, add 12 parts of superabsorbent resin to the above glue solution, and stir evenly to obtain a mixture.

[0128] In the third step, after cooling the above mixture to 25 °C, carry out vacuum freeze-drying to obtain the polysaccharide aerogel.

[0129] The pore sizes of the polysaccharide aerogels of Examples 1-6 and Comparative Examples 1-3 were tested by scanning electron microscopy. Specifically, the polysaccharide aerogel was fixed on the sample stage with conductive glue, and sputter coating was carried out under vacuum conditions. The microstructure of the sample was observed by the JSM6390LV SEM system (JEOL, Tokyo, Japan) at a voltage of 15 kV. The specific parameters are shown in Table 1, and the test results are shown in Table 2.

[0130] Table 1

[0131]

[0132] Table 2

[0133]

[0134] From the data of Example 1 and Example 2, it can be seen that as the content of salt and syrup increases, the water absorption multiple of the water-absorbing resin decreases, and as the content of konjac increases, the free water in the glue solution decreases. Therefore, the size of the ice crystals formed is smaller, and the average diameter of the pores of the polysaccharide aerogel formed after freeze-drying is smaller;

[0135] From the data of Example 2 and Example 3, it can be seen that as the starch content increases significantly, the viscosity of the glue solution increases and the free water content decreases. Therefore, the pore size formed by ice crystal formation decreases, and the overall pore size of the aerogel decreases;

[0136] From the data of Example 2 and Example 4, it can be seen that as the content of fibers increases and the starch content decreases, the ice crystals formed by free water in the glue solution increase. At the same time, the disordered arrangement of fibers in the glue solution will also form relatively large pores, resulting in an increase in the average diameter of the polysaccharide aerogel and a decrease in the content of the water-absorbing resin, increasing the non-uniformity of the pore size of the aerogel;

[0137] From the data of Example 2 and Example 5, it can be seen that as the content of konjac and the water-absorbing resin increases, the free water content in the glue solution decreases significantly. And due to the high content of the water-absorbing resin, the water content in the glue solution system is fixed. Therefore, the water absorption multiple of the water-absorbing resin is limited, and the average pore size of the formed aerogel is the smallest;

[0138] From the data of Example 2 and Example 6, it can be seen that as the content of konjac and syrup increases, the water absorption multiple of the water-absorbing resin in the high-syrup solution decreases. The high-concentration syrup water will inhibit the formation of ice crystals. At the same freezing temperature, the high-concentration syrup reduces the ice crystal growth point. Therefore, the ice crystals formed in the glue solution are larger, resulting in larger pores in the aerogel.

[0139] In Comparative Example 1, due to the excessive content of konjac and starch, the solids in the glue solution are large, the viscosity increases, and the glue solution becomes dough-like, which is not suitable for making aerogels;

[0140] In Comparative Example 2, the content of starch and fibers accounts for a relatively large proportion. As the fiber content increases, it is easy to agglomerate in the glue solution, resulting in uneven dispersion of the aerogel. Therefore, the formed pore structure has a large deviation and the pore sizes are extremely uneven;

[0141] From the data of Examples 2 and 4 and Comparative Example 3, it can be seen that as the content of the water-absorbing resin, as well as the syrup and salt increases, it will cause the water-absorbing resin not to absorb water in the solution. At the same time, it will also cause the ice crystal crystallization point of the entire glue solution to decrease, the ice crystals formed as a whole to increase, and the pores of the aerogel formed to increase and be uneven, resulting in poor filtration performance and adsorption effect of the aerogel.

[0142] The above results illustrate that the water-absorbing resin has a relatively strong polarity and can adsorb the free water in the polysaccharide macromolecular glue solution to reach an equilibrium condition, thereby forming stable hydrogel balls, and will not affect the water content of the water-absorbing resin hydrogel balls during the stirring and blending and freezing processes, thus effectively ensuring the space occupancy effect and the uniformity of the occupancy of the water-absorbing resin.

[0143] In addition, by using water-absorbing resins with different particle sizes and different water absorption ratios, as well as different glue solutions, the water absorption of the water-absorbing resin can be controlled, and the size structure of the aerogel can be better controlled, weakening uncontrollable factors, and forming a polysaccharide aerogel with the required internal pore size.

[0144] In the description of this specification, the description referring to terms such as "one embodiment / way", "some embodiments / ways", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment / way or example are included in at least one embodiment / way or example of this application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment / way or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments / ways or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments / ways or examples described in this specification and the features of different embodiments / ways or examples.

[0145] It should be noted that in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, the element defined by the statement "including one..." does not exclude the existence of another identical element in the process, method, article or device including the said element. In this application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0146] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but rather will be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A polysaccharide aerogel with controllable pore size, characterized in that, The polysaccharide aerogel comprises the following components by weight: 5-20 parts of konjac, 10-40 parts of starch, 10-40 parts of fiber, 1-20 parts of plasticizer, 1-5 parts of preservative, 0.1-5 parts of syrup, 0.1-5 parts of salt, and 1-10 parts of water-absorbing resin.

2. The polysaccharide aerogel according to claim 1, characterized in that: The water-absorbing resin is pre-treated by water absorption, and the water absorption amount of the pre-treated water-absorbing resin is 50-100 g / g.

3. The polysaccharide aerogel according to claim 1, characterized in that: The water-absorbing resin is any one or a combination of several of sodium polyacrylate, polyacrylamide, konjac-modified water-absorbing resin, starch acrylate polymer, starch-acrylonitrile graft copolymer, acrylamide-acrylonitrile-acrylic acid terpolymer.

4. The polysaccharide aerogel according to claim 3, characterized in that: The water-absorbing resin is any one or a combination of several of sodium polyacrylate, polyacrylamide or konjac-modified water-absorbing resin, and the particle mesh number of the water-absorbing resin is 50-300 meshes.

5. The polysaccharide aerogel according to claim 1, characterized in that: The syrup is any one or a combination of several of malt syrup, golden syrup, fructose syrup, sucrose syrup; The concentration of the syrup is 0.01 g / ml - 0.5 g / ml.

6. The polysaccharide aerogel according to claim 1, characterized in that: The salt is any one or a combination of several of sodium chloride, calcium chloride, magnesium chloride.

7. A method for preparing the polysaccharide aerogel according to claim 1, characterized in that, It includes the steps: Take 5-20 parts of konjac, 10-40 parts of starch, 10-40 parts of fiber, 1-20 parts of plasticizer, 1-5 parts of preservative, 0.1-5 parts of syrup, 0.1-5 parts of salt and add them into water, mix and stir and heat up to 80-90 °C to obtain a glue solution; Take 1-10 parts of water-absorbing resin and add it to the glue solution, and stir evenly to obtain a mixture; After cooling the mixture to 20-35 °C, carry out vacuum freeze-drying to obtain the polysaccharide aerogel.

8. The preparation method according to claim 7, characterized in that, Before adding it to the glue solution, it further includes: The water-absorbing resin is pre-treated by water absorption, and the water absorption amount of the pre-treated water-absorbing resin is 50-100 g / g.

9. The preparation method according to claim 7, characterized in that: When mixing and stirring and heating up to 80-90 °C, the rotation speed is 150 r / min, and the heating rate range is 1-2 °C / min; When taking 1-10 parts of water-absorbing resin and adding it to the glue solution and stirring evenly, the rotation speed is 200 r / min.

10. Application of the polysaccharide aerogel according to any one of claims 1-6 in a filter material.

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