Moisture-absorbing resin material using grapefruit white capsules and preparation method of moisture-absorbing resin material

Abstract

The invention discloses a moisture absorption resin material using grapefruit white capsules and a preparation method thereof, and belongs to the technical field of resin materials, and the preparation method comprises the following steps: firstly, treating small grapefruit white capsule blocks with an enzyme, freeze-drying, grinding and sieving to obtain white capsule powder; secondly, mixing the white capsule powder with a dispersing agent, a grafting solution and water, adding starch paste and a monomer, and polymerizing to form a compound; and finally, washing the compound with an ethanol water solution, and drying to obtain the moisture absorption resin material. Compared with the prior art, by accurately controlling the reaction conditions, the prepared resin material has excellent moisture absorption performance and mechanical strength, keeps biocompatibility and biodegradability at the same time, and is suitable for sanitary napkins.

Description

Technical Field

[0001] The invention relates to the technical field of resin materials, and in particular to a hygroscopic resin material utilizing grapefruit white capsules and a preparation method thereof. Background Art

[0002] As society pays more and more attention to environmental protection and sustainable development, the development of new bio-based materials has become an important research direction. Especially in the field of hygroscopic and moisturizing materials, the demand for high-performance, environmentally friendly, and renewable resources is growing. Grapefruit white capsule, as an agricultural byproduct, has become one of the research focuses due to its rich cellulose and hemicellulose content.

[0003] Traditional hygroscopic materials mostly rely on chemically synthesized polymers, such as sodium polyacrylate, which have excellent water absorption properties but have problems such as poor biodegradability and high production costs. In addition, the production process of synthetic polymers is often accompanied by environmental pollution and unsustainable resource consumption.

[0004] In order to solve the above problems, the present invention focuses on using the natural polymer material - grapefruit white capsule, and develops a new type of hygroscopic resin material through bioenzyme treatment and graft copolymerization technology. This material not only maintains the biocompatibility and biodegradability of natural polymers, but also significantly improves its water absorption and water retention capacity through specific chemical modification.

[0005] In terms of preparation method, the present invention adopts freeze drying, ball milling, gelatinization and other processes, which can well maintain the porous structure and chemical composition of grapefruit white capsule. By introducing components such as starch paste and sodium acrylate, and selecting suitable initiators and crosslinking agents, the present invention successfully prepares a resin material with good mechanical properties and water absorption.

[0006] In addition, the preparation process of the present invention is simple, low-cost, and easy to scale up, and has significant social and economic value. Through the present invention, not only a new way is provided for the high-value utilization of grapefruit white capsule, an agricultural byproduct, but also a new idea is provided for the development of high-performance, environmentally friendly hygroscopic materials.

[0007] China's invention patent CN111548463B discloses a hygroscopic resin material using grapefruit white capsule and its preparation method. The raw materials for preparing the hygroscopic resin material include: grapefruit white capsule part, span solution, grafting solution, dispersant, crosslinking agent and initiator, and the grafting solution includes glycerol, acrylamide and sodium alginate. The white capsule part of grapefruit is used as the raw material and combined with the grafting solution to form a hygroscopic material with good pore structure and fiber structure and large specific surface area, and has high water absorption performance. The white capsule of grapefruit peel used has excellent water retention and water absorption, and the fiber component and structure of grapefruit peel white capsule are fully and effectively utilized. The water absorption rate of the prepared hygroscopic resin material can reach more than 450g / g, the raw material source is simple, environmentally friendly and green, the preparation is simple and easy, and it has a wide range of application value. However, the absorption rate of the hygroscopic resin material of the invention to salt water is not high enough, and the mechanical properties are poor. Summary of the invention

[0008] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a hygroscopic resin material using grapefruit white capsule with good hygroscopicity and mechanical properties and a preparation method thereof.

[0009] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0010] A method for preparing a hygroscopic resin material using grapefruit white capsule is as follows:

[0011] Step 1, tearing 80 to 120 portions of grapefruit white capsule into small pieces of 0.5 to 2 cm in size, treating with enzymes, filtering to remove the enzyme, and then freeze-drying, grinding the freeze-dried white capsule small pieces with a ball mill, sieving, and obtaining white capsule powder;

[0012] Step 2, mixing the white capsule powder prepared in step 1 with 1 to 3 parts of a dispersant, 8 to 12 parts of a grafting solution and 80 to 12,000 parts of water and stirring for 1 to 3 hours to obtain a mixture, then mixing 250 to 350 parts of starch with 800 to 1,200 parts of water, gelatinizing at 50 to 70° C. for 50 to 70 minutes to form a starch paste, then mixing the starch paste with the mixture, adding 50 to 70 parts of a monomer, stirring evenly, standing for 15 to 30 hours, heating to 50 to 70° C. and stirring for 30 to 50 minutes, after stopping heating, adding 10 to 30 parts of an initiator and 4 to 6 parts of a cross-linking agent and heating to 70 to 90° C., stirring for 4 to 6 hours to form a composite;

[0013] Step 3: Cool the composite prepared in step 2 to room temperature, then wash it with a 70-80 wt % ethanol aqueous solution to remove unreacted monomers and initiators, and dry it to obtain a hygroscopic resin material.

[0014] The enzyme treatment comprises treating the mixture with 0.4-0.6 parts by weight of acetyl xylan esterase and 0.1-0.3 parts by weight of laccase at 35-45° C. for 1-3 hours, and then treating the mixture with 0.1-0.3 parts by weight of peroxidase at 25-35° C. for 3-8 hours.

[0015] The freeze-drying temperature is -20 to -40°C.

[0016] The sieving is through a 200-400 mesh sieve.

[0017] The dispersant is polyvinyl pyrrolidone.

[0018] The grafting solution is composed of glycerol, acrylamide and sodium alginate in a mass ratio of 1-3:2-4:4-6.

[0019] The monomer is sodium acrylate.

[0020] The initiator is ammonium persulfate.

[0021] The cross-linking agent is 1,3,5-triacryloylhexahydro-1,3,5-triazine.

[0022] The hygroscopic resin material is used in sanitary napkins.

[0023] In the preparation method of the hygroscopic resin material using grapefruit white capsule, the functions of each substance are as follows:

[0024] As the main raw material, grapefruit white capsule provides polysaccharide structures such as cellulose, which is the basic skeleton of hygroscopic resin.

[0025] Acetylxylan esterase is a biological enzyme used to treat grapefruit white capsule to remove acetyl groups and increase the hydrophilicity of polysaccharides, thereby improving hygroscopicity.

[0026] Laccase is another biological enzyme that may be used to further modify white powder and improve its structural properties.

[0027] Peroxidase is used in bleaching and disinfecting processes to remove unwanted colored matter and microorganisms.

[0028] Freeze drying maintains the integrity of the white cyst structure by removing moisture. Since the material is dried in a frozen state, the volume of the material remains almost unchanged, the original porous structure is maintained, and no concentration occurs. Rapid rehydration, the material after freeze drying is loose and porous, and dissolves quickly and completely after adding water, and almost immediately restores its original properties. Compared with traditional drying, the freeze drying process protects some easily oxidized substances. It can maintain the natural characteristics and biological activity of white cysts.

[0029] The freeze-dried white capsules are ground and sieved using a ball mill to obtain uniform white capsule powder in preparation for subsequent reactions.

[0030] Polyvinyl pyrrolidone (dispersant) helps white capsule powder to disperse better in water and prevent agglomeration.

[0031] Grafting solution (glycerol, acrylamide and sodium alginate): used to improve the grafting effect and water absorption of white capsule powder and enhance the structure and performance of the resin.

[0032] Starch is mixed with water and heated to gelatinize, forming a starch paste, which provides additional water absorption when mixed with white capsule powder.

[0033] Sodium acrylate (monomer) as a water-absorbing monomer participates in the polymerization reaction to increase the water absorption of the resin.

[0034] Ammonium persulfate (initiator) starts the polymerization reaction.

[0035] 1,3,5-Triacryloylhexahydro-1,3,5-triazine (cross-linking agent) promotes the connection between polymer chains to form a stable three-dimensional network structure.

[0036] The ethanol aqueous solution is used to wash the synthesized resin, remove unreacted monomers and initiators, and purify the product.

[0037] The solvent in the washed resin is removed by drying to obtain the final hygroscopic resin material.

[0038] Compared with the prior art, it has the following beneficial effects:

[0039] 1) The present invention utilizes grapefruit white capsule to prepare a hygroscopic resin material. Grapefruit white capsule, as an agricultural byproduct, can be converted into a high-value-added hygroscopic resin material through the method of the present invention, thereby realizing the resource utilization of waste.

[0040] 2) The present invention utilizes grapefruit white capsule to prepare the hygroscopic resin material. The entire preparation process adopts biological enzyme treatment and physical freeze-drying technology, which reduces the use of chemical solvents, is more environmentally friendly, and is suitable for use on sensitive skin.

[0041] 3) The present invention utilizes grapefruit white capsule to prepare a hygroscopic resin material by introducing hydrophilic monomers such as starch paste and sodium acrylate, and selecting a suitable initiator and a cross-linking agent. The prepared hygroscopic resin material has good hygroscopic properties and is drier and more comfortable during use.

[0042] 4) The present invention uses grapefruit white capsule to prepare a hygroscopic resin material by controlling the amount of the cross-linking agent and the reaction conditions to obtain a resin material with a certain mechanical strength. The strong tensile performance of the material means that the sanitary napkin is less likely to be damaged during use, providing better durability and comfort. DETAILED DESCRIPTION

[0043] Main sources of substances:

[0044] Grapefruit white capsule: purchased from Guangdong Tongmei Food Co., Ltd.

[0045] Peroxidase: Wuhan KMK Biopharmaceutical Technology Co., Ltd., catalog number: KMKHN6955786.

[0046] Acetylxylan esterase: Nanjing Beiyu Biotechnology Co., Ltd., product number: MZBY-E-AXEAO-3KU.

[0047] Cellulase: Ningxia Xiasheng Industrial Group Co., Ltd., product number: FFG-0672.

[0048] Hemicellulase: Ningxia Xiasheng Industrial Group Co., Ltd., product number: FDG-2255.

[0049] Laccase: Zhengzhou Weifeng Biotechnology Co., Ltd., product number: WF-019, enzyme activity: 100,000.

[0050] Polyvinyl pyrrolidone: Jinhai Iodine Chemical (Qingdao) Co., Ltd., product number: PVP K30.

[0051] Starch: Shenzhen Tuojian Biotechnology Co., Ltd., product number: 2864.

[0052] Example 1

[0053] A method for preparing a hygroscopic resin material using grapefruit white capsule is as follows:

[0054] Step 1, tear 100g of grapefruit white capsule into small pieces of 1cm in size, treat with 0.5g of acetyl xylan esterase and 0.2g of laccase at 40℃ for 2h, and then treat with 0.2g of peroxidase at 30℃ for 5h, filter to remove the enzyme, and then freeze-dry at -40℃, grind the freeze-dried white capsule small pieces with a ball mill, and pass through a 300-mesh sieve to obtain white capsule powder;

[0055] Step 2, the white capsule powder prepared in step 1 is mixed with 2g polyvinyl pyrrolidone, 10g grafting solution and 100g water and stirred for 2h, wherein the grafting solution is composed of glycerol, acrylamide and sodium alginate in a mass ratio of 2:3:5 to obtain a mixture, and then 300g starch is mixed with 1000g water, and gelatinized at 60°C for 60 minutes to form a starch paste, and then the starch paste is mixed with the mixture, and 60g sodium acrylate is added, and after stirring evenly, it is allowed to stand for 24 hours, heated to 60°C and stirred for 40 minutes, and after stopping heating, 10g ammonium persulfate and 5g 1,3,5-triacryloylhexahydro-1,3,5-triazine are added and heated to 80°C, and stirred for 5h to form a complex;

[0056] Step 3: Cool the composite prepared in step 2 to room temperature, then wash it with a 75 wt % ethanol aqueous solution to remove unreacted monomers and initiators, and dry it to obtain a hygroscopic resin material.

[0057] Example 2

[0058] A method for preparing a hygroscopic resin material using grapefruit white capsule is as follows:

[0059] Step 1, tear 100g of grapefruit white capsule into small pieces of 1cm in size, treat with 0.5g of cellulase and 0.2g of laccase at 40℃ for 2h, and then treat with 0.2g of peroxidase at 30℃ for 5h, filter to remove the enzyme, and then freeze-dry at -40℃, grind the freeze-dried white capsule small pieces with a ball mill, and pass through a 300-mesh sieve to obtain white capsule powder;

[0060] Step 2, the white capsule powder prepared in step 1 is mixed with 2g polyvinyl pyrrolidone, 10g grafting solution and 100g water and stirred for 2h, wherein the grafting solution is composed of glycerol, acrylamide and sodium alginate in a mass ratio of 2:3:5 to obtain a mixture, and then 300g starch is mixed with 1000g water, and gelatinized at 60°C for 60 minutes to form a starch paste, and then the starch paste is mixed with the mixture, and 60g sodium acrylate is added, and after stirring evenly, it is allowed to stand for 24 hours, heated to 60°C and stirred for 40 minutes, and after stopping heating, 10g ammonium persulfate and 5g 1,3,5-triacryloylhexahydro-1,3,5-triazine are added and heated to 80°C, and stirred for 5h to form a complex;

[0061] Step 3: Cool the composite prepared in step 2 to room temperature, then wash it with a 75 wt % ethanol aqueous solution to remove unreacted monomers and initiators, and dry it to obtain a hygroscopic resin material.

[0062] Example 3

[0063] A method for preparing a hygroscopic resin material using grapefruit white capsule is as follows:

[0064] Step 1, tear 100g of grapefruit white capsule into small pieces of 1cm in size, treat with 0.5g hemicellulase and 0.2g laccase at 40℃ for 2h, and then treat with 0.2g peroxidase at 30℃ for 5h, filter to remove the enzyme, and then freeze-dry at -40℃, grind the freeze-dried white capsule small pieces with a ball mill, and pass through a 300-mesh sieve to obtain white capsule powder;

[0065] Step 2, the white capsule powder prepared in step 1 is mixed with 2g polyvinyl pyrrolidone, 10g grafting solution and 100g water and stirred for 2h, wherein the grafting solution is composed of glycerol, acrylamide and sodium alginate in a mass ratio of 2:3:5 to obtain a mixture, and then 300g starch is mixed with 1000g water, and gelatinized at 60°C for 60 minutes to form a starch paste, and then the starch paste is mixed with the mixture, and 60g sodium acrylate is added, and after stirring evenly, it is allowed to stand for 24 hours, heated to 60°C and stirred for 40 minutes, and after stopping heating, 10g ammonium persulfate and 5g 1,3,5-triacryloylhexahydro-1,3,5-triazine are added and heated to 80°C, and stirred for 5h to form a complex;

[0066] Step 3: Cool the composite prepared in step 2 to room temperature, then wash it with a 75 wt % ethanol aqueous solution to remove unreacted monomers and initiators, and dry it to obtain a hygroscopic resin material.

[0067] Example 4

[0068] A method for preparing a hygroscopic resin material using grapefruit white capsule is as follows:

[0069] Step 1, tear 100g of grapefruit white capsule into small pieces of 1cm in size, treat with 0.5g of acetyl xylan esterase and 0.2g of laccase at 40℃ for 2h, and then treat with 0.2g of peroxidase at 30℃ for 5h, filter to remove the enzyme, and then freeze-dry at -40℃, grind the freeze-dried white capsule small pieces with a ball mill, and pass through a 300-mesh sieve to obtain white capsule powder;

[0070] Step 2, the white capsule powder prepared in step 1 is mixed with 2g polyvinyl pyrrolidone, 10g grafting solution and 100g water and stirred for 2h, wherein the grafting solution is composed of glycerol, N-(2-hydroxyethyl) acrylamide and sodium hyaluronate in a mass ratio of 2:3:5 to obtain a mixture, and then 300g starch is mixed with 1000g water, and gelatinized at 60°C for 60 minutes to form a starch paste, and then the starch paste is mixed with the mixture, and 60g sodium acrylate is added, and after stirring evenly, it is allowed to stand for 24 hours, heated to 60°C and stirred for 40 minutes, and after stopping heating, 10g ammonium persulfate and 5g 1,3,5-triacryloylhexahydro-1,3,5-triazine are added and heated to 80°C, and stirred for 5h to form a complex;

[0071] Step 3: Cool the composite prepared in step 2 to room temperature, then wash it with a 75 wt % ethanol aqueous solution to remove unreacted monomers and initiators, and dry it to obtain a hygroscopic resin material.

[0072] Example 5

[0073] A method for preparing a hygroscopic resin material using grapefruit white capsule is as follows:

[0074] Step 1, tear 100g of grapefruit white capsule into small pieces of 1cm in size, treat with 0.5g of acetyl xylan esterase and 0.2g of laccase at 40℃ for 2h, and then treat with 0.2g of peroxidase at 30℃ for 5h, filter to remove the enzyme, and then freeze-dry at -40℃, grind the freeze-dried white capsule small pieces with a ball mill, and pass through a 300-mesh sieve to obtain white capsule powder;

[0075] Step 2, the white capsule powder prepared in step 1 is mixed with 2g polyvinyl pyrrolidone, 10g grafting solution and 100g water and stirred for 2h, wherein the grafting solution is composed of glycerol, acrylamide and sodium alginate in a mass ratio of 2:3:5 to obtain a mixture, and then 300g starch is mixed with 1000g water, and gelatinized at 60°C for 60 minutes to form a starch paste, and then the starch paste is mixed with the mixture, and 60g sodium acrylate is added, and after stirring evenly, it is allowed to stand for 24 hours, heated to 60°C and stirred for 40 minutes, and after stopping heating, 10g ammonium persulfate and 5g di[(1-oxo-2-propenyl)amino]-acetic acid are added and heated to 80°C, and stirred for 5h to form a complex;

[0076] Step 3: Cool the composite prepared in step 2 to room temperature, then wash it with a 75 wt % ethanol aqueous solution to remove unreacted monomers and initiators, and dry it to obtain a hygroscopic resin material.

[0077] Example 6

[0078] A method for preparing a hygroscopic resin material using grapefruit white capsule is as follows:

[0079] Step 1, tear 100g of grapefruit white capsule into small pieces of 1cm in size, treat with 0.5g of acetyl xylan esterase and 0.2g of laccase at 40℃ for 2h, and then treat with 0.2g of peroxidase at 30℃ for 5h, filter to remove the enzyme, and then freeze-dry at -40℃, grind the freeze-dried white capsule small pieces with a ball mill, and pass through a 300-mesh sieve to obtain white capsule powder;

[0080] Step 2, the white capsule powder prepared in step 1 is mixed with 2g polyvinyl pyrrolidone, 10g grafting solution and 100g water and stirred for 2h, wherein the grafting solution is composed of glycerol, acrylamide and sodium alginate in a mass ratio of 2:3:5 to obtain a mixture, and then 300g starch is mixed with 1000g water, and gelatinized at 60°C for 60 minutes to form a starch paste, and then the starch paste is mixed with the mixture, and 60g sodium acrylate is added, and after stirring evenly, it is allowed to stand for 24 hours, heated to 60°C and stirred for 40 minutes, and after stopping heating, 10g ammonium persulfate and 5g melamine formaldehyde resin are added and heated to 80°C, and stirred for 5h to form a composite;

[0081] Step 3: Cool the composite prepared in step 2 to room temperature, then wash it with a 75 wt % ethanol aqueous solution to remove unreacted monomers and initiators, and dry it to obtain a hygroscopic resin material.

[0082] Example 7

[0083] A method for preparing a hygroscopic resin material using grapefruit white capsule is as follows:

[0084] Step 1, tear 100g of grapefruit white capsule into small pieces of 1cm in size, treat with 0.5g of acetyl xylan esterase and 0.2g of laccase at 40℃ for 2h, and then treat with 0.2g of peroxidase at 30℃ for 5h, filter to remove the enzyme, and then freeze-dry at -40℃, grind the freeze-dried white capsule small pieces with a ball mill, and pass through a 300-mesh sieve to obtain white capsule powder;

[0085] Step 2, the white capsule powder prepared in step 1 is mixed with 2g polyvinyl pyrrolidone, 10g grafting solution and 100g water and stirred for 2h, wherein the grafting solution is composed of glycerol, acrylamide and sodium alginate in a mass ratio of 2:3:5 to obtain a mixture, and then 300g starch is mixed with 1000g water, and gelatinized at 60°C for 60 minutes to form a starch paste, and then the starch paste is mixed with the mixture, and 60g sodium acrylate is added, and after stirring evenly, it is allowed to stand for 24 hours, heated to 60°C and stirred for 40 minutes, and after stopping heating, 10g ammonium persulfate and 5g N,N"-methylenebisacrylamide are added and heated to 80°C, and stirred for 5h to form a composite;

[0086] Step 3: Cool the composite prepared in step 2 to room temperature, then wash it with a 75 wt % ethanol aqueous solution to remove unreacted monomers and initiators, and dry it to obtain a hygroscopic resin material.

[0087] Comparative Example 1

[0088] A method for preparing a hygroscopic resin material using grapefruit white capsule is as follows:

[0089] Step 1, tear 100g of grapefruit white capsule into small pieces of 1cm in size, freeze-dry at -40°C, grind the freeze-dried white capsule small pieces using a ball mill, and pass through a 300-mesh sieve to obtain white capsule powder;

[0090] Step 2, the white capsule powder prepared in step 1 is mixed with 2g polyvinyl pyrrolidone, 10g grafting solution and 100g water and stirred for 2h, wherein the grafting solution is composed of glycerol, acrylamide and sodium alginate in a mass ratio of 2:3:5 to obtain a mixture, and then 300g starch is mixed with 1000g water, and gelatinized at 60°C for 60 minutes to form a starch paste, and then the starch paste is mixed with the mixture, and 60g sodium acrylate is added, and after stirring evenly, it is allowed to stand for 24 hours, heated to 60°C and stirred for 40 minutes, and after stopping heating, 10g ammonium persulfate and 5g 1,3,5-triacryloylhexahydro-1,3,5-triazine are added and heated to 80°C, and stirred for 5h to form a complex;

[0091] Step 3: Cool the composite prepared in step 2 to room temperature, then wash it with a 75 wt % ethanol aqueous solution to remove unreacted monomers and initiators, and dry it to obtain a hygroscopic resin material.

[0092] Comparative Example 2

[0093] A method for preparing a hygroscopic resin material using grapefruit white capsule is as follows:

[0094] Step 1, tear 100g of grapefruit white capsule into small pieces of 1cm in size, treat with 0.5g of acetyl xylan esterase and 0.2g of laccase at 40℃ for 2h, and then treat with 0.2g of peroxidase at 30℃ for 5h, filter to remove the enzyme, and then freeze-dry at -40℃, grind the freeze-dried white capsule small pieces with a ball mill, and pass through a 300-mesh sieve to obtain white capsule powder;

[0095] Step 2, the white capsule powder prepared in step 1 is mixed with 2g polyvinyl pyrrolidone, 10g grafting solution and 100g water and stirred for 2h, wherein the grafting solution is composed of glycerol, acrylamide and sodium alginate in a mass ratio of 2:3:5 to obtain a mixture, and then 300g starch is mixed with 1000g water, and gelatinized at 60°C for 60 minutes to form a starch paste, and then the starch paste is mixed with the mixture, and 60g sodium acrylate is added, and after stirring evenly, it is allowed to stand for 24 hours, heated to 60°C and stirred for 40 minutes, and after stopping heating, 10g ammonium persulfate is added and heated to 80°C, and stirred for 5h to form a complex;

[0096] Step 3: Cool the composite prepared in step 2 to room temperature, then wash it with a 75 wt % ethanol aqueous solution to remove unreacted monomers and initiators, and dry it to obtain a hygroscopic resin material.

[0097] Comparative Example 3

[0098] A method for preparing a hygroscopic resin material using grapefruit white capsule is as follows:

[0099] Step 1, tear 100g of grapefruit white capsule into small pieces of 1cm in size, treat with 0.5g of acetyl xylan esterase and 0.2g of laccase at 40℃ for 2h, and then treat with 0.2g of peroxidase at 30℃ for 5h, filter to remove the enzyme, and then freeze-dry at -40℃, grind the freeze-dried white capsule small pieces with a ball mill, and pass through a 300-mesh sieve to obtain white capsule powder;

[0100] Step 2, the white capsule powder prepared in step 1 is mixed with 10g of grafting solution and 100g of water and stirred for 2h, wherein the grafting solution is composed of glycerol, acrylamide and sodium alginate in a mass ratio of 2:3:5 to obtain a mixture, and then 300g of starch is mixed with 1000g of water, and gelatinized at 60°C for 60 minutes to form a starch paste, and then the starch paste is mixed with the mixture, and 60g of sodium acrylate is added, and after stirring evenly, it is allowed to stand for 24 hours, heated to 60°C and stirred for 40 minutes, and after stopping heating, 10g of ammonium persulfate and 5g of 1,3,5-triacryloylhexahydro-1,3,5-triazine are added and heated to 80°C, and stirred for 5h to form a composite;

[0101] Step 3: Cool the composite prepared in step 2 to room temperature, then wash it with a 75 wt % ethanol aqueous solution to remove unreacted monomers and initiators, and dry it to obtain a hygroscopic resin material.

[0102] Comparative Example 4

[0103] A method for preparing a hygroscopic resin material is as follows:

[0104] Step 1, 300g of starch and 1000g of water are mixed, and gelatinized at 60°C for 60 minutes to form a starch paste. Then, 60g of sodium acrylate is added to the starch paste, and after stirring evenly, it is allowed to stand for 24 hours, heated to 60°C and stirred for 40 minutes, and after stopping heating, 10g of ammonium persulfate and 5g of 1,3,5-triacryloylhexahydro-1,3,5-triazine are added, and heated to 80°C, and stirred for 5 hours to form a complex;

[0105] Step 2: Cool the composite prepared in step 1 to room temperature, then wash it with a 75 wt % ethanol aqueous solution to remove unreacted monomers and initiators, and dry it to obtain a hygroscopic resin material.

[0106] Test Example 1

[0107] Moisture absorption performance test

[0108] After drying, the hygroscopic resin materials prepared in Examples 1 to 7 of the present invention and Comparative Examples 1 to 4 are crushed using a high-speed universal grinder, sieved using a sample sieve, and the hygroscopicity of the resin with a particle size of less than 1 mm is measured. Take a certain mass of the sieved sample and spread it evenly in a weighing bottle. Place the weighing bottle in the upper space of a sealed container, and a saturated potassium chloride solution is placed in the sealed container. Maintain the temperature of the test environment at 25°C. Use a saturated sodium chloride solution to control the relative humidity to 84%. Place the sample under the set relative humidity conditions for 48 hours, then take out the sample and record the experimental data.

[0109] Calculation of moisture absorption rate: R = (ba) / a

[0110] Where a represents the weight of the resin before moisture absorption, and b represents the weight of the resin after moisture absorption at relative humidity for 24 hours.

[0111] The test results are averaged and are shown in Table 1.

[0112] Table 1

[0113]

[0114]

[0115] Test Example 2

[0116] Tensile properties test

[0117] The mechanical properties of the hygroscopic resin materials prepared in Examples 1 to 7 and Comparative Examples 1 to 4 of the present invention were tested in accordance with the standard and method of GB / T 1040.2-2022 "Determination of tensile properties of plastics Part 2: Test conditions for molded and extruded plastics". Test rate: 10 mm / min, test results recorded: tensile strength (unit: MPa), elongation at break (unit: %).

[0118] Each group was tested 10 times and the average value was taken. The test results are shown in Table 2.

[0119] Table 2

[0120] Experimental protocol Tensile strength(MPa) Elongation at break (%) Example 1 61.4 238.3 Example 2 54.2 200.5 Example 3 56.2 208.9 Example 4 58.6 221.2 Example 5 56.6 211.5 Example 6 56.1 211.0 Example 7 52.4 197.3 Comparative Example 1 57.5 213.2 Comparative Example 2 56.7 205.7 Comparative Example 3 52.1 195.6 Comparative Example 4 49.8 168.9

[0121] It can be seen from test examples 1 to 2 that the hygroscopic resin material obtained in Example 1 of the present invention has a higher moisture absorption rate and stronger tensile properties.

[0122] From Examples 1, 2 and 3, we can see that the main difference is the type of enzyme used. Example 1 uses acetyl xylan esterase, while Example 2 uses cellulase, and Example 3 uses hemicellulase. Acetyl xylan esterase is an enzyme that specifically acts on the removal of acetyl groups on xylan. Acetylation is a common modification of plant cell wall polysaccharides, in which the addition of acetyl groups can increase its hydrophobicity. Acetylated xylan may only be soluble in organic solvents due to the hydrophobicity of acetyl groups, while low-acetylated xylan retains a certain hydrophilicity. Therefore, acetyl xylan esterase may increase the hydrophilicity of xylan in white capsule powder by removing acetyl groups, thereby improving its interaction with water and water absorption capacity. In addition, acetylation modification may also affect the cross-linking between polysaccharides and the structure of the cell wall. The removal of acetyl groups may promote the cross-linking of polysaccharides in white capsule powder, which helps to form a more stable polymer network structure. If cellulase or hemicellulase is used, the fiber structure of the white capsule may be destroyed and the tensile properties may be reduced. This may be the reason why the resin material in Example 1 exhibits strong tensile properties.

[0123] The only difference between Example 1 and Example 4 is the composition of the grafting solution. The acrylamide used in Example 1 is a highly hydrophilic monomer, and its amide group can form hydrogen bonds with water molecules, thereby enhancing water absorption. Although the N-(2-hydroxyethyl) acrylamide used in Example 4 is also hydrophilic, its hydroxyethyl side chain may affect its ability to form hydrogen bonds with water to a certain extent. Sodium alginate is a linear polysaccharide that can provide good flexibility and help form a relatively soft and elastic polymer network. In contrast, although sodium hyaluronate is also a polysaccharide, its structure and molecular weight distribution may be different from those of sodium alginate, which may affect the tensile properties of the final resin. The combination of acrylamide and sodium alginate may be easier to form a uniform cross-linked network, and this network structure helps to improve the water absorption and mechanical strength of the material. The combination of N-(2-hydroxyethyl) acrylamide and sodium hyaluronate may be different when forming a network, which may affect its hygroscopicity and mechanical properties.

[0124] The main difference between Example 1 and other Examples 5 to 7 and Comparative Example 2 lies in the type of cross-linking agent used. The cross-linking agent used in Example 1 is 1,3,5-triacryloylhexahydro-1,3,5-triazine, while the other examples use different types of cross-linking agents or no cross-linking agent. 1,3,5-triacryloylhexahydro-1,3,5-triazine as a cross-linking agent may have the following advantages when compared with di[(1-oxo-2-propenyl)amino]-acetic acid, melamine formaldehyde resin and N,N"-methylenebisacrylamide: 1,3,5-triacryloylhexahydro-1,3,5-triazine contains three acryloyl groups in the molecule, which means that it can react with three different polymer chains to form more cross-linking points, thereby increasing the stability and mechanical strength of the network. The triazine ring structure of 1,3,5-triacryloylhexahydro-1,3,5-triazine may provide a relatively planar and stable chemical environment, which is helpful in the polymerization process. The correct arrangement and crosslinking of polymer chains are maintained during the crosslinking process. In contrast, di[(1-oxo-2-propenyl)amino]-acetic acid usually has two functional groups and may form fewer crosslinking points, but its amino functional group may provide additional hydrogen bonding interactions, affecting water absorption. Melamine formaldehyde resin is a traditional crosslinking agent that usually has a higher crosslinking density and better thermal stability, but it may be more difficult to control the uniformity of crosslinking. N,N"-methylenebisacrylamide contains two acryloyl groups and can form bifunctional crosslinks, but its molecule is smaller and may not be as good as trifunctional 1,3,5-triacryloylhexahydro-1,3,5-triazine in providing mechanical strength. The advantage of 1,3,5-triacryloylhexahydro-1,3,5-triazine is its trifunctional structure, which may provide more crosslinking points when forming a polymer network, thereby enhancing the mechanical properties and stability of the material. In addition, the molecular structure of 1,3,5-triacryloylhexahydro-1,3,5-triazine may help to improve the strength of the material without sacrificing hygroscopicity, which is very important for hygroscopic resin materials.

Claims

1. A method for preparing a hygroscopic resin material using grapefruit white capsules, It is characterized in that The following steps are involved: Step 1, tearing 80 to 120 portions of grapefruit white capsule into small pieces of 0.5 to 2 cm in size, treating with enzymes, filtering to remove the enzyme, and then freeze-drying, grinding the freeze-dried white capsule small pieces with a ball mill, and passing through a 200 to 400 mesh sieve to obtain white capsule powder; Step 2, mixing the white capsule powder prepared in step 1 with 1 to 3 parts of a dispersant, 8 to 12 parts of a grafting solution and 80 to 12,000 parts of water and stirring for 1 to 3 hours to obtain a mixture, then mixing 250 to 350 parts of starch with 800 to 1,200 parts of water, gelatinizing at 50 to 70° C. for 50 to 70 minutes to form a starch paste, then mixing the starch paste with the mixture, adding 50 to 70 parts of a monomer, stirring evenly, standing for 15 to 30 hours, heating to 50 to 70° C. and stirring for 30 to 50 minutes, after stopping heating, adding 10 to 30 parts of an initiator and 4 to 6 parts of a cross-linking agent and heating to 70 to 90° C., stirring for 4 to 6 hours to form a composite; Step 3: Cool the composite prepared in step 2 to room temperature, then wash it with a 70-80 wt % ethanol aqueous solution to remove unreacted monomers and initiators, and dry it to obtain a hygroscopic resin material.

2. The method for preparing the hygroscopic resin material using grapefruit white capsule as claimed in claim 1, It is characterized in that The enzyme treatment comprises treating the mixture with 0.4-0.6 parts by weight of acetyl xylan esterase and 0.1-0.3 parts by weight of laccase at 35-45° C. for 1-3 hours, and then treating the mixture with 0.1-0.3 parts by weight of peroxidase at 25-35° C. for 3-8 hours.

3. The method for preparing the hygroscopic resin material using grapefruit white capsule as claimed in claim 1, It is characterized in that The freeze-drying temperature is -20 to -40°C.

4. The method for preparing the hygroscopic resin material using grapefruit white capsule as claimed in claim 1, It is characterized in that The dispersant is polyvinyl pyrrolidone.

5. The method for preparing the hygroscopic resin material using grapefruit white capsule as claimed in claim 1, It is characterized in that The grafting solution is composed of glycerol, acrylamide and sodium alginate in a mass ratio of 1-3:2-4:4-6.

6. The method for preparing the hygroscopic resin material using grapefruit white capsule as claimed in claim 1, It is characterized in that The monomer is sodium acrylate.

7. The method for preparing the hygroscopic resin material using grapefruit white capsule as claimed in claim 1, It is characterized in that The initiator is ammonium persulfate.

8. The method for preparing the hygroscopic resin material using grapefruit white capsule as claimed in claim 1, It is characterized in that The cross-linking agent is 1,3,5-triacryloylhexahydro-1,3,5-triazine.

9. A hygroscopic resin material using grapefruit white capsule, It is characterized in that The preparation method is as described in any one of claims 1 to 8.

10. An application of a hygroscopic resin material using grapefruit white capsules, It is characterized in that The hygroscopic resin material as claimed in claim 9 is used in a sanitary napkin.

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