Preparation method of corn starch type agricultural water-retaining agent
Agricultural water-retaining agents are prepared by using corn starch as raw material through graft copolymerization and cross-linking reaction, which solves the problems of non-renewable and difficult degradation of traditional petroleum-based materials, achieves the effects of efficient water retention and biodegradation, and is suitable for agriculture and landscaping.
Patent Information
- Application Number
- CN202510773630.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-11
- Publication Date
- 2025-09-23
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Traditional petroleum-based agricultural water-retaining agents rely on non-renewable resources and are difficult to degrade, leading to environmental pollution and high costs, limiting their large-scale application.
Corn starch is used as the main raw material, and the agricultural water-retaining agent is prepared through graft copolymerization and cross-linking reaction. The use of renewable resources ensures that the material is degradable in the natural environment, and the water-retaining performance is improved through the cross-linking structure.
The prepared corn starch-based agricultural water-retaining agent has high water absorption rate and good biodegradability, can significantly improve soil water use efficiency, reduce irrigation frequency, promote crop growth, and reduce environmental pollution risks.
Smart Images
Figure CN120682416A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of agriculture, and in particular to a method for preparing a corn starch-based agricultural water-retaining agent. Background Art
[0002] With the continuous growth of the global population and the impact of climate change, water shortage has become one of the important factors restricting agricultural production. Agricultural water use accounts for more than 70% of global freshwater consumption. How to improve water resource utilization efficiency has become the focus of attention of governments and scientific research institutions around the world. Agricultural water-retaining agents, as functional materials that can absorb and retain water, have shown great application potential in improving soil water retention and increasing crop yields.
[0003] Traditional agricultural water-retaining agents are mostly based on petroleum-based materials such as polyacrylic acid and polyacrylamide. Although these materials have good water absorption and water retention properties, their non-renewable and difficult to degrade nature pose serious environmental problems. First, the preparation process of petroleum-based materials relies on non-renewable fossil resources, and long-term use may lead to resource depletion. Second, these materials are difficult to degrade in the natural environment, and long-term accumulation will cause pollution to soil and water bodies, affecting the ecological balance. In addition, the high cost of petroleum-based water-retaining agents limits their application in large-scale agricultural production. Therefore, technicians in this field provide a method for preparing a corn starch-based agricultural water-retaining agent to solve the problems raised in the above background technology. Summary of the Invention
[0004] (1) Technical problems solved In view of the shortcomings of the existing technology, the present invention provides a method for preparing a corn starch-based agricultural water-retaining agent, which solves the problem that the existing preparation method relies on non-renewable fossil resources and may cause pollution to soil and water bodies after long-term use.
[0005] (2) Technical solution To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for preparing a corn starch-based agricultural water-retaining agent, comprising: preparing raw materials, wherein the raw materials include corn starch, acrylic acid, sodium hydroxide, potassium persulfate, N,N'-methylenebisacrylamide and deionized water; The preparation steps include starch pretreatment, starch graft copolymerization, cross-linking reaction and product treatment; Product performance testing, including water absorption rate testing, water retention performance testing and biodegradability testing; Application examples include agricultural planting and landscaping.
[0006] Preferably, the selection criteria for the raw material preparation are: Corn starch: Use food grade or industrial grade corn starch to ensure that its purity reaches more than 98% and the particle size is 100 mesh to 200 mesh; Acrylic acid: Use analytically pure acrylic acid with a content of ≥99%. High-purity acrylic acid can reduce side reactions and improve the efficiency of graft copolymerization. Sodium hydroxide, use analytical grade sodium hydroxide with a content of ≥96%. Sodium hydroxide is used to adjust the pH value of the reaction system; Potassium persulfate, using analytically pure potassium persulfate with a content of ≥99%, is used as an initiator to trigger the graft copolymerization reaction; N,N'-methylenebisacrylamide, using analytically pure N,N'-methylenebisacrylamide, with a content of ≥98%, as a cross-linking agent, can form a cross-linked structure between polymer chains, thereby improving the strength and stability of the water-retaining agent; Deionized water: Use laboratory-made or purchased deionized water that meets the standards to ensure that there are no impurities and ion interference.
[0007] Preferably, the preparation step comprises the following steps: S1. Starch pretreatment: 100 g corn starch and 500 g deionized water were added to a reactor and stirred at 300 rpm for 10 minutes to ensure that the starch was evenly dispersed in the water. The heating device was turned on and the mixture in the reactor was heated to 85°C. Stirring was maintained at this temperature for 30 minutes. The gelatinization process fully expanded the starch granules and stretched the molecular chains, which is conducive to the subsequent graft copolymerization reaction. The heating device was turned off and the gelatinized starch solution in the reactor was cooled to room temperature to prevent the high temperature from affecting the subsequent reaction. S2. Starch graft copolymerization: 100 g of acrylic acid was slowly added to the cooled gelatinized starch solution at a ratio of 1:1. The mixture was stirred at 500 rpm for 10 minutes using a mechanical stirrer to ensure thorough mixing of the acrylic acid and starch solution. The pH of the reaction system was adjusted to 7 to 8 using a 2M sodium hydroxide solution. This pH adjustment helps control the rate and efficiency of the graft copolymerization reaction. 2 g of potassium persulfate was added as an initiator at a ratio of 0.02:1, and the mixture was stirred evenly. The initiator initiates the graft copolymerization reaction. The reactor was heated to 70°C and stirred at this temperature for 2 hours. During the reaction, the acrylic acid monomers were grafted onto the starch molecular chains to form a graft copolymer. S3. Cross-linking reaction. After the graft copolymerization reaction is completed, 2 g of N, N'-methylenebisacrylamide is added as a cross-linking agent at a mass ratio of 0.02:1 to starch and stirred evenly. The role of the cross-linking agent is to form a cross-linked structure between the polymer chains, thereby improving the strength and stability of the water-retaining agent. The reaction is continued at 70 ° C with stirring for 1 hour to complete the cross-linking reaction. During the reaction, the cross-linking agent forms a three-dimensional network structure between the polymer chains, thereby enhancing the water-retaining performance of the water-retaining agent. S4. Process the product by turning off the heating device and cooling the reaction product to room temperature; repeatedly washing the product with deionized water to remove unreacted monomers and impurities, repeating the washing process 3 to 5 times until the washing water is neutral; drying the washed product at 60°C to constant weight to obtain a corn starch-based agricultural water-retaining agent. A vacuum drying oven or a conventional oven can be used during the drying process.
[0008] Preferably, the product performance test includes: Water absorption rate test: place 1 gram of dry water retaining agent in 1000 ml of deionized water, soak for 24 hours and measure its water absorption rate. The water absorption rate should reach more than 500 times; Water retention performance test: place the water-absorbing water-retaining agent in a natural environment and measure its water retention performance. The water retention performance should be maintained for more than 7 days, and the weight loss should not exceed 10%; Place the water-retaining agent in the soil and measure its biodegradation performance. The biodegradation rate should reach more than 90% and the degradation time should not exceed 3 months.
[0009] Preferably, the application examples include: Agricultural planting: mixing the prepared corn starch-based agricultural water-retaining agent with soil at a ratio of 1:10 and using it to grow corn and wheat can significantly increase crop yield and water use efficiency; When used in landscaping, mixing the water retaining agent with soil in a ratio of 1:20 can reduce the frequency of irrigation and save water resources.
[0010] (3) Beneficial effects The present invention provides a method for preparing a corn starch-based agricultural water-retaining agent. It has the following beneficial effects: In the present invention, corn starch is used as the main raw material. Corn starch comes from renewable crops and is inexhaustible. Compared with traditional petroleum-based water-retaining agents, it reduces dependence on non-renewable resources and conforms to the concept of sustainable development. At the same time, the corn starch-based water-retaining agent can be degraded by microorganisms in the natural environment and eventually converted into carbon dioxide and water, without causing secondary pollution to the soil and water bodies. This solves the problem that traditional petroleum-based water-retaining agents are difficult to degrade and accumulate over a long period of time, causing environmental pollution.
[0011] In the present invention, the water-retaining agent prepared through graft copolymerization and cross-linking reaction has a high water absorption rate and can absorb hundreds or even thousands of times its own weight in water, so that it can effectively retain soil moisture in agricultural applications, reduce irrigation frequency, and save water resources.
[0012] In the present invention, the water-retaining agent can effectively retain soil moisture, reduce drought stress of plants, improve the drought resistance of plants, is applicable to various crops, and can significantly increase crop yield and water use efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 Schematic diagram of the overall preparation process of the present invention. DETAILED DESCRIPTION
[0014] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0015] Example 1: like Figure 1 As shown, an embodiment of the present invention provides a method for preparing a corn starch-based agricultural water-retaining agent, comprising: preparing raw materials, wherein the raw materials include corn starch, acrylic acid, sodium hydroxide, potassium persulfate, N,N'-methylenebisacrylamide and deionized water; The preparation steps include starch pretreatment, starch graft copolymerization, cross-linking reaction and product treatment; Product performance testing, including water absorption rate testing, water retention performance testing and biodegradability testing; Application examples include agricultural planting and landscaping.
[0016] The selection criteria for raw material preparation are: Corn starch: Use food grade or industrial grade corn starch to ensure that its purity reaches more than 98% and the particle size is 100 mesh to 200 mesh; Acrylic acid: Use analytically pure acrylic acid with a content of ≥99%. High-purity acrylic acid can reduce side reactions and improve the efficiency of graft copolymerization. Sodium hydroxide, use analytical grade sodium hydroxide with a content of ≥96%. Sodium hydroxide is used to adjust the pH value of the reaction system; Potassium persulfate, using analytically pure potassium persulfate with a content of ≥99%, is used as an initiator to trigger the graft copolymerization reaction; N,N'-methylenebisacrylamide, using analytically pure N,N'-methylenebisacrylamide, with a content of ≥98%, as a cross-linking agent, can form a cross-linked structure between polymer chains, thereby improving the strength and stability of the water-retaining agent; Deionized water: Use laboratory-made or purchased deionized water that meets the standards to ensure that there are no impurities and ion interference.
[0017] The preparation process includes the following steps: S1. Starch pretreatment: 100 g corn starch and 500 g deionized water were added to a reactor and stirred at 300 rpm for 10 minutes to ensure that the starch was evenly dispersed in the water. The heating device was turned on and the mixture in the reactor was heated to 85°C. Stirring was maintained at this temperature for 30 minutes. The gelatinization process fully expanded the starch granules and stretched the molecular chains, which is conducive to the subsequent graft copolymerization reaction. The heating device was turned off and the gelatinized starch solution in the reactor was cooled to room temperature to prevent the high temperature from affecting the subsequent reaction. S2. Starch graft copolymerization: 100 g of acrylic acid was slowly added to the cooled gelatinized starch solution at a ratio of 1:1. The mixture was stirred at 500 rpm for 10 minutes using a mechanical stirrer to ensure thorough mixing of the acrylic acid and starch solution. The pH of the reaction system was adjusted to 7 to 8 using a 2M sodium hydroxide solution. This pH adjustment helps control the rate and efficiency of the graft copolymerization reaction. 2 g of potassium persulfate was added as an initiator at a ratio of 0.02:1, and the mixture was stirred evenly. The initiator initiates the graft copolymerization reaction. The reactor was heated to 70°C and stirred at this temperature for 2 hours. During the reaction, the acrylic acid monomers were grafted onto the starch molecular chains to form a graft copolymer. S3. Cross-linking reaction. After the graft copolymerization reaction is completed, 2 g of N, N'-methylenebisacrylamide is added as a cross-linking agent at a mass ratio of 0.02:1 to starch and stirred evenly. The role of the cross-linking agent is to form a cross-linked structure between the polymer chains, thereby improving the strength and stability of the water-retaining agent. The reaction is continued at 70 ° C with stirring for 1 hour to complete the cross-linking reaction. During the reaction, the cross-linking agent forms a three-dimensional network structure between the polymer chains, thereby enhancing the water-retaining performance of the water-retaining agent. S4. Process the product by turning off the heating device and cooling the reaction product to room temperature; repeatedly washing the product with deionized water to remove unreacted monomers and impurities, repeating the washing process 3 to 5 times until the washing water is neutral; drying the washed product at 60°C to constant weight to obtain a corn starch-based agricultural water-retaining agent. A vacuum drying oven or a conventional oven can be used during the drying process.
[0018] Product performance testing includes; Water absorption rate test: place 1 gram of dry water retaining agent in 1000 ml of deionized water, soak for 24 hours and measure its water absorption rate. The water absorption rate should reach more than 500 times; Water retention performance test: place the water-absorbing water-retaining agent in a natural environment and measure its water retention performance. The water retention performance should be maintained for more than 7 days, and the weight loss should not exceed 10%; Place the water-retaining agent in the soil and measure its biodegradation performance. The biodegradation rate should reach more than 90% and the degradation time should not exceed 3 months.
[0019] Application examples include: Agricultural planting: mixing the prepared corn starch-based agricultural water-retaining agent with soil at a ratio of 1:10 and using it to grow corn and wheat can significantly increase crop yield and water use efficiency; When used in landscaping, mixing the water retaining agent with soil in a ratio of 1:20 can reduce the frequency of irrigation and save water resources.
[0020] Test example: including the following steps: S1. Preparation of water-retaining agent: weigh 100 g corn starch, add 500 g deionized water, stir well, place the mixture in a constant temperature water bath, heat and stir at 85 ° C for 30 minutes to fully gelatinize the starch, turn off the heating device, and cool the gelatinized starch solution to room temperature; Add 100 g of acrylic acid to the gelatinized starch solution and stir evenly. Use 2 M sodium hydroxide solution to adjust the pH to 7 to 8. Add 2 g of potassium persulfate as an initiator and stir evenly. Place the reaction system in a constant temperature water bath at 70°C and stir for 2 hours. Add 2 g of N,N'-methylenebisacrylamide as a cross-linking agent, stir evenly, and continue stirring and reacting at 70°C for 1 hour; Turn off the heating device, cool the reaction product to room temperature, repeatedly wash the product with deionized water to remove unreacted monomers and impurities, repeat the washing process 3 to 5 times until the washing water is neutral, place the washed product in a vacuum drying oven, and dry it at 60° C. to constant weight to obtain a corn starch-based agricultural water-retaining agent; S2. Performance test, water absorption test: weigh 1 gram of dry water-retaining agent, put it into 1000 ml of deionized water, and soak it at room temperature for 24 hours to allow it to fully absorb water. Filter out excess water with a filter, weigh the water-retaining agent after water absorption, and calculate the water absorption rate using the following formula: , For the water retention performance test, place the water-retaining agent after absorbing water in a natural environment, weigh it once a day, record the weight change, and observe continuously for 7 days. The water retention rate area calculation formula of the water-retaining agent is: , For the biodegradability test, the water retaining agent was buried in the soil at a depth of about 10 cm. Samples were taken out every week to observe their morphological changes, weigh and record them. The observation was continued for 12 weeks, and the biodegradation rate was calculated using the following formula: , For actual application test, select a test field, mix water retaining agent with soil at a ratio of 1:10, plant corn, set up control group and experimental group, regularly measure soil moisture and crop growth, and record crop yield; Test results and discussion: The test results show that the water absorption rate of the water retaining agent is 550 times, which shows that the water retaining agent has excellent water absorption performance. After 7 days of observation, the water retention rate of the water retaining agent remained above 85%, showing good water retention performance; After 12 weeks of testing, the biodegradation rate of the water retaining agent reached 92%, indicating that it has good biodegradability in the natural environment; The soil moisture in the experimental group was significantly higher than that in the control group, and the corn grew well, with yields increasing by about 20%. This indicates that the water retaining agent can effectively improve the soil's water retention capacity and promote crop growth. This test example verifies that the preparation method of the corn starch-based agricultural water-retaining agent is feasible and that the water-retaining agent has excellent water absorption, water retention, and biodegradation properties. In actual agricultural applications, the water-retaining agent can significantly increase soil moisture, promote crop growth, and increase crop yield. These results demonstrate the effectiveness and application value of the present invention in agricultural production.
[0021] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the invention, and the scope of the invention is defined by the appended claims and their equivalents.
Claims
1. A method for preparing a corn starch-based agricultural water-retaining agent, characterized in that: include: preparing raw materials, wherein the raw materials include corn starch, acrylic acid, sodium hydroxide, potassium persulfate, N,N'-methylenebisacrylamide and deionized water; The preparation steps include starch pretreatment, starch graft copolymerization, cross-linking reaction and product treatment; Product performance testing, including water absorption rate testing, water retention performance testing and biodegradability testing; Application examples include agricultural planting and landscaping.
2. The method for preparing a corn starch-based agricultural water-retaining agent according to claim 1, wherein: The selection criteria for the raw material preparation are: Corn starch: Use food grade or industrial grade corn starch to ensure that its purity reaches more than 98% and the particle size is 100 mesh to 200 mesh; Acrylic acid: Use analytically pure acrylic acid with a content of ≥99%. High-purity acrylic acid can reduce side reactions and improve the efficiency of graft copolymerization. Sodium hydroxide, use analytical grade sodium hydroxide with a content of ≥96%. Sodium hydroxide is used to adjust the pH value of the reaction system; Potassium persulfate, using analytically pure potassium persulfate with a content of ≥99%, is used as an initiator to trigger the graft copolymerization reaction; N,N'-methylenebisacrylamide, using analytically pure N,N'-methylenebisacrylamide, with a content of ≥98%, as a cross-linking agent, can form a cross-linked structure between polymer chains, thereby improving the strength and stability of the water-retaining agent; Deionized water: Use laboratory-made or purchased deionized water that meets the standards to ensure that there are no impurities and ion interference.
3. The method for preparing a corn starch-based agricultural water-retaining agent according to claim 1, wherein: The preparation step comprises the following steps: S1. Starch pretreatment: 100 g corn starch and 500 g deionized water were added to a reactor and stirred at 300 rpm for 10 minutes to ensure that the starch was evenly dispersed in the water. The heating device was turned on and the mixture in the reactor was heated to 85°C. Stirring was maintained at this temperature for 30 minutes. The gelatinization process fully expanded the starch granules and stretched the molecular chains, which is conducive to the subsequent graft copolymerization reaction. The heating device was turned off and the gelatinized starch solution in the reactor was cooled to room temperature to prevent the high temperature from affecting the subsequent reaction. S2. Starch graft copolymerization: 100 g of acrylic acid was slowly added to the cooled gelatinized starch solution at a ratio of 1:
1. The mixture was stirred at 500 rpm for 10 minutes using a mechanical stirrer to ensure thorough mixing of the acrylic acid and starch solution. The pH of the reaction system was adjusted to 7 to 8 using a 2M sodium hydroxide solution. This pH adjustment helps control the rate and efficiency of the graft copolymerization reaction. 2 g of potassium persulfate was added as an initiator at a ratio of 0.02:1, and the mixture was stirred evenly. The initiator initiates the graft copolymerization reaction. The reactor was heated to 70°C and stirred at this temperature for 2 hours. During the reaction, the acrylic acid monomers were grafted onto the starch molecular chains to form a graft copolymer. S3. Cross-linking reaction. After the graft copolymerization reaction is completed, 2 g of N, N'-methylenebisacrylamide is added as a cross-linking agent at a mass ratio of 0.02:1 to starch and stirred evenly. The role of the cross-linking agent is to form a cross-linked structure between the polymer chains, thereby improving the strength and stability of the water-retaining agent. The reaction is continued at 70 ° C with stirring for 1 hour to complete the cross-linking reaction. During the reaction, the cross-linking agent forms a three-dimensional network structure between the polymer chains, thereby enhancing the water-retaining performance of the water-retaining agent. S4. Process the product by turning off the heating device and cooling the reaction product to room temperature; repeatedly washing the product with deionized water to remove unreacted monomers and impurities, repeating the washing process 3 to 5 times until the washing water is neutral; drying the washed product at 60°C to constant weight to obtain a corn starch-based agricultural water-retaining agent. A vacuum drying oven or a conventional oven can be used during the drying process.
4. The method for preparing a corn starch-based agricultural water-retaining agent according to claim 1, wherein: The product performance tests include: Water absorption rate test: place 1 gram of dry water retaining agent in 1000 ml of deionized water, soak for 24 hours and measure its water absorption rate. The water absorption rate should reach more than 500 times; Water retention performance test: place the water-absorbing water-retaining agent in a natural environment and measure its water retention performance. The water retention performance should be maintained for more than 7 days, and the weight loss should not exceed 10%; Place the water-retaining agent in the soil and measure its biodegradation performance. The biodegradation rate should reach more than 90% and the degradation time should not exceed 3 months.
5. The method for preparing a corn starch-based agricultural water-retaining agent according to claim 1, wherein: The application examples include: Agricultural planting: mixing the prepared corn starch-based agricultural water-retaining agent with soil at a ratio of 1:10 and using it to grow corn and wheat can significantly increase crop yield and water use efficiency; When used in landscaping, mixing the water retaining agent with soil in a ratio of 1:20 can reduce the frequency of irrigation and save water resources.