CN108219145B - Organic silicon modified starch type slow-release material and preparation method thereof - Google Patents

Abstract

The invention provides an organic silicon modified starch type slow-release material and a preparation method thereof, wherein the organic silicon modified starch type slow-release material is prepared from the following components in parts by weight: 60 parts of starch, 5-10 parts of pasting agent, 25-35 parts of etherifying agent, 1-5 parts of stabilizer, 400 parts of water, 1-5 parts of catalyst, 5-10 parts of acrylic monomer, 1-5 parts of chloroplatinic acid and 5-10 parts of hydrogen-containing silicone oil, wherein the stabilizer is carboxymethyl cellulose. The slow release material prepared by the invention can greatly prolong the service life and the use times of the slow release material, and has better absorption promoting effect on silicon crops such as rice. Because of the low surface energy of the organic silicon, an effect similar to a breathing film is formed on the surface of the soil, water vapor is well controlled to enter and exit the soil, the crops are kept in a state of balanced moisture and salt, the healthy production of the crops is facilitated, and the manual nursing time and the cost are greatly reduced.

Description

Organic silicon modified starch type slow-release material and preparation method thereof

Technical Field

The invention relates to the field of high polymer materials, in particular to an organic silicon modified starch type slow release material and a preparation method thereof.

Technical Field

The slow release technology is that specific measures are taken to slow down the release speed of active substances within a certain time so that the active substances maintain a certain effective concentration in a system. The active ingredients and the slow-release materials can be divided into physical slow release and chemical slow release according to whether the active ingredients and the slow-release materials are subjected to chemical reaction. The prior slow release technology is mainly applied to a medicine slow release material, is used for solving the problem of concentration peak valley of a medicine in a human body, improves the effectiveness of the medicine and avoids adverse reactions.

The research of the slow release material in the fields of agriculture, forestry, pot culture, greening and the like is less compared with the medicine field, and in the application range, the slow release material is required to have longer service life, better suction and release control capability and no harm to the environment. However, the fertilizers applied in agriculture at present can be absorbed and utilized by crops really less, most of the fertilizers are lost due to the influence of self factors and external factors, the utilization rate of the fertilizers is reduced, and meanwhile, serious pollution is brought to the environment. And the traditional fertilizing mode needs a large amount of labor, which does not improve the production efficiency today when the labor cost is increasingly high. Therefore, how to improve the utilization rate of the fertilizer in agriculture is an important problem to be solved urgently at home and abroad.

Disclosure of Invention

In order to solve the problems, the invention aims to provide a slow release material which can be used for a long time, has better absorption and release effects on water and water-soluble substances, improves the slow release validity period, reduces the influence of severe weather (big water, drought and the like) on vegetation production, and reduces the manual nursing cost.

The invention provides an organic silicon modified starch type slow-release material, which is prepared from the following components in parts by weight: : 60 parts of starch, 5-10 parts of pasting agent, 25-35 parts of etherifying agent, 1-5 parts of stabilizer, 400 parts of water, 1-5 parts of catalyst, 5-10 parts of acrylic monomer, 1-5 parts of chloroplatinic acid and 5-10 parts of hydrogen-containing silicone oil, wherein the stabilizer is carboxymethyl cellulose.

Further, the pasting agent is sodium hydroxide, potassium hydroxide and potassium carbonate.

The etherifying agent is propylene oxide.

The catalyst is benzoyl peroxide, potassium persulfate and sodium peroxide.

The acrylic monomer is one or more of acrylic acid, methyl methacrylate and ethyl methacrylate.

The hydrogen-containing silicone oil has the viscosity of 100-10000cps and the hydrogen value of 0.1-1%.

In a second aspect, the present invention provides a method for preparing the above-mentioned organosilicon modified starch slow-release material, which sequentially comprises the following steps:

1) uniformly mixing a pasting agent and water, adding the mixture into starch, stirring at normal temperature, pasting starch milk, adding an etherifying agent, and heating to 50-70 ℃ for etherification reaction;

2) adding a catalyst, stirring uniformly, adding an acrylic monomer, heating to 70-90 ℃ to react for 1-3 hours, and vacuumizing and distilling;

3) adding hydrogen-containing silicone oil and chloroplatinic acid, controlling the temperature at 70-90 ℃, reacting for 1-3 hours, vacuumizing, distilling, cooling, and adding a stabilizer to obtain the organic silicon modified starch type slow-release material.

In a second aspect, the present invention provides a method for preparing the above-mentioned organosilicon modified starch slow-release material, which sequentially comprises the following steps:

1) uniformly mixing a pasting agent and water, adding the mixture into starch, stirring at normal temperature, pasting starch milk, adding an etherifying agent, and heating to 60 ℃ for etherification reaction;

2) adding a catalyst, stirring uniformly, adding an acrylic monomer, heating to 70-90 ℃ to react for 2 hours, and vacuumizing and distilling for 1 hour;

3) adding hydrogen-containing silicone oil and chloroplatinic acid, controlling the temperature at 80 ℃, reacting for 2 hours, vacuumizing and distilling for 1 hour, cooling, and adding a stabilizer to obtain the organic silicon modified starch type slow-release material

The third aspect of the invention provides the application of the organic silicon modified starch type slow release material in the agricultural field.

The using method comprises the following steps: when the slow release material is applied, the required water or other water-soluble substances and the slow release material are uniformly mixed to form a gel object, and then the gel object is covered on the soil surface.

The technical scheme provided by the invention has the following beneficial effects:

1. the organic silicon modified grafted starch can greatly prolong the service life and the use times of the slow-release material, and has better absorption promoting effect on silicon crops such as rice. Because of the low surface energy of the organic silicon, an effect similar to a breathing film is formed on the surface of the soil, water vapor is well controlled to enter and exit the soil, the crops are kept in a state of balanced moisture and salt, the healthy production of the crops is facilitated, and the manual nursing time and the cost are greatly reduced.

2. The slow release material is suitable for various soil environments, has strong tolerance to chemical fertilizers, organic fertilizers and the like, and has a wide application range.

3. The slow release material of the invention does not need to be recovered after use, the effective service life can reach more than 3 months, and the crop production cycle is completely met.

Drawings

FIG. 1: slow release behavior of DSWU under different water absorption conditions (A distilled water; B tap water; C0.9% NaCI).

FIG. 2: slow release behaviour of DSWU in soil (A Urea; B Urea + Water absorbent; C DSWU)

FIG. 3: water retention behavior of DSWU in soil (A blank; B soil + fertilizer (soil/fertilizer: 100/1))

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.

Example 1

1) Uniformly mixing 5g of sodium hydroxide and 300g of water, adding the mixture into 60g of starch, stirring at normal temperature, gelatinizing starch milk, adding 25g of propylene oxide, and heating to 50 ℃ for etherification reaction;

2) adding 1g of benzoyl peroxide, stirring uniformly, adding 5g of acrylic acid, heating to 70 ℃, reacting for 1 hour, and carrying out vacuum distillation for 1 hour;

3) adding 5g of hydrogen-containing silicone oil (with the viscosity of 100cps and the hydrogen content of 0.1%) and 1g of chloroplatinic acid, controlling the temperature at 70 ℃, reacting for 1 hour, vacuumizing and distilling for 1 hour, cooling, and adding 1g of carboxymethyl cellulose to obtain the organic silicon modified starch type slow release material.

Example 2

1) Uniformly mixing 6g of potassium hydroxide and 350g of water, adding the mixture into 60g of starch, stirring at normal temperature, gelatinizing starch milk, adding 30g of propylene oxide, and heating to 60 ℃ for etherification reaction;

2) adding 2g of potassium persulfate, stirring uniformly, adding 7g of methyl methacrylate, heating to 80 ℃, reacting for 3 hours, and carrying out vacuum distillation for 0.5 hour;

3) adding 8g of hydrogen-containing silicone oil (the viscosity is 5000cps, and the hydrogen-containing value is 0.4%) and 3g of chloroplatinic acid, controlling the temperature at 90 ℃, reacting for 1.5 hours, vacuumizing and distilling for 0.3 hour, cooling, and adding 2.5g of carboxymethyl cellulose to obtain the organic silicon modified starch type slow-release material.

Example 3

1) Mixing 7g of potassium carbonate and 400g of water uniformly, adding the mixture into 60g of starch, stirring at normal temperature, gelatinizing starch milk, adding 35g of propylene oxide, and heating to 60 ℃ for etherification reaction;

2) adding 5g of sodium peroxide, stirring uniformly, adding 10g of ethyl methacrylate, heating to 90 ℃, reacting for 3 hours, and vacuumizing and distilling for 2 hours;

3) adding 9g of hydrogen-containing silicone oil (with the viscosity of 10000cps and the hydrogen content of 1%) and 2g of chloroplatinic acid, controlling the temperature at 80 ℃, reacting for 1 hour, vacuumizing and distilling for 1 hour, cooling, and adding 5g of carboxymethyl cellulose to obtain the organic silicon modified starch type slow-release material.

Example 4

1) Uniformly mixing 8g of pasting agent potassium hydroxide and 00g of water, adding the mixture into 60g of starch, stirring at normal temperature, pasting starch milk, adding 25g of propylene oxide, and heating to 60 ℃ for etherification reaction;

2) adding 3g of potassium persulfate, stirring uniformly, adding 3g of acrylic acid and 5g of methyl methacrylate, heating to 75 ℃, reacting for 2 hours, and carrying out vacuum distillation for 1 hour;

3) adding 10g of hydrogen-containing silicone oil (the viscosity is 8000cps, and the hydrogen-containing value is 0.8%) and 3g of chloroplatinic acid, controlling the temperature at 80 ℃, reacting for 2 hours, vacuumizing and distilling for 1 hour, cooling, and adding 3.5g of carboxymethyl cellulose to obtain the organosilicon modified starch type slow-release material.

Example 5

1) Uniformly mixing 7g of sodium hydroxide and 300g of water, adding the mixture into 60g of starch, stirring at normal temperature, gelatinizing starch milk, adding 35g of propylene oxide, and heating to 60 ℃ for etherification reaction;

2) adding 3g of benzoyl peroxide, stirring uniformly, adding 2g of acrylic acid, 4g of methyl methacrylate and 3g of ethyl methacrylate, heating to 80 ℃, reacting for 2 hours, and carrying out vacuum distillation for 1 hour;

3) adding 10g of hydrogen-containing silicone oil (the viscosity is 3000cps, and the hydrogen-containing value is 0.4%) and 1.5g of chloroplatinic acid, controlling the temperature at 80 ℃, reacting for 2 hours, vacuumizing and distilling for 1 hour, cooling, and adding 3.5g of carboxymethyl cellulose to obtain the organosilicon modified starch type slow-release material.

Preparation of N-containing slow release fertilizer (DSWU): 2.98g of urea, 3mL of water and 8mL of the organic silicon modified starch type slow release material prepared in the example 1 are added into a 100mL beaker, stirred until the materials are completely dissolved, the beaker is placed into a constant temperature furnace at 70 ℃, dried until the weight is constant, taken out and crushed to obtain the N-containing slow release fertilizer. Elemental analysis showed that the nitrogen content was 21.2%.

Test example 1: influence of Water absorption on N Slow Release in DSWU

The determination method comprises the following steps: 0.5g of the sample was placed in each beaker containing 200mL of distilled water, tap water, and 0.9% NaCI solution. The beaker was then placed at 25 ℃. At regular intervals (24 hours), 2mL of liquid was removed from the beaker for nitrogen content determination, while 2mL of distilled water was added to keep the amount of solvent constant.

Method for measuring Water absorption: accurately weighing 0.5g DSWU sample, placing into a beaker with 200mL tap water, soaking at room temperature for 90 min, filtering with self-made nylon net (pore diameter 0.076ram), standing for 5 min on the net, taking off and weighing, and recording as M₁The water absorption was calculated as follows:

as a result: the water absorption of DSWU in distilled water, tap water and 0.9% NaCl solution was 142, 76 and 3lg/g, respectively. As can be seen from fig. 1: under different water absorption conditions, the slow release trend of nitrogen in the solution is similar, and the release percentage is gradually increased along with the time. Except that the smaller the water absorption, the smaller the nitrogen release rate.

Test example 2: effect of temperature on N Release in DSWU

The determination method comprises the following steps: a sample (0.5 g) was placed in a beaker containing 200mL of distilled water, and then the beaker was placed at 15, 25 and 35 ℃ respectively. At regular intervals (24 hours), 2mL of liquid was removed from the beaker for nitrogen content determination, while 2mL of distilled water was added to keep the amount of solvent constant.

The nitrogen content of the solution was determined by the Kjeldahl method (Ci). The amount of nitrogen released was calculated using the following formula:

mixing 1g DSWU with 180g dry soil (sieved by a 26-mesh sieve), putting into a 300mL beaker, adding 120g tap water, making 8 in parallel (adding distilled water to keep the water content in each sample unchanged in the experimental process), and taking one in I, 2, 5, 10, 15, 20, 25 and 30 days, respectively, and adding 0.01M CaCl₂The solution is leached to measure the nitrogen content. A blank sample and two control samples are simultaneously made, wherein fertilizer is not added in the blank sample, urea which has nitrogen content such as 1g of N-containing slow release fertilizer and is not treated at all is added in one control sample, and a mixture of 1g of urea particles and super absorbent (self-made sample, the water absorption rate is 250g/g) powder is added in the other control sample, wherein the total nitrogen content of the urea is equal to 1g of DSWU. The nitrogen content in the above samples was determined by the Kasei digestion method. The amount of nitrogen released was calculated using the following formula:

wherein, C_iNitrogen content obtained by determining nitrogen by Kjeldahl, V CaCl₂Volume of solution.

And (4) conclusion: the release behaviour of a mixture of urea, urea and PAA water absorbent, DSWU in soil is shown in figure 2. As can be seen from fig. 2: urea has released more than 95% of its nutrients on the day of addition to the soil (line a in figure 2); whereas the mixture of urea and PAA water absorbent, when added to the soil, released the rate of nutrient release somewhat slower than pure urea (line B in figure 2), but still significantly higher than the nitrogen release rate of DSWU. As shown by line C in fig. 2, DSWU released 10, 16 and 69 wt% nitrogen at days 6, 15 and 90, respectively. The content of the DSWU is not more than 15% at day 2 and not more than 75% at day 28, and the DSWU meets the slow release standard of the European standard committee on slow release fertilizers, and shows that the DSWU has good slow release performance.

Test example 3: determination of maximum water content of soil

The soil used in the experiment was taken from Lanzhou, Gansu, and is typical of the soil in the northwest arid area of China. 2g of DSWU fertilizer and 200g of dry soil (sieved by a 26-mesh sieve) are uniformly mixed, and then the mixture is put into a PVC pipe with the diameter of 4.5cm and the pore diameter of 0.076mm which is wrapped by gauze at the bottom and is weighed as W₁. Suspending the pipe in the air, gradually pouring tap water from the upper part until water seeps out from the bottom, standing, weighing when the water does not seep out, and recording as W₂. Meanwhile, a control experiment is carried out (DSWU fertilizer is not added, and other conditions are the same as the above), and the maximum water content (marked as W%) of the soil is calculated according to the following formula:

and (4) conclusion: experiments show that the maximum water content of the soil without DSWU is 30.2%, and the maximum water content of the soil after DSWU fertilizer is added is 41.8%, which is improved by about 11.6%. The DSWU fertilizer prepared by the method has good water absorption performance in soil, can obviously improve the water content of the soil, and effectively stores rainwater or irrigation water, so that the utilization rate of water resources is improved. This is a great advantage of DSWU over general slow release fertilizers.

Test example 4: determination of soil Water Retention

2g of DSWU fertilizer and 200g of dry soil are mixed uniformly and then are put into a 300mL beaker, 200g of tap water is added, and the weight is recorded as W₁Standing at room temperature, weighing every 5 days, and recording as W₂The observation was continued for 30 days, while a control experiment was performed (without DSWU fertilizer, the other conditions were the same as above). The water loss (denoted as W%) was calculated by the following formula:

and (4) conclusion: fig. 2 shows the results of water retention experiments of DSWU in soil. As can be seen from fig. 2, the water retention of the soil with DSWU was better than that of the soil without DSWU. The water evaporation rate of the soil without DSWU is 47.8% and 98.4% on 30 days and 90 days respectively; the soil water evaporation rate of DSWU is 26.9% and 73.7% at 30 days and 90 days, respectively. After three months, the water content of the soil containing DSWU was about 24.7% higher than that of the soil without DSWU. The DSWU fertilizer prepared by the method has good water absorption capacity and good water retention capacity after being added into soil, can slow down the evaporation of water in the soil, slowly releases the stored water, enables the water to be fully absorbed by crops, effectively improves the utilization rate of water resources, and has good application prospect in arid areas, areas with water shortage or areas with large daily evaporation capacity.

Test example 5: vegetable effect test

And (3) test environment: intelligent greenhouse with total area of 5000m²Selecting 400m²As a test area.

Tomato variety 1: gray (73-571) RZ F1 hybrid.

Tomato variety 2: jiasina (74-112) RZ F1 hybrid.

Common fertilizer: urea, nitrogen content is more than or equal to 46.4%, manufacturer: anhui Spongsheng chemical Co., Ltd; diammonium phosphate with total nutrient not less than 61%, N-available P₂O₅-K₂O (16-45-0), manufacturer: six countries chemical industry, ltd, Anhui. The formula proportion of the two fertilizers is 1: 1.

(1) the composite slow-release water-soluble fertilizer prepared by mixing the carrier of the embodiment 4 of the invention with the common fertilizer is compared with other types of fertilizers, and the total planting area is 400m²And the planting area is divided into 4 planting areas randomly. A common fertilizer is applied to a planting area 1 (tomato variety 1), and the composite slow-release water-soluble fertilizer prepared in the embodiment 4 is applied to a planting area 2 (tomato variety 1); a conventional water soluble fertilizer sold in the market is applied to the planting area 3 (tomato variety 1), and the composite slow-release water soluble fertilizer prepared in the embodiment 4 is applied to the planting area 4 (tomato variety 2).

(2) Before flowering, 10mL of compound slow-release water-soluble fertilizer is applied to root soil of the planting area 2 and the planting area 4 every week; applying 10mL (with the concentration of 0.2%) of common fertilizer to the soil at the root of 1 planting area; and applying 10mL of conventional water-soluble fertilizer to the soil at the roots of the planting area 3.

(3) Applying 20mL of compound slow-release water-soluble fertilizer to the root soil of the planting area 2 and the planting area 4 every 5 days after flowering; applying 20mL (with the concentration of 0.2%) of common fertilizer to the soil at the root of 1 planting area; and applying 20mL of conventional water-soluble fertilizer to the root soil of the 3 planting areas.

(4) Measuring tomato growth indexes, and measuring plant height (from cotyledon node to growth point) by using a ruler; measuring the thickness of the cotyledon node parallel to the cotyledon unfolding direction by using a vernier caliper; analyzing the leaf area by using a desktop scanner and image analysis software; the plants are washed clean by deionized water, the surface moisture is absorbed, the plants are cut at the connection part of roots and stems and are divided into overground parts and underground parts, the fresh weight is measured by a ten-thousandth electronic balance (manufacturer: Shanghai Jinghai apparatus Co., Ltd., model: FA2004N), the plants are de-enzymed in an electric heating constant temperature air-blast drying oven (manufacturer: Shanghai Sanfa scientific apparatus Co., Ltd., model: DHG-9070) at 105 ℃ for 20min, then the temperature is reduced to 70 ℃ and the constant weight is dried, and the dry weight is measured by the ten-thousandth electronic balance. The strong seedling index is calculated according to the following formula:

strong seedling index (stem thickness/height + underground dry weight/above-ground dry weight) × whole plant dry weight.

The influence of the fertilization types on the quantity and the properties of the tomato seedlings is shown in the table 2.

TABLE 2 determination of the influence of fertilization type on the quantity and properties of tomato seedlings

The test result shows that:

compared with other fertilization types, the tomato applying the composite slow-release water-soluble fertilizer has a developed root system; the fruit has strong resistance to the navel rot, good fruit surface luster, regular maturity and good taste; the yield is increased by 25.7 percent compared with the common fertilizer.

Secondly, cucumber (variety: summer light (22-35) RZ F1 hybrid) is subjected to comparative fertilization in an intelligent greenhouse by the same test method, and the test result is obtained in the same way as the tomato test.

The carrier and the water-soluble substance are prepared into the slow-release water-soluble fertilizer, and the slow-release water-soluble fertilizer is only required to be placed on the soil surface in the fertilizing process, so that the slow-release water-soluble fertilizer is convenient to drip irrigation and integrated with water and fertilizer, thereby reducing the labor cost of economic crop planting, saving labor and time, and reducing the later fertilizing cost of crops. Not only can improve the yield of crops, but also can improve the quality of the crops.

It should be understood that the above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, so that the equivalent changes and modifications made in the light of the above disclosure and the appended claims are all within the scope of the present invention.

Claims (2)

1. An organic silicon modified starch type slow release material is characterized in that the organic silicon modified starch type slow release material is prepared from the following components in parts by weight: 60 parts of starch, 5-10 parts of pasting agent, 25-35 parts of etherifying agent, 1-5 parts of stabilizer, 400 parts of water, 1-5 parts of catalyst, 5-10 parts of acrylic monomer, 1-5 parts of chloroplatinic acid and 5-10 parts of hydrogen-containing silicone oil, wherein the stabilizer is carboxymethyl cellulose;

the pasting agent is one of sodium hydroxide, potassium hydroxide and potassium carbonate;

the etherifying agent is propylene oxide;

the catalyst is one of benzoyl peroxide, potassium persulfate and sodium peroxide;

the acrylic monomer is one or more of acrylic acid, methyl methacrylate and ethyl methacrylate;

the hydrogen-containing silicone oil has the viscosity of 100-10000cps and the hydrogen-containing value of 0.1-1%;

the preparation method of the organic silicon modified starch type slow-release material comprises the following steps:

1) uniformly mixing a pasting agent and water, adding the mixture into starch, stirring at normal temperature, pasting the starch milk, and then adding an etherifying agent to carry out etherification reaction;

2) adding a catalyst, stirring uniformly, adding an acrylic monomer, reacting, and vacuumizing and distilling;

3) adding hydrogen-containing silicone oil and chloroplatinic acid, reacting for 1-3 hours, vacuumizing, distilling, cooling, and adding a stabilizer to obtain the organosilicon modified starch type slow-release material.

2. The organosilicon modified starch type slow release material according to claim 1, wherein the preparation method of the organosilicon modified starch type slow release material comprises:

1) uniformly mixing a pasting agent and water, adding the mixture into starch, stirring at normal temperature, pasting starch milk, adding an etherifying agent, and heating to 50-70 ℃ for etherification reaction;

2) adding a catalyst, stirring uniformly, adding an acrylic monomer, heating to 70-90 ℃ to react for 1-3 hours, and vacuumizing and distilling;

3) adding hydrogen-containing silicone oil and chloroplatinic acid, controlling the temperature at 70-90 ℃, reacting for 1-3 hours, vacuumizing, distilling, cooling, and adding a stabilizer to obtain the organic silicon modified starch type slow-release material.

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