CN114287421B - A kind of anti-ultraviolet biopesticide compound microcapsule and preparation method thereof - Google Patents

Abstract

The invention provides an anti-ultraviolet biological pesticide composite microcapsule and a preparation method thereof, belonging to the technical field of pesticide microcapsules. The invention provides an anti-ultraviolet biological pesticide composite microcapsule, which comprises a microcapsule capsule wall material and biological pesticide wrapped in the microcapsule capsule wall material; the microcapsule material is polyurethane, and the microcapsule material contains lignin-inorganic semiconductor nano-composite. According to the invention, the lignin-inorganic semiconductor nano-composite is introduced into the microcapsule capsule wall material as an ultraviolet shielding agent, and under the illumination condition, photo-generated electrons are transferred to lignin molecules under the traction action of lignin unsaturated bonds, so that the separation of photo-generated electron-hole pairs in a semiconductor can be promoted, and the ultraviolet resistance of the microcapsule capsule wall material can be remarkably improved; meanwhile, lignin has the characteristic of antioxidation, and can eliminate photodegradation of biological pesticides by the photocatalytic activity of semiconductors.

Description

A kind of anti-ultraviolet biopesticide compound microcapsule and preparation method thereof

technical field

The invention relates to the technical field of pesticide microcapsules, in particular to an anti-ultraviolet biological pesticide composite microcapsule and a preparation method thereof.

Background technique

In recent years, the development of green agriculture has become the main theme of agricultural production. Biological pesticides have advantages in the fields of organic agriculture, pollution-free agriculture and green agricultural pest control. Biopesticide refers to the use of living organisms (fungi, bacteria, insect viruses, genetically modified organisms, natural enemies, etc.) or their metabolites (pheromones, auxins, naphthaleneacetic acid, 2,4-D, etc.) to kill agricultural pests or Inhibitory preparations. Compared with chemical pesticides, biological pesticides have the advantages of strong selectivity, harmless to humans and animals, and little impact on the environment.

Pesticide microencapsulation technology can coat the active substances of solid and liquid pesticides in degradable capsules to make tiny capsules. Making bio-pesticides into microcapsules can endow pesticides with good slow-release performance, which can prolong the duration of the drug by 2 to 3 times; after bio-pesticides are made into microcapsules, the amount of the original drug can be reduced to 1/2 of the original amount ~1/3, significantly reducing the amount of pesticide application.

However, most biopesticides have the characteristics of UV degradation. After biopesticides are applied to outdoor fields, ultraviolet rays in sunlight will induce their photodegradation, which reduces the field control effect of biopesticides.

Contents of the invention

In view of this, the object of the present invention is to provide an anti-ultraviolet biopesticide composite microcapsule and a preparation method thereof. The anti-ultraviolet biopesticide composite microcapsule provided by the present invention has good anti-ultraviolet degradation performance.

In order to achieve the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

The invention provides an anti-ultraviolet biopesticide composite microcapsule, comprising a microcapsule material and a biopesticide wrapped in the microcapsule material;

The material of the microcapsule material is polyurethane, and the material of the microcapsule contains lignin-inorganic semiconductor nanocomposite.

Preferably, the lignin-inorganic semiconductor composite material is one of lignin- _TiO2 nanocomposites, lignin-ZnO nanocomposites, lignin- _SiO2 nanocomposites and lignin- _CeO2 nanocomposites species or several.

Preferably, the content of the lignin-inorganic semiconductor nanocomposite in the microcapsule material is 30-50wt%.

Preferably, the preparation method of the lignin-TiO _{nanocomposite} comprises the following steps:

Mix quaternized alkali lignin, inorganic acid, butyl titanate and water for hydrothermal reaction to obtain lignin- _TiO2 nanocomposite;

The preparation method of described lignin-SiO _{nanocomposite} comprises the following steps:

Mix quaternized alkali lignin, inorganic acid, ethyl orthosilicate and water for hydrothermal reaction to obtain lignin- _TiO2 nanocomposite;

The preparation method of the lignin-ZnO nanocomposite comprises the following steps:

Mix quaternized alkali lignin, inorganic alkali, soluble zinc salt and water, carry out hydrothermal reaction, adjust the pH value to 6-8, and obtain lignin-ZnO nanocomposite;

The preparation method of described lignin-CeO _{nanocomposite} comprises the following steps:

Mix the quaternized alkali lignin, inorganic alkali, soluble cerium salt and water, carry out hydrothermal reaction, adjust the pH value to 7.8, and obtain the lignin- _CeO2 nanocomposite.

Preferably, the biopesticide is gibberellin, emamectin benzoate, matrine, liuyangmycin, abamectin, methoxyabamectin, Jinggangmycin, polyoxin, ningnanmycin , Zhongshengmycin and agricultural anti-12 in one or more.

Preferably, the particle size of the lignin-inorganic semiconductor composite material is 150-300 nm, and the particle size of the ultraviolet-resistant biological pesticide composite microcapsule is 500-800 nm.

The invention provides a preparation method of the above-mentioned anti-ultraviolet biopesticide composite microcapsules, comprising the following steps:

Mix biopesticides, isocyanate compounds and organic solvents to obtain an oil phase;

mixing the lignin-inorganic semiconductor nanocomposite, co-emulsifier and water to obtain an aqueous phase;

The oil phase and the water phase are mixed and emulsified to obtain an O/W Pickering emulsion;

The O/W type Pickering emulsion is mixed with a chain extender to carry out interfacial polymerization reaction to obtain the anti-ultraviolet biopesticide composite microcapsules.

Preferably, the isocyanate compounds are toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, tetramethylxylylene diisocyanate, One or more of isocyanate and lysine diisocyanate;

The chain extender is polyol and/or polyamine.

Preferably, the mass ratio of the isocyanate compound to the biological pesticide is 2-15:5-25;

The mass ratio of the isocyanate compound to the lignin-inorganic semiconductor nanocomposite is 2-15:1-5;

The mass ratio of the isocyanate compound to the chain extender is 2-15:1-5.

Preferably, the temperature of the interfacial polymerization reaction is 50-80° C., and the time is 2-5 hours.

The invention provides an anti-ultraviolet biological pesticide composite microcapsule, comprising a microcapsule material and a biological pesticide wrapped in the microcapsule material; the material of the microcapsule material is polyurethane, and the microcapsule material is polyurethane. Contains lignin-inorganic semiconductor nanocomposites. In the invention, the lignin-inorganic semiconductor nanocomposite is introduced into the microcapsule material as an ultraviolet shielding agent. Under the condition of light, photogenerated electrons are transferred to lignin molecules under the traction of lignin unsaturated bonds, which can promote The separation of photogenerated electron-hole pairs can significantly improve the anti-ultraviolet performance of microcapsule materials; at the same time, lignin has anti-oxidation properties, which can eliminate the photodegradation of biological pesticides caused by the photocatalytic activity of semiconductors. In the present invention, polyurethane has the advantages of excellent mechanical properties, thermal stability, good biocompatibility, etc., and the lignin-inorganic semiconductor nanocomposite is added to the biopesticide microcapsule suspension system as a Pickering emulsifier to further improve The anti-ultraviolet photolysis performance of the original drug.

Description of drawings

Fig. 1 is the microstructure picture of the obtained anti-ultraviolet biological pesticide composite microcapsule of the embodiment of the present invention 1;

Fig. 2 is the anti-ultraviolet effect of the obtained anti-ultraviolet biological pesticide composite microcapsules of the embodiment of the present invention 1;

Fig. 3 is the anti-ultraviolet effect of the obtained anti-ultraviolet biological pesticide composite microcapsule of the embodiment of the present invention 2;

Fig. 4 is the anti-ultraviolet effect of the obtained anti-ultraviolet biological pesticide composite microcapsules of the embodiment of the present invention 3;

Figure 5 shows the anti-ultraviolet effect of the anti-ultraviolet biological pesticide composite microcapsules obtained in Example 4 of the present invention.

Detailed ways

The invention provides an anti-ultraviolet biopesticide composite microcapsule, comprising a microcapsule material and a biopesticide wrapped in the microcapsule material;

The material of the microcapsule material is polyurethane, and the material of the microcapsule contains lignin-inorganic semiconductor nanocomposite.

In the present invention, the lignin-inorganic semiconductor composite material is preferably lignin- _TiO nanocomposite, lignin-ZnO nanocomposite, lignin- _SiO nanocomposite and lignin- _CeO nanocomposite One or more of them; in the present invention, the particle size of the lignin-inorganic semiconductor composite material is preferably 150-300 nm, more preferably 200-250 nm.

The content of the lignin-inorganic semiconductor nanocomposite in the microcapsule material is preferably 30-50 wt%, more preferably 35-45%, more preferably 40%.

In the present invention, the preparation method of the lignin- _TiO nanocomposite preferably comprises the following steps:

Mix quaternized alkali lignin, inorganic acid, butyl titanate and water for hydrothermal reaction to obtain lignin- _TiO2 nanocomposite.

The present invention has no special requirements on the source of the quaternized alkali lignin (QAL), and conventional commercially available quaternized alkali lignin in the field can be used or self-prepared. When preparing the quaternized alkali lignin by itself, the preparation method preferably includes:

The alkali lignin is mixed with 3-chloro-2-hydroxypropyl ammonium chloride for substitution reaction to obtain quaternized alkali lignin.

In the present invention, the mass ratio of the alkali lignin (AL) to 3-chloro-2-hydroxypropylammonium chloride is preferably 1-10:1, more preferably 3-6:1.

In the present invention, the mixing method is preferably stirring and mixing, and the temperature of the substitution reaction is preferably 70-90° C., more preferably 80-85° C.; the time is preferably 4 hours.

After the substitution reaction, the present invention preferably performs post-treatment on the obtained substitution reaction liquid. In the present invention, the post-treatment preferably includes:

The obtained substitution reaction solution is dialyzed and freeze-dried to obtain a quaternized alkali lignin solid.

In the present invention, the molecular weight cut-off of the dialysis is preferably 1000-5000, more preferably 2000-3000. The present invention has no special requirements on the freeze-drying method, and the freeze-drying method known to those skilled in the art can be used.

The invention mixes quaternized alkali lignin, inorganic acid, butyl titanate and water to carry out hydrothermal reaction. In the present invention, the inorganic acid is preferably hydrochloric acid and/or sulfuric acid, and the concentration of the inorganic acid is preferably 20-50 wt%, more preferably 30-40 wt%. In the present invention, the quaternized alkali lignin is preferably mixed with water to obtain an aqueous solution with a concentration of 20-60 wt%, and then the pH value of the obtained aqueous solution is adjusted to 1-5, more preferably 2-3, by using inorganic acid.

In the present invention, the mass ratio of the quaternized alkali lignin to butyl titanate is preferably 1:3˜3:1.

In the present invention, the temperature of the hydrothermal reaction is preferably 100° C., and the time is preferably 6 hours.

After the hydrothermal reaction, the present invention preferably separates the obtained hydrothermal reaction liquid from solid to liquid, washes and dries the solid to obtain the lignin-TiO ₂ nanocomposite solid.

In the present invention, the preparation method of the lignin- _SiO nanocomposite preferably comprises the following steps:

Mix quaternized alkali lignin, inorganic acid, ethyl orthosilicate and water for hydrothermal reaction to obtain lignin- _TiO2 nanocomposite.

In the present invention, the source of the quaternized alkali lignin is the same as above, and will not be repeated here.

In the present invention, the specific preparation process of the lignin- _SiO2 nanocomposite is similar to that of the lignin- _TiO2 nanocomposite, the only difference being that the raw material butyl titanate is replaced by tetraethyl orthosilicate, which is not mentioned here. Let me repeat.

In the present invention, the preparation method of the lignin-ZnO nanocomposite preferably comprises the following steps:

Mix quaternized alkali lignin, inorganic alkali, soluble zinc salt and water, carry out hydrothermal reaction, adjust pH value to 6-8, more preferably 7.8, and obtain lignin-ZnO nanocomposite.

In the present invention, the source of the quaternized alkali lignin is the same as above, and will not be repeated here. In the present invention, the inorganic base is preferably NaOH. In the present invention, the quaternized alkali lignin is preferably mixed with water to obtain an aqueous solution with a concentration of 20-60 wt%, and then the pH value of the obtained aqueous solution is adjusted to 8-12, more preferably 9-10, by using an inorganic base.

In the present invention, the soluble zinc salt is preferably one or more of zinc acetate, zinc chloride, zinc nitrate and zinc sulfate. In the present invention, the mass ratio of the quaternized alkali lignin to the soluble zinc salt is preferably 1:3˜3:1.

In the present invention, the temperature of the hydrothermal reaction is preferably 85° C., and the time is preferably 4 hours.

After the hydrothermal reaction, the present invention preferably separates the obtained hydrothermal reaction liquid from solid to liquid, washes and dries the solid to obtain the lignin-ZnO nanocomposite.

In the present invention, the preparation method of the lignin- _CeO nanocomposite preferably comprises the following steps:

Mix the quaternized alkali lignin, inorganic alkali, soluble cerium salt and water, carry out hydrothermal reaction, adjust the pH value to 7.8, and obtain the lignin- _CeO2 nanocomposite.

In the present invention, the source of the quaternized alkali lignin is the same as above, and will not be repeated here. In the present invention, the inorganic base is preferably NaOH. In the present invention, the quaternized alkali lignin is preferably mixed with water to obtain an aqueous solution with a concentration of 20-60 wt%, and then the pH value of the obtained aqueous solution is adjusted to 8-12, more preferably 9-10, by using an inorganic base.

In the present invention, the soluble cerium salt is preferably one or more of cerium sulfate, cerium nitrate and cerium chloride. In the present invention, the mass ratio of the quaternized alkali lignin to the soluble cerium salt is preferably 1:3˜3:1.

In the present invention, the temperature of the hydrothermal reaction is preferably 65° C., and the time is preferably 4 hours.

After the hydrothermal reaction, the present invention preferably separates the obtained hydrothermal reaction liquid from solid to liquid, washes and dries the solid to obtain the lignin-CeO ₂ nanocomposite.

In the present invention, the biopesticide is preferably gibberellin, emamectin benzoate, matrine, liuyangmycin, avermectin, methoxyabamectin, Jinggangmycin, polyoxin, One or more of Nanbactin, Zhongshengmycin and Nongkang 12. In the present invention, the mass content of the biopesticide in the anti-ultraviolet biopesticide composite microcapsules is preferably 2-20%, more preferably 5-15%, and even more preferably 10%.

In the present invention, the particle size of the anti-ultraviolet biopesticide composite microcapsules is preferably 500-800 nm, more preferably 600-700 nm.

The invention provides a preparation method of the above-mentioned anti-ultraviolet biopesticide composite microcapsules, comprising the following steps:

Mix biopesticides, isocyanate compounds and organic solvents to obtain an oil phase;

mixing the lignin-inorganic semiconductor nanocomposite, co-emulsifier and water to obtain an aqueous phase;

The oil phase and the water phase are mixed and emulsified to obtain an O/W Pickering emulsion;

The O/W type Pickering emulsion is mixed with a chain extender to carry out interfacial polymerization reaction to obtain the anti-ultraviolet biopesticide composite microcapsules.

The invention mixes biological pesticides, isocyanate compounds and organic solvents to obtain an oil phase. In the present invention, the isocyanate compounds are toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, tetramethylphthalylene One or more of base diisocyanate and lysine diisocyanate.

In the present invention, the organic solvent is preferably n-butyl acetate, isobutyl acetate, sec-butyl acetate, N,N-dimethyloctylamide, N,N-dimethyldecylamide, No. 200 solvent oil And one or more of No. 150 solvent naphtha.

In the present invention, the mass ratio of the isocyanate compound to the biological pesticide is preferably 2-15:5-25, more preferably 5-10:10-15.

In the present invention, the mass ratio of the isocyanate compound to the organic solvent is preferably 2-15:5-20, more preferably 5-10:10-15.

The present invention has no special requirements on the mixing method, and a mixing method well known to those skilled in the art can be used.

In the invention, the lignin-inorganic semiconductor nanocomposite, co-emulsifier and water are mixed to obtain the water phase. In the present invention, the co-emulsifier is preferably one or more of PVA, Tween-80, EL-40, EL-60, AEO-6, AEO-9 and Triton X-100, more preferably Preferred is PVA.

In the present invention, the mass ratio of the isocyanate compound to the lignin-inorganic semiconductor nanocomposite is preferably 2-15:1-5, more preferably 5-10:2-4.

In the present invention, the mixing method is preferably stirring and mixing.

In the invention, the oil phase and the water phase are mixed and emulsified to obtain an O/W type Pickering emulsion. In the present invention, the emulsification is preferably carried out under the condition of stirring, and the stirring rate is preferably 300-1000 rpm, more preferably 500-800 rpm.

In the invention, the O/W type Pickering emulsion is mixed with a chain extender to carry out interfacial polymerization reaction to obtain the anti-ultraviolet bio-pesticide composite microcapsule. In the present invention, the chain extender is preferably polyol and/or polyamine. In the present invention, the polyol is preferably one or more of polyether polyol, ethylene glycol, hexylene glycol, glycerol and pentaerythritol. In the present invention, the polyether polyol is preferably one or more of polyoxyethylene diol with a molecular weight of 200 to 4000, polyoxypropylene diol with a molecular weight of 200 to 4000, and polytetrahydrofuran diol with a molecular weight of 250 to 2000. Several kinds.

In the present invention, the polyamines are preferably ethylenediamine, hexamethylenediamine, isophoronediamine, 1,2-propylenediamine, butylenediamine, diethylenetriamine, triethylenetetramine and tetraethylenediamine. One or more of pentamines.

In the present invention, the mass ratio of the isocyanate compound to the chain extender is preferably 2-15:1-5, more preferably 5-10:2-4. In the present invention, the interfacial polymerization is preferably carried out under the condition of stirring, and the stirring rate is preferably 300-1000 rpm, more preferably 500-800 rpm.

In the present invention, the temperature of the interfacial polymerization reaction is preferably 50-80° C., more preferably 60-70° C.; the time is preferably 2-5 hours, more preferably 3-4 hours.

After the interfacial polymerization reaction, the present invention preferably adds an antifreeze agent and a dispersant to the obtained interfacial polymerization reaction liquid to obtain an anti-ultraviolet biopesticide composite microcapsule aqueous suspension. The present invention has no special requirements on the specific types of the antifreezing agent and dispersant, and the antifreezing agent and dispersant known to those skilled in the art can be used.

In the present invention, in the anti-ultraviolet biopesticide composite microcapsule aqueous suspension, the mass percentage of the antifreeze is preferably 1-3%, and the mass percentage of the dispersant is preferably 1-3%.

The anti-ultraviolet biopesticide composite microcapsules provided by the present invention and the preparation method thereof are described in detail below in conjunction with the examples, but they cannot be interpreted as limiting the protection scope of the present invention.

Example 1

(1) Preparation of quaternized alkali lignin

100 g of an alkali lignin solution at a concentration of 25% by weight was added to the reactor flask. At 85°C, 3 g of 3-chloro-2-hydroxypropylammonium chloride was added dropwise. After the dropwise addition was completed, the reaction was continued for 4 hours, and the reaction liquid was purified by dialysis and freeze-dried to obtain quaternized alkali lignin.

(2) Preparation of lignin-ZnO nanocomposites

After dissolving quaternized alkali lignin powder and 1g NaOH in 100g water, mix and stir with 5g Zn(Ac) ₂ solution, and keep warm at 85°C for 4h. Cool to room temperature, adjust the pH of the solution to 7.8, centrifuge, wash and dry to obtain the quaternized alkali lignin-ZnO nanocomposite.

(3) Preparation of biopesticide microcapsules by Pickering emulsion interfacial polymerization

First, 6 g of emamectin benzoate, 15 g of isobutyl acetate and 8 g of diphenylmethane-4,4'-diisocyanate were mixed and stirred at room temperature until completely dissolved to form an oil phase.

Secondly, disperse 2g of lignin-ZnO nanocomposite into 60g of water, add 1g of co-emulsifier PVA, as the water phase. Mix the water phase with the oil phase, stir and disperse to form an O/W Pickering emulsion.

At 60°C, the Pickering emulsion prepared above was transferred to a three-necked flask equipped with a mechanical stirrer and a thermometer, and stirred evenly at a speed of 500 rpm. Add 10g of ethylenediamine with a concentration of 20wt% to the above solution for interfacial polymerization for 2 hours to form UV-resistant emamectin emamectin microcapsules. Add 1.5g of antifreeze and 1.5g of dispersant to the above system to obtain 5.7wt% Anti-ultraviolet emamectin benzoate microcapsule aqueous suspension.

The microstructure pictures of the obtained UV-resistant emamectin benzoate microcapsules are shown in Figure 1, and (a) and (b) in Figure 1 are pictures of different magnifications respectively. It can be seen from Fig. 1 that the anti-ultraviolet emamectin emamectin salt microcapsules provided by the present invention have a regular spherical shape and a particle diameter of 500-800 nm.

The difference between the preparation of ordinary ordinary emamectin benzoate microcapsules and the preparation of UV-resistant emamectin benzoate microcapsules is that the lignin-inorganic semiconductor nanocomposite with ultraviolet shielding is not added as the Pickering emulsifier, and the emulsifier used is PVA.

Prepare the above-mentioned anti-ultraviolet emamectin benzoate microcapsule suspension agent methanol dispersion liquid of the same concentration, the former drug methanol solution of emamectin emamectin salt and the ordinary emamectin emamectin salt microcapsule methanol dispersion liquid, and the solutions are respectively placed under ultraviolet light (36W, 254nm) to irradiate, Sampling at intervals, using high performance liquid chromatography to calculate the concentration, the remaining content of the original drug and the time relationship diagram are shown in Figure 2, as can be seen from Figure 2, the common emamectin benzoate microcapsules and the anti-ultraviolet emamectin benzoate microcapsules Capsules have a certain protective effect on the degradation of emamectin benzoate, but the degradation rate of emamectin benzoate in the anti-ultraviolet emamectin benzoate microcapsules is significantly lower than that of the original drug and ordinary emamectin benzoate microcapsules, indicating that the anti-ultraviolet emamectin benzoate Microcapsules have good anti-ultraviolet effect.

Example 2

(1) Preparation of quaternized alkali lignin

100 g of an alkali lignin solution at a concentration of 25% by weight was added to the reactor flask. At 85°C, 5 g of 3-chloro-2-hydroxypropylammonium chloride was added dropwise. After the dropwise addition was completed, the reaction was continued for 4 hours, and the reaction liquid was purified by dialysis and freeze-dried to obtain quaternized alkali lignin.

(2) Preparation of quaternized alkali lignin- _TiO2 nanocomposites

Under stirring, the quaternized alkali lignin was formulated into a 5% aqueous solution, and the pH of the solution was adjusted to be 1. 5 g of butyl titanate was added to the above solution, and reacted at 100° C. for 6 h. After the reaction, the precipitate was collected, washed, and dried to obtain QAL-TiO ₂ .

(3) Preparation of biopesticide microcapsules by Pickering emulsion interfacial polymerization

First, 3g Jinggangmycin, 10g n-butyl acetate and 9g isophorone diisocyanate were stirred and mixed at room temperature until completely dissolved to form an oil phase;

Secondly, 2g of quaternized alkali lignin-TiO2 nanocomposite is dispersed into 60g of water, and 1g of co-emulsifier PVA is added as the water phase;

Finally, mix the water phase and the oil phase, stir and disperse to form an O/W Pickering emulsion.

At 50°C, the Pickering emulsion prepared above was transferred to a three-necked flask equipped with a mechanical stirrer and a thermometer, and stirred evenly at a speed of 400 rpm. Add 10g of 30wt% triethylenetetramine to the above solution for interfacial polymerization to form UV-resistant Jinggangmycin microcapsules, add 1g of antifreeze and 1g of dispersant to the above system to obtain 3wt% of UV-resistant Jinggangmycin Suspension microcapsules in water.

The method with reference to Example 1 prepares common Jinggangmycin microcapsules, prepares the above-mentioned anti-ultraviolet Jinggangmycin microcapsule suspension agent methanol dispersion of the same concentration, Jinggangmycin former drug methanol solution and common Jinggangmycin microcapsules methanol dispersion, and The solution is respectively placed under ultraviolet light (36W, 254nm) to irradiate, and samples are taken at regular intervals, and the concentration is calculated by high performance liquid chromatography. , ordinary Jinggangmycin microcapsules and anti-ultraviolet Jinggangmycin microcapsules both play a certain protective effect on the degradation of Jinggangmycin, but the degradation rate of Jinggangmycin in anti-ultraviolet Jinggangmycin microcapsules is significantly lower than that of the original drug and Ordinary Jinggangmycin microcapsules show that the anti-ultraviolet Jinggangmycin microcapsules have good anti-ultraviolet effect.

Example 3

(1) Preparation of quaternized alkali lignin

100 g of an alkali lignin (AL) solution at a concentration of 25 wt% was added to the reactor flask. At 85°C, 10 g of 3-chloro-2-hydroxypropylammonium chloride was added dropwise. After the dropwise addition was completed, the reaction was continued for 4 h, and the reaction liquid was purified by dialysis and lyophilized to obtain QAL. The reaction scheme is as follows:

(2) Preparation of quaternized lignin- _SiO2 nanocomposites

Under stirring, 6g of quaternized lignin- _SiO2 nanocomposite was formulated into a certain concentration of aqueous suspension. Add 10g of tetraethyl orthosilicate to the above solution, react at 100°C for 6h, collect the precipitate after the reaction, wash and dry to obtain the quaternized lignin- _SiO2 nanocomposite.

(3) Preparation of biopesticide microcapsules by Pickering emulsion interfacial polymerization

First, 5 g of abamectin, 12 g of sec-butyl acetate and 8 g of isophorone diisocyanate were mixed and stirred at room temperature until completely dissolved to form an oil phase.

Second, 1 g of quaternized lignin-SiO _{nanocomposite} was dispersed into 70 g of water, and 1 g of co-emulsifier PVA was added as the water phase. Mix the water phase with the oil phase, stir and disperse to form an O/W Pickering emulsion.

At 65°C, the Pickering emulsion prepared above was transferred to a three-necked flask equipped with a mechanical stirrer and a thermometer, and stirred evenly at a certain speed. 15g of glycerol with a concentration of 50wt% was added to the above solution to carry out interfacial polymerization for 3h to form UV-resistant avermectin microcapsules, and 1g of antifreeze and 1g of dispersant were added to the above system to obtain 5wt% of antifreeze Ultraviolet Abamectin Microcapsule Water Suspension Concentrate.

The method with reference to embodiment 1 prepares common avermectin microcapsules, prepares the above-mentioned anti-ultraviolet avermectin microcapsule suspension agent methanol dispersion of the same concentration, the former drug methanol solution of avermectin and common avermectin microcapsules methanol Dispersion liquid, the solution is placed under the irradiation of ultraviolet lamp (36W, 254nm) respectively, takes a sample at regular intervals, calculates the concentration with high performance liquid chromatography, and its original drug residual content and time relationship figure are as shown in Figure 4, from Figure 4 It can be seen that both the common avermectin microcapsules and the anti-ultraviolet abamectin microcapsules have a certain protective effect on the degradation of avermectin, but the avermectin in the anti-ultraviolet avermectin microcapsules The degradation rate of the anti-ultraviolet abamectin microcapsules is obviously lower than that of the original drug and common avermectin microcapsules, which shows that the anti-ultraviolet effect of the avermectin microcapsules is good.

Example 4

(1) Preparation of quaternized alkali lignin

100 g of an alkali lignin solution at a concentration of 25% by weight was added to the reactor flask. At 85°C, 4 g of 3-chloro-2-hydroxypropylammonium chloride were added dropwise. After the dropwise addition was completed, the reaction was continued for 4 hours, and the reaction liquid was purified by dialysis and freeze-dried to obtain quaternized alkali lignin.

(2) Preparation of lignin- _CeO2 nanocomposites

Dissolve quaternized alkali lignin powder and 10g NaOH in 100g water, mix and stir with CeCl ₃ solution, and keep warm at 85°C for 4h. Cool to room temperature, adjust the pH of the solution to 7.8, centrifuge, wash and dry to obtain the quaternized alkali lignin-CeO ₂ nanocomposite.

(3) Preparation of biopesticide microcapsules by Pickering emulsion interfacial polymerization

First, 2 g of gibberellin, 8 g of isobutyl acetate, and 8 g of diphenylmethane-4,4′-diisocyanate were mixed and stirred at room temperature until completely dissolved to form an oil phase.

Second, 2 g of lignin- _CeO nanocomposites were dispersed into 65 g of water, and 1 g of PVA was added, as the water phase. Mix the water phase with the oil phase, stir and disperse to form an O/W Pickering emulsion.

At 60°C, the Pickering emulsion prepared above was transferred to a three-necked flask equipped with a mechanical stirrer and a thermometer, and stirred evenly at a speed of 500 rpm. 15g of tetraethylenepentamine with a concentration of 10wt% was added to the above solution for interfacial polymerization for 2 hours to form UV-resistant gibberellin microcapsules, and 1.5g of antifreeze and 1.5g of dispersant were added to the above system to obtain 2wt % anti-ultraviolet gibberellin microcapsules aqueous suspension.

The method for referring to Example 1 prepares common gibberellin microcapsules, prepares the above-mentioned anti-ultraviolet gibberellin microcapsule suspension agent methanol dispersion of the same concentration, the former drug methanol solution of gibberellin and common gibberellin microcapsule methanol dispersion, and The solution is respectively placed under ultraviolet light (36W, 254nm) to irradiate, and samples are taken at regular intervals, and the concentration is calculated by high performance liquid chromatography. , both ordinary gibberellin microcapsules and anti-ultraviolet gibberellin microcapsules have a certain protective effect on the degradation of gibberellin, but the degradation rate of gibberellin in anti-ultraviolet gibberellin microcapsules is significantly lower than that of the original drug and Ordinary gibberellin microcapsules show that the anti-ultraviolet gibberellin microcapsules have good anti-ultraviolet effect.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (1)

1. A composite microcapsule of anti-ultraviolet biopesticide, comprising a microcapsule material and a biopesticide wrapped in the microcapsule material; The material of the microcapsule material is polyurethane, and the microcapsule material contains lignin-inorganic semiconductor nanocomposites; The lignin-inorganic semiconductor composite material is a lignin-ZnO nanocomposite; the biopesticide is emamectin benzoate; The preparation of the anti-ultraviolet biopesticide composite microcapsules is as follows: (1) Preparation of quaternized alkali lignin: Add 100g of alkali lignin solution with a concentration of 25wt% into the reactor flask, add 3g of 3-chloro-2-hydroxypropylammonium chloride dropwise at 85°C, after the addition is complete, continue the reaction for 4h, and dialyze the reaction solution After purification and lyophilization, quaternized alkali lignin is obtained; (2) Preparation of lignin-ZnO nanocomposites: Dissolve quaternized alkali lignin powder and 1g NaOH in 100g water, mix and stir with 5g Zn(Ac) ₂ solution, keep warm at 85°C for 4 hours, cool to room temperature, adjust the pH of the solution to 7.8, centrifuge, wash and dry to obtain quaternary Ammonified alkali lignin-ZnO nanocomposite; (3) Preparation of biopesticide microcapsules by Pickering emulsion interfacial polymerization method: First, 6 g of emamectin benzoate, 15 g of isobutyl acetate and 8 g of diphenylmethane-4,4'-diisocyanate were mixed and stirred at room temperature until completely dissolved to form an oil phase; Secondly, disperse 2g of lignin-ZnO nanocomposite into 60g of water, add 1g of co-emulsifier PVA as the water phase, mix the water phase with the oil phase, stir and disperse, and form an O/W type Pickering emulsion; At 60°C, transfer the Pickering emulsion prepared above to a three-necked flask equipped with a mechanical stirrer and a thermometer, stir evenly at a speed of 500 rpm, and add 10 g of ethylenediamine with a concentration of 20 wt% to the above solution for interfacial polymerization 2h, forming microcapsules of anti-ultraviolet emamectin benzoate; the microcapsules of anti-ultraviolet emamectin benzoate have a regular spherical shape and a particle diameter of 500-800 nm.