阅读说明：本技术 一种基于单宁酸修饰的叶面亲和型农药纳米微胶囊制备方法 (Preparation method of leaf surface affinity type pesticide nano microcapsule based on tannic acid modification ) 是由 曾章华 余曼丽 孙长娇 崔海信 于 2019-08-14 设计创作，主要内容包括：本发明公开了一种基于单宁酸修饰的叶面亲和型农药纳米微胶囊制备方法,属于农药制备领域。本发明的叶面亲和型农药纳米微胶囊以改性淀粉为农药载体形成的纳米微球为囊芯,以单宁酸和三氯化铁的螯合物为囊壁,优越之处在于单宁酸在多种材料表面具有黏附特性,有利于减少农药分子的滚落脱靶。此外,纳米材料的小尺寸、大比表面积,也可以提高药液在作物叶面的滞留量、增大与有害生物的接触面积,提高农药有效利用率。与目前使用较多的原位聚合法和界面聚合法相比,本发明原材生物相容性好,对生产者安全,并且制备工艺简单,生产成本与设备投资成本低,不产生污染物,产品质量稳定可靠,可以有效提高农药的叶面滞留率,具有非常广阔的应用前景。(The invention discloses a preparation method of a leaf surface affinity type pesticide nano microcapsule based on tannic acid modification, and belongs to the field of pesticide preparation. The foliar affinity type pesticide nano microcapsule takes nano microspheres formed by taking modified starch as a pesticide carrier as a capsule core and a chelate of tannic acid and ferric trichloride as a capsule wall, and has the advantages that the tannic acid has adhesion property on the surfaces of various materials, and is beneficial to reducing the target falling off of pesticide molecules. In addition, the small size and the large specific surface area of the nano material can also improve the retention of the liquid medicine on the leaf surfaces of crops, increase the contact area with pests and improve the effective utilization rate of pesticides. Compared with the prior in-situ polymerization method and the interfacial polymerization method which are used more, the invention has the advantages of good raw material biocompatibility, safety for producers, simple preparation process, low production cost and equipment investment cost, no pollutant generation, stable and reliable product quality, capability of effectively improving the retention rate of the foliage of the pesticide and very wide application prospect.)

1. A preparation method of a leaf surface affinity type pesticide nano microcapsule based on tannic acid modification is characterized by comprising the following steps:

(1) preparation of aqueous solution

Dissolving polyvinyl alcohol in water to prepare an aqueous phase solution with the weight concentration of 0.5-2.0%;

(2) preparation of organic phase solution

The weight ratio of the insoluble pesticide to the modified starch acetate is 1-2: 1-5, dissolving in an organic solvent to obtain an organic phase solution;

(3) preparation of pesticide starch nano microsphere

According to the volume ratio of the organic phase solution to the aqueous phase solution of 1: 3-10, mixing and stirring uniformly to obtain a primary emulsion, performing ultrasonic treatment on the primary emulsion, and stirring at normal temperature until the organic solvent is completely volatilized to obtain a pesticide nano microsphere aqueous suspension;

(4) surface affinity modification of nano-microspheres

Sequentially adding ferric trichloride aqueous solution with weight concentration of 0.1-1.0% and tannic acid aqueous solution with weight concentration of 0.4-4.0% into the nano-microspheres, and stirring and reacting for 0.5-1.0h at room temperature to obtain the affinity pesticide nano-microcapsule water suspension.

2. The preparation method of the foliar-affinity pesticide nano-microcapsule according to claim 1, wherein the insoluble pesticide in the step (2) is emamectin benzoate, abamectin, lambda-cyhalothrin, chlorantraniliprole or azoxystrobin at a weight concentration of 30-80%.

3. The method for preparing foliar-affinity pesticide nano-microcapsules according to claim 1, wherein the modified starch acetate in the step (2) is obtained by the following method: uniformly dispersing corn starch in glacial acetic acid, adding cooled acetic anhydride, adding p-toluenesulfonic acid into a reaction solution after 15 minutes, stirring the reaction mixed solution at 80 ℃ for 3 hours, continuously washing the mixture with deionized water to obtain a solid, and finally drying the solid in a vacuum oven at 50 ℃ overnight to obtain the modified starch acetate.

4. The method for preparing foliar-affinity pesticide nano-microcapsules according to claim 1, wherein the organic solvent in the step (3) is dichloromethane or chloroform.

5. The preparation method of foliar affinity type pesticide nano-microcapsules according to claim 1, wherein the ultrasonic treatment in the step (3) is ultrasonic treatment for 3-5min under the condition of power of 300-500W.

6. The pesticide nano-microcapsule obtained by the preparation method of the foliar affinity type pesticide nano-microcapsule according to any one of claims 1 to 5.

7. The pesticide nano-microcapsule according to claim 6, wherein the average particle size of the nano-microcapsule is less than 1 μm.

[ technical field ] A method for producing a semiconductor device

The invention belongs to the field of pesticide preparation, and particularly relates to a preparation method of a leaf surface affinity type pesticide nano microcapsule based on tannic acid modification.

[ background of the invention ]

The pesticide is an important material basis for defending major biological disasters, guaranteeing national grain production and promoting the continuous and stable increase of the yield of agricultural products. However, the traditional pesticide formulation has extremely low effective utilization rate, and in the field pesticide application process, most of the pesticide liquid falls off target and enters the surrounding environment, so that the pesticide is seriously applied in excess, and a series of problems of environmental pollution, agricultural product quality safety and the like are caused.

The surface of the crop leaf has various hydrophobic micro-nano structures (such as a waxy layer, villi, mastoid and the like), so that pesticide liquid drops are difficult to attach to the leaf and roll off targets. Based on the above, the pesticide dosage function is improved by advanced carrier materials and loading methods, the foliar deposition barrier of pesticide molecules is overcome, the pesticide off-target is reduced, and the method has important significance for relieving the current pesticide residue and environmental pollution in China and realizing the important strategic layout of 'pesticide reduction and efficiency improvement'.

In recent years, the nanotechnology is combined with pesticide development to develop a pesticide nano drug delivery system, and the development has become one of the research hotspots of the nanotechnology in the field of agricultural application. On one hand, the nano material has the effects of small size and large specific surface area, so that the affinity with a target tissue can be enhanced, the retention amount of the liquid medicine on the leaf surface of crops can be greatly improved, and the contact area with harmful organisms can be increased, thereby improving the effective utilization rate of pesticide and reducing the using amount of the pesticide; on the other hand, the pesticide nano drug-loading system matched with the structural characteristics of the target organism surface is designed by utilizing the surface modifiability of the nano carrier, so that the behaviors of adhesion, infiltration, deposition and the like of pesticides can be improved, the pesticides can be uniformly covered on the surface of crops, and the pesticide can be efficiently operated in harmful organisms to play the pesticide effect.

The plant tannin is a plant polyphenol, widely exists in barks, roots, leaves and fruits, and has the advantages of low price, good biocompatibility and the like. In addition, a large number of hydrophobic aromatic rings and hydrophilic phenolic hydroxyl groups in the molecular structure of the tannic acid are easy to interact with various materials through hydrogen bonds, hydrophobicity, pi-pi stacking and the like, and the tannic acid has strong adhesion characteristics on the surfaces of various materials. At present, no relevant documents and patent reports about the modification of a pesticide nano drug delivery system by tannic acid to improve the leaf surface deposition efficiency are found.

[ summary of the invention ]

Aiming at the defects, the invention provides the foliar affinity type pesticide nano microcapsule and the preparation method thereof by using tannic acid with wide sources and good biocompatibility as an affinity material to modify the surface of the nano microsphere.

The purpose of the invention is realized by the following modes:

the invention provides a preparation method of tannin-modified leaf surface affinity type pesticide nano-microcapsules, which comprises the following steps:

(1) preparation of aqueous solution

Dissolving polyvinyl alcohol in water to prepare an aqueous phase solution with the weight concentration of 0.5-2.0%;

(2) preparation of organic phase solution

The weight ratio of the insoluble pesticide to the modified starch acetate is 1-2: 1-5, dissolving in an organic solvent to obtain an organic phase solution;

(3) preparation of pesticide starch nano microsphere

According to the volume ratio of the organic phase solution to the aqueous phase solution of 1: 3-10, mixing and stirring uniformly to obtain a primary emulsion, performing ultrasonic treatment on the primary emulsion, and stirring at normal temperature until the organic solvent is completely volatilized to obtain a pesticide nano microsphere aqueous suspension;

(4) surface affinity modification of nano-microspheres

Sequentially adding ferric trichloride aqueous solution with weight concentration of 0.1-1.0% and tannic acid aqueous solution with weight concentration of 0.4-4.0% into the nano-microspheres, and stirring and reacting for 0.5-1.0h at room temperature to obtain the affinity pesticide nano-microcapsule water suspension.

Further, the indissoluble pesticide is emamectin benzoate, abamectin, lambda-cyhalothrin, chlorantraniliprole or azoxystrobin with the weight concentration of 30-80%.

Further, the modified starch acetate is obtained by the following method: uniformly dispersing corn starch in glacial acetic acid, adding cooled acetic anhydride, adding p-toluenesulfonic acid into a reaction solution after 15 minutes, stirring the reaction mixed solution at 80 ℃ for 3 hours, continuously washing the mixture with deionized water to obtain a solid, and finally drying the solid in a vacuum oven at 50 ℃ overnight to obtain the modified starch acetate.

Further, the organic solvent is dichloromethane or chloroform.

Further, the ultrasonic treatment is specifically ultrasonic treatment for 3-5min under the condition of power of 300-500W.

The invention also provides the pesticide nano-microcapsule prepared by the preparation method of the foliar affinity type pesticide nano-microcapsule.

Furthermore, the average grain diameter of the nano-microcapsule is less than 1 μm.

The invention is characterized in that: the method provided by the invention is used for constructing the leaf surface affinity type pesticide nano drug carrying system based on the tannic acid aiming at the hydrophobic micro-nano structure on the surface of the crop leaf, so that the leaf surface deposition obstacle of pesticide molecules is overcome, the nano drug carrying system can be more remained in the leaf surface micro-nano structure after the liquid medicine is evaporated, the leaf surface deposition efficiency of the pesticide is favorably improved, and the effective utilization rate is improved.

The invention has the beneficial effects that: the leaf surface affinity type pesticide nano microcapsule based on the tannic acid prepared by the invention has good deposition effect on the leaf surface of crops; the average grain diameter is less than 1 μm, the drug-loading rate can reach more than 30%, the encapsulation rate can reach more than 70%, and the slow-release agent has slow-release performance and higher leaf surface adhesiveness. The method has the advantages of simple process, low production cost and equipment investment cost, no pollutant generation and stable and reliable product quality. Therefore, the tannin-based leaf surface affinity type pesticide nano microcapsule and the preparation method thereof have very wide application prospects.

[ description of the drawings ]

FIG. 1 TEM imaging of Starch acetate nanospheres (Starch-NS).

FIG. 2 TEM imaging of Tannin-based leaf surface affinity nanocapsules (Tannin-Starch-NS).

Figure 3 is a release behavior diagram of abamectin technical and nano-microcapsule thereof.

Figure 4 stability testing of nanocapsules.

Figure 5 leaf retention of nanocapsules.

[ detailed description ] embodiments

The principles and features of this invention are described in conjunction with the following examples, which are set forth merely to illustrate the invention and are not intended to limit the scope of the invention.