CN104621102B

CN104621102B - Method for preparing adhesive abamectin polydopamine microcapsule by emulsion interface polymerization method

Info

Publication number: CN104621102B
Application number: CN201410310095.7A
Authority: CN
Inventors: 贾鑫; 盛文波; 李卫; 刘志勇
Original assignee: Shihezi University
Current assignee: Shihezi University
Priority date: 2014-06-26
Filing date: 2014-06-26
Publication date: 2020-08-21
Anticipated expiration: 2034-06-26
Also published as: CN104621102A

Abstract

The invention relates to a method for preparing an adhesive abamectin polydopamine microcapsule by an emulsion interface polymerization method. Aiming at the problems that the abamectin is easy to decompose when exposed to light and most of formulations of the abamectin can not effectively stay on the leaf surfaces of plants. The invention takes Tris-HCl buffer solution containing hexadecyl trimethyl ammonium chloride (1.5 percent m/v water phase) as water solution, and n-butyl alcohol solution containing abamectin as oil phase; the method comprises the steps of carrying out oxidative self-polymerization on an emulsion interface by dopamine (with the concentration of 1mg/mL), mechanically stirring for 24 hours at room temperature, and centrifugally washing to obtain the abamectin polydopamine microcapsule with adhesiveness and photostability, wherein the microcapsule has temperature and pH controlled release properties. The method can prepare the abamectin controlled-release polydopamine microcapsule with uniform size, high load capacity and adhesiveness, has high yield and simple steps, and can be used for industrialization.

Description

Method for preparing adhesive abamectin polydopamine microcapsule by emulsion interface polymerization method

Technical Field

The invention relates to a method for preparing microcapsules with adhesiveness, temperature controlled release, pH controlled release and photostability by emulsifying abamectin and then carrying out oxidative self-polymerization on an emulsion interface by dopamine and derivatives thereof.

Background

China is a big agricultural country, and pests are frequently and repeatedly transmitted. The application of chemical pesticides to prevent and treat diseases, insects and weeds is the main and effective prevention and treatment means at present. However, only 20-30% of the currently sprayed pesticide is remained and deposited on the target, and 70-80% of the currently sprayed pesticide is drifted or lost into soil, so that the environment for living of animals and human beings is polluted. The two main reasons for pesticide waste and loss are as follows: firstly, pesticides applied to crops cannot be used according to the growth requirements of the crops, and most of the pesticides can volatilize or be decomposed after being exposed to the sun and rain, so that the pesticides cannot be effectively utilized; secondly, the commonly used pesticide formulations do not form an effective spreading and retention on the surface of the crops, resulting in a rapid loss of most pesticides after application.

The abamectin is a novel agricultural and livestock dual-purpose antibiotic with high efficiency, low toxicity and high selectivity, and is a substitute product of high-toxicity pesticides in China. However, the abamectin is a substance which is easily decomposed under light, and the improvement of the light stability of the abamectin has important significance for agricultural development of the abamectin and prolonging of the lasting period. At present, embedding abamectin in a controlled release material by adopting a loading technology is an effective way for delaying the photodecomposition and slowly releasing the abamectin. Wherein, polyethylene glycol and hollow porous nano SiO₂Gelatin, TiO₂Mesoporous activated carbon, inorganic mineral diatomite and natural and synthetic high molecular materials are all commonly used as stable slow release carriers of abamectin to prepare slow release preparations. However, the avermectin slow-release formulations reported in the literature at present are all focused on the research of improving the photostability and slow release of the avermectin, and the controlled-release avermectin formulations with the release rule changed according to the change of the external environmental conditions are rarely reported. In particular, few researchers have noticed the interaction of these insecticides with different plant foliage. Therefore, it is important to develop a novel pesticide formulation which has a strong acting force with the leaf surface of the plant, prolongs the retention time of the plant on the surface of the crop, and has photostability and controlled release property.

Disclosure of Invention

Aiming at the problems that abamectin is easy to decompose under the action of light, the use amount of common emulsion type organic matters is large, and the retention time of the common emulsion type organic matters on different plant leaf surfaces is different, so that the utilization rate is low, the use amount is large and the environment is polluted, the bionic adhesion abamectin polydopamine microcapsule is prepared by an emulsion polymerization method based on dopamine chemistry by combining a controlled release technology from the bionic angle; the release kinetics research shows that the microcapsule has controlled slow release and light stability; scanning electron microscopy verifies that the bionic polydopamine microcapsule water suspension system has adhesive performance on cotton and corn leaf surfaces. The research lays a theoretical foundation for the development and application of the bionic adhesive abamectin polydopamine controlled-release pesticide. Meanwhile, technical support is provided for the research and development and application of the controlled-release pesticide suitable for Xinjiang crops and environmental characteristics. The technical scheme adopted by the invention comprises the following steps:

firstly, dissolving 1.5g of hexadecyl trimethyl ammonium chloride (1.5% m/v water phase) in 100mL of Tris-HCl (pH 8.5) buffer solution to obtain a water solution of a surfactant, and dissolving 0.1g of abamectin in 10mL of n-butyl alcohol to obtain an oil phase; then quickly adding the oil phase into the above aqueous solution, and stirring vigorously for 30 min; then 0.1g dopamine (1 mg/mL) is added to carry out oxidative autopolymerization on the interface of the emulsion, and mechanical stirring is carried out at room temperature for 24h at 300 r/min. Water is centrifugally washed for 3-4 times, and vacuum drying is carried out at 45 ℃ to obtain the microcapsule with adhesiveness and light stability, wherein the microcapsule has temperature and pH controlled release performance. The loading capacity of the avermectin in the microcapsule can reach 66.5 percent, and the yield can reach 75 to 85 percent.

Drawings

The abamectin polydopamine microcapsule obtained by the emulsion interface polymerization method is observed by a field emission scanning electron microscope, and the figure shows that the microcapsule has uniform size, the grain diameter of about 215nm and good adhesion. FIG. 1 is an SEM photograph of the abamectin polydopamine microcapsule.

Detailed Description

The present invention is further illustrated by the following examples, but the present invention is not limited to the examples.

Example 1 an aqueous solution of a surfactant was prepared by dissolving 1.5g cetyltrimethylammonium chloride (1.5% m/v aqueous phase) in 100mL of tris-HCl (pH 8.5) buffer, and 0.1g of abamectin was dissolved in 10mL of n-butanol to obtain an oil phase; then quickly adding the oil phase into the above aqueous solution, and stirring vigorously for 30 min; then 0.1g dopamine (1 mg/mL) is added to carry out oxidative autopolymerization on the interface of the emulsion, and mechanical stirring is carried out at room temperature for 24h at 300 r/min. Water is centrifugally washed for 3-4 times, and vacuum drying is carried out at 45 ℃ to obtain the microcapsule with adhesiveness and light stability, wherein the microcapsule has temperature and pH controlled release performance. The loading capacity of the avermectin in the microcapsule can reach 66.5 percent, and the yield can reach 75 to 85 percent.

Claims

1. A method for preparing adhesive abamectin polydopamine microcapsules by an emulsion interface polymerization method is characterized by comprising the following steps:

firstly, dissolving 1.5g of hexadecyl trimethyl ammonium chloride in 100mL of Tris-HCl solution with the pH =8.5 to obtain a water solution of a surfactant, and dissolving 0.1g of abamectin in 10mL of n-butyl alcohol to obtain an oil phase; then quickly adding the oil phase into the above aqueous solution, and stirring vigorously for 30 min; then adding 0.1g of dopamine to carry out oxidative autopolymerization on an emulsion interface, mechanically stirring for 24 hours at room temperature of 300r/min, washing and centrifuging the reaction product for 3-4 times by using water, separating out microcapsules with uniform size, and drying in vacuum at 45 ℃ to obtain a microcapsule reaction product with adhesiveness and light stability; the avermectin loading amount in the microcapsule reaches 66.5%, and the yield reaches 75-85%.