CN115462384B

CN115462384B - DCOIT sustained-release nanocapsule taking silicon dioxide as carrier and preparation method and application thereof

Info

Publication number: CN115462384B
Application number: CN202210921106.XA
Authority: CN
Inventors: 赵士贵; 刘化通; 成雪晴; 卢涛; 周传健; 张晨; 程潇; 王�华
Original assignee: Shandong University
Current assignee: Shandong University
Priority date: 2022-08-02
Filing date: 2022-08-02
Publication date: 2024-04-09
Anticipated expiration: 2042-08-02
Also published as: CN115462384A

Abstract

The invention provides a DCOIT sustained release nano capsule taking silicon dioxide as a carrier, and a preparation method and application thereof. The preparation method of the invention comprises the following steps: dropwise adding amino alkoxy silane into deionized water under the stirring condition to obtain an amino alkoxy silane aqueous solution; dissolving DCOIT and alkoxy silane in dimethylbenzene to obtain mixed solution; under the stirring condition, the mixed solution is slowly dripped into the amino alkoxy silane aqueous solution, and the DCOIT slow-release nano-capsule taking silicon dioxide as a carrier is obtained through the reaction of stirring, separation, washing and drying of the obtained reaction solution. The method can improve the embedding rate and the drug-loading rate of the nanocapsules and improve the utilization rate of the DCOIT bactericide in the use process; the DCOIT nanocapsule prepared by the method is regular in sphericity, high in embedding rate and drug loading rate, capable of effectively relieving the burst release phenomenon of the drug in the initial stage of use, and good in DCOIT slow release effect.

Description

DCOIT sustained-release nanocapsule taking silicon dioxide as carrier and preparation method and application thereof

Technical Field

The invention relates to a DCOIT sustained release nano-capsule taking silicon dioxide as a carrier, and a preparation method and application thereof, and belongs to the technical field of nano-capsule preparation.

Background

Marine biofouling presents serious problems for global marine navigation, marine communications and the exploitation and utilization of marine resources. For many years, various anti-fouling strategies have been implemented to prevent and control biological fouling processes, such as mechanical cleaning, electrolysis of seawater, and brushing of anti-fouling coatings. Among them, brushing an antifouling paint containing an antifouling agent is the most convenient and most widely used treatment method. Traditional antifouling agents, which generally include organic mercury, toxic lead and cuprous oxide, pose a serious threat to the marine environment and human health. Therefore, development of an environment-friendly bactericide and improvement of the utilization rate of the bactericide have been an important research topic in the field of ship antifouling paint.

In the 90 s of the 20 th century, rohm & Hass company of America successfully developed a compound of the chemical name 4, 5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT) and began to market its registrar number Sea-Nine 211. DCOIT is white to faint yellow powder, has the characteristics of low toxicity, long-acting and broad-spectrum sterilization and algae removal, and has the characteristics of rapid degradation in the environment and small accumulation in organisms. The "Presidential Green Chemistry Challenge" prize and the "chemical environment winning prize" are obtained in 1996 and 1997 respectively, and are praised as environment-friendly bactericides. However, similar to other types of bactericides, the DCOIT content is high, the release speed is high, and the release concentration is far higher than the effective concentration for inhibiting the adhesion of marine fouling organisms in the initial use period; in the later stage of use, the DCOIT content is low, the release speed is slow, and the requirement of inhibiting the adhesion of organisms is difficult to achieve. The microcapsule has the unique advantage of realizing slow release of the core material, so that the development of the DCOIT microcapsule has important significance for fully utilizing the DCOIT in the use process and achieving the long-acting antifouling effect.

There are also several literature and patent reports about the preparation of drug-loaded nanocapsules using silica as a carrier. For example, chinese patent document CN108676615a mixes lavender essence with ethyl orthosilicate, a silane coupling agent in a reaction kettle to form an oil phase; adding water phase formed by water and ethanol into the oil phase, adding an emulsifying agent and stirring; and adding an alkaline catalyst into the emulsion to react, and obtaining the lavender slow-release essence after the reaction is completed. Chinese patent document CN104548105a discloses a hollow silica microcapsule encapsulated with a hydrophobic substance using a surfactant micelle solubilized with a hydrophobic substance as a template, and a method for preparing the same. Adding a surfactant into an ethanol solution, and uniformly stirring; then adding a mixture of a silicon source and a hydrophobic substance, adding alkali liquor as a catalyst for hydrolysis condensation of the silicon source, and adjusting pH to react at room temperature; and centrifuging the obtained product, washing with water, and drying at low temperature to obtain the hollow silica microcapsule encapsulated with the hydrophobic substance. Such patents use different silica precursors and synthesis conditions to prepare silica-supported nanocapsules, while enabling coating of the core material to some extent, have the following problems: (1) The preparation process requires adding additional surfactant and acid or alkali catalyst, and the preparation conditions are strict, thereby increasing the additional production cost. (2) The steps are carried out in multiple steps, the reaction time is long, and the industrial production of the nanocapsules is not easy to carry out. (3) The prepared nano capsule has low encapsulation rate and poor encapsulation effect, and can not control the long-term and stable release of the anti-fouling agent.

Therefore, the research and development of the preparation method of the DCOIT nanocapsule has the advantages of simple process, easy realization, low cost, contribution to industrial production, high embedding rate and drug loading rate and excellent slow release effect.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a DCOIT sustained release nano capsule taking silicon dioxide as a carrier, and a preparation method and application thereof. The method can improve the embedding rate and the drug-loading rate of the nanocapsules and improve the utilization rate of the DCOIT bactericide in the use process; the DCOIT nanocapsule prepared by the method is regular in sphericity, high in embedding rate and drug loading rate, capable of effectively relieving the burst release phenomenon of the drug in the initial stage of use, and good in DCOIT slow release effect.

The technical scheme of the invention is as follows:

a DCOIT sustained release nanocapsule taking silicon dioxide as a carrier, wherein the nanocapsule comprises a core material and a wall material; the core material is a xylene solution of DCOIT; the wall material is organic modified silicon dioxide and is prepared by the self-catalytic reaction of amino alkoxy silane and alkoxy silane at an oil-water interface.

According to a preferred aspect of the invention, the nanocapsules have a microscopic morphology of: nanospheres with particle size of 500-800 nm.

The preparation method of the DCOIT sustained release nanocapsule taking silicon dioxide as a carrier comprises the following steps:

(1) Dropwise adding amino alkoxy silane into deionized water under the stirring condition to obtain an amino alkoxy silane aqueous solution;

(2) Dissolving DCOIT and alkoxy silane in dimethylbenzene to obtain mixed solution; under the stirring condition, the mixed solution is slowly dripped into the amino alkoxy silane aqueous solution, and the DCOIT slow-release nano-capsule taking silicon dioxide as a carrier is obtained through the reaction of stirring, separation, washing and drying of the obtained reaction solution.

According to the present invention, in the step (1), the aminoalkoxysilane is one or a combination of two or more of 3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, 3-aminopropyl methyldimethoxysilane, and 3-aminopropyl methyldiethoxysilane; preferably, the aminoalkoxysilane is 3-aminopropyl trimethoxysilane (APS).

According to the invention, in the steps (1) and (2), the stirring speed is 500-1250rpm.

According to a preferred embodiment of the invention, in step (1), the volume ratio of aminoalkoxysilane to deionized water is 1:50-100.

According to the present invention, in the step (2), the alkoxysilane is preferably one or a combination of two or more of tetraethyl orthosilicate, methyltrimethoxysilane, ethyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, and diethyldiethoxysilane; preferably, the alkoxysilane is methyltrimethoxysilane (MTMS).

According to a preferred embodiment of the invention, in step (2), the volume ratio of alkoxysilane to xylene is from 0.2 to 2:1, preferably from 0.25 to 1.5:1.

According to a preferred embodiment of the invention, in step (2), the ratio of the mass of DCOIT to the volume of xylene is between 0.1 and 0.5:1g/mL.

According to the invention, in the step (2), the volume ratio of the alkoxysilane in the mixed solution to the aminoalkoxysilane in the aqueous aminoalkoxysilane solution in the step (1) is 1 to 3:1.

Preferably according to the invention, in step (2), the temperature of the reaction is from 15 ℃ to 45 ℃; the reaction time is 6-24h.

Preferably, according to the present invention, in step (2), the separation is separation of nanocapsules using a centrifuge; the washing is carried out 3-5 times by using water; the drying is carried out at 30-50 ℃ for 12-24h.

According to the invention, in step (2), the dropping rate is preferably 0.5 to 2mL/min.

The DCOIT slow release nano capsule using silicon dioxide as a carrier is applied to be used as a functional chemical additive for preventing fungi and bacteria from growing; preferably, the nanocapsules are used as additives in paints, rubber, plastics, lubricating oils or wood.

The invention has the technical characteristics and beneficial effects that:

1. in the process of preparing the silica DCOIT sustained-release nanocapsule, the core material DCOIT is dissolved in the dimethylbenzene to be used as an oil phase, so that the diffusion probability of the DCOIT into the water phase is effectively reduced, and the embedding rate of the microcapsule is improved. And the invention is different fromThe present invention utilizes the autocatalytic reaction of aminoalkoxysilane and alkoxysilane, preferably methyltrimethoxysilane (MTMS) and 3-aminopropyl trimethoxysilane (APS), at the oil/water interface to encapsulate the core DCOIT in silicone nanocapsules, and the process does not require additional stepsThe external surfactant and catalyst have simple preparation process, easy realization of preparation conditions and lower cost.

2. The forming process of the wall material comprises the following steps: (1) When the aminoalkoxysilane is dissolved in water, the amino group will first protonate, and the positively charged protonated aminoalkoxysilane will then exhibit amphiphilic properties; (2) When the mixed solution of the alkoxy silane and DCOIT xylene is added into the amino alkoxy silane aqueous solution drop by drop, the protonated amino alkoxy silane is dispersed at the interface of the oil phase droplet; (3) Protonation of the amino groups will result in an increase in the pH of the system, providing an alkaline environment for hydrolysis and condensation of the aminoalkoxysilane and alkoxysilane at the water-oil interface, where the DCOIT oil droplets act as spherical soft templates; (4) As the reaction time is prolonged, the amino alkoxysilane and alkoxysilane in the oil phase are continuously consumed, and the thickness of the shell is continuously increased, so that the organically modified silica capsule wall containing the DCOIT oil phase is formed.

3. In the method of the invention, the feeding sequence and the feeding mode of the amino alkoxy silane and the alkoxy silane need to be controlled, if the feeding sequence is exchanged or the amino alkoxy silane and the alkoxy silane are initially added into a reaction system together, the embedding rate and the drug loading rate of the obtained nanocapsule are reduced. In the preparation process of the nanocapsule, the addition amount of the reacted amino alkoxysilane and the alkoxysilane is important for the embedding rate and the drug loading rate of the obtained nanocapsule, the proportion of the amino alkoxysilane and the alkoxysilane needs to be controlled within the range of the invention, the proportion is too high or too low, and the embedding rate and the drug loading rate of the obtained microcapsule are reduced. The amino alkoxysilane and the type of the alkoxysilane of the present invention have a certain influence on the entrapment rate and drug loading rate of the obtained microcapsule. Namely, the preparation method of the invention is taken as a whole and jointly acts to realize the effect of the invention.

4. The silica DCOIT sustained-release nanocapsule prepared by the method is white or brown white powdery uniform spheres, has compact surface and no obvious defects, has the average particle size of 500-800nm, and is easier to uniformly disperse in a coating; the embedding rate of the silica DCOIT nanocapsules is 45-55%, and the silica DCOIT nanocapsules have good embedding rate and drug loading rate; the wall material has strong impermeability and good slow-release performance, and can effectively slow down the burst-release phenomenon of the drug in the initial use period; the silica DCOIT nanocapsule obtained by the invention has the advantages of excellent heat resistance, excellent mechanical properties of wall materials and good thermal stability within 230 ℃.

5. The silicon dioxide DCOIT nanocapsule process has wide sources of raw materials and low cost; the preparation process of the silica DCOIT nanocapsule is simple, the reaction process is short, and the industrial production is facilitated; the nanocapsule obtained by the invention not only can be used for marine antifouling coatings, but also can be applied to various industrial fields such as rubber, plastics, fibers, lubricating oil, wood industry and the like, and the application range of the nanocapsule is widened.

Drawings

FIG. 1 is an SEM image of a silica-supported DCOIT sustained release nanocapsule prepared in example 1; wherein A is a nanocapsule aggregate morphology map; b is a profile of the ruptured nanocapsules.

FIG. 2 is an infrared spectrum of DCOIT sustained release nanocapsules, DCOIT and blank nanocapsules prepared in example 1 using silica as a carrier.

FIG. 3 shows TG curves of DCOIT slow release nanocapsules, DCOIT and blank nanocapsules prepared in example 1 and using silica as a carrier.

FIG. 4 shows the slow release curves of the DCOIT slow release nanocapsules prepared in example 1 and using silicon dioxide as a carrier and DCOIT raw drugs at different temperatures.

Detailed Description

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

The raw materials used in the examples are all conventional raw materials and are commercially available unless otherwise specified; the methods used in the examples, unless otherwise specified, are all prior art.

Example 1

(1) With mechanical stirring at 1000rpm, 0.5mL of APS was added dropwise to 50mL of deionized water for 1min to give an aqueous APS solution. In this step, the positively charged protonated APS shows amphiphilic properties due to the protonation of the amino group.

(2) 0.25g DCOIT and 1mL MTMS were dissolved in 1mL xylene, slowly added dropwise to the APS aqueous solution with stirring at 1000rpm for 2min to form an oil-in-water emulsion, the temperature of the reaction system was adjusted to 25℃and the reaction was stirred for 12 hours.

(3) Then separating the nanocapsules from the mixture by using a centrifuge, washing with distilled water for 3 times, and drying in an electrothermal blowing drying oven at 40 ℃ for 12 hours to obtain the DCOIT sustained release nanocapsules taking silicon dioxide as a carrier.

An SEM image of the DCOIT slow release nanocapsules prepared in this example and using silica as a carrier is shown in fig. 1. It can be seen from fig. 1A that the dried nanocapsules maintain a smoother and more complete structure with few cracks, indicating that the wall structure of the nanocapsules can better protect the DCOIT component inside during the drying process, thereby maintaining the spherical structure of the nanocapsules, and the particle size of the nanocapsules is about 600-700nm. Fig. 1B is a scanned picture of a few broken nanocapsules from which it can be seen that the nanocapsules have a distinct hollow structure, forming a microcapsule structure.

The infrared spectra of the DCOIT sustained-release nanocapsules (drug-loaded nanocapsules), DCOIT and blank nanocapsules (blank nanocapsules are prepared as described in this example, except that DCOIT is not added in step (2)) prepared in this example are shown in fig. 2, and it can be seen from fig. 2 that characteristic peaks of wall materials and core materials appear in the spectra of the DCOIT nanocapsules, which proves that the prepared nanocapsules successfully coat DCOIT.

The TG curves of the DCOIT slow release nanocapsules (drug-loaded nanocapsules), DCOIT and blank nanocapsules (preparation method is the same as above) prepared in this example are shown in fig. 3, and it can be seen from fig. 3 that the mass loss of the microcapsules is smaller within 230 ℃, which indicates that the microcapsules can maintain the stability of DCOIT to a certain extent, but the wall structure of the microcapsules can be damaged under the high temperature (above 230 ℃) condition, so that the DCOIT is decomposed. In view of the above, the processing temperature of the microcapsules is not preferably higher than 230 ℃.

The release curves of the DCOIT slow release nanocapsules and DCOIT raw medicines prepared in the embodiment and taking silicon dioxide as a carrier are shown in figure 4. As can be seen from fig. 4, the DCOIT drug substance has a relatively fast release rate, and the release trend after 16 hours indicates that the release is substantially complete. The release rate of the nanocapsule prepared by the embodiment is far smaller than that of DCOIT original medicine, so that the burst release phenomenon of the medicine in the initial use period is effectively slowed down, and the nanocapsule has a good slow release effect. The cumulative release of DCOIT in nanocapsules at 20, 30, 40 ℃ reaches 42.79%, 48.56% and 56.85%, respectively; this is because the brownian motion of DCOIT molecules increases with increasing temperature, and the amount of release increases; in addition, the pores and the number of cracks on the shell layer increase after the expansion of the shell material, further resulting in an increase in the release rate of DCOIT. In conclusion, the nano shell provides a barrier for DCOIT, prolongs the release time of the DCOIT, and has a good slow release effect.

The embedding rate (the ratio of the mass of DCOIT in the nanocapsules to the addition amount of DCOIT) of the DCOIT slow-release nanocapsules taking silicon dioxide as a carrier obtained in the embodiment is 47.37%, and the drug loading rate (the ratio of the mass of DCOIT in the nanocapsules to the mass of the nanocapsules) is 27.50%; less mass loss within 200 ℃ and good thermal stability.

Example 2

(1) With mechanical stirring at 750rpm, 0.25mL of APS was added dropwise to 25mL of deionized water for 1min to give an aqueous APS solution. In this step, the positively charged protonated APS shows amphiphilic properties due to the protonation of the amino group.

(2) 0.25g DCOIT and 0.25mL MTMS were dissolved in 1.0mL xylene, slowly added dropwise to the APS aqueous solution with stirring at 750rpm for 2min to form an oil-in-water emulsion, the temperature of the reaction system was adjusted to 15℃and the reaction was allowed to proceed for 6 hours with stirring and then returned to room temperature.

The embedding rate of the DCOIT sustained release nanocapsule with the silicon dioxide as a carrier obtained in the embodiment is 44.42%, and the drug loading rate is 26.30%; less mass loss within 200 ℃ and good thermal stability.

Example 3

(1) With mechanical stirring at 1250rpm, 0.75mL of APS was added dropwise to 75mL of deionized water for 1min to give an aqueous APS solution. In this step, the positively charged protonated APS shows amphiphilic properties due to the protonation of the amino group.

(2) 0.25g DCOIT and 1.5mL MTMS were dissolved in 1.0mL xylene, slowly added dropwise to the APS aqueous solution with stirring at 1250rpm for 2min to form an oil-in-water emulsion, the temperature of the reaction system was adjusted to 35℃and the reaction was allowed to proceed for 18 hours with stirring and then returned to room temperature.

The embedding rate of the DCOIT sustained release nanocapsule with the silicon dioxide as a carrier obtained in the embodiment is 47.47%, and the drug loading rate is 26.53%; less mass loss within 200 ℃ and good thermal stability.

Example 4

(1) Under mechanical stirring at 750rpm, 1.00mL of APS was added dropwise to 50mL of deionized water for 1min to give an aqueous APS solution. In this step, the positively charged protonated APS shows amphiphilic properties due to the protonation of the amino group.

(2) 0.25g DCOIT and 1.5mL MTMS were dissolved in 1.0mL xylene, slowly added dropwise to the APS aqueous solution with stirring at 750rpm for 2min to form an oil-in-water emulsion, the temperature of the reaction system was adjusted to 45℃and the reaction was allowed to proceed for 12 hours with stirring and then returned to room temperature.

The embedding rate of the silica DCOIT nanocapsules obtained in the embodiment is 43.70%, and the drug loading rate is 25.66%; less mass loss at 200 ℃ and good thermal stability.

Example 5

(1) With mechanical stirring at 500rpm, 0.5mL of APS was added dropwise to 25mL of deionized water for 1min to give an aqueous APS solution. In this step, the positively charged protonated APS shows amphiphilic properties due to the protonation of the amino group.

(2) 0.25g DCOIT and 0.75mL MTMS were dissolved in 1.0mL xylene, slowly added dropwise to the APS aqueous solution with stirring at 500rpm for 2min to form an oil-in-water emulsion, the temperature of the reaction system was adjusted to 25℃and the reaction was allowed to proceed for 24 hours with stirring and then returned to room temperature.

The embedding rate of the silica DCOIT nanocapsule obtained in the embodiment is 46.99%, and the drug loading rate is 26.66%; less mass loss at 200 ℃ and good thermal stability.

Example 6

(1) With mechanical stirring at 1000rpm, 0.25mL of APS was added dropwise to 25mL of deionized water for 1min to give an aqueous APS solution. In this step, the positively charged protonated APS shows amphiphilic properties due to the protonation of the amino group.

(2) 0.25g DCOIT and 0.75mL MTMS were dissolved in 1.0mL xylene, slowly added dropwise to the APS aqueous solution with stirring at 1000rpm for 2min to form an oil-in-water emulsion, the temperature of the reaction system was adjusted to 35℃and the reaction was allowed to proceed for 6 hours with stirring and then returned to room temperature.

The silica DCOIT nanocapsule obtained in the embodiment has an embedding rate of 48.17% and a drug loading rate of 27.18%; less mass loss within 200 ℃ and good thermal stability.

Example 7

(1) Under mechanical stirring at 1000rpm, 0.5mL of 3-aminopropyl methyldimethoxy silane was added dropwise to 50mL of deionized water for 1min to obtain an aqueous solution of 3-aminopropyl methyldimethoxy silane. In this step, the protonated 3-aminopropyl methyldimethoxy silane, which is positively charged, shows amphiphilic properties due to the protonation of the amino group.

(2) 0.25g of DCOIT and 1mL of dimethyl dimethoxy silane are dissolved in 1mL of dimethylbenzene, slowly added dropwise into a 3-aminopropyl methyl dimethoxy silane aqueous solution under the stirring condition of 1000rpm for 2min to form an oil-in-water emulsion, the temperature of a reaction system is adjusted to 25 ℃, and the reaction is stirred for 12 hours.

(3) Then separating the nanocapsules from the mixture by using a centrifuge, washing with distilled water for 3 times, and drying in an electrothermal blowing drying oven at 40 ℃ for 12 hours to obtain the slow release nanocapsules of the organic modified silica coated DCOIT.

The comparative example showed that the silica DCOIT nanocapsules obtained in example 1 were partially broken (the breakage amount was greater than that in example 1) and the coating effect was poor, the embedding rate was 34.23%, and the drug loading was 16.89%.

Example 8

(2) 0.25g DCOIT and 2mL MTMS were dissolved in 1mL xylene, slowly added dropwise to the APS aqueous solution with stirring at 1000rpm for 2min to form an oil-in-water emulsion, the temperature of the reaction system was adjusted to 25℃and the reaction was stirred for 12 hours.

The embedding rate of the DCOIT sustained-release nanocapsule with the silicon dioxide as a carrier obtained in the embodiment is 35.42%, and the drug loading rate is 20.22%; less mass loss within 200 ℃ and good thermal stability.

Comparative example 1

(1) 0.25g of DCOIT, 0.5mL of APS and 1.0mL of MTMS were dissolved in 1.0mL of xylene, slowly added dropwise to 50mL of deionized water under mechanical stirring at 1000rpm for 2min to form an oil-in-water emulsion, the temperature of the reaction system was adjusted to 25℃and the reaction was stirred for 12 hours.

(2) Then separating the nanocapsules from the mixture by using a centrifuge, washing with distilled water for 3 times, and drying in an electrothermal blowing drying oven at 40 ℃ for 12 hours to obtain the slow release nanocapsules of the organic modified silica coated DCOIT.

The comparative example showed that the silica DCOIT nanocapsules obtained in example 1 had an uneven particle size distribution and a poor coating effect, i.e., an embedding rate of 37.12% and a drug loading rate of 19.44%.

The preferred embodiments of the present invention and the corresponding comparative examples are described in detail above, and are the results of experiments performed by the inventors taking a lot of time. Various modifications and adaptations to these embodiments will be readily apparent to those skilled in the art without the need for inventive faculty. Therefore, all technical solutions obtained by the person skilled in the art without departing from the present invention shall fall within the protection scope of the present invention.

Claims

1. The DCOIT sustained release nanocapsule is characterized by comprising a core material and a wall material; the core material is a xylene solution of DCOIT; the wall material is organic modified silicon dioxide and is formed by the self-catalytic reaction of amino alkoxy silane and alkoxy silane at an oil-water interface;

the amino alkoxy silane is 3-aminopropyl trimethoxy silane; the alkoxy silane is methyltrimethoxy silane.

2. The silica-supported DCOIT sustained release nanocapsule of claim 1, wherein the nanocapsule has a microscopic morphology of: nanospheres with particle size of 500-800 nm.

3. The method for preparing the DCOIT sustained release nanocapsule using silica as a carrier according to claim 1 or 2, comprising the steps of:

(1) Dropwise adding amino alkoxy silane into deionized water under the stirring condition to obtain an amino alkoxy silane aqueous solution; the amino alkoxy silane is 3-aminopropyl trimethoxy silane;

(2) Dissolving DCOIT and alkoxy silane in dimethylbenzene to obtain mixed solution; under the stirring condition, slowly dripping the mixed solution into an amino alkoxy silane aqueous solution, stirring for reaction, separating, washing and drying the obtained reaction solution to obtain the DCOIT slow-release nano-capsule taking silicon dioxide as a carrier; the alkoxy silane is methyltrimethoxy silane.

4. A method for preparing a silica-supported DCOIT sustained release nanocapsule according to claim 3, comprising one or more of the following conditions:

i. in the steps (1) and (2), the stirring speed is 500-1250rpm;

ii. In the step (1), the volume ratio of the amino alkoxy silane to the deionized water is 1:50-100.

5. A method for preparing a DCOIT slow release nanocapsule with silica as a carrier according to claim 3, wherein in step (2), one or more of the following conditions are included:

i. the volume ratio of the alkoxy silane to the dimethylbenzene is 0.2-2:1;

ii. The mass to volume xylene ratio of DCOIT is 0.1-0.5:1g/mL.

6. The method for preparing a DCOIT slow release nanocapsule using silica as a carrier according to claim 3, wherein in the step (2), the volume ratio of the alkoxysilane in the mixed solution to the aminoalkoxysilane in the aqueous solution of the aminoalkoxysilane in the step (1) is 1-3:1.

7. A method for preparing a DCOIT slow release nanocapsule with silica as a carrier according to claim 3, wherein in step (2), one or more of the following conditions are included:

i. the temperature of the reaction is 15-45 ℃; the reaction time is 6-24h;

ii. The separation is to separate the nanocapsules by using a centrifuge; the washing is carried out 3-5 times by using water; the drying is carried out for 12-24 hours at 30-50 ℃;

iii, the dropping speed is 0.5-2mL/min.

8. Use of a DCOIT slow release nanocapsule according to claim 1 or 2 supported on silica as a functional chemical additive for preventing fungal and bacterial growth.

9. Use of the DCOIT slow release nanocapsules with silica as a carrier according to claim 8 as an additive in paint, rubber, plastic, lubricating oil or wood.