A Class of Intelligent Sustained-Release Materials Based on Photothermal Conversion, Their Preparation and Applications

Abstract

The present invention discloses a class of intelligent slow-release materials based on photothermal conversion, and their preparation and applications. Using a porous material as a substrate, a mixed solution formed by a bio-pheromone and a phase change material is injected into the porous material substrate, and a photothermal material is combined on the surface layer of the porous material. The slow-release process of the bio-pheromone under sunlight irradiation is realized by utilizing the heat conversion characteristics of the photothermal material. It has the characteristics of fast response speed, long slow-release time, parallel to the biological rhythm of pests, eco-friendly, no environmental pollution, and no toxicity to humans.

Description

Technical Field

[0001] The present invention relates to a class of intelligent sustained-release materials based on photothermal conversion, their preparation and applications. By loading and slowly releasing pheromones, long-term and intelligent comprehensive prevention and control of forest pests can be achieved, belonging to the fields of photothermal materials and sustained-release materials. Background Art

[0002] As a phytophagous insect, bark beetles are widely distributed between the phloem and xylem of coniferous trees such as pine trees and fir trees. They damage the tender shoots, branches or felled trees of coniferous forests in the form of adults and larvae, causing the trees to wither and lose their carbon capture, storage and utilization capabilities. With global climate change, the positive feedback intensifies the formation of the greenhouse effect, and the number of bark beetles has increased sharply. Due to the hidden habits of bark beetles, it is difficult to prevent and supervise them. Current prevention measures mainly include removing infected trees, using chemical insecticides and artificially introducing natural enemies, etc. Removing infected trees requires a large amount of manpower and material resources, and involves burning, increasing the hidden danger of forest fires; insecticides have the hidden danger of killing beneficial insects and probiotics and destroying the healthy development of the local ecological environment; introducing natural enemies may disrupt the local ecological balance, leading to the risk of rapid outbreak and extinction of species. At the same time, the above methods are only effective for local and early bark beetle infestations and are difficult to apply to moderately and severely infested bark beetle epidemic areas. Therefore, developing an intelligent regulation method with high selectivity and high sensitivity to bark beetles is of great significance for tree protection, greenhouse effect mitigation, etc.

[0003] Since the concept of pheromones was proposed in 1966, they have been widely used. Pheromones have many advantages such as small dosage, strong effect and specificity, providing ideas for the effective control of bark beetles. However, the characteristic that pheromones are easy to volatilize also causes the defects of short action time and easy failure. For this reason, some patents such as CN201810414865.0 have proposed the concept of slow release to solve the above problems. However, for specific insects, they generally only move during the day, and even if pheromones are released at night, there is no effect. And these sustained-release materials cannot achieve intelligent regulation and release continuously for 24 hours a day, resulting in serious waste of pheromones and shortening the action time of pheromones. Summary of the Invention

[0004] The present invention aims to provide a class of intelligent slow-release materials based on photothermal conversion reactions, as well as their preparation methods and applications. The intelligent slow-release materials of the present invention have the characteristic of releasing synchronously with the biological rhythm of pests, specifically releasing during the flying period of pests, and maximizing the regulation of pest behavior, thereby achieving long-term and effective prevention and control of pests. This method uses a porous material as the substrate, injects a mixed solution formed by a bio-pheromone and a phase change material into the porous material substrate, and combines a photothermal material on the surface layer of the porous material. The slow-release process of the bio-pheromone under sunlight irradiation is realized by utilizing the thermal conversion characteristics of the photothermal material. It has the characteristics of fast response speed, long slow-release time, parallel to the biological rhythm of pests, ecological friendliness, no environmental pollution, and no harm to the human body.

[0005] The intelligent slow-release material based on photothermal conversion reaction provided by the present invention comprises a porous material, a bio-pheromone, a phase change material, and a photothermal material. Among them, with the porous material as the substrate, a mixed solution formed by the bio-pheromone and the phase change material is injected into the porous material substrate, and the photothermal material is combined on the surface layer of the porous material.

[0006] Among them, the porous material has a large number of pores, the porosity ranges from 50% to 100%; the pore size distribution ranges from 0.01 to 10 mm, and the pore sizes are evenly distributed;

[0007] The porous material can be made of one or more of synthetic polymer materials such as polyethylene, polyvinyl chloride, polypropylene, polyurethane, and polydimethylsiloxane;

[0008] The photothermal material is a thin layer of nano-particle black material, which can achieve a photothermal conversion efficiency of 50% - 100%. The depth of the microchannel can be 1 - 1000 microns, and it has strong absorption within the wavelength range of 200 - 3000 nm;

[0009] The photothermal material can be obtained by directly coating a solution containing the photothermal material (the photothermal material can specifically be carbon nanotubes, graphite, polydopamine, polypyrrole, or polyaniline) on the surface of the porous material, or by adding an oxidant on the surface of the porous material and oxidizing another monomer substance through a fumigation method,

[0010] Among them, the other substance can be dopamine, pyrrole, or aniline, etc.

[0011] Specifically as follows: Let the monomer contact the oxidant coated on the surface layer of the porous material in the form of steam, and the monomer automatically polymerizes to form a polymer to obtain the photothermal material.

[0012] The bio-pheromone is a chemical substance that has an attracting or repelling effect on the pests to be controlled.

[0013] The pest to be controlled and prevented is bark beetle, and the bio-pheromones can be divided into four categories: (1) Chemical substances such as sesquiterpenoids and monoterpenoids; (2) Fatty acid derivatives; (3) Amino acid derivatives; (4) Bio-synthetic sources of unknown origin;

[0014] Preferably, the bio-pheromones can be 2-methyl-3-buten-2-ol, 3-methyl-3-buten-1-ol, ipsdienol, ipsenol, trans-myrcenol, cis-verbenol, trans-verbenol, verbenone, 3-methyl-2-cyclohexen-1-ol, Dendroctonus brevicomis aggregating pheromone, Dendroctonus frontalis Zimmermann pheromone, 2-hydroxy-4,4,6-trimethyl-2,5-cyclohexadien-1-one, emarginol, pinene (α,β), myrcene, etc.

[0015] The bio-pheromones used can be the single products or compound products listed above.

[0016] The bark beetle groups targeted by the bio-pheromones can be one or more of the genera Ips or Dendroctonus, specifically including: Ips acuminatus, Ips typographus, Ips subelongatus, Ips nitidus, Ips shangrilaensis, Ips confusus, Ips duplicatus, Ips brunneus, Ips calligraphus, Ips cembrae, Dendroctonus armandi, Dendroctonus valens, Dendroctonus frontalis, Dendroctonus brevicomis, etc.

[0017] The bio-pheromones are mixed with the phase change material in a mass ratio of 1% - 50%.

[0018] The phase change material has good waterproofness, can be blended with the bio-pheromones, and can be evenly filled into the pores of the porous material.

[0019] The phase change temperature of the phase change material is between 15°C and 75°C.

[0020] The phase change material specifically includes alloys, paraffins, organic acids, etc.

[0021] The application of the above intelligent slow-release material based on the photothermal conversion reaction in forest pest control also belongs to the protection scope of the present invention.

[0022] When the intelligent slow-release material is used for bark beetle control, the bio-pheromones contained in the intelligent slow-release material have an attracting or repelling effect on bark beetles;

[0023] The bio-pheromone may be one or a mixture of several of 2-methyl-3-buten-2-ol, 3-methyl-3-buten-1-ol, ipsdienol, ipsenol, trans-myrcenol, cis-verbenol, trans-verbenol, verbenone, 3-methyl-2-cyclohexen-1-ol, western pine beetle attractant, southern pine beetle attractant, 2-hydroxy-4,4,6-trimethyl-2,5-cyclohexadien-1-one, emarginol, pinene (α, β), and myrcene.

[0024] The present invention has the following beneficial effects:

[0025] (1) This product combines the characteristics of strong action, small dosage, and specific action of bio-pheromones, and combines the characteristics of photothermal slow release, simulating the biological habits and biological rhythms of pests, realizing the intelligent slow release of bio-pheromones, having the characteristics of small release amount per unit time and long-term release, and reducing the cost of pest control.

[0026] (2) The photothermal conversion material makes full use of the solar energy under natural conditions. As a non-contact and non-invasive intelligent material, it conforms to the actual situation of controlling pine beetles under unmanned field conditions.

[0027] (3) Due to the designability of the phase change temperature of the phase change material, this product can program and control the slow release characteristics at different rates. According to the severity of the epidemic situation in the affected area, different phase change materials are designed to balance short-term rapid release and long-term effective release.

[0028] (4) The production steps of this product are simple, the cost is low, the product is convenient to carry, and it can be mass-produced.

[0029] The present invention uses a phase change material to coat the bio-pheromone to achieve a controllable release of preserving the bio-pheromone in the solid state and releasing it in the liquid state. The photothermal conversion material can make full use of the solar energy under natural conditions to convert light energy into heat energy. By combining the photothermal material with the phase change material, the phase change material can only achieve the intelligent release of the bio-pheromone when illuminated. Utilizing the biological rhythm of pine beetles and the similar dependence of the photothermal conversion material on the light intensity, the intelligent release of the bio-pheromone is realized only when the pine beetles are active, improving the efficiency of the bio-pheromone and prolonging its release time. In addition, the photothermal conversion material, as a non-contact and non-invasive material, conforms to the actual situation of controlling pine beetles under unmanned field conditions. At the same time, due to the designability of the phase change temperature of the phase change material, slow release characteristics at different rates can be achieved. According to the severity of the epidemic situation in the affected area, different phase change materials are designed to balance short-term rapid release and long-term effective release. Therefore, the development of intelligent photothermal slow release trapping materials has broad application prospects in the integrated prevention and control of pests and diseases. Description of the Drawings

[0030] Figure 1Schematic diagram for the preparation of the intelligent photothermal slow-release material.

[0031] Figure 2 Physical photograph of the intelligent photothermal slow-release material.

[0032] Figure 3 UV-Vis-NIR reflection spectrum of the intelligent photothermal slow-release material.

[0033] Figure 4 Photothermal irradiation-dark cycle response diagram of the intelligent photothermal slow-release material.

[0034] Figure 5 Long-term slow-release mass loss-time variation diagram of the intelligent photothermal slow-release material.

[0035] Figure 6 Diagram of capturing bark beetles in the forest farm experiment of the intelligent photothermal slow-release material.

[0036] Figure 7 Statistical chart of capturing bark beetles in the forest farm by the short-term intelligent photothermal slow-release material.

[0037] Figure 8 Statistical chart of capturing bark beetles in the forest farm by the long-term intelligent photothermal slow-release material. Detailed implementation manners

[0038] The present invention will be further described in detail below in conjunction with the detailed implementation manners. The examples given are only for clarifying the present invention, rather than limiting the scope of the present invention. The following examples can be used as a guide for those of ordinary skill in the art to make further improvements, and do not limit the present invention in any way.

[0039] The experimental methods in the following examples are all conventional methods unless otherwise specified, and are carried out according to the techniques or conditions described in the literature in this field or according to the product instructions. The materials, reagents, etc. used in the following examples can be obtained from commercial sources unless otherwise specified.

[0040] Example 1: Preparation of the intelligent photothermal slow-release material

[0041] As Figure 1 shown, the intelligent photothermal slow-release material is prepared according to the following steps:

[0042] (1) The porous substrate is formed by in-situ polymerization using the template method, and its shape is similar to that of the template. By adding 44 g of polyethylene glycol, 9.872 g of isocyanate, and 13.44 g of triisocyanurate mixed monomer raw materials into the sugar cube template, and under vacuum at 60 °C, heat polymerization is carried out for 10 minutes to form; the polymerized substance is soaked in warm water (40 °C) for 2 hours to completely remove the sugar cube.

[0043] The above-mentioned sugar cube template is a commercially purchased sugar cube, specifically the Zhengbei brand pure sugar cube; polyethylene glycol is sourced from Shanghai Aladdin Biochemical Technology Co., Ltd.; isocyanate is sourced from; isocyanate is sourced from Merck KGaA; tris-isocyanate is sourced from Covestro (China) Co., Ltd.

[0044] The porosity ranges from 40% to 70%.

[0045] (2) By means of oxidative polymerization on the substrate material obtained in step (1), a thin photothermal polymer layer is formed. Specifically, first apply a layer of oxidant (0.1 mol / L ammonium persulfate solution), fumigate pure pyrrole (sourced from Merck KGaA), polymerize at 25 °C for 5 minutes, then remove the oxidant with a cleaning solvent (pure water and 5% ethanol solution), and bake in an oven at 60 °C for 60 minutes. The resulting material is the black material with photothermal conversion ability.

[0046] (3) Mix bioactive substances: α-pinene or verbenone into the phase change material (modified paraffin) at 60 °C to form a mixed solution with a bioactive substance mass fraction of 10%.

[0047] (4) Mix the solution described in step (3) with the material from step (2) at 60 °C.

[0048] (5) Return to room temperature to obtain the intelligent photothermal slow-release material. The physical photograph of the prepared intelligent photothermal slow-release material is as Figure 2 shown. (Camera model: EOS 5D Mark II, sourced from Canon Inc., Japan)

[0049] Example 2. Response of the intelligent photothermal slow-release material to sunlight

[0050] (1) Detection of the ultraviolet-visible-near-infrared reflection spectrum of the intelligent photothermal slow-release material: Grind the intelligent photothermal slow-release material (containing α-pinene) prepared in Example 1 into small particles, select 0.1 g of the sample, compact it into a tablet with a press and then fill it into a solid ultraviolet-visible-near-infrared detector, and use an integrating sphere for detection. (Model: UV-3600PLUS, Shimadzu Corporation, Japan), the detection wavelength is selected as 300 - 1000 nm, and the scanning speed is selected as 600 nm / min. The experimental results are as Figure 3 shown. As Figure 3 can be seen, the substrate material without the modified photothermal polymer itself has poor light absorption performance, and 60% - 80% of the light is reflected. After modifying the photothermal polymer, the reflectance drops sharply to 10% and below within the entire detection wavelength range, confirming good light absorption performance.

[0051] (2) Detection of the photothermal response performance of the intelligent photothermal slow-release material: Fix the intelligent photothermal slow-release material (containing α-pinene) prepared in Example 1 under a solar simulator (model INC, Solarbeam-02-3A, Yiguang Technology Co., Ltd., USA), and adjust the light intensity power to one standard solar light intensity. Adjust and maintain the room temperature at 25 °C. Conduct an experiment with a cycle of 300 seconds of illumination and 300 seconds of darkness for 10 cycles. The experimental results are as Figure 4 shown. As Figure 4 can be seen, in the 10 cycles, the response values of each cycle are basically the same. That is, when illuminated for 300 seconds, the temperature in each cycle changes by approximately 35 °C compared to before illumination. And during the 300-second dark interval for temperature reduction, the temperature in each cycle almost drops to room temperature. The cyclic illumination experiment confirms the good photothermal conversion performance and excellent cyclic stability performance of the intelligent photothermal slow-release material.

[0052] Example 3. Detection of the long-term slow-release performance of the intelligent photothermal slow-release material

[0053] Fix the intelligent photothermal slow-release material (containing α-pinene) prepared in Example 1 in an electronic balance (model: MS-TS, Mettler Toledo China Co., Ltd.), and record the change in the mass loss of the slow-release material over 48 hours under the irradiation of one standard solar light intensity. Keep the room temperature at 25 °C. The experimental results are as Figure 5 shown. After 48 hours of continuous irradiation, the intelligent photothermal slow-release material has a mass loss of about 0.16 grams. The mass loss rate remains relatively stable during this process.

[0054] Example 4. Intelligent slow-release performance of the intelligent photothermal slow-release material in an actual forest farm

[0055] (1) Preparation for the forest farm experiment: Take the intelligent photothermal slow-release material prepared in Example 1 to an actual forest farm to explore its effect on bark beetles. Place the slow-release material on a cross-shaped dark trap (produced by Zhongjie Sifang Co., Ltd.), and hang it at a height of 1.5 meters in the forest with a wire. Place one cage of traps every 50 meters, as Figure 6 shown. Place the intelligent photothermal slow-release material on top of the trap so that it can receive sunlight, as Figure 7 shown. The pests are induced by the pheromone and collected in the collection room, as Figure 8 shown. At 8:00 am, 12:00 noon, and 16:00 pm every day, count the number of pests in the collection room. Detect the slow-release characteristics of different types of pheromones, the presence or absence of photothermal conversion materials, phase change materials with different phase change temperatures, and intelligent slow-release detection under different weather conditions respectively.

[0056] (2) Detection of different types of bio-pheromones: Different types of intelligent slow-release materials were placed separately in the same forest farm with similar environments, and the number of trapped pests was detected. The results are shown in Table 1. Compared with the control group, the trapping ability of the commercial lure core (produced by Zhongjie Sifang Biotech Co., Ltd., Ips typographus attractant) was limited. The attracting bio-pheromone (α-pinene) had strong attracting properties, and an average of 39 pests were attracted within five days. The repellent bio-pheromone (verbenone) showed extremely strong repellent properties, and no pests were captured by the device equipped with the repellent. In this embodiment, the phase change temperature of the phase change material was set at 25°C.

[0057] Table 1 Detection of different types of bio-pheromones

[0058] The first day The second day The third day The fourth day The fifth day Group Pheromone type Unit: (pcs) 1 None (control group) 6 3 0 6 5 2 Commercial lure 3 2 7 2 4 3 Lure 57 35 40 40 22 4 Repellent 0 0 0 0 0

[0059] (3) Detection with or without photothermal conversion materials: In this embodiment, the phase change temperature of the phase change material was set at 25°C, and the bio-pheromone was selected as the attracting type (α-pinene). Taking the unmodified photothermal conversion material (referring to the same preparation method except without the last step of oxidation) as the control group, the trapping situation of the experimental group with modified photothermal conversion materials was explored. As shown in Table 2, the results showed that the experimental group with photothermal conversion materials showed stronger trapping performance, and the number of trapped pests was about 4 times that of the control group.

[0060] Table 2 Detection of the influence of photothermal conversion materials

[0061] The first day The second day The third day The fourth day The fifth day Group With or without photothermal conversion Unit: (pcs) 1 None (control group) 9 9 14 13 11 2 Yes (experimental group) 57 35 40 40 22

[0062] (4) Detection of the slow-release characteristics of phase change materials with different phase change temperatures: In this embodiment, the phase change temperatures of the phase change materials were set at five groups of 25, 30, 35, 40, and 45°C (the phase change materials used were modified paraffins with different melting ranges, and the temperature represented the average melting range of the paraffin used. The paraffins were all from Zhenjiang Runzhou Zezhong Special Wax Factory), and they were compared with each other. The bio-pheromone was the attracting type (α-pinene), and all were modified with photothermal conversion materials. As shown in Table 3, the results showed that the slow-release effect of the slow-release materials with higher phase change temperatures within five days was inferior to that of the groups with lower phase change temperatures.

[0063] Table 3 Detection of the influence of phase change temperature

[0064] The first day The second day The third day The fourth day The fifth day Group Phase change temperature (°C) <![CDATA[Unit: (pcs) 5 > 1 25 57 35 40 40 22 2 30 33 26 24 17 22 3 35 18 23 10 11 17 4 40 2 8 3 5 1 5 45 3 3 2 4 3

[0065] (5) Detection of intelligent slow-release characteristics under different weather conditions: In this embodiment, the phase change temperature of the phase change material is set at 25 °C, the bio-pheromone is the attracting type (α-pinene), and the photo-thermal conversion material is modified to explore its slow-release effect under different weather conditions and its long-term slow-release effect. As shown in Table 4, the results show that the intelligent slow-release material has a good attracting effect under sunny and cloudy conditions, while it does not release under rainy conditions. The effective natural days of action are at least up to 21 days.

[0066] Table 4 Detection of the influence of different weather conditions

[0067] Sunny day Cloudy day Overcast day Rainy day The twenty-first day Group Unit: (pcs) 1 57 40 7 1 18

[0068] The present invention has been described in detail above. For those skilled in the art, without departing from the gist and scope of the present invention and without unnecessary experiments, the present invention can be implemented within a relatively wide range under equivalent parameters, concentrations and conditions. Although specific embodiments of the present invention are given, it should be understood that the present invention can be further improved. In short, according to the principle of the present invention, this application is intended to cover any modification, use or improvement of the present invention, including those that depart from the scope disclosed in this application and are made by conventional techniques known in the art.

Claims

1. A photothermal intelligent slow-release material, comprising a porous material, a bio-pheromone, a phase change material and a photothermal material, wherein, using the porous material as a substrate, a mixed solution formed by the bio-pheromone and the phase change material is injected into the porous material substrate, and the photothermal material is combined on the surface layer of the porous material; the porous material has a large number of pores, the porosity ranges from 50% to 100%; the pore size distribution ranges from 0.01 to 10 mm; the porous material is made of a synthetic polymer material; the synthetic polymer material is one or more of polyethylene, polyvinyl chloride, polypropylene, polyurethane, and polydimethylsiloxane; the photothermal material is a layer of nano-particle black material; the nano-particle black material is carbon nanotubes, graphite, polydopamine, polypyrrole or polyaniline; the bio-pheromone is one or a mixture of several of 2-methyl-3-buten-2-ol, 3-methyl-3-buten-1-ol, ipsdienol, ipsenol, trans-linalool, cis-verbenol, trans-verbenol, verbenone, 3-methyl-2-cyclohexen-1-ol, western pine beetle attractant, southern pine beetle attractant, 2-hydroxy-4,4,6-trimethyl-2,5-cyclohexadien-1-one, emarginol, α-pinene, β-pinene, myrcene; the phase change temperature of the phase change material ranges from 15°C to 75°C; the phase change material is any one of alloy types, paraffin types, and organic acid types.

2. The photothermal intelligent slow-release material according to claim 1, characterized in that: the bio-pheromone is mixed with the phase change material in a mass ratio of 1% to 50%.

3. Use of the photothermal intelligent slow-release material according to claim 1 or 2 in forest pest control.

4. The use according to claim 3, characterized in that: the intelligent slow-release material is used for controlling bark beetles.

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