Blue-light carbon dot light-conversion agricultural film and preparation method thereof

Abstract

This invention relates to a blue-light carbon dot conversion agricultural film and its preparation method, belonging to the field of agricultural planting technology. It addresses at least one of the problems of existing carbon dot conversion agricultural film preparation methods, such as complexity, low efficiency, high raw material loss, and low fluorescence intensity. This invention uses ammonium citrate and artemisinin as carbon dot precursors to directly generate blue-light carbon dots in situ during the melt processing of a polymer matrix. This eliminates the need for pre-synthesizing and post-processing carbon dots before incorporating them into the polymer matrix, simplifying the preparation process and improving the efficiency of the conversion film. Furthermore, the in-situ generated blue-light carbon dots exhibit better dispersion in the polymer matrix, are less prone to aggregation, and ensure the uniformity of the overall light conversion performance of the conversion film. Simultaneously, the obtained blue-light carbon dots can stably absorb ultraviolet light and convert it into blue light required for plant photosynthesis, enabling long-term stable light conversion and meeting the application requirements of agricultural conversion films.

Description

Technical Field

[0001] This invention relates to the field of agricultural planting technology, and in particular to a blue light carbon dot light-converting agricultural film and its preparation method. Background Technology

[0002] Light-converting films absorb a portion of ultraviolet light and yellow-green light, which plants utilize less efficiently, from sunlight and convert them into red-orange and blue-violet light that are highly effective for photosynthesis. An ideal light-converting film can convert the spectrum that is harmful to plant growth or cannot be absorbed by chlorophyll into red-orange and blue-violet light that chlorophyll can effectively utilize, thereby improving light energy utilization efficiency. Agricultural light-converting films are designed based on this principle, enabling crops to utilize solar energy more efficiently. The application of light-converting films can significantly improve the overall utilization rate of light energy, promote plant growth, and achieve earlier maturity and increased yield.

[0003] Carbon dots, as a novel nanomaterial, possess advantages such as excellent light conversion properties, good biocompatibility, and low preparation cost. Agricultural films prepared using blue carbon dots as light-converting agents can effectively capture ultraviolet light and convert it into the blue light required by plants, significantly improving the efficiency of photosynthesis. Furthermore, introducing carbon dots as a light-converting agent into traditional agricultural films aligns with the development needs of green agriculture.

[0004] In the existing technology, the synthesis of carbon dot light-converting agricultural film requires the separate synthesis of carbon dots, purification treatment and then incorporation into the polymer matrix. The preparation method is complicated and the production process is prone to raw material loss, which reduces the preparation efficiency of the light-converting film. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide a blue carbon dot light-converting agricultural film and its preparation method, so as to solve at least one of the problems of existing carbon dot light-converting agricultural film preparation methods, such as complexity, low preparation efficiency, large raw material loss, and low fluorescence intensity.

[0006] In a first aspect, the present invention provides a method for preparing a blue light carbon dot photocatalytic agricultural film, comprising the following steps: S1: The polymer matrix, ammonium citrate, artemisinin and additives are mixed and then granulated and dried to obtain blue carbon dot conversion masterbatch; S2: The blue carbon dot light-converting masterbatch is processed by blown film forming or tablet forming to obtain the blue carbon dot light-converting agricultural film.

[0007] Furthermore, the polymer matrix is ​​one or more of low-density polyethylene, linear low-density polyethylene, and ethylene-vinyl acetate copolymer; The additives include one or more of the following: PE wax, naphthenic oil, antioxidant, lanthanum oxide, anti-drip agent, dibenzyl sorbitol, maleic anhydride-grafted polyethylene, pentaerythritol stearate, plastic defoaming masterbatch, and titanate.

[0008] Furthermore, in S1, by weight, there are 50-500 parts of polymer matrix, 1.6-16 parts of ammonium citrate, 0.9-9 parts of artemisinin, and 3-35 parts of adjuvants.

[0009] Furthermore, in S1, the mixing speed is 800~1000 r / min, and the time is 10~15 min.

[0010] Furthermore, in S1, a twin-screw granulator is used for granulation. The temperature of the feed section of the granulator is 130~140℃, the temperature of the melting section is 140~150℃, and the temperature of the die head section is 150~160℃.

[0011] Furthermore, in S2, the blown film forming process includes: adding the blue carbon dot light-converting masterbatch into a blown film machine, and sequentially undergoing extrusion, blowing, cooling, traction, and winding processes to obtain the blue carbon dot light-converting agricultural film.

[0012] Furthermore, the die head temperature of the blown film machine is 150~170℃, and the traction speed is 0.5~10m / min.

[0013] Furthermore, in S2, the pressing and molding process includes: adding the blue carbon dot light-converting masterbatch into a two-roll open mill, mixing and melting it, transferring it to a flat vulcanizing machine, controlling the vulcanizing temperature and pressure, holding the pressure to form the film, demolding it, and obtaining the blue carbon dot light-converting agricultural film.

[0014] Furthermore, the vulcanization temperature is 140~160℃, the pressure is 8~20MPa, and the pressure holding molding is 3~5min.

[0015] Secondly, the present invention provides a blue light carbon dot light-converting agricultural film prepared by the above method.

[0016] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: 1. This invention uses ammonium citrate and artemisinin as carbon dot precursors to directly generate blue light-emitting carbon dots in situ during the melt processing of a polymer matrix. This eliminates the need for pre-synthesizing and post-processing carbon dots before incorporating them into the polymer matrix, simplifying the preparation process of carbon dot light-converting agricultural films. It also avoids raw material losses that occur during the separate preparation and transfer of carbon dots, effectively improving the preparation efficiency of the light-converting film. Furthermore, the in-situ generated blue light-emitting carbon dots exhibit better dispersion in the polymer matrix and are less prone to aggregation, ensuring the uniformity of the overall light-converting performance of the agricultural film. Simultaneously, the resulting blue light-emitting carbon dots can stably absorb ultraviolet light and convert it into the blue light required for plant photosynthesis, enabling them to maintain a stable light-converting effect over a long period and meeting the application requirements of agricultural light-converting films.

[0017] 2. The precursors used in the carbon dots prepared by the method of this invention are ammonium citrate and artemisinin. The luminescence performance of carbon dots prepared by ammonium citrate or artemisinin alone is lower than that of the composite of artemisinin and ammonium citrate, indicating that ammonium citrate and artemisinin have a certain synergistic effect in the preparation of carbon dots, which can enhance the luminescence intensity of the carbon dots. The light-converting agricultural film prepared by this invention has excellent light conversion performance, can efficiently realize the conversion of ultraviolet light to blue light, and improve the use effect of the light-converting agricultural film.

[0018] 3. The blue light carbon dot light-converting agricultural film prepared by this invention emits wavelengths around 440 nm. It can selectively absorb ultraviolet light (wavelength 200 ~ 400 nm) from sunlight and efficiently convert the ultraviolet energy that is ineffective for plant photosynthesis into 440 nm blue light, which significantly improves crop photosynthesis and yield.

[0019] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0020] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0021] Figure 1 This is a photograph of the optical conversion masterbatch prepared in Example 1 of the present invention; Figure 2 This is a photograph of the light-converting agricultural film prepared in Example 1 of the present invention; Figure 3 The excitation and emission spectra of the light-converting film prepared in Example 1 of this invention; Figure 4 This is a comparison diagram of the fluorescence intensity of agricultural films prepared in Example 2 and Comparative Examples 1-5 of the present invention. Detailed Implementation

[0022] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0023] A specific embodiment of the present invention discloses a method for preparing a blue light carbon dot photocatalytic agricultural film, comprising the following steps: S1: The polymer matrix, ammonium citrate, artemisinin and additives are mixed and then granulated and dried to obtain blue carbon dot conversion masterbatch; S2: The blue carbon dot light-converting masterbatch is processed by blown film forming or tablet forming to obtain the blue carbon dot light-converting agricultural film.

[0024] Compared with existing technologies, this invention uses ammonium citrate and artemisinin as carbon dot precursors to directly generate blue light-emitting carbon dots in situ during the melt processing of the polymer matrix. This eliminates the need for pre-synthesizing and post-processing carbon dots before incorporating them into the polymer matrix, simplifying the preparation process of the carbon dot light-converting agricultural film. It also avoids raw material losses that occur during the separate preparation and transfer of carbon dots, effectively improving the preparation efficiency of the light-converting film. Furthermore, the in-situ generated blue light-emitting carbon dots exhibit better dispersion in the polymer matrix and are less prone to aggregation, ensuring the uniformity of the overall light-converting performance of the agricultural film. Simultaneously, the resulting blue light-emitting carbon dots can stably absorb ultraviolet light and convert it into the blue light required for plant photosynthesis, enabling them to maintain a stable light-converting effect over a long period and meeting the application requirements of agricultural light-converting films.

[0025] The precursors used in the carbon dots prepared by the method of this invention are ammonium citrate and artemisinin. The luminescence performance of carbon dots prepared by ammonium citrate or artemisinin alone is lower than that of carbon dots prepared by combining artemisinin and ammonium citrate, indicating that ammonium citrate and artemisinin have a certain synergistic effect in the preparation of carbon dots, which can enhance the luminescence intensity of the carbon dots. The light-converting agricultural film prepared by this invention has excellent light conversion performance, can efficiently convert ultraviolet light to blue light, and improves the performance of the light-converting agricultural film.

[0026] Specifically, in S1, the polymer matrix is ​​one or more of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and ethylene-vinyl acetate copolymer (EVA). The additives include one or more of the following: PE wax, naphthenic oil, antioxidant, lanthanum oxide, anti-drip agent, dibenzyl sorbitol, maleic anhydride grafted polyethylene (MAH-g-PE), pentaerythritol stearate (PETS), plastic defoaming masterbatch, and titanate. When multiple additives are selected, the substances can be mixed in any proportion.

[0027] In this invention, naphthenic oil is used as a dispersant to improve the system's fluidity and reduce processing difficulty; dibenzyl sorbitol is used as a nucleating agent to enhance the uniformity of light transmission and mechanical properties of the agricultural film; pentaerythritol (PETS) is used as a lubricant to reduce friction between materials and equipment during processing and prevent film adhesion; antioxidants can delay the oxidative aging of materials during processing and use, extending the service life of the agricultural film; plastic defoaming masterbatch is used to remove residual trace moisture and air bubbles from the materials, preventing pinholes and air bubbles after film formation; anti-drip agent can reduce the surface tension of the agricultural film, reduce the condensation of water vapor on the film surface inside the greenhouse, and ensure the light transmission efficiency of the agricultural film; PE wax can increase the smoothness of the product; lanthanum oxide has a strong absorption and blocking effect on infrared rays, which can improve the heat preservation performance of the agricultural film; MAH-g-PE can bond to the surface of the light conversion agent and inhibit agglomeration.

[0028] It should be noted that the antioxidants and anti-drip agents in this invention are conventional raw materials in the art. The antioxidants are, for example, antioxidant 1010 or antioxidant 168, and the anti-drip agents are, for example, commonly used anti-drip agents such as Dow Chemical's Tergitol 15-s-7.

[0029] Specifically, in S1, by weight, the polymer matrix comprises 50-500 parts (e.g., 50, 70, 90, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, 400, 420, 440, 460, 480, 500 parts), and ammonium citrate comprises 1.6-16 parts (e.g., 1.6, 2, ...). 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 parts), artemisinin 0.9-9 parts (e.g., 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9 parts) and adjuvants 3-35 parts (e.g., 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35 parts).

[0030] Preferably, in S1, the mixing speed is 800~1000 r / min, for example, 800 r / min, 820 r / min, 840 r / min, 860 r / min, 880 r / min, 900 r / min, 920 r / min, 940 r / min, 960 r / min, 980 r / min, or 1000 r / min, and the time is 10~15 min, for example, 10 min, 11 min, 13 min, 14 min, or 15 min.

[0031] Specifically, in S1, a twin-screw granulator is used for granulation. The feed section temperature of the granulator is 130~140℃, for example, 130℃, 132℃, 134℃, 136℃, 138℃, or 140℃; the melting section temperature is 140~150℃, for example, 140℃, 142℃, 144℃, 146℃, 148℃, or 150℃; and the die head section temperature is 150~160℃, for example, 150℃, 152℃, 154℃, 156℃, 158℃, or 160℃.

[0032] Specifically, in S2, the blown film forming process includes: adding the blue carbon dot light-converting masterbatch into a blown film machine, and sequentially undergoing extrusion, blowing, cooling, traction, and winding processes to obtain the blue carbon dot light-converting agricultural film.

[0033] Preferably, the die head temperature of the blown film machine is 150~170℃, for example, 150℃, 152℃, 154℃, 156℃, 158℃, 160℃, 162℃, 164℃, 166℃, 168℃, 170℃, and the traction speed is 0.5~10m / min, for example, 0.5m / min, 1m / min, 2m / min, 3m / min, 4m / min, 5m / min, 6m / min, 7m / min, 8m / min, 9m / min, 10m / min.

[0034] It should be noted that excessively high die temperatures can cause melt cracking, making the prepared film brittle and resulting in a "sharkskin" effect, while excessively low temperatures can lead to rough crystal points or film surface.

[0035] Specifically, in S2, the pressing process includes: adding the blue carbon dot conversion masterbatch into a two-roll open mill, mixing and melting, transferring to a flat vulcanizing machine, controlling the vulcanization temperature and pressure, holding the pressure to form, demolding, and obtaining the blue carbon dot conversion agricultural film.

[0036] Preferably, the melting temperature is 140~160℃, for example, 140℃, 142℃, 144℃, 146℃, 148℃, 150℃, 152℃, 154℃, 156℃, 158℃, or 160℃, and the melting time is 5~8 minutes, for example, 5 minutes, 5.5 minutes, 6 minutes, 6.5 minutes, 7 minutes, 7.5 minutes, or 8 minutes. Excessive temperature or time will cause the melt to crack and the film to become brittle; excessively low temperature or short time will result in a rough film surface.

[0037] More preferably, the vulcanization temperature is 140~160℃, for example, 140℃, 142℃, 144℃, 146℃, 148℃, 150℃, 152℃, 154℃, 156℃, 158℃, or 160℃; the pressure is 8~20MPa, for example, 8MPa, 12MPa, 14MPa, 16MPa, 18MPa, or 20MPa; and the pressure holding time is 3~5 minutes, for example, 3 minutes, 3.5 minutes, 4 minutes, 4.5 minutes, or 5 minutes. Excessive temperature, pressure, and time will cause bubbles to form in the molded film; excessively low temperature and pressure will prevent the film from forming.

[0038] Preferably, in S2, when the tableting process is selected, the polymer matrix in S1 also includes the addition of light-converting agricultural film in two stages, that is, a portion of light-converting masterbatch is added in S1, and the remaining polymer matrix and light-converting masterbatch are added in S2 for tableting process. The types of polymer matrices added in the two stages may be the same or different.

[0039] More preferably, the mass ratio of the polymer matrix added for the first time in S1 to the polymer matrix added for the second time in S2 is 1:4.

[0040] It should be noted that the addition of the polymer matrix in two stages during the tableting process of this invention can increase the uniformity of mixing and ensure the uniformity of the overall light conversion performance of the light-converting agricultural film.

[0041] Another specific embodiment of the present invention discloses a blue light carbon dot light-converting agricultural film prepared by the above method, wherein the thickness of the agricultural film is 0.1~2mm.

[0042] The thickness of the agricultural film of the present invention can ensure that the agricultural film has good light transmittance and mechanical strength, and can meet the actual use requirements of covering, heat preservation and light conversion efficiency in facility agriculture. At the same time, it is compatible with various molding processes such as blow molding and sheeting, so that the prepared light-converting agricultural film has stable and reliable performance.

[0043] The blue light carbon dot photoluminescent agricultural film prepared by this invention emits wavelengths around 440 nm. It can selectively absorb ultraviolet light (wavelength 200 ~ 400 nm) from sunlight and efficiently convert the ultraviolet energy that is ineffective for plant photosynthesis into 440 nm blue light, which significantly improves crop photosynthesis and yield.

[0044] The technical solution of the present invention will be further explained below with reference to specific embodiments. The manufacturer of the drop-free agent is Dow Chemical Tergitol 15-s-7, and all other raw materials in the present invention are commercially available.

[0045] Example 1 The preparation method of the blue light carbon dot conversion agricultural film in this embodiment includes the following steps: S1: 500 parts of low-density polyethylene (LDPE), 16 parts of ammonium citrate, 9 parts of artemisinin and 32 parts of additives are mixed to obtain a premix. The mixing speed is 800 r / min and the time is 15 min. The premix is ​​granulated by a twin-screw granulator. The temperature of the feed section of the twin-screw granulator is controlled at 140℃, the temperature of the melting section is 150℃ and the temperature of the die head section is 160℃. After melt mixing, extrusion, pelletizing and cooling drying, blue carbon dot conversion masterbatch is obtained. The additives include 16 parts naphthenic oil, 1.5 parts dibenzyl sorbitol, 3 parts pentaerythritol for PETS, 5 parts antioxidant 1010, 5 parts plastic defoaming masterbatch, and 1.5 parts anti-drip agent. S2: The blue carbon dot light-converting masterbatch is added to a blown film machine. The die temperature is 150℃ and the traction speed is 0.5m / min. The film goes through extrusion, blowing, cooling, traction and winding processes in sequence to obtain a blue carbon dot light-converting agricultural film with an average thickness of 0.1mm.

[0046] The light-conversion masterbatch prepared in this embodiment is as follows: Figure 1 As shown in the figure, the prepared light conversion masterbatch particles are uniformly distributed in size, with no obvious agglomeration, adhesion, or fragmentation, indicating that the light conversion masterbatch prepared by the above method has good dispersibility.

[0047] The light-converting agricultural film prepared in this embodiment is as follows: Figure 2 As shown, it emits blue light under 365 nm ultraviolet light irradiation. The excitation and emission spectra of the light-converting film prepared in this embodiment are as follows. Figure 3 As shown, the maximum emission occurs at around 436 nm, exhibiting blue fluorescence, further proving the successful preparation of the blue light conversion film.

[0048] Example 2 The preparation method of the blue light carbon dot conversion agricultural film in this embodiment includes the following steps: S1: 40 parts of low-density polyethylene (LDPE), 10 parts of ethylene-vinyl acetate copolymer (EVA), 1.6 parts of ammonium citrate, 0.9 parts of artemisinin, and 3.2 parts of additives are mixed to obtain a premix. The mixing speed is 900 r / min and the time is 12.5 min. The premix is ​​granulated by a twin-screw granulator. The temperature of the feed section of the twin-screw granulator is controlled at 135℃, the temperature of the melting section is 145℃, and the temperature of the die head section is 155℃. After melt mixing, extrusion, pelletizing, cooling and drying, blue carbon dot conversion masterbatch is obtained. The additives include 1.6 parts naphthenic oil, 0.15 parts dibenzyl sorbitol, 0.3 parts pentaerythritol for PETS, 0.5 parts antioxidant 1010, 0.5 parts plastic defoaming masterbatch, and 0.15 parts anti-drip agent. S2: Add the blue carbon dot light-converting masterbatch to a two-roll mill, mix and melt at a temperature of 140°C for 8 minutes, transfer to a flat vulcanizing machine, control the vulcanizing temperature at 140°C and the pressure at 8MPa, hold the pressure for 3 minutes, demold, and obtain a blue carbon dot light-converting agricultural film with an average thickness of 0.1 mm.

[0049] The light-converting masterbatch and light-converting agricultural film prepared in this embodiment were tested in Example 1. The results were basically the same as those in Example 1. Due to space limitations, they will not be listed one by one.

[0050] Example 3 The preparation method of the blue light carbon dot conversion agricultural film in this embodiment includes the following steps: S1: 40 parts of low-density polyethylene (LDPE), 10 parts of linear low-density polyethylene (LLDPE), 1.6 parts of ammonium citrate, 0.9 parts of artemisinin, and 3.2 parts of additives are mixed to obtain a premix. The mixing speed is 1000 r / min and the time is 10 min. The premix is ​​granulated by a twin-screw granulator. The temperature of the feed section of the twin-screw granulator is controlled at 130℃, the temperature of the melting section is 140℃, and the temperature of the die head section is 150℃. After melt mixing, extrusion, pelletizing, cooling and drying, blue carbon dot conversion masterbatch is obtained. The additives include 1.6 parts naphthenic oil, 0.15 parts dibenzyl sorbitol, 0.3 parts pentaerythritol for PETS, 0.5 parts antioxidant 1010, 0.5 parts plastic defoaming masterbatch, and 0.15 parts anti-drip agent. S2: Add the blue carbon dot light-converting masterbatch to a two-roll mill, mix and melt at a temperature of 150°C for 7.5 minutes, transfer to a flat vulcanizing machine, control the vulcanizing temperature at 150°C and the pressure at 14MPa, hold the pressure for 4 minutes, demold, and obtain a blue carbon dot light-converting agricultural film with an average thickness of 0.1 mm.

[0051] The light-converting masterbatch and light-converting agricultural film prepared in this embodiment were tested in Example 1. The results were basically the same as those in Example 1. Due to space limitations, they will not be listed one by one.

[0052] Example 4 The preparation method of the blue light carbon dot conversion agricultural film in this embodiment includes the following steps: S1: 50 parts of low-density polyethylene (LDPE), 1.6 parts of ammonium citrate, 0.9 parts of artemisinin and 3.2 parts of additives are mixed to obtain a premix. The mixing speed is 850 r / min and the time is 14 min. The premix is ​​granulated by a twin-screw granulator. The temperature of the feed section of the twin-screw granulator is controlled at 132℃, the temperature of the melting section is 148℃ and the temperature of the die head section is 153℃. After melt mixing, extrusion, pelletizing and cooling drying, blue carbon dot conversion masterbatch is obtained. The additives include 1.6 parts naphthenic oil, 0.15 parts dibenzyl sorbitol, 0.3 parts pentaerythritol for PETS, 0.5 parts antioxidant 1010, 0.5 parts plastic defoaming masterbatch, and 0.15 parts anti-drip agent. S2: Add the blue carbon dot light-converting masterbatch to a two-roll mill, mix and melt at a temperature of 145°C for 6 minutes, transfer to a flat vulcanizing machine, control the vulcanizing temperature at 160°C and the pressure at 8MPa, hold the pressure for 5 minutes, demold, and obtain a blue carbon dot light-converting agricultural film with an average thickness of 0.1mm.

[0053] The light-converting masterbatch and light-converting agricultural film prepared in this embodiment were tested in Example 1. The results were basically the same as those in Example 1. Due to space limitations, they will not be listed one by one.

[0054] Example 5 The preparation method of the blue light carbon dot conversion agricultural film in this embodiment includes the following steps: S1: 10 parts of ethylene-vinyl acetate copolymer (EVA), 1.6 parts of ammonium citrate, 0.9 parts of artemisinin and 3.2 parts of additives are mixed to obtain a premix. The mixing speed is 950 r / min and the time is 11 min. The premix is ​​granulated by a twin-screw granulator. The temperature of the feed section of the twin-screw granulator is controlled at 138℃, the temperature of the melting section is 142℃ and the temperature of the die head section is 152℃. After melt mixing, extrusion, pelletizing and cooling drying, blue carbon dot conversion masterbatch is obtained. The additives include 1.6 parts naphthenic oil, 0.15 parts dibenzyl sorbitol, 0.3 parts pentaerythritol for PETS, 0.5 parts antioxidant 1010, 0.5 parts plastic defoaming masterbatch, and 0.15 parts anti-drip agent. S2: Take another 40 parts of low-density polyethylene (LDPE) and mix it with the masterbatch prepared in S2 in a two-roll mill. Mix and melt at a temperature of 145°C for 6 minutes. Transfer to a flat vulcanizing machine and control the vulcanization temperature at 145°C and the pressure at 15MPa. Hold the pressure for 5 minutes and demold to obtain a blue carbon dot light-converting agricultural film with an average thickness of 1mm.

[0055] The light-converting masterbatch and light-converting agricultural film prepared in this embodiment were tested in Example 1. The results were basically the same as those in Example 1. Due to space limitations, they will not be listed one by one.

[0056] Example 6 The preparation method of the blue light carbon dot conversion agricultural film in this embodiment includes the following steps: S1: 50 parts of low-density polyethylene (LDPE), 1.6 parts of ammonium citrate, 0.9 parts of artemisinin and 3.65 parts of additives are mixed to obtain a premix. The mixing speed is 800 r / min and the time is 14 min. The premix is ​​granulated by a twin-screw granulator. The temperature of the feed section of the twin-screw granulator is controlled at 134℃, the temperature of the melting section is 149℃ and the temperature of the die head section is 157℃. After melt mixing, extrusion, pelletizing and cooling drying, blue carbon dot conversion masterbatch is obtained. The additives include 2 parts PE wax, 0.05 parts titanate, 0.15 parts dibenzyl sorbitol, 0.3 parts pentaerythritol stearate, 0.5 parts antioxidant 1010, 0.5 parts plastic defoaming masterbatch, and 0.15 parts anti-drip agent. S2: Add the blue carbon dot light-converting masterbatch to a two-roll mill, mix and melt at a temperature of 145°C for 5 minutes, transfer to a flat vulcanizing machine, control the vulcanizing temperature at 155°C and the pressure at 10MPa, hold the pressure for 4.5 minutes, demold, and obtain a blue carbon dot light-converting agricultural film with an average thickness of 2mm.

[0057] The light-converting masterbatch and light-converting agricultural film prepared in this embodiment were tested in Example 1. The results were basically the same as those in Example 1. Due to space limitations, they will not be listed one by one.

[0058] Comparative Example 1 The preparation method of the agricultural film in this embodiment is similar to that in Example 2. The difference is that in S1, ammonium citrate is not added, but replaced with an equal mass of artemisinin.

[0059] Comparative Example 2 The preparation method of the agricultural film in this embodiment is similar to that in Example 2. The difference is that in S1, artemisinin is not added, but is replaced with an equal mass of ammonium citrate.

[0060] Comparative Example 3 The preparation method of the agricultural film in this embodiment is similar to that in Example 2. The difference is that in S1, ammonium citrate and artemisinin are not added, but are replaced with an equal mass of low-density polyethylene.

[0061] Comparative Example 4 The preparation method of the agricultural film in this embodiment is similar to that in Example 2. The difference is that in S1, the amount of artemisinin added is 0.4 parts and the amount of LDPE is 40.5 parts.

[0062] Comparative Example 5 The method for preparing agricultural film in this embodiment is similar to that in embodiment 2. The difference is that in S1, the temperature of the granulator feed section is 150°C, the temperature of the melting section is 160°C, and the temperature of the die head section is 170°C.

[0063] Experimental Example 1 The fluorescence intensity of the agricultural films prepared in Example 2 was compared with that of Comparative Examples 1-5, and the results are as follows: Figure 4 As shown in the figure, it can be seen that in Comparative Example 1, ammonium citrate was completely replaced with an equal amount of artemisinin. It can be seen that compared with the fluorescence intensity of Example 2, the fluorescence intensity of Comparative Example 1 was significantly reduced (the inset in the figure is a schematic diagram of the fluorescence intensity coordinates of Comparative Example 1 after being reduced in size), indicating that ammonium citrate is indispensable for improving fluorescence intensity.

[0064] In Comparative Example 2, artemisinin was completely replaced with an equal amount of ammonium citrate. It can be seen that the fluorescence intensity of Comparative Example 2 was significantly reduced compared to that of Example 2, indicating that artemisinin has a significant effect on improving fluorescence intensity.

[0065] Comparative Example 3, without the addition of ammonium citrate and artemisinin as optical conversion agents, showed no fluorescence and is not shown in the figure.

[0066] Comparative Example 4 reduced the amount of artemisinin added, and the fluorescence intensity was slightly lower than that of Example 2, further demonstrating that artemisinin has an effect on improving fluorescence intensity.

[0067] Comparative Example 5 changed the temperature, increasing the overall temperature by 10°C. The graph shows that the fluorescence intensity decreased compared to Example 2, indicating that temperature also affects the fluorescence intensity of the conversion film. The graph also shows that the fluorescence intensity of all comparative examples was lower than that of Example 2.

[0068] The fluorescence intensity of the agricultural films prepared in the examples and comparative examples at a wavelength of approximately 440 nm is shown in Table 1.

[0069] Table 1

[0070] As shown in Table 1, the agricultural film prepared by this invention has a fluorescence intensity ≥17.35e at a wavelength of approximately 440 nm. 4 Preferably, the fluorescence intensity is 17.35 e. 4 ~18.02e 4 .

[0071] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a blue light carbon dot-converted agricultural film, characterized in that, Includes the following steps: S1: The polymer matrix, ammonium citrate, artemisinin and additives are mixed and then granulated and dried to obtain blue carbon dot conversion masterbatch; S2: The blue carbon dot light-converting masterbatch is processed by blown film forming or tablet forming to obtain the blue carbon dot light-converting agricultural film.

2. The method for preparing a blue light carbon dot-converted agricultural film according to claim 1, characterized in that, The polymer matrix is ​​one or more of low-density polyethylene, linear low-density polyethylene, and ethylene-vinyl acetate copolymer; The additives include one or more of the following: PE wax, naphthenic oil, antioxidant, lanthanum oxide, anti-drip agent, dibenzyl sorbitol, maleic anhydride-grafted polyethylene, pentaerythritol stearate, plastic defoaming masterbatch, and titanate.

3. The method for preparing a blue light carbon dot-converted agricultural film according to claim 1, characterized in that, In S1, by weight, there are 50-500 parts of polymer matrix, 1.6-16 parts of ammonium citrate, 0.9-9 parts of artemisinin, and 3-35 parts of adjuvants.

4. The method for preparing a blue light carbon dot-converting agricultural film according to any one of claims 1-3, characterized in that, In S1, the mixing speed is 800~1000 r / min and the mixing time is 10~15 min.

5. The method for preparing a blue light carbon dot photoconverting agricultural film according to any one of claims 1-3, characterized in that, In S1, a twin-screw granulator is used for granulation. The temperature of the feed section of the granulator is 130~140℃, the temperature of the melting section is 140~150℃, and the temperature of the die head section is 150~160℃.

6. A method for preparing a blue light carbon dot-converting agricultural film according to any one of claims 1-3, characterized in that, In S2, the blown film forming process includes: adding the blue carbon dot light-converting masterbatch into a blown film machine, and sequentially performing extrusion, blowing, cooling, traction, and winding processes to obtain the blue carbon dot light-converting agricultural film.

7. The method for preparing a blue light carbon dot-converted agricultural film according to claim 6, characterized in that, The die head temperature of the blown film machine is 150~170℃, and the traction speed is 0.5~10m / min.

8. The method for preparing a blue light carbon dot-converted agricultural film according to claim 1, characterized in that, In S2, the pressing process includes: adding the blue carbon dot light-converting masterbatch into a two-roll open mill, mixing and melting, transferring to a flat vulcanizing machine, controlling the vulcanizing temperature and pressure, holding the pressure to form, demolding, and obtaining the blue carbon dot light-converting agricultural film.

9. The method for preparing a blue light carbon dot-converted agricultural film according to claim 8, characterized in that, The vulcanization temperature is 140~160℃, the pressure is 8~20MPa, and the pressure holding molding is 3~5min.

10. A blue light carbon dot photoconverting agricultural film prepared by the method of any one of claims 1-9.

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