A thermosensitive molybdenum disulfide composite nanomaterial and its application in controlling crop chilling injury.

Abstract

This invention discloses a thermosensitive molybdenum disulfide composite nanomaterial and its application in controlling crop chilling injury, belonging to the field of chilling agent technology. The invention utilizes a mixture of monomers (N-isopropylacrylamide and N-tert-butylacrylamide), a crosslinking agent, a surfactant, and a MoS2 dispersion, heated for a period of time; subsequently, an initiator is added, and the reaction continues for a period of time; after the reaction is completed, the mixture is cooled and dialyzed to obtain the thermosensitive molybdenum disulfide composite nanomaterial. This composite nanomaterial is dispersed in water to prepare a suspension, which is then applied to crops such as corn and soybeans via foliar spraying, thereby enhancing their cold resistance and increasing the biomass of chilled crops such as corn and soybeans. The method of this invention is simple and efficient, and has good application prospects.

Description

Technical Field

[0001] This invention belongs to the field of novel crop antifreeze technology, specifically relating to a temperature-sensitive molybdenum disulfide composite nanomaterial and its application in controlling crop chilling injury. Background Technology

[0002] The continued growth of the global population has led to a significant increase in food demand. However, frequent low-temperature freezing disasters pose a serious threat to global food security, and their frequency and impact are expanding year by year. In current agricultural practices, chemical antifreeze agents are a routine means of enhancing crop cold resistance. However, excessive application or improper handling can induce phytotoxic reactions, thereby hindering normal physiological processes and even leading to environmental pollution risks. Specifically, reported antifreeze agents include abscisic acid (ABA), salicylic acid (SA), betaine, polyamines, calcium ions, ethephon, proline, chitosan, spermidine, and sodium nitroprusside (nitric oxide donor). These substances are used in plant stress resistance, especially in cold resistance. However, high concentrations of abscisic acid may inhibit plant growth and are costly and susceptible to environmental degradation; excessive use of salicylic acid may cause oxidative damage, and its effectiveness depends on the application concentration and environmental conditions; betaine has limited effectiveness on some crops and requires multiple applications, increasing costs; polyamines (such as putrescine) are easily decomposed at high or low temperatures, and excessive use can lead to cytotoxicity; calcium ions (Ca... 2+ It needs to have antagonistic effects with other elements and requires precise concentration control; ethephon (ETH) may accelerate aging; it has a risk of phytotoxicity to sensitive crops (such as tomatoes); proline has low efficiency when applied exogenously and needs to be used in combination with other stress-resistant substances; the molecular weight of chitosan affects the effect and may change the soil microbial community; spermidine is costly and has poor stability, requiring special storage conditions; excessive sodium nitroprusside produces toxicity and is easily decomposed under light, so it needs to be stored away from light.

[0003] Therefore, developing novel plant cold-resistant agents that combine biosafety and high functional efficiency has become an urgent need for modern agriculture. Summary of the Invention

[0004] [Technical Issues]

[0005] A thermosensitive molybdenum disulfide composite nanomaterial is provided and applied to the regulation of crop chilling injury.

[0006] [Technical Solution]

[0007] This invention provides a thermosensitive molybdenum disulfide composite nanomaterial for regulating crop chilling injury. The preparation method of the thermosensitive molybdenum disulfide composite nanomaterial includes the following steps:

[0008] The monomer, crosslinking agent, surfactant and MoS2 dispersion were mixed and heated to react for a period of time; then the initiator was added and the reaction was continued for a period of time; after the reaction was completed, the mixture was cooled and dialyzed to obtain the thermosensitive molybdenum disulfide composite nanomaterial, denoted as P(NIPAm-TBA)-MoS2 NMs (abbreviated as PNT-MoS2 NMs);

[0009] The monomers are N-isopropylacrylamide (NIPAm) and N-tert-butylacrylamide (TBA).

[0010] In one embodiment of the present invention, the mass ratio of N-isopropylacrylamide to N-tert-butylacrylamide in the monomer is (2-4):1. Specifically, 3:1 is optional.

[0011] In one embodiment of the present invention, the crosslinking agent is N,N'-methylenebisacrylamide (BIS).

[0012] In one embodiment of the present invention, the mass fraction of the crosslinking agent relative to the monomer is 2%-5%. More preferably, it is 2%-3%.

[0013] In one embodiment of the present invention, the surfactant is sodium dodecyl sulfate (SDS).

[0014] In one embodiment of the invention, the surfactant has a mass fraction of 2%-5% relative to the monomer. More preferably, it is 3%-5%.

[0015] In one embodiment of the present invention, the concentration of the MoS2 dispersion is 0.1-1.0 mg / mL. Specifically, 0.5 mg / mL may be selected.

[0016] In one embodiment of the invention, the mass fraction of MoS2 relative to the monomer is 2%-5%. Further options include 3%-5%.

[0017] In one embodiment of the present invention, the temperature of the heating reaction is 60-90°C, specifically 70°C.

[0018] In one embodiment of the present invention, the heating reaction time is 20-60 minutes. Specifically, 30 minutes may be selected.

[0019] In one embodiment of the present invention, the initiator is selected from any one or more of the following: ammonium persulfate (APS), azobisisobutyronitrile (AIBN), and potassium persulfate (KPS).

[0020] In one embodiment of the present invention, the initiator has a mass fraction of 5%-8% relative to the monomer.

[0021] In one embodiment of the present invention, an initiator is added and the reaction continues for 3-6 hours. Specifically, 4 hours may be selected.

[0022] In one embodiment of the present invention, PNT-MoS2 NMs exhibit an irregular network structure and a smooth surface.

[0023] In one embodiment of the present invention, the preparation method of the PNT-MoS2 NMs specifically includes:

[0024] The monomers N-isopropylacrylamide (NIPAm), N-tert-butylacrylamide (TBA), the crosslinking agent N,N'-methylenebisacrylamide (BIS), and the surfactant sodium dodecyl sulfate (SDS) were dissolved in a 0.5 mg / mL MoS2 dispersion. After mixing, the mixture was heated to 70 °C and held at this temperature for 30 minutes under nitrogen protection. Subsequently, ammonium persulfate (APS) solution was rapidly injected into the reaction mixture, and the reaction continued for 4 hours. Finally, after the reaction was completed, the product, after natural cooling, was placed in a dialysis bag (MWCO = 10000, 45 mm) and dialyzed in a large beaker containing 5 L of ultrapure water for 5 days, with the ultrapure water being changed 3 times a day to remove unreacted monomers and surfactants, yielding purified PNT-MoS2 NMs.

[0025] This invention also provides the application of the above-mentioned temperature-sensitive molybdenum disulfide composite nanomaterial in the control of crop chilling injury.

[0026] In one embodiment of the present invention, the nanomaterial is a PNT-modified molybdenum disulfide nanocomposite material.

[0027] In one embodiment of the invention, the application involves dispersing PNT-MoS2 NMs in water to obtain a suspension; then spraying the suspension onto crop leaves.

[0028] In one embodiment of the present invention, the crop is a vegetable. Specifically, it includes leafy greens such as lettuce, spinach, coriander, and bok choy.

[0029] In one embodiment of the present invention, the plant is an agricultural crop, including corn, soybeans, rice, etc.

[0030] In one embodiment of the present invention, the concentration of the suspension is 200-500 mg / L; preferably 500 mg / L.

[0031] The present invention also provides the application of the above-mentioned temperature-sensitive molybdenum disulfide composite nanomaterial in the preparation of crop antifreeze.

[0032] In one embodiment of the present invention, the crop antifreeze agent further includes any one or more of the following: inorganic salts, sugars, organic alcohols, etc.

[0033] In one embodiment of the present invention, the inorganic salt includes any one or more of the following: potassium dihydrogen phosphate and potassium nitrate.

[0034] In one embodiment of the present invention, the carbohydrates include any one or more of the following: glucose, sucrose, and trehalose.

[0035] In one embodiment of the present invention, the organic alcohols include any one or more of the following: propylene glycol and ethylene glycol.

[0036] The main contents of this invention include:

[0037] (1) Preparation of temperature-sensitive molybdenum disulfide composite nanomaterials (PNT-MoS2 NMs);

[0038] (2) The photothermal properties of molybdenum disulfide nanomaterials (MoS2 NMs), PNT-MoS2 NMs and molybdenum disulfide large particles (MoS2 BPs) with different concentrations were investigated through in vitro experiments.

[0039] (3) The temperature-sensitive properties of PNT-MoS2 NMs were determined through in vitro experiments;

[0040] (4) By applying different concentrations of MoS2 NMs, PNT-MoS2 NMs and plant antifreeze to corn and soybeans through foliar spraying, we can explore their effects on enhancing the cold resistance of corn and soybeans.

[0041] [Beneficial Effects]

[0042] This invention disperses PNT-MoS2 NMs in water to obtain a suspension; then, the suspension is sprayed onto the leaves of corn and soybeans. By using foliar spraying, the cold resistance of corn and soybeans is regulated, enhancing their cold tolerance and significantly increasing the aboveground and underground biomass of chilled corn and soybean seedlings, demonstrating excellent application prospects. The effectiveness of different materials in enhancing the cold resistance of corn and soybeans is as follows: 500 mg / L PNT-MoS2 NMs > 200 mg / L PNT-MoS2 NMs ≈ 200 mg / L MoS2 NMs > 1667 mg / L plant antifreeze > 500 mg / L MoS2 NMs.

[0043] Furthermore, the thermosensitive molybdenum disulfide composite nanomaterial has a significant thermosensitive control function, which can avoid photothermal damage that may be caused by excessive use. Attached Figure Description

[0044] Figure 1(A) SEM image of PNT-MoS2 NMs; (B) Elemental distribution image of PNT-MoS2 NMs.

[0045] Figure 2 Photothermal temperature rise curves (AC) of different concentrations of MoS2 NMs, PNT-MoS2 NMs and MoS2 BPs under sunlight irradiation, and photothermal temperature rise curves (D) of 500 mg / L MoS2 NMs, PNT-MoS2 NMs, MoS2 BPs and deionized water under sunlight irradiation.

[0046] Figure 3 The relationship between the hydrodynamic diameter of 500 mg / L PNT-MoS2 NMs and temperature (A) and the phenotypic images of PNT-MoS2 NMs at 4℃-25℃-4℃ (B).

[0047] Figure 4 Effects of foliar application of MoS2 NMs, PNT-MoS2 NMs, PNT, PNT+Mo+S, and plant antifreeze on (A) aboveground and underground biomass of maize and (B) aboveground and underground biomass of soybean under low temperature stress. Detailed Implementation

[0048] The present invention will be further described below with reference to specific embodiments.

[0049] The embodiments provided below are not intended to limit the scope of this invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to this invention by those skilled in the art in conjunction with existing common knowledge also fall within the scope of protection claimed by this invention.

[0050] The structure of the N-isopropylacrylamide involved in this invention is shown below:

[0051]

[0052] The structure of the N-tert-butylacrylamide involved in this invention is shown below:

[0053]

[0054] The structure of the N,N'-methylenebisacrylamide involved in this invention is shown below:

[0055]

[0056] The structure of the sodium dodecyl sulfate involved in this invention is shown below:

[0057]

[0058] Example 1: Preparation of Thermosensitive Molybdenum Disulfide Composite Nanomaterials

[0059] 0.86 g of monomer N-isopropylacrylamide (NIPAm), 0.28 g of N-tert-butylacrylamide (TBA), 0.03 g of crosslinking agent N,N'-methylenebisacrylamide (BIS), and 0.04 g of surfactant sodium dodecyl sulfate (SDS) were dissolved in 80 mL of 0.5 mg / mL MoS2 dispersion. After thorough mixing, the mixture was heated to 70 °C and held at this temperature for 30 minutes under nitrogen protection. Subsequently, 0.06 g of ammonium persulfate (APS) solution (dissolved in 5 mL of ultrapure water) was rapidly injected into the reaction solution, and the reaction continued for 4 hours. Finally, after the reaction was completed, the product, after natural cooling, was placed in a dialysis bag (MWCO = 10000, 45 mm) and then placed in a large beaker containing 5 L of ultrapure water for dialysis for 5 days, during which the ultrapure water was changed 3 times a day to remove unreacted monomers and surfactants, yielding purified molybdenum disulfide composite nanomaterials, denoted as PNT-MoS2 NMs.

[0060] Material characterization:

[0061] The morphology and elemental distribution of PNT-MoS2 NMs were characterized using scanning electron microscopy (SEM). The results showed that PNT-MoS2 NMs exhibited an irregular network structure, which was not significantly different from the SEM image of PNT NMs in the inset, and the surface was smooth, proving that MoS2 NMs were encapsulated within PNT NMs. Furthermore, the addition of MoS2 NMs did not alter the structure of the PNT NMs. Figure 1 A). Figure 1 B is the SEM-EDS elemental distribution image of PNT-MoS2 NMs. It can be seen that sulfur (S) and molybdenum (Mo) elements are uniformly distributed in PNT NMs and are in the same position, which further illustrates that MoS2 NMs are uniformly distributed in PNT NMs.

[0062] Example 2: Photothermal properties of different concentrations of MoS2 NMs, PNT-MoS2 NMs, and MoS2 BPs

[0063] The PNT-MoS2 NMs obtained in Example 1 were dispersed in water to prepare PNT-MoS2 NMs suspensions of 50, 100, 200 and 500 mg / L.

[0064] Molybdenum disulfide nanomaterials (MoS2 NMs) and molybdenum disulfide macroparticles (MoS2 BPs) were dispersed in water to prepare solutions with concentrations of 50, 100, 200 and 500 mg / L.

[0065] Take 2 mL of the solution and place it in a centrifuge tube. Under sunlight, record the temperature change and image using an infrared thermal imager, with pure water as a control.

[0066] Molybdenum disulfide nanomaterials (MoS2 NMs) were prepared as follows: 0.35 g of Na2MoO4·2H2O was dissolved in 60 mL of ultrapure water, and the pH was adjusted to 6.5 with 1 mol / L HCl, followed by stirring for 10 minutes. Simultaneously, 0.4 g of L-cysteine ​​was dissolved in 80 mL of ultrapure water. After complete dissolution, the two solutions were mixed and stirred for 40 minutes. The mixture was then transferred to a 200 mL stainless steel hydrothermal reactor with a polytetrafluoroethylene liner and reacted at 200 °C for 15 hours. After the reaction, the black precipitate was collected by centrifugation and washed repeatedly with deionized water and anhydrous ethanol, and finally dried at 80 °C for 12 hours to obtain the molybdenum disulfide nanomaterials. These MoS2 NMs exhibited a typical sheet-like structure with an average size of 173.82 ± 15.20 nm.

[0067] The purity of the large molybdenum disulfide particles (MoS2 BPs) is GR, CAS number 1317-33-5, and it can be purchased from Beijing Innocare Technology Co., Ltd.

[0068] The results showed that, under the same irradiation time, the temperature increased significantly with increasing concentrations of MoS2 NMs and PNT-MoS2 NMs. After 200 min of sunlight irradiation, the temperature of 500 mg / L MoS2 NMs rose to 42.5 °C; the temperature of PNT-MoS2 NMs at a concentration of 500 mg / L reached 34 °C after 200 min of sunlight irradiation. Figure 2 A, B). The photothermal effects of the three materials are in the following order: MoS2 NMs > PNT-MoS2 NMs > MoS2 BPs. Figure 2 C, D).

[0069] Example 3: Thermosensitive properties of PNT-MoS2 NMs

[0070] The PNT-MoS2 NMs obtained in Example 1 were dispersed in water to prepare a 500 mg / L PNT-MoS2 NMs suspension.

[0071] The suspension was sonicated in an ice bath for 1 hour to ensure uniform dispersion. Subsequently, the hydrodynamic diameter was measured using a nanoparticle size analyzer at different temperatures (6–38 °C), with measurements taken at 2 °C intervals. Before testing, the PNT-MoS2 NMs solution was kept at the test temperature for 10 minutes to allow for swelling equilibrium. Measurements were taken four times at each temperature, and the average value was taken as the hydrodynamic diameter.

[0072] The results show that the hydrodynamic diameter of PNT-MoS2 NMs decreases with increasing temperature, exhibiting good temperature-sensitive properties. At lower temperatures, the amide groups in PNT-MoS2 NMs form hydrogen bonds with water molecules, allowing the molecular chains to fully extend, resulting in a larger hydrodynamic diameter. Above 24.2℃, the interaction between isopropyl groups strengthens, while the hydrogen bonding between the amide groups and water molecules weakens, causing PNT-MoS2 NMs to contract, thus reducing their hydrodynamic diameter. Figure 3 A). Under ambient temperature changes of 4℃-25℃-4℃, PNT-MoS2 NMs can undergo a reversible phase transition, specifically a "solution-solid-solution" transformation. Figure 3 B).

[0073] Example 4: Application of PNT-MoS2 NMs to regulate the cold resistance of corn and soybean

[0074] The PNT-MoS2 NMs obtained in Example 1 were dispersed in water to prepare PNT-MoS2 NMs suspensions of 200 and 500 mg / L.

[0075] Maize (Zea mays L.) and soybean (Glycine max L.) were used as test crops. First, maize (Dafeng 30) and soybean (Zhonghuang 57) seeds were disinfected with a 5% sodium hypochlorite solution for 5 minutes, followed by multiple rinses with deionized water. The disinfected seeds were then soaked in deionized water for 6 hours (maize) and 3 hours (soybean), respectively, before being placed in seedling trays lined with moist filter paper and germinated in the dark at 25℃. When the maize and soybean seedlings reached approximately 3 cm in height, uniformly growing seedlings were transplanted into pots containing 600 g of soil. When the maize seedlings had three leaves and one bud, and the soybean seedlings had two pairs of compound leaves, their leaves were sprayed with different concentrations (200 and 500 mg / L) of PNT-MoS2 NMs suspension, 5 mL daily for 5 consecutive days. The healthy control group and the cold injury control group were sprayed with the same volume of deionized water. Healthy plants sprayed with 500 mg / L PNT-MoS2 NMs suspension (Healthy + 5PMo), plants sprayed with 500 mg / L PNT (500PNT) suspension, plants sprayed with 500 mg / L PNT + Na2SO4 + Na2MoO4 suspension (500PNT + Mo + S), and plants sprayed with 1667 mg / L commercially available plant antifreeze (commercially recommended concentration) served as controls. Two days later, corn and soybeans were placed in a light incubator for low-temperature stress, with day / night temperatures set at 10 / 8℃, a light / dark cycle of 14 / 10h, relative humidity at 60% ± 5%, and light intensity at 16800 Lux. The healthy control group had a day / night temperature of 25 / 20℃, with all other environmental conditions kept consistent. After one week, photosynthetic parameters, chlorophyll fluorescence parameters, and relative chlorophyll content of corn and soybeans were measured. Destructive sampling was then performed, and crop fresh weight was recorded.

[0076] The results showed that foliar application of 200 mg / L MoS2 NMs, 200 mg / L PNT-MoS2, 500 mg / L PNT-MoS2, and plant antifreeze significantly increased the aboveground and underground biomass of chilled maize and soybean seedlings. Among these, the 500 mg / L PNT-MoS2 treatment group exhibited the best cold resistance, significantly increasing the aboveground (69%) and underground (142%) and (76%) biomass of chilled maize and soybean seedlings, respectively, which was superior to equal amounts of MoS2 NMs, PNT, PNT+Mo+S, and plant antifreeze. Figure 4 The results showed that 500 mg / L PNT-MoS2 had the best effect on enhancing the cold resistance of maize and soybean, and was significantly better than the enhancement effect of traditional plant antifreeze agents. Specific results are shown in Table 1.

[0077] Table 1. Results of different cold-resistant agents regulating the cold resistance of maize and soybean.

[0078]

[0079] Example 5

[0080] 0.76 g of monomer N-isopropylacrylamide (NIPAm), 0.38 g of N-tert-butylacrylamide (TBA), 0.03 g of crosslinking agent N,N'-methylenebisacrylamide (BIS), and 0.04 g of surfactant sodium dodecyl sulfate (SDS) were dissolved in 80 mL of 0.5 mg / mL MoS2 dispersion. After thorough mixing, the mixture was heated to 70 °C and held at this temperature for 30 minutes under nitrogen protection. Subsequently, 0.06 g of ammonium persulfate (APS) solution (dissolved in 5 mL of ultrapure water) was rapidly injected into the reaction solution, and the reaction continued for 4 hours. Finally, after the reaction was completed, the product, after natural cooling, was placed in a dialysis bag (MWCO = 10000, 45 mm) and placed in a large beaker containing 5 L of ultrapure water for dialysis for 5 days, during which the ultrapure water was changed 3 times a day to remove unreacted monomers and surfactants, yielding purified PNT-MoS2 NMs.

[0081] Example 6

[0082] 0.91 g of monomer N-isopropylacrylamide (NIPAm), 0.23 g of N-tert-butylacrylamide (TBA), 0.03 g of crosslinking agent N,N'-methylenebisacrylamide (BIS), and 0.04 g of surfactant sodium dodecyl sulfate (SDS) were dissolved in 80 mL of 0.5 mg / mL MoS2 dispersion. After thorough mixing, the mixture was heated to 70 °C and held at this temperature for 30 minutes under nitrogen protection. Subsequently, 0.06 g of ammonium persulfate (APS) solution (dissolved in 5 mL of ultrapure water) was rapidly injected into the reaction solution, and the reaction continued for 4 hours. Finally, after the reaction was completed, the product, after natural cooling, was placed in a dialysis bag (MWCO = 10000, 45 mm) and then placed in a large beaker containing 5 L of ultrapure water for dialysis for 5 days, during which the ultrapure water was changed 3 times a day to remove unreacted monomers and surfactants, yielding purified PNT-MoS2 NMs.

[0083] Example 7

[0084] 0.91 g of monomer N-isopropylacrylamide (NIPAm), 0.23 g of N-tert-butylacrylamide (TBA), 0.03 g of crosslinking agent N,N'-methylenebisacrylamide (BIS), and 0.04 g of surfactant sodium dodecyl sulfate (SDS) were dissolved in 80 mL of 0.5 mg / mL MoS2 dispersion. After thorough mixing, the mixture was heated to 70 °C and maintained at this temperature for 30 minutes under nitrogen protection. Subsequently, potassium persulfate (KPS) solution (0.06 g, dissolved in 5 mL of ultrapure water) was rapidly injected into the reaction solution, and the reaction continued for 4 hours. Finally, after the reaction was completed, the product, after natural cooling, was placed in a dialysis bag (MWCO = 10000, 45 mm) and placed in a large beaker containing 5 L of ultrapure water for dialysis for 5 days, during which the ultrapure water was changed 3 times a day to remove unreacted monomers and surfactants, yielding purified PNT-MoS2 NMs.

[0085] Example 8

[0086] 0.86 g of monomer N-isopropylacrylamide (NIPAm), 0.28 g of N-tert-butylacrylamide (TBA), 0.03 g of crosslinking agent N,N'-methylenebisacrylamide (BIS), and 0.04 g of surfactant sodium dodecyl sulfate (SDS) were dissolved in 80 mL of 0.5 mg / mL MoS2 dispersion. After thorough mixing, the mixture was heated to 70 °C and maintained at this temperature for 30 minutes under nitrogen protection. Subsequently, ammonium persulfate (APS) solution (0.06 g, dissolved in 5 mL of ultrapure water) was rapidly injected into the reaction solution, and the reaction continued for 4 hours. Finally, after the reaction was completed, the product, after natural cooling, was placed in a dialysis bag (MWCO = 10000, 45 mm) and then placed in a large beaker containing 5 L of ultrapure water for dialysis for 5 days, during which the ultrapure water was changed 3 times a day to remove unreacted monomers and surfactants, yielding purified PNT-MoS2 NMs.

[0087] Example 9

[0088] 0.86 g of monomer N-isopropylacrylamide (NIPAm), 0.28 g of N-tert-butylacrylamide (TBA), 0.02 g of crosslinking agent N,N'-methylenebisacrylamide (BIS), and 0.04 g of surfactant sodium dodecyl sulfate (SDS) were dissolved in 80 mL of 0.5 mg / mL MoS2 dispersion. After thorough mixing, the mixture was heated to 70 °C and held at this temperature for 30 minutes under nitrogen protection. Subsequently, 0.06 g of ammonium persulfate (APS) solution (dissolved in 5 mL of ultrapure water) was rapidly injected into the reaction solution, and the reaction continued for 4 hours. Finally, after the reaction was completed, the product, after natural cooling, was placed in a dialysis bag (MWCO = 10000, 45 mm) and then placed in a large beaker containing 5 L of ultrapure water for dialysis for 5 days, during which the ultrapure water was changed 3 times a day to remove unreacted monomers and surfactants, yielding purified PNT-MoS2 NMs.

[0089] Example 10

[0090] 0.86 g of monomer N-isopropylacrylamide (NIPAm), 0.28 g of N-tert-butylacrylamide (TBA), 0.03 g of crosslinking agent N,N'-methylenebisacrylamide (BIS), and 0.03 g of surfactant sodium dodecyl sulfate (SDS) were dissolved in 80 mL of 0.5 mg / mL MoS2 dispersion. After thorough mixing, the mixture was heated to 70 °C and maintained at this temperature for 30 minutes under nitrogen protection. Subsequently, 0.06 g of ammonium persulfate (APS) solution (dissolved in 5 mL of ultrapure water) was rapidly injected into the reaction solution, and the reaction continued for 4 hours. Finally, after the reaction was completed, the product, after natural cooling, was placed in a dialysis bag (MWCO = 10000, 45 mm) and placed in a large beaker containing 5 L of ultrapure water for dialysis for 5 days, during which the ultrapure water was changed 3 times a day to remove unreacted monomers and surfactants, yielding purified PNT-MoS2 NMs.

[0091] Example 11

[0092] 0.86 g of monomer N-isopropylacrylamide (NIPAm), 0.28 g of N-tert-butylacrylamide (TBA), 0.03 g of crosslinking agent N,N'-methylenebisacrylamide (BIS), and 0.03 g of surfactant sodium dodecyl sulfate (SDS) were dissolved in 400 mL of 0.1 mg / mL MoS2 dispersion. After thorough mixing, the mixture was heated to 70 °C and maintained at this temperature for 30 minutes under nitrogen protection. Subsequently, 0.06 g of ammonium persulfate (APS) solution (dissolved in 5 mL of ultrapure water) was rapidly injected into the reaction solution, and the reaction continued for 4 hours. Finally, after the reaction was completed, the product, after natural cooling, was placed in a dialysis bag (MWCO = 10000, 45 mm) and placed in a large beaker containing 5 L of ultrapure water for dialysis for 5 days, during which the ultrapure water was changed 3 times a day to remove unreacted monomers and surfactants, yielding purified PNT-MoS2 NMs.

[0093] Example 12

[0094] 0.86 g of monomer N-isopropylacrylamide (NIPAm), 0.28 g of N-tert-butylacrylamide (TBA), 0.03 g of crosslinking agent N,N'-methylenebisacrylamide (BIS), and 0.03 g of surfactant sodium dodecyl sulfate (SDS) were dissolved in 40 mL of 1 mg / mL MoS2 dispersion. After thorough mixing, the mixture was heated to 70 °C and held at this temperature for 30 minutes under nitrogen protection. Subsequently, ammonium persulfate (APS) solution (0.06 g, dissolved in 5 mL of ultrapure water) was rapidly injected into the reaction solution, and the reaction continued for 4 hours. Finally, after the reaction was completed, the product, after natural cooling, was placed in a dialysis bag (MWCO = 10000, 45 mm) and placed in a large beaker containing 5 L of ultrapure water for dialysis for 5 days, during which the ultrapure water was changed 3 times a day to remove unreacted monomers and surfactants, yielding purified PNT-MoS2 NMs.

[0095] Example 13

[0096] 0.86 g of monomer N-isopropylacrylamide (NIPAm), 0.28 g of N-tert-butylacrylamide (TBA), 0.03 g of crosslinking agent N,N'-methylenebisacrylamide (BIS), and 0.03 g of surfactant sodium dodecyl sulfate (SDS) were dissolved in 80 mL of 0.5 mg / mL MoS2 dispersion. After thorough mixing, the mixture was heated to 90 °C and held at this temperature for 20 minutes under nitrogen protection. Subsequently, 0.06 g of ammonium persulfate (APS) solution (dissolved in 5 mL of ultrapure water) was rapidly injected into the reaction solution, and the reaction continued for 4 hours. Finally, after the reaction was completed, the product, after natural cooling, was placed in a dialysis bag (MWCO = 10000, 45 mm) and then placed in a large beaker containing 5 L of ultrapure water for dialysis for 5 days, changing the ultrapure water 3 times a day to remove unreacted monomers and surfactants, yielding purified PNT-MoS2 NMs.

[0097] Example 14

[0098] 0.86 g of monomer N-isopropylacrylamide (NIPAm), 0.28 g of N-tert-butylacrylamide (TBA), 0.03 g of crosslinking agent N,N'-methylenebisacrylamide (BIS), and 0.03 g of surfactant sodium dodecyl sulfate (SDS) were dissolved in 80 mL of 0.5 mg / mL MoS2 dispersion. After thorough mixing, the mixture was heated to 60 °C and maintained at this temperature for 60 minutes under nitrogen protection. Subsequently, 0.06 g of ammonium persulfate (APS) solution (dissolved in 5 mL of ultrapure water) was rapidly injected into the reaction solution, and the reaction continued for 4 hours. Finally, after the reaction was completed, the product, after natural cooling, was placed in a dialysis bag (MWCO = 10000, 45 mm) and placed in a large beaker containing 5 L of ultrapure water for dialysis for 5 days, during which the ultrapure water was changed 3 times a day to remove unreacted monomers and surfactants, yielding purified PNT-MoS2 NMs.

[0099] Example 15: Application of PNT-MoS2 NMs to regulate the cold resistance of rice

[0100] The PNT-MoS2 NMs obtained in Example 1 were dispersed in water to prepare a 500 mg / L PNT-MoS2 NMs suspension; then applied to rice leaves, and the experimental procedure was the same as in Example 4.

[0101] The results showed that PNT-MoS2 NMs could enhance the cold resistance of rice.

[0102] Example 16: Application of PNT-MoS2 NMs to regulate the cold resistance of vegetables

[0103] The PNT-MoS2 NMs obtained in Example 1 were dispersed in water to prepare a 500 mg / L PNT-MoS2 NMs suspension; then applied to the leaves of vegetables (lettuce, spinach, coriander, bok choy, and other leafy greens), and the experimental procedure was the same as in Example 4.

[0104] The results showed that PNT-MoS2 NMs could enhance the cold resistance of various vegetables.

[0105] Example 17: Application of Thermosensitive Molybdenum Disulfide Composite Nanomaterials in the Preparation of Crop Antifreeze

[0106] A crop antifreeze agent comprises the following components: the thermosensitive molybdenum disulfide composite nanomaterial obtained in Example 1, an inorganic salt, a sugar, and an organic alcohol. Specifically, the inorganic salt is potassium dihydrogen phosphate, the sugar is trehalose, and the organic alcohol is propylene glycol.

[0107] Example 18: Application of Thermosensitive Molybdenum Disulfide Composite Nanomaterials in the Preparation of Crop Antifreeze

[0108] A crop antifreeze agent comprises the following components: the thermosensitive molybdenum disulfide composite nanomaterial obtained in Example 1, inorganic salts, sugars, and organic alcohols. Specifically: the inorganic salt is potassium nitrate, the sugars are glucose and sucrose, and the organic alcohol is ethylene glycol.

[0109] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A thermosensitive molybdenum disulfide composite nanomaterial for regulating crop chilling injury, characterized in that, The preparation method of the thermosensitive molybdenum disulfide composite nanomaterial includes the following steps: The monomer, crosslinking agent, surfactant and MoS2 dispersion were mixed and heated to react for a period of time; then the initiator was added and the reaction was continued for a period of time; after the reaction was completed, the mixture was cooled and dialyzed to obtain thermosensitive molybdenum disulfide composite nanomaterials. Among them, the monomers are N-isopropylacrylamide and N-tert-butylacrylamide; The mass ratio of N-isopropylacrylamide to N-tert-butylacrylamide in the monomers is (2-4):1; The crosslinking agent is N,N'-methylenebisacrylamide, and the mass fraction of the crosslinking agent relative to the monomer is 2%-5%. The surfactant is sodium dodecyl sulfate, and the mass fraction of the surfactant relative to the monomer is 2%-5%. The mass fraction of MoS2 relative to the monomer is 2%-5%; The initiator has a relative mass fraction of 5%-8% of the monomer.

2. The thermosensitive molybdenum disulfide composite nanomaterial according to claim 1, characterized in that, The concentration of the MoS2 dispersion was 0.1-1.0 mg / mL.

3. The thermosensitive molybdenum disulfide composite nanomaterial according to claim 1, characterized in that, The heating reaction is carried out at a temperature of 60-90℃ for 20-60 minutes.

4. The thermosensitive molybdenum disulfide composite nanomaterial according to claim 1, characterized in that, The initiator is selected from any one or more of the following: ammonium persulfate, azobisisobutyronitrile, potassium persulfate.

5. The thermosensitive molybdenum disulfide composite nanomaterial according to claim 1, characterized in that, Add an initiator and continue the reaction for 3-6 hours.

6. The application of the thermosensitive molybdenum disulfide composite nanomaterial according to any one of claims 1-5 in the control of crop chilling injury.

7. The application according to claim 6, characterized in that, The application involves dispersing temperature-sensitive molybdenum disulfide composite nanomaterials in water to obtain a suspension; then spraying the suspension onto crop leaves.

8. The application according to claim 6, characterized in that, The crops mentioned are vegetables, corn, soybeans, and rice.

9. The application according to claim 6, characterized in that, The concentration of the suspension is 200-500 mg / L.

10. The application of the thermosensitive molybdenum disulfide composite nanomaterial according to any one of claims 1-5 in the preparation of crop antifreeze.

11. The application according to claim 10, characterized in that, The crop antifreeze agent further includes any one or more of the following: inorganic salts, sugars, and organic alcohols; wherein: Inorganic salts include any one or more of the following: potassium dihydrogen phosphate, potassium nitrate; Carbohydrates include any one or more of the following: glucose, sucrose, and trehalose; Organic alcohols include any one or more of the following: propylene glycol and ethylene glycol.

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