Rosin-modified sodium alginate aggregate gel for pheromones and its preparation method and application

Abstract

The present application provides a rosin modified sodium alginate aggregate gel for carrying pheromone. The present application also provides a preparation method of the rosin modified sodium alginate aggregate gel for carrying pheromone, comprising the following steps: performing esterification reaction on rosin with glycidyl methacrylate to obtain rosin esterification product; adding the rosin esterification product into a sodium alginate solution with a mass concentration of 1-4% according to a mass ratio of 1:0.5-2, uniformly mixing, heating and stirring, and then performing ultrasonic treatment for 1-6 h, and then adding a saturated calcium chloride solution to perform deionization treatment, while vibrating and stirring for 5-10 min, and then freezing at-20 to-5 DEG C for 1-6 h to obtain the rosin modified sodium alginate aggregate gel for carrying pheromone. The present application also provides application of the rosin modified sodium alginate aggregate gel for carrying pheromone. The present application helps to promote the wide application of insect pheromone in agricultural pest control.

Description

Technical Field

[0001] This invention belongs to the field of agricultural pest control, and in particular relates to a rosin-modified sodium alginate aggregate gel for carrying pheromones, its preparation method and application. Background Technology

[0002] Insect sex pheromones, as an environmentally friendly pesticide alternative, have played an important role in pest control in orchards and some field crops. However, due to their inherent volatility and biodegradability, specific carriers are necessary to achieve optimal results. Unfortunately, traditional inert materials often fail to effectively control the rapid initial release of insect sex pheromones, and their effective duration is relatively short. Therefore, there is an urgent need to develop a novel carrier to better regulate the release behavior of insect sex pheromones, thereby improving their practicality and durability in pest control.

[0003] Hydrophobic hydrogels are a type of three-dimensional network structure gel, typically formed by physical or chemical cross-linking of polymers. They swell in water but do not dissolve, exhibiting good biocompatibility and biodegradability, while also possessing high mechanical strength and elasticity. The three-dimensional porous network structure of hydrogels presents a heterogeneous, sheet-like network structure, providing adsorption sites and controllable diffusion pathways for pheromone molecules. These properties of hydrophobic hydrogels make them ideal carriers for drugs and bioactive substances.

[0004] Hydrophobic supramolecular aggregate hydrogels can control the release rate of pheromones, achieving a sustained-release effect. This sustained-release property can prolong the duration of pheromone action, reduce the frequency of use, thereby improving control efficacy and reducing costs. Insect pheromones have high biological activity and specificity; hydrophobic hydrogels, as carriers, can maintain pheromone specificity, ensuring that they only affect the target insects without affecting other organisms.

[0005] Therefore, there is an urgent need for a gel carrier that can continuously and stably release functional rosin-modified sodium alginate aggregates to meet user needs. Summary of the Invention

[0006] One object of the present invention is to provide a rosin-modified sodium alginate aggregate gel for carrying pheromones, a method for preparing the gel, and its application, and to provide at least the advantages described below.

[0007] Another objective of this invention is to provide a rosin-modified sodium alginate aggregate gel for carrying pheromones, its preparation method, and its application, which will help promote the widespread use of insect pheromones in agricultural pest control.

[0008] The technical solution of the present invention is as follows: A method for preparing rosin-modified sodium alginate aggregate gel for carrying pheromones, comprising the following steps: Rosin esterification products were obtained by esterification reaction of rosin solution with glycidyl methacrylate. Rosin esterification was added to a sodium alginate solution with a mass concentration of 1-4% at a mass ratio of 1:0.5-2. After mixing and heating until homogeneous, the mixture was ultrasonically treated for 1-6 hours. Then, a saturated calcium chloride solution was added for deionization treatment, while vibrating and stirring for 5-10 minutes. After that, the mixture was frozen at -20~-5℃ for 1-6 hours to prepare a rosin-modified sodium alginate aggregate gel for carrying pheromones.

[0009] Preferably, in the method for preparing rosin-modified sodium alginate aggregate gel for carrying pheromones, the rosin esterification product obtained by esterification reaction of rosin solution and glycidyl methacrylate includes the following steps: adding rosin and toluene in a mass ratio of 1:5 to a reaction flask, ultrasonically stirring under nitrogen atmosphere until a uniformly dispersed rosin solution is obtained, adding glycidyl methacrylate, heating to boiling, adding the catalyst triethylamine and the inhibitor hydroquinone, ultrasonically stirring for 7 hours, distilling the crude product to remove toluene, adding dichloromethane to the crude product, washing three times with water to remove hydroquinone, distilling to remove dichloromethane, and obtaining the rosin esterification product, which is stored at 5°C. The molar ratio of rosin to glycidyl methacrylate is 1:1, and the mass ratio of the catalyst triethylamine to the inhibitor hydroquinone is 2~5:1. The concentration of the rosin solution is 4.8~17wt%.

[0010] Preferably, in the method for preparing the rosin-modified sodium alginate aggregate gel for carrying pheromones, the sodium alginate solution is prepared by the following method; Sodium alginate was added to deionized water and mixed well. Nitrogen gas was introduced, and the mixture was heated and stirred thoroughly. Potassium persulfate was then added and stirred until homogeneous. The reaction was carried out with a high-speed battery for 0.2 to 0.5 hours. The reaction solution was then allowed to stand. The mass ratio of sodium alginate to potassium persulfate was 10:1.

[0011] The rosin-modified sodium alginate aggregate gel for carrying pheromones is prepared using the aforementioned method for preparing the rosin-modified sodium alginate aggregate gel for carrying pheromones.

[0012] The application of rosin-modified sodium alginate aggregate gel for pheromone transport includes the following steps: Dodecanol and Tween 80 in a mass ratio of 1-5‰ were added to the rosin-modified sodium alginate copolymer gel. After mixing and stirring, the mixture was allowed to stand and freeze for 1-6 hours at -20~-5℃. The mass ratio of dodecanol to Tween 80 was 1:5-20.

[0013] The present invention has the following beneficial effects: The surface of rosin-modified sodium alginate aggregates consists of a dense, low-porosity layer with a “orange peel-like” appearance formed by tightly stacked submicron-sized irregular particles. Inside this layer are numerous secondary micropores, forming a permeable pore system. This multi-level pore structure provides adsorption sites and controllable diffusion pathways for pheromone molecules. Rosin's main component, rosin acid, is a monocarboxylic acid with a tricyclic phenanthrene backbone. Under the action of triethylamine, rosin carboxylic acid is deprotonated to generate a carboxylate group. The carboxylate group nucleophilically attacks the epoxy ring of glycidyl methacrylate, causing the epoxy ring to open and forming an ester bond, thus obtaining a rosin ester monomer molecule with a double bond at the end of the carbon chain. The rosin ester reacts with the hydroxyl groups of sodium alginate under the action of potassium persulfate as an initiator to undergo an addition polymerization reaction, resulting in a hydrophobic supramolecular rosin-modified sodium alginate copolymer. Hydrophobic hydrogels can control the release rate of pheromones, achieving a sustained-release effect. This sustained-release property can prolong the duration of pheromone action, reduce the frequency of use, thereby improving control efficacy and reducing costs. Insect pheromones have high biological activity and specificity; hydrophobic hydrogels, as carriers, can maintain pheromone specificity, ensuring that they only affect the target insects without affecting other organisms.

[0014] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0015] Figure 1 These are before-and-after comparison images of the rosin-modified sodium alginate aggregate and the dodecyl rosin-modified sodium alginate aggregate prepared in Example 1 of this invention. Figure 2 This is a SEM image of the sample of the hydrogel prepared in Example 1 after freeze-drying; Figure 3 This is the FTIR image of the hydrogel in Comparative Example 1; Figure 4 The image shows the XRD pattern of the hydrogel in Comparative Example 2. Figure 5 The following are the TG, DTG, and DSC graphs of the hydrogel in Comparative Example 3; Figure 6 This is a sustained-release curve of the dodecanol rosin-modified sodium alginate aggregate gel prepared in Example 1. Detailed Implementation

[0016] The present invention will now be described in further detail so that those skilled in the art can implement it based on the description.

[0017] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not imply the presence or addition of one or more other elements or combinations thereof.

[0018] The following description, with reference to preferred embodiments, illustrates the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are merely illustrative of the present invention and not intended to limit the scope of protection of the present invention.

[0019] This invention provides a method for preparing rosin-modified sodium alginate aggregate gel for carrying pheromones, comprising the following steps: A rosin esterification reaction was carried out using rosin solution and glycidyl methacrylate to obtain rosin esterified products. The reaction included the following steps: rosin and toluene were added to a reaction flask in a mass ratio of 1:5, and the mixture was ultrasonically stirred under nitrogen atmosphere until a uniformly dispersed rosin solution was obtained. Glycidyl methacrylate was added, and the mixture was heated to boiling. Triethylamine (catalyst) and hydroquinone (inhibitor) were then added, and the mixture was ultrasonically stirred for 7 hours. The crude product was distilled to remove toluene. Dichloromethane was added to the crude product, and the mixture was washed three times with water to remove hydroquinone. Dichloromethane was then distilled to remove the hydroquinone, yielding the rosin esterified product, which was stored at 5°C. The molar ratio of rosin to glycidyl methacrylate was 1:1, and the mass ratio of triethylamine (catalyst) to hydroquinone (inhibitor) was 2-5:1. The concentration of the rosin solution was 4.8-17 wt%.

[0020] Sodium alginate was added to deionized water and mixed well. Nitrogen gas was introduced, and the mixture was heated and stirred thoroughly. Potassium persulfate was then added and stirred until homogeneous. The reaction was carried out with a high-speed battery for 0.2 to 0.5 hours. The reaction solution was then allowed to stand. The mass ratio of sodium alginate to potassium persulfate was 10:1.

[0021] Rosin esterification was added to a sodium alginate solution with a mass concentration of 1-4% at a mass ratio of 1:0.5-2. After mixing and heating until homogeneous, the mixture was ultrasonically treated for 1-6 hours. Then, a saturated calcium chloride solution was added for deionization treatment, while vibrating and stirring for 5-10 minutes. After that, the mixture was frozen at -20~-5℃ for 1-6 hours to prepare a rosin-modified sodium alginate aggregate gel for carrying pheromones.

[0022] The present invention also provides a rosin-modified sodium alginate aggregate gel for carrying pheromones, which is prepared by the aforementioned method for preparing the rosin-modified sodium alginate aggregate gel for carrying pheromones.

[0023] This invention also provides the application of rosin-modified sodium alginate aggregate gel for carrying pheromones, which is applied to carrying pheromones and includes the following steps: Dodecanol and Tween 80 in a mass ratio of 1-5‰ were added to the rosin-modified sodium alginate copolymer gel. After mixing and stirring, the mixture was allowed to stand and freeze for 1-6 hours at -20~-5℃. The mass ratio of dodecanol to Tween 80 was 1:5-20.

[0024] Example 1:

[0025] A rosin-modified sodium alginate aggregate gel for carrying pheromones is prepared as follows: S1. Preparation of rosin esters: (1) Add 10.00 g of rosin (RS) and 50 mL of toluene to a reaction flask and stir continuously with a magnetic force. Purge nitrogen gas at a rate of 20 mL / min to remove dissolved oxygen until a uniformly dispersed rosin solution with a concentration of 4.8~17 wt is obtained.

[0026] (2) Glycidyl methacrylate (GMA) was added to the rosin solution at a molar ratio of RS:GMA of 1:1, along with triethylamine as the catalyst and hydroquinone as the inhibitor. The mixture was heated to boiling and stirred for 7 hours. The crude product was distilled to remove toluene. Dichloromethane was added to the crude product, and the mixture was washed three times with water to remove hydroquinone. Dichloromethane was then distilled to remove more hydroquinone, yielding the esterified rosin product RSG, which was stored at 5°C for later use.

[0027] S2. Preparation of sodium alginate solution: Add sodium alginate to deionized water and mix well. Pour in nitrogen gas, heat and stir thoroughly. Then add potassium persulfate and stir until homogeneous. Stir the reaction using a high-speed battery for 0.2-0.5 hours and let the reaction solution stand. The concentration of sodium alginate solution is 1-4 wt%.

[0028] Preparation of S3, rosin-modified sodium alginate copolymer: The sodium alginate solution obtained in step S2 is mixed with the rosin esterified product obtained in step S1 in a certain proportion and heated and stirred until uniform. The resulting mixed solution is then ultrasonically treated for 1-6 hours. Saturated calcium chloride solution is added dropwise to the reaction solution for deionization while vibrating and stirring. The reaction time is 5-10 minutes until a rosin-modified sodium alginate copolymer gel is formed. The gel is then frozen at -20 to -5°C for 1-6 hours. The mass ratio of glycidyl methacrylate to sodium alginate in the sodium alginate solution is 1-10, and the mass ratio of sodium alginate to rosin esterified product RSG is 1:0.5-2.

[0029] S4. Preparation of pheromone-loaded rosin-modified sodium alginate aggregate gel: Lauryl alcohol was used as a pheromone substitute. After the rosin-modified sodium alginate copolymer gel was formed in step S3, lauryl alcohol (C) was added as a pheromone. 12 Mix OH and Tween 80 thoroughly, and freeze the mixture at -20~-5℃ for 1~6h; the mass ratio of pheromone substances to the modified sodium alginate copolymer gel is 1~5‰.

[0030] The dodecanol rosin-modified sodium alginate aggregate gel C prepared in Example 1 12 The changes in OH@RSG&SA / rosin-modified sodium alginate copolymer gel RSG&SA upon exposure to air were compared, and the results are as follows: Figure 1 As shown in the figure, a, c, and e are C 12 OH@RSG&SA, b, d, and f in the figure represent RSG&SA. After 30 days of observation, it can be seen that the amount of substance is decreasing, and the portion that can be degraded in the environment is being observed.

[0031] The rosin-modified sodium alginate aggregate gel prepared in Example 1 was characterized by SEM after freeze-drying. The results are as follows: Figure 2 As shown. Figure A is a SEM image of freeze-dried RSG&SA emulsion; Figure B is a magnified SEM image of freeze-dried RSG&SA emulsion; Figure C is a SEM image of C. 12 SEM image of freeze-dried OH@RSG&SA emulsion; D represents C 12 Magnified SEM image of OH@RSG&SA emulsion freeze-dried. Figure 2 It can be seen that the pure rosin-modified sodium alginate aggregate gel (RSG&SA) is relatively loose, while the rosin-modified sodium alginate aggregate gel carrying lauryl alcohol has a relatively dense and porous sheet-like structure. Scanning electron microscopy clearly revealed the porous microstructure of the gel, and in this embodiment, C... 12 OH@RSG&SA has higher density than RSG&SA, but C 12 The C in OH@RSG&SA 12OH is a volatile compound, and the C in the three-dimensional porous network structure changes with environment and time. 12 As OH groups gradually decrease, the network channels in the outer layer of the gel open, allowing C in the inner layer to... 12 OH diffuses through network channels.

[0032] Method for testing pheromone content in rosin-modified sodium alginate aggregate gels used for carrying pheromones: Using dodecyl alcohol instead of pheromones, C from Example 1 was collected. 12 Add 1 mL of n-hexane to the OH@RSG&SA carrier, shake well, and sonicate at 30°C for 15 min to transfer lauryl alcohol to the organic phase. Repeat this process 4 times. Combine the organic phases, dehydrate, and bring the volume to 5 mL. Dilute to an appropriate concentration and determine the actual lauryl alcohol content in the sample using gas chromatography. The experiment was performed in triplicate.

[0033] Comparative Example 1: Equal masses of glycidyl methacrylate (GMA), rosin (RS), rosin ester (RSG), sodium alginate (SA), a mixture of rosin and sodium alginate (RS+SA), and the rosin-modified sodium alginate aggregates (RSG&SA) obtained in Example 1 were dried, ground into a fine powder with potassium bromide, and pressed into thin sheets. The samples were characterized by FTIR scanning in the wavelength range of 450 cm⁻¹ to 4000 cm⁻¹. Figure 3 As shown in the figure, the -COOH stretching vibration absorption peak of RS at 1200-1700 cm⁻¹ disappears, while GMA shows characteristic absorption peaks of carboxylate I and II bands at 1720.3 cm⁻¹, 1694.5 cm⁻¹, and 1635.9 cm⁻¹, respectively. The disappearance of the hydroxyl absorption peak and the formation of the carboxylate absorption peak indicate that the amino groups on GMA and RS have undergone esterification. The infrared characteristic absorption peaks of the rosin esterified RSG hydrogel appear at 1694.5 cm⁻¹ and 1635.9 cm⁻¹, indicating the presence of double bonds in RSG.

[0034] Comparative Example 2: Equal masses of glycidyl methacrylate (GMA), rosin (RS), rosin ester (RSG), sodium alginate (SA), a mixture of rosin and sodium alginate (RS+SA), and the rosin-modified sodium alginate aggregate (RSG&SA) obtained in Example 1 were used. X-ray diffraction (XRD) was employed to characterize the crystallinity and crystal form of the samples within the 5-80° range, assessing the influence of crystal structure on drug release stability. The X-ray diffraction patterns are shown below. Figure 4As shown in the XRD images, rosin RS, rosin ester RSG, sodium alginate SA, and the mixture of rosin and sodium alginate RS+SA show characteristic peaks at 15°, glycidyl methacrylate GMA shows a characteristic peak at 21.5°, while the rosin-modified sodium alginate aggregate RSG&SA has no peak, indicating that RSG&SA in Comparative Example 1 has a more stable structure.

[0035] Comparative Example 3: Take the same amount of dodecanol C 12 OH, Rosin-modified sodium alginate aggregates RSG & SA obtained in Example 1, and Dodecanol-modified sodium alginate aggregate C obtained in Example 1. 12 OH@RSG&SA used a HITACHI STA200 simultaneous thermal analyzer (TG-DSC) to test the heating curves of the samples from 0 to 600 °C, and characterized the Tg of the prepared hydrogel. Figure 5 As shown in Figure (a), the thermogravimetric analysis (TG) curve of the sample of Comparative Example 3 at 0–600℃ is shown; Figure (b) is the differential thermogravimetric analysis (DTG) curve of the sample of Comparative Example 3 at 0–600℃ is shown; and Figure (c) is the DSC curve of the sample of Comparative Example 3 at 0–600℃ is shown. Figure (a) shows that the first stage of weight loss occurred at 0–600℃, mainly due to the evaporation of moisture from the material, resulting in a sharp decrease in mass. A second significant mass loss occurred at 250±10℃–350℃, due to the decomposition of the internal organic macromolecular structure. Figure (b) shows that C… 12 OH, RSG&SA, C 12 The maximum weight loss temperatures of OH@RSG&SA were 182.9℃, 217.5℃, and 425.4℃, respectively. From the first stage of weight loss, combined with XRD and FTIR, it can be seen that RS, after modification with GMA, has better water solubility due to the reduced crystallinity of the modified RS. The second stage of mass loss shows that the addition of RSG&SA leads to a more stable hydrogel structure, reducing the decomposition rate of organic macromolecules and thus decreasing the mass loss rate. Figure (b) shows that C... 12 OH@RSG&SA exhibits two glass transition temperatures, 182.9℃ and 419.5℃ respectively, indicating that RSG&SA and C... 12 The interactions between OH groups result in a more stable structure for the C12OH@RSG&SA hydrogel. This also confirms that the hydrogel provided in this embodiment is a three-dimensional network hydrogel.

[0036] The sustained-release test was performed on the dodecanol rosin-modified sodium alginate aggregate C12OH@RSG&SA gel prepared in Example 1. The release curve of the hydrogel is shown below. Figure 6As shown. This test mainly determines the actual content of dodecanol in the gel carrier. Weigh 10g C 12 OH@RSG & α-CD were placed in petri dishes and left outdoors for 120 days. The release of dodecanol was measured daily for the first 5 days, every 5 days from days 5 to 30, every 10 days from days 30 to 60, and every 30 days from days 60 to 120. Figure 6 It can be seen that 20% is released in the first 10 days, and 50% is released from day 10 to day 60. That is, in sustained-release formulations, ≤50% of C can be released after 60 days. 12 The presence of OH indicates that the rosin-modified sodium alginate aggregate RSG&SA gel prepared in this embodiment has a sustained-release pheromone effect.

[0037] Using the dodecanol content corresponding to day 0 as the initial content, calculate C. 12 The cumulative release rate of dodecanol in OH@RSG&SA was determined, a release curve was plotted, the sustained-release mechanism was analyzed, and its theoretical duration of effect was determined. Cumulative release rate = (C 12 Initial content of dodecanol in OH@RSG&SA - C after release 12 (Actual content of dodecanol in OH@RSG&SA) / C 12 The initial content of dodecanol in OH@RSG&SA × 100%.

[0038] In summary, this invention enables the preparation of rosin-modified sodium alginate aggregate gels with excellent sustained-release properties, achieving a sustained-release effect of pheromones. Insect pheromones possess high bioactivity and specificity; hydrophobic hydrogels, acting as carriers, can maintain pheromone specificity, ensuring that they only affect the target insects without affecting other organisms. This gel contributes to promoting the widespread application of insect pheromones in agricultural pest control. Although embodiments of this invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for this invention, and further modifications can be readily implemented by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, this invention is not limited to the specific details.

Claims

1. A method for preparing rosin-modified sodium alginate aggregate gel for carrying pheromones, characterized in that, Includes the following steps: Rosin esterification products were obtained by esterification reaction of rosin solution with glycidyl methacrylate. Rosin esterification was added to a sodium alginate solution with a mass concentration of 1-4% at a mass ratio of 1:0.5-2. After mixing and heating until homogeneous, the mixture was ultrasonically treated for 1-6 hours. Then, a saturated calcium chloride solution was added for deionization treatment, while vibrating and stirring for 5-10 minutes. After that, the mixture was frozen at -20~-5℃ for 1-6 hours to prepare a rosin-modified sodium alginate aggregate gel for carrying pheromones.

2. The method for preparing rosin-modified sodium alginate aggregate gel for carrying pheromones as described in claim 1, characterized in that, The esterification reaction of rosin solution with glycidyl methacrylate yields rosin esterified products, including the following steps: rosin and toluene are added to a reaction flask in a mass ratio of 1:5, and the mixture is ultrasonically stirred under nitrogen atmosphere until a uniformly dispersed rosin solution is obtained. Glycidyl methacrylate is added, and the mixture is heated to boiling. Triethylamine (catalyst) and hydroquinone (inhibitor) are then added, and the mixture is ultrasonically stirred for 7 hours. The crude product is distilled to remove toluene. Dichloromethane is added to the crude product, and the mixture is washed three times with water to remove hydroquinone. Dichloromethane is then distilled to remove the remaining dichloromethane, yielding the esterified rosin product, which is stored at 5°C. The molar ratio of rosin to glycidyl methacrylate is 1:1, and the mass ratio of the catalyst triethylamine to the inhibitor hydroquinone is 2~5:

1. The concentration of the rosin solution is 4.8~17wt%.

3. The method for preparing rosin-modified sodium alginate aggregate gel for carrying pheromones as described in claim 2, characterized in that, The sodium alginate solution was prepared using the following method; Sodium alginate was added to deionized water and mixed well. Nitrogen gas was introduced, and the mixture was heated and stirred thoroughly. Potassium persulfate was then added and stirred until homogeneous. The reaction was carried out with a high-speed battery for 0.2 to 0.5 hours. The reaction solution was then allowed to stand. The mass ratio of sodium alginate to potassium persulfate was 10:

1.

4. A rosin-modified sodium alginate aggregate gel for carrying pheromones, characterized in that, It is prepared by the method for preparing rosin-modified sodium alginate aggregate gel for carrying pheromones as described in any one of claims 1-3.

5. The application of rosin-modified sodium alginate aggregate gel for carrying pheromones, characterized in that, When applied to pheromones, the following steps are included: Dodecanol and Tween 80 in a mass ratio of 1-5‰ were added to the rosin-modified sodium alginate copolymer gel. After mixing and stirring, the mixture was allowed to stand and freeze for 1-6 hours at -20~-5℃. The mass ratio of dodecanol to Tween 80 was 1:5-20.

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