Core-shell structure polystyrene / polylactic acid spinning fiber loaded with pheromone and preparation method of core-shell structure polystyrene / polylactic acid spinning fiber

Abstract

The invention discloses a core-shell structure polystyrene / polylactic acid spinning fiber loaded with pheromone and a preparation method of the core-shell structure polystyrene / polylactic acid spinning fiber. A coaxial electrostatic spinning method is adopted for preparation, a core solution is a polylactic acid solution and sex pheromone mixed solution, a shell solution is a polystyrene solution, a formed spinning film is collected on an aluminum roller wrapped with sulfate transparent paper, and the polystyrene / polylactic acid spinning fiber of the core-shell structure is obtained. The fiber is uniform in spinning morphology and has a core-shell structure, and the diameter of the fiber is about 2.24-3.55 microns. The method is simple, economical and efficient, has good adjustability in solution preparation and electrostatic spinning processes, is suitable for preparing polystyrene / polylactic acid spinning fibers with core-shell structures capable of loading insect sex pheromones of different types and concentrations, and realizes long-acting slow release of sex information through a polystyrene and polylactic acid dual slow release system. The slow release period of the sex pheromone in the spinning fiber can reach 8-14 weeks, and the sex pheromone can be applied to the aspects of biological prevention and control of neutral pheromone isotropic interference prevention and control of pests for a long time.

Description

Technical Field

[0001] The invention belongs to the technical field of electrostatic spinning, and in particular relates to a core-shell structure polystyrene / polylactic acid spinning fiber loaded with sex pheromone and a preparation method thereof. Background Art

[0002] Electrospinning is a technology that uses high-voltage electrostatic field forces to prepare nano-scale ultrafine fibers. Its core principle is to form a strong electric field of thousands to tens of thousands of volts between the spinneret and the grounded receiving device through a high-voltage power supply, so that the polymer solution or melt forms droplets at the outlet of the spinneret due to surface tension. When the electric field force overcomes the surface tension, the droplets are stretched into a conical structure (called a Taylor cone), and then the charged jet is ejected from the top of the cone and flies to the receiving device under the acceleration of the electric field. During the process, the jet swings violently and continues to stretch due to whipping instability. At the same time, the solvent evaporates rapidly to solidify the polymer, and finally deposits on the receiving device to form a disordered or ordered nanofiber membrane. The key influencing factors of this technology include solution properties (such as polymer concentration, solvent volatility and conductivity), process parameters (such as voltage, distance between the spinneret and the receiving device, liquid supply speed) and ambient temperature and humidity. Its characteristics are that it can prepare fibers with small diameter, high specific surface area and controllable structure. Coaxial electrospinning refers to a technology that consists of two coaxially arranged conductive nozzles. The advantage of this device is that it can encapsulate the core material in the shell material in one step and produce a core-shell structure. The core-shell structure can better isolate the core material from the influence of the external environment.

[0003] Insect pheromones, also known as insect external hormones, are trace chemicals released by individual insects to regulate or induce the behavior and response of other individuals of the same species. Its types include insect sex pheromones, tracer pheromones, alarm pheromones and aggregation pheromones. Insect pheromones are currently mainly used for insect detection, trapping and disorientation. Among them, disorientation is the main means of pest control. By changing the concentration of specific insect pheromones in the environment around crops, insects cannot perceive the opposite sex, thereby interfering with insect mating, reducing the reproduction of pests, and thus achieving the purpose of reducing pests. Natural insect pheromones have specific stereochemical structures, and most of them are mixtures of organic oxygen-containing compounds. Although insect pheromones have high biological activity and safety, from the perspective of practical application, the direct application of pheromones in the field is often ineffective. This is because most pheromone molecules are highly volatile and easily affected by environmental factors such as temperature, sunlight, wind and rain. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that insect sex pheromones are highly volatile and have a short effective period and to provide a method for preparing a core-shell structure polystyrene / polylactic acid spinning fiber loaded with sex pheromones.

[0005] The above purpose is achieved through the following technical solutions: A method for preparing a core-shell structure polystyrene / polylactic acid spinning fiber loaded with sex pheromone, the specific steps are: Step 1: First, dissolve polystyrene in tetrahydrofuran (THF) to obtain a shell solution for electrospinning; dissolve polylactic acid (PLA) in dichloromethane (DCM) and N,N-dimethylformamide (DMF), and stir until completely dissolved to obtain a polylactic acid solution. Add sex pheromone to the polylactic acid solution and continue stirring to obtain a core solution for electrospinning; the mass percentage concentration of polystyrene in the shell solution is 15-20%, the mass percentage concentration of polylactic acid in the core solution is 5-15%, and the mass percentage concentration of sex pheromone is 0.2-5%.

[0006] Step 2: Using an aluminum drum wrapped with sulfate transparent paper as a spinning receiving device, coaxial electrospinning is performed under the conditions of 15-30°C and a relative humidity of 20-50%, the inner needle sprays out the core solution, and the outer needle sprays out the shell solution; the spinning membrane formed by coaxial electrospinning is collected on the aluminum drum wrapped with sulfate transparent paper to obtain a core-shell structured polystyrene / polylactic acid spinning fiber membrane; The process parameters of coaxial electrostatic spraying are as follows: the inner diameter of the inner needle is 0.40 mm, the inner diameter of the outer needle is 0.71 mm, the voltage is 12~16 kV, the feeding rate of the shell solution is 0.4~0.6 mL / h; the feeding rate of the core solution is 1.2~1.8 mL / h, and the distance between the receiving device and the nozzle is 10~20 cm.

[0007] Step 3: Transfer the core-shell structure polystyrene / polylactic acid spinning fibers loaded with sex pheromones into an antistatic plastic bag for storage.

[0008] Preferably, the sex pheromone in step 1 is the sex pheromone of the rice stem borer, the citrus fruit fly or the codling moth, or an active ingredient thereof.

[0009] Preferably, in step 1, the stirring temperature is 10-30° C., the stirring speed is 100-200 rpm, and the stirring time is 3-12 h.

[0010] Preferably, the collection temperature in step 2 is room temperature and the drum speed is 200-500 rpm.

[0011] Preferably, the core-shell polystyrene / polylactic acid spinning fibers obtained in step 2 have a size of 2.24-3.55 μm and present a uniform spinning morphology and a core-shell structure.

[0012] The present invention also provides the pheromone-loaded core-shell structure polystyrene / polylactic acid spinning fiber obtained by the above preparation method.

[0013] Beneficial effects of the present invention: 1. The present invention proposes a method for preparing core-shell structured polystyrene / polylactic acid spinning fibers, which is combined with coaxial electrospinning technology and has the characteristics of simple operation, low cost and easy industrialization.

[0014] 2. Polylactic acid (PLA) is an organic acid with the chemical formula C3H6O3. It is a small molecule organic acid produced in the process of biological fermentation. In the polymerization reaction, lactic acid monomers are linked together by ester bonds to form a polylactic acid polymer chain. Polylactic acid has good biocompatibility and biodegradability. It can be completely degraded in 6-12 months under natural conditions. It is environmentally friendly and non-toxic.

[0015] 3. Polystyrene (PS) is a polymer material with a unique molecular structure and multiple excellent properties. Its molecular chain is polymerized from styrene monomers, and the continuous phenyl groups give polystyrene excellent thermal stability, fluidity and easy processing and molding.

[0016] 4. The present invention optimizes the spinning structure, adopts a core-shell spinning structure, and uses a coaxial electrospinning method to prepare core-shell structure polystyrene / polylactic acid spinning fibers containing insect pheromones. Its average diameter is 2.24-3.55 μm, the spinning presents a uniform morphology and has an obvious core-shell structure. After spinning and naturally drying for 24 hours, the surface presents a porous structure.

[0017] 5. The spinning membrane can be loaded with different types and concentrations of insect sex pheromones. The dual sustained-release system of polystyrene and polylactic acid realizes the long-term sustained-release of sex pheromones. The sustained-release period of sex pheromones in the spinning fiber can reach 8-14 weeks, which can be used in biological control to prevent and control pests by neutral pheromone interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the preparation method of the present invention; Figure 2 This is a picture of the core-shell structured polystyrene / polylactic acid spun fiber in Example 1 of the present invention taken under a camera.

[0019] Figure 3 This is a morphological diagram of the core-shell structured polystyrene / polylactic acid spun fibers in Example 1 of the present invention after dyeing under an ultra-depth-of-field microscope.

[0020] Figure 4 This is a partial magnified image of the fiber surface under a scanning electron microscope of the core-shell structure polystyrene / polylactic acid spun fiber in Example 1 of the present invention after natural drying.

[0021] Figure 5 This is a morphology diagram of the core-shell structured polystyrene / polylactic acid spun fiber in Example 1 of the present invention under a transmission electron microscope.

[0022] Figure 6 This is the cumulative release curve of the sex pheromone of Chilo suppressalis in the core-shell structured polystyrene / polylactic acid spun fiber in Example 1 of the present invention. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is further explained and illustrated in the form of specific embodiments below. It should be understood that these embodiments are only for illustrative purposes and they do not limit the present invention in any way.

[0024] Example 1: A method for preparing a core-shell structured polystyrene / polylactic acid spinning fiber loaded with rice stem borer sex pheromone Step 1: Preparation of electrospinning solution: First, 15wt% polystyrene was dissolved in tetrahydrofuran (THF) to obtain the shell solution for electrospinning; 8wt% polylactic acid was dissolved in dichloromethane and N,N-dimethylformamide (4:1), and stirred until completely dissolved to obtain a polylactic acid solution. 2wt% Chilo suppressalis pheromone (active ingredients are Z-11-hexadecenal cis-11-hexadecenal, Z-13-octadecenal cis-13-octadecenal, and Z-9-hexadecenal cis-9-hexadecenal) was added to the polylactic acid solution and continued to stir to obtain the core solution for electrospinning. All solutions were stirred at room temperature at a stirring speed of 200 rpm for 6 hours.

[0025] Step 2: Electrostatically spray the above spray solution at 20°C and 50% relative humidity. The inner diameter of the coaxial needle is 0.40 mm, the inner diameter of the outer needle is 0.71 mm, the voltage is 12 kV, the feeding rate of the shell solution is 1.4 mL / h; the feeding rate of the core solution is 0.4 mL / h, and the distance between the receiving device and the nozzle is 15 cm. The spun fibers formed by coaxial electrospinning are collected on an aluminum drum wrapped with sulfate transparent paper.

[0026] Step 3: Move the core-shell structured polystyrene / polylactic acid spun fibers into an antistatic plastic bag.

[0027] The diameter of the obtained core-shell structured polystyrene / polylactic acid spinning fibers is about 3.34 μm, and the sustained-release period of the rice stem borer sex pheromone in the spinning fibers is about 12 weeks.

[0028] Example 2: A method for preparing a core-shell structured polystyrene / polylactic acid spinning fiber loaded with Bactrocera dorsalis sex pheromone The difference between this embodiment and embodiment 1 is that the sex pheromone used in step 1 is methyl eugenol, which is mixed with the PLA solution at a concentration of 1.0 wt % to obtain a core solution.

[0029] The diameter of the obtained polystyrene / polylactic acid spun fibers was about 3.26 μm, and the sustained-release period of the Bactrocera dorsalis sex pheromone in the spun fibers was about 14 weeks.

[0030] Example 3: A method for preparing a core-shell structured polystyrene / polylactic acid spinning fiber loaded with codling moth sex pheromone The difference between this embodiment and Example 1 is that the sex pheromone used in step 1 is the active ingredient of the sex pheromone of codling moth (cis, trans-8,10-dodecadien-1-ol (E,E)-8,10-Dodecadien-1-ol, abbreviated as Codlemone), and is mixed with 10% PLA solution at a concentration of 2wt% to obtain a core solution.

[0031] The diameter of the obtained polystyrene / polylactic acid spun fibers was about 3.43 μm, and the sustained-release period of the codling moth sex pheromone in the spun fibers was about 13 weeks.

[0032] Example 5: A method for preparing a core-shell structured polystyrene / polylactic acid spinning fiber loaded with rice stem borer sex pheromone The difference between this embodiment and embodiment 1 is that in step 2, the feeding rate of the shell solution is 1.8 mL / h; the feeding rate of the core solution is 0.5 mL / h.

[0033] The diameter of the obtained core-shell structured polystyrene / polylactic acid spinning fibers was about 2.96 μm, and the sustained-release period of the rice stem borer sex pheromone during spinning was about 9 weeks.

[0034] Example 6: A method for preparing a core-shell structured polystyrene / polylactic acid spinning fiber loaded with rice stem borer sex pheromone The difference between this embodiment and embodiment 1 is that in step 2, the feeding rate of the shell solution is 1.2 mL / h; the feeding rate of the core solution is 0.4 mL / h.

[0035] The diameter of the obtained core-shell structured polystyrene / polylactic acid spinning fiber is about 3.37 μm, and the sustained release period of the rice stem borer pheromone in the fiber is about 8 weeks.

[0036] Example 7: A method for preparing a core-shell structured polystyrene / polylactic acid spinning fiber loaded with rice stem borer sex pheromone The difference between this embodiment and embodiment 1 is that in step 1, the concentration of PLA is 5 wt %.

[0037] The diameter of the obtained core-shell structured polystyrene / polylactic acid spinning fibers was about 2.42 μm, and the sustained release period of the fruit fly sex pheromone in the fibers was about 6 weeks.

[0038] Example 8: A method for preparing a core-shell structured polystyrene / polylactic acid spinning fiber loaded with rice stem borer sex pheromone The difference between this embodiment and embodiment 1 is that the concentration of PLA in step 1 is 10 wt %.

[0039] The diameter of the obtained core-shell structured polystyrene / polylactic acid spinning fibers was about 3.22 μm, and the sustained-release period of the rice stem borer sex pheromone in the fibers was about 10 weeks.

[0040] Example 9: A method for preparing a core-shell structured polystyrene / polylactic acid spinning fiber loaded with Bactrocera dorsalis sex pheromone The difference between this embodiment and embodiment 2 is that the voltage applied in step 2 is 16 kV.

[0041] The diameter of the obtained core-shell structure polystyrene / polylactic acid spinning fiber is about 3.16 μm, and the sustained release period of the oriental fruit fly sex pheromone in the fiber is about 11 weeks.

[0042] Example 10: A method for preparing a core-shell structured polystyrene / polylactic acid spinning fiber loaded with Bactrocera dorsalis sex pheromone The difference between this embodiment and embodiment 2 is that in step 1, the concentration of PLA is 10wt%; the concentration of PS is 18wt%.

[0043] The diameter of the obtained core-shell structured polystyrene / polylactic acid spinning fibers was about 3.66 μm, and the sustained-release period of the Bactrocera dorsalis sex pheromone in the spinning fibers was about 9 weeks.

[0044] Figure 2 The picture shown is a photo of the core-shell structured polystyrene / polylactic acid spinning fiber taken under a camera, showing that it has a film-like and uniform morphological feature.

[0045] The morphology of the core material after dyeing under the ultra-depth microscope is shown in the figure below. Figure 3 As shown in the figure, the dye in the core liquid slightly invades the shell liquid during the spinning process, but the core-shell structure can still be seen; the local enlarged picture of the spinning surface under a scanning electron microscope after natural drying is shown in the figure Figure 4 As shown in the figure, it can be seen that the spinning surface presents a porous structure; the transmission electron microscope photo is shown in Figure 5 As shown, the shell layer wraps the core layer. Due to the interface mixing caused by the difference in solvent evaporation rates of the two materials and the natural contrast limitation of the undyed treatment, the light and dark surfaces are not very obvious.

[0046] like Figure 6The figure shows the cumulative release curve of the sex pheromone of the rice stem borer in the core-shell polystyrene / polylactic acid spun fiber in Example 5 of the present invention. The rice stem borer sex pheromone has a burst release phenomenon in the first 3 weeks, and the release rate tends to slow down after the 3rd week. Only a very small amount of the sex pheromone of the rice stem borer is released from the 12th week to the 14th week. At the 14th week, the frog core-shell polystyrene / polylactic acid spun fiber still has 9.88% of the sex pheromone of the rice stem borer.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made to the present invention shall be included in the protection scope of the present invention.

[0048] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

[0049] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for preparing a core-shell structure polystyrene / polylactic acid spinning fiber loaded with sex pheromones, characterized in that: The specific steps of this method are: Step 1: firstly dissolve polystyrene in tetrahydrofuran to obtain an electrospinning shell solution; dissolve polylactic acid in dichloromethane and N,N-dimethylformamide, and stir until completely dissolved to obtain a polylactic acid solution; Adding sex pheromone into the polylactic acid solution and continuing to stir to obtain the core solution for electrospinning; The mass percentage concentration of polystyrene in the shell solution is 15-20%, the mass percentage concentration of polylactic acid in the core solution is 5-15%, and the mass percentage of sex pheromone is 0.2-5%. Step 2: Using an aluminum drum wrapped with sulfate transparent paper as a spinning receiving device, coaxial electrospinning is performed under the conditions of 15-30°C and a relative humidity of 20-50%, the inner needle sprays the core solution, and the outer needle sprays the shell solution. The fibers formed by coaxial electrospinning are collected on the aluminum drum wrapped with sulfate transparent paper to obtain a core-shell structure polystyrene / polylactic acid fiber membrane; The process parameters of coaxial electrostatic spraying are as follows: the inner diameter of the inner needle is 0.40 mm, the inner diameter of the outer needle is 0.71 mm, the voltage is 12~16 kV, the feeding rate of the shell solution is 0.4~0.6 mL / h; the feeding rate of the core solution is 1.2~1.8 mL / h, and the distance between the receiving device and the nozzle is 10~20 cm.

2. The method for preparing the core-shell structure polystyrene / polylactic acid spinning fiber loaded with sex pheromone according to claim 1, characterized in that: The sex pheromone described in step 1 is the sex pheromone of the rice stem borer, the citrus fruit fly or the codling moth or its effective component.

3. The method for preparing the core-shell structure polystyrene / polylactic acid spinning fiber loaded with sex pheromone according to claim 1, characterized in that: The stirring temperature described in step 1 is 10-30° C., the stirring speed is 100-200 rpm, and the stirring time is 3-12 h.

4. The method for preparing the core-shell structure polystyrene / polylactic acid spinning fiber loaded with sex pheromone according to claim 1, characterized in that: The collection temperature in step 2 is room temperature, the rotation speed of the aluminum drum wrapped with sulfate transparent paper is 200-500 rpm, and it needs to be naturally dried for 24 hours after collection.

5. The method for preparing the core-shell structure polystyrene / polylactic acid spinning fiber loaded with sex pheromone according to claim 1, characterized in that: The pheromone-loaded core-shell polystyrene / polylactic acid spinning fibers prepared in step 2 are transferred to an antistatic plastic bag for storage.

6. A core-shell structure polystyrene / polylactic acid spinning fiber loaded with sex pheromone prepared by the method as claimed in any one of claims 1 to 4.

7. The core-shell structured polystyrene / polylactic acid spinning fiber loaded with sex pheromone according to claim 6, characterized in that: The diameter of the core-shell polystyrene / polylactic acid spinning fiber loaded with sex pheromone is 2.24-3.55 μm, showing a uniform spinning morphology and a core-shell structure.

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