PLA-based flexible triboelectric materials with enhanced flame retardancy and high temperature resistance through core-shell structure and their preparation method

Abstract

This invention discloses a PLA-based flexible triboelectric material with enhanced flame retardancy and high temperature resistance through a core-shell structure, and its preparation method, belonging to the field of triboelectric material technology. The preparation method of this invention includes the following technical steps: (1) adding carboxylated multi-walled carbon nanotubes to dichloromethane and N-N-dimethylformamide and ultrasonically dispersing them to obtain a dispersion; (2) adding polylactic acid to the above dispersion and magnetically stirring to obtain a core-layer spinning solution; (3) adding calcium phytate and polylactic acid to dichloromethane and N-N-dimethylformamide and magnetically stirring to obtain a shell-layer spinning solution; (4) loading the core and shell-layer spinning solutions into two injectors respectively and performing coaxial electrospinning to obtain a PLA-based nanofiber membrane; (5) drying in a drying oven to obtain a PLA-based flexible triboelectric material. This invention obtains a material with flame retardancy, high temperature resistance, and high triboelectric properties by coaxial electrospinning a PLA / C-MWCNT core-layer solution and a PLA / PA-Ca shell-layer solution.

Description

Technical Field

[0001] This invention relates to the field of triboelectric materials technology, specifically to PLA-based flexible triboelectric materials with enhanced flame retardancy and high temperature resistance through a core-shell structure, and their preparation methods. Background Technology

[0002] With the advent of the industrial age, advanced technologies such as the Internet of Things (IoT), big data, and artificial intelligence have driven the rapid development of portable and wearable devices. However, traditional wearable devices rely on batteries that are prone to expansion and explosion in high-temperature environments, severely limiting their application in such conditions. Triboelectric nanogenerators (TENGs), based on the synergistic effect of triboelectricity and electrostatic induction, represent an emerging energy harvesting technology that can convert widely distributed, minute low-frequency energy in the environment into electrical energy, thereby enabling sensing functions. Due to their simple structure, wide range of material choices, and high energy conversion efficiency, wearable devices for high-temperature environments have been developed based on TENG technology. Among these, green, environmentally friendly, and biodegradable triboelectric materials are becoming a key area for TENG development due to their recyclability in the natural environment and harmlessness to the human body. However, most biodegradable triboelectric materials, including polyvinyl alcohol, cellulose, and polylactic acid (PLA), exhibit unstable electrical output performance, flammability, and the risk of dripping at high temperatures. Therefore, it is essential to develop a flame-retardant, biodegradable, high-performance triboelectric material for self-powered sensing in extreme environments such as high temperatures and for sustainable environmental development.

[0003] In recent years, PLA, a bio-based material with excellent biocompatibility, good biodegradability, and outstanding processability, has been widely used as a superior triboelectric material. However, PLA's low crystallinity and linear chain structure limit its application in high-temperature environments such as fire zones, exhibiting severe dripping and poor thermal stability, making it unsuitable for high-temperature conditions. Adding flame retardants such as calcium phytate (PA-Ca), hydroxyapatite, and chitosan could improve PLA's anti-dripping properties and enhance its flame retardancy. Treatment with nucleating agents, blending, and crosslinking modifications can improve PLA's heat resistance. Electrospinning technology can endow PLA with abundant porous micro / nano structures and high specific surface area, thereby improving its triboelectric properties. However, simultaneously improving all three properties of PLA remains a challenge. Summary of the Invention

[0004] To address the above problems, this invention provides a PLA-based flexible triboelectric material with enhanced flame retardancy and high temperature resistance through a core-shell structure, and its preparation method. By coaxial electrospinning a PLA / C-MWCNT core layer solution and a PLA / PA-Ca shell layer solution, a PLA-based flexible triboelectric material with high temperature resistance, flame retardancy, and high triboelectric properties is prepared.

[0005] This invention is achieved through the following technical solution:

[0006] A method for preparing PLA-based flexible triboelectric materials with enhanced flame retardancy and high-temperature resistance through a core-shell structure includes the following steps:

[0007] (1) Carboxylated multi-walled carbon nanotubes (C-MWCNTs) were added to dichloromethane (DCM) and dimethylformamide (DMF) solvents and ultrasonically dispersed to obtain a dispersion;

[0008] (2) Polylactic acid (PLA) was added to the above dispersion and magnetically stirred to obtain PLA / C-MWCNT core spinning solution;

[0009] (3) Add calcium phytate (PA-Ca) and PLA to DCM and DMF solvents and stir magnetically to obtain PLA / PA-Ca shell spinning solution;

[0010] (4) The two core-shell spinning solutions from steps (2) and (3) are respectively loaded into the injector and coaxial electrospinning is performed to obtain PLA-based nanofiber membranes.

[0011] (5) The PLA-based nanofiber membrane obtained in step (4) is dried in a drying oven to obtain PLA-based flexible triboelectric material.

[0012] As a further preferred option, in step (1), 3.59g of C-MWCNT is added to each liter of solvent.

[0013] As a further preferred option, in step (1), the volume ratio of DCM to DMF is 7:3.

[0014] As a further preferred option, in step (1), the ultrasound duration is 1.5-2 hours.

[0015] As a further preferred option, in step (2), the amount of PLA added is 9% of the mass of the dispersion.

[0016] As a further preferred embodiment, in step (3), the amount of PLA added is 9% of the solvent mass; the amount of PA-Ca is 10-30 wt% of PLA. The performance is best when the amount of PA-Ca added is 20 wt% of PLA.

[0017] As a further preferred option, in step (3), the volume ratio of DCM to DMF is 7:3.

[0018] As a further preferred embodiment, the magnetic stirring time in steps (2) and (3) is 10-12 hours.

[0019] As a further preferred embodiment, in step (4), the coaxial needle is model 22G / 17G, and the injection speed of the core spinning solution is set to 1.5 mL·h. -1 The injection rate of the shell spinning solution was set to 2.0 mL / h. -1 The receiving distance was set to 20cm, the spinning voltage was set to 20kV, the ambient temperature was controlled at 25℃, and the relative humidity was 40%.

[0020] As a further preferred option, in step (5), the drying temperature is 60°C and the drying time is 20-24 hours.

[0021] The core-shell structure-enhanced flame-retardant and high-temperature resistant PLA-based flexible triboelectric material prepared by the method of this invention has flame-retardant and high-temperature resistant properties and can be applied in high-temperature fire environments.

[0022] The preparation principle of the core-shell structure-enhanced flame-retardant and high-temperature resistant PLA-based flexible triboelectric material of the present invention:

[0023] The PA-Ca shell absorbs combustion free radicals at high temperatures to form a dense phosphorus-containing carbon layer, thus exerting a flame-retardant effect. The C-MWCNT core layer acts as a nucleating agent and conductive filler, improving the crystallinity of PLA and forming more conductive paths within the material, promoting faster transport and movement of triboelectric charges. The synergistic effect of the core-shell bifunctional layers achieves a dual improvement in flame retardancy and electrical output performance. Nanofiber materials prepared by electrospinning technology possess high specific surface area and high porosity, making them ideal for loading conductive nanoparticles. This invention constructs a PLA-based flexible biodegradable triboelectric material with a core (PLA / C-MWCNT) and shell (PLA / PA-Ca) structure to enhance flame retardancy and high-temperature resistance through coaxial electrospinning technology. This is mainly achieved by utilizing the inhibitory effect of PO· free radicals generated from the combustion decomposition of PA-Ca and the physical barrier effect of the dense carbon layer, thereby improving flame retardancy. Simultaneously, electrospinning overcomes the brittleness of PLA and C-MWCNT, giving the film sufficient flexibility. Furthermore, PLA molecules can be degraded under the action of proteinase K solution, making it environmentally friendly and pollution-free.

[0024] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0025] 1. The core-shell structured PLA-based flexible triboelectric material prepared in this invention enhances flame retardancy and high-temperature resistance. During combustion, the PO· free radicals generated capture HO· and H· combustion free radicals, thus interrupting combustion. Simultaneously, the dense char layer after combustion acts as a physical barrier, blocking external heat and oxygen, giving flammable PLA excellent flame retardant properties. It produces no molten droplets after ignition and self-extinguishes after being removed from the flame.

[0026] 2. The core-shell structured PLA-based flexible triboelectric material prepared in this invention exhibits excellent biodegradability, being environmentally friendly and pollution-free, as the ester bonds in the PLA molecules can be hydrolyzed under the action of proteinase K solution, achieving degradation within 7 days. Furthermore, it does not fracture or suffer permanent damage after significant deformation under bending stress, and can still undergo multiple bending cycles, demonstrating excellent flexibility.

[0027] 3. The PLA-based flexible triboelectric material with enhanced flame retardancy and high temperature resistance prepared by this invention has the highest open circuit voltage of 76.21V at room temperature, and still exhibits excellent triboelectric properties at high temperatures (160℃, 52.19V; after combustion, 9.81V). Attached Figure Description

[0028] Figure 1 This is a schematic diagram illustrating the preparation of the PLA-based flexible triboelectric material of the present invention.

[0029] Figure 2 This is a SEM image of the PLA-based flexible triboelectric material prepared in Example 4 of the present invention at magnification of 2000.

[0030] Figure 3 The image shows the EDS elemental distribution of the PLA-based flexible triboelectric material prepared in Example 4 of this invention.

[0031] Figure 4 This is a diagram showing the self-extinguishing combustion of the PLA-based flexible triboelectric material of the present invention under an alcohol lamp flame.

[0032] Figure 5 The graph shows the heat release rate of different PLA-based flexible triboelectric materials at different temperatures.

[0033] Figure 6 This is a diagram showing the degradation of the PLA-based flexible triboelectric material of the present invention in a protease solution.

[0034] Figure 7 Voltage diagrams for different PLA-based flexible triboelectric materials at room temperature.

[0035] Figure 8 Voltage diagrams of the PLA-based flexible triboelectric material prepared in Example 4 of this invention at different high temperatures.

[0036] Figure 9 The image shows the triboelectric properties of the PLA-based flexible triboelectric material prepared in Example 4 of this invention after 20 seconds of combustion.

[0037] Table 1 shows the flame retardant ratings of the different PLA-based flexible triboelectric materials of the present invention. Detailed Implementation

[0038] The present invention will be further described in detail below through embodiments. These embodiments are only used to illustrate the present invention and do not limit the scope of protection of the present invention.

[0039] Example 1

[0040] Preparation of PLA-based flexible triboelectric materials:

[0041] 9 wt% PLA powder was dissolved in a mixed solvent of DCM and DMF (7:3, v / v) and stirred continuously at room temperature for 12 h with a magnetic stirrer to obtain a homogeneous spinning solution. This solution was then injected into a 10 mL plastic syringe equipped with a 22G needle for electrospinning. The voltage for electrospinning was 20 kV, and the feed rate was 1.5 mL / h. -1 The collection rate is 130 r·min -1 The distance between the needle tip and the roller collector was 20 cm. The temperature and humidity were maintained at 25℃ and 40%, respectively. Finally, after drying in an oven at 60℃ for 24 hours, it was obtained and named Pure PLA.

[0042] Example 2

[0043] Preparation of PLA-based flexible triboelectric materials:

[0044] C-MWCNT, comprising 3 wt% of PLA powder, was ultrasonically dispersed in a mixed solvent of DCM and DMF (7:3, v / v). Then, 9 wt% of PLA powder was dissolved in the mixed solvent, and the mixture was stirred continuously at room temperature for 12 h using a magnetic stirrer, followed by ultrasonic dispersion for 2 h to obtain a homogeneous PLA / C-MWCNT solution. Subsequently, the PLA / C-MWCNT solution was injected into a 10 mL plastic syringe equipped with a 22G needle for electrospinning. The voltage during electrospinning was 20 kV, and the feed rate was 1.5 mL / h. -1 The collection rate is 130 r·min -1The distance between the needle tip and the roller collector was 20 cm. The temperature and humidity were maintained at 25℃ and 40%, respectively. Finally, after drying in a drying oven at 60℃ for 24 hours, it was obtained and named P / C3.

[0045] Example 3

[0046] A method for preparing PLA-based flexible triboelectric materials with enhanced flame retardancy and high-temperature resistance through a core-shell structure includes the following steps:

[0047] (1) Add 3 wt% of C-MWCNT (approximately 3.59 g of C-MWCNT per liter of mixed solvent) to a mixed solvent of DCM and DMF (7:3, v / v) and ultrasonically disperse for 2 h to obtain a dispersion.

[0048] (2) Dissolve 9 wt% PLA powder into the above dispersion and stir magnetically for 12 h to obtain a uniform PLA / C-MWCNT core spinning solution.

[0049] (3) Add 9 wt% PLA powder to a mixed solvent of DCM and DMF (7:3, v / v), then add PA-Ca accounting for 10 wt% of PLA, and stir magnetically for 12 h to obtain PLA / PA-Ca shell spinning solution.

[0050] (4) The two core-shell spinning solutions from steps (2) and (3) were respectively loaded into 10 mL plastic syringes, and coaxial electrospinning was performed using a 22G / 17G (core / shell) needle. The voltage during the electrospinning process was 20 kV, and the feed rate was 1.5 mL·h. -1 (nucleus) and 2.0 mL·h -1 (Shell), collection rate is 130 r·min -1 The distance between the needle and the roller collector was 20 cm. Temperature and humidity were maintained at 25℃ and 40%, respectively. Electrospinning was performed using a plastic syringe with a coaxial needle model of 22G / 17G, and the injection rate of the core spinning solution was set to 1.5 mL / h. -1 The injection rate of the shell spinning solution was set to 2.0 mL / h. -1 The receiving distance was set to 20cm, the spinning voltage was set to 20kV, the ambient temperature was controlled at 25℃, the relative humidity was 40%, and PLA-based nanofiber membranes were obtained after electrospinning for 5 hours.

[0051] (5) The PLA-based nanofiber membrane obtained in step (4) is dried in a drying oven at 60°C for 24 hours to obtain a PLA-based flexible triboelectric material, named P / C3P10.

[0052] Example 4

[0053] A method for preparing PLA-based flexible triboelectric materials with enhanced flame retardancy and high-temperature resistance through a core-shell structure includes the following steps:

[0054] (1) Add 3 wt% of C-MWCNT (approximately 3.59 g of C-MWCNT per liter of mixed solvent) to a mixed solvent of DCM and DMF (7:3, v / v) and ultrasonically disperse for 2 h to obtain a dispersion.

[0055] (2) Dissolve 9 wt% PLA powder into the above dispersion and stir magnetically for 12 h to obtain a uniform PLA / C-MWCNT core spinning solution.

[0056] (3) Add 9 wt% PLA powder to a mixed solvent of DCM and DMF (7:3, v / v), then add PA-Ca accounting for 20 wt% of PLA, and stir magnetically for 12 h to obtain PLA / PA-Ca shell spinning solution.

[0057] (4) The two core-shell spinning solutions from steps (2) and (3) were respectively loaded into 10 mL plastic syringes, and coaxial electrospinning was performed using a 22G / 17G (core / shell) needle. The voltage during the electrospinning process was 20 kV, and the feed rate was 1.5 mL·h. -1 (nucleus) and 2.0 mL·h -1 (Shell), collection rate is 130 r·min -1 The distance between the needle and the roller collector was 20 cm. Temperature and humidity were maintained at 25℃ and 40%, respectively. Electrospinning was performed using a plastic syringe with a coaxial needle model of 22G / 17G, and the injection rate of the core spinning solution was set to 1.5 mL / h. -1 The injection rate of the shell spinning solution was set to 2.0 mL / h. -1 The receiving distance was set to 20cm, the spinning voltage was set to 20kV, the ambient temperature was controlled at 25℃, the relative humidity was 40%, and PLA-based nanofiber membranes were obtained after electrospinning for 5 hours.

[0058] (5) The PLA-based nanofiber membrane obtained in step (4) is dried in a drying oven at 60°C for 24 hours to obtain a PLA-based flexible triboelectric material, named P / C3P20.

[0059] Example 5

[0060] A method for preparing PLA-based flexible triboelectric materials with enhanced flame retardancy and high-temperature resistance through a core-shell structure includes the following steps:

[0061] (1) Add 3 wt% of C-MWCNT (approximately 3.59 g of C-MWCNT per liter of mixed solvent) to a mixed solvent of DCM and DMF (7:3, v / v) and ultrasonically disperse for 2 h to obtain a dispersion.

[0062] (2) Dissolve 9 wt% PLA powder into the above dispersion and stir magnetically for 12 h to obtain a uniform PLA / C-MWCNT core spinning solution.

[0063] (3) Add 9 wt% PLA powder to a mixed solvent of DCM and DMF (7:3, v / v), then add PA-Ca accounting for 30 wt% of PLA, and stir magnetically for 12 h to obtain PLA / PA-Ca shell spinning solution.

[0064] (4) The two core-shell spinning solutions from steps (2) and (3) were respectively loaded into 10 mL plastic syringes, and coaxial electrospinning was performed using a 22G / 17G (core / shell) needle. The voltage during the electrospinning process was 20 kV, and the feed rate was 1.5 mL·h. -1 (nucleus) and 2.0 mL·h -1 (Shell), collection rate is 130 r·min -1 The distance between the needle and the roller collector was 20 cm. Temperature and humidity were maintained at 25℃ and 40%, respectively. Electrospinning was performed using a plastic syringe with a coaxial needle model of 22G / 17G, and the injection rate of the core spinning solution was set to 1.5 mL / h. -1 The injection rate of the shell spinning solution was set to 2.0 mL / h. -1 The receiving distance was set to 20cm, the spinning voltage was set to 20kV, the ambient temperature was controlled at 25℃, the relative humidity was 40%, and PLA-based nanofiber membranes were obtained after electrospinning for 5 hours.

[0065] (5) The PLA-based nanofiber membrane obtained in step (4) is dried in a drying oven at 60°C for 24 hours to obtain PLA-based flexible triboelectric material, named P / C3P30.

[0066] Material morphology characterization analysis

[0067] (I) SEM Analysis

[0068] The P / C3P20 flexible triboelectric material of Example 4 was characterized and analyzed using scanning electron microscopy (SEM). Figure 2 As shown, Figure 2 The image shows the P / C3P20 flexible triboelectric material of Example 4 at a magnification of 2000.

[0069] Depend on Figure 2 It can be seen that C-MWCNT and PA-Ca are uniformly dispersed on PLA nanofibers, and the prepared P / C3P20 flexible triboelectric material is a nanofiber membrane.

[0070] The P / C3P20 flexible triboelectric material of Example 4 was characterized and analyzed using an energy dispersive spectrometer (EDS). Figure 3 As shown, Figure 3 The image shows the EDS diagram of the P / C3P20 flexible triboelectric material in Example 4.

[0071] Depend on Figure 3 It can be seen that C-MWCNT and PA-Ca are uniformly dispersed on the inner and outer layers of PLA nanofibers, and the presence of Ca element indicates that PA-Ca has been successfully introduced into PLA.

[0072] Material performance testing and analysis

[0073] (II) Flame retardant performance test

[0074] The materials obtained in Examples 1-5 were subjected to flame retardancy rating tests (UL-94), and the test results are as follows: Figure 4 As shown in Table 1. Figure 4 The image shows the self-extinguishing properties of the PLA-based flexible triboelectric material of the present invention under flame. Table 1 shows the flame retardant ratings of different PLA-based flexible triboelectric materials.

[0075] Table 1 Flame retardancy ratings of different PLA-based flexible triboelectric materials

[0076]

[0077] Depend on Figure 4 As ab shows, Pure PLA and P / C3 burn to the 125mm mark within 3 seconds after the first ignition, and cannot be re-ignited. Figure 4 c indicates that P / C3P10 produces molten droplets in both ignitions, and these droplets ignite the absorbent cotton below. From Figure 4 As can be seen from d, P / C3P20 produces no molten droplets after its first ignition and self-extinguishes after being removed from the ignition source; after extinguishing itself, it ignites again 8 seconds later when brought near an ignition source and self-extinguishes after being removed from the ignition source. From Figure 4 As shown in Table 1, P / C3P30 produces no molten droplets after its first ignition and self-extinguishes after being removed from the ignition source; after extinguishing, it ignites again near an ignition source 3 seconds later and self-extinguishes after being removed from the ignition source. Therefore, the flame retardancy ratings are obtained. Pure PLA and P / C3 have the lowest flame retardancy ratings, with no rating. P / C3P10 reaches the VTM-2 rating. P / C3P20 and P / C3P30 have the highest flame retardancy ratings, reaching the VTM-0 rating.

[0078] The materials obtained in Examples 1-5 were subjected to flame retardancy tests, and the test results are as follows: Figure 5 As shown. Figure 5 The graph shows the heat release rate of PLA-based flexible triboelectric materials with different compositions at different temperatures.

[0079] Depend on Figure 5 It can be seen that, compared with Pure PLA flexible triboelectric material, the peak heat release rate (pHRR) of P / C3 flexible triboelectric material decreased by only 5.07%. However, compared with PurePLA flexible triboelectric material, the peak heat release rate (pHRR) of P / C3P20 flexible triboelectric material was significantly reduced by 23.64%. This indicates that compared with P / C3 with only C-MWCNT added, the addition of PA-Ca can greatly reduce the heat release and fire hazard of polylactic acid (P / C3P20) combustion.

[0080] (III) Degradability Test

[0081] The P / C3P20 material prepared in Example 4 was immersed in a proteinase K solution at 50°C for degradation testing. The test results are as follows: Figure 6 As shown. Figure 6 This is a degradation diagram of the P / C3P20 flexible triboelectric material in Example 4 in a protease solution.

[0082] Depend on Figure 6 It is known that P / C3P20 flexible triboelectric material can degrade in 7 days, demonstrating good biodegradability.

[0083] (iv) Electrical performance testing at room temperature

[0084] The materials obtained in Examples 1-5 and fluorinated ethylene propylene (FEP) were cut into 2cm × 2cm squares and attached to an acrylic plate coated with conductive adhesive as positive and negative electrode materials. The positive and negative electrode plates were respectively mounted on a TENGs electrical test bench to form a vertical-contact separation mode TENGs. Testing was performed at a frequency of 2Hz, and the test results are as follows. Figure 7 As shown. Figure 7 In this context, Pure PLA, P / C3, P / C3P10, P / C3P20, and P / C3P30 represent the materials prepared in Examples 1-5, respectively. Figure 7 The voltage diagrams for PLA-based flexible triboelectric materials in Examples 1-5 are shown at room temperature.

[0085] Depend on Figure 7It can be seen that the voltage of PLA-based flexible triboelectric material increases with the increase of C-MWCNT content; subsequently, with the increase of PA-Ca, the voltage of PLA-based flexible triboelectric material first increases and then decreases, reaching a maximum at 20wt%. P / C3P20 flexible triboelectric material has the highest open-circuit voltage (76.21V).

[0086] (V) Electrical performance testing at different high temperatures

[0087] The P / C3P20 flexible triboelectric material and FEP prepared in Example 4 were cut into 2cm × 2cm squares and attached to a heat-resistant glass plate coated with conductive adhesive, serving as the positive and negative electrode materials. The positive and negative electrode plates were respectively mounted on a TENGs electrical test bench, forming a vertical-contact separation mode TENGs. The temperature of the heating plate was controlled by a temperature control chamber to regulate the temperature of the positive electrode plate. Testing was conducted at a frequency of 2Hz, and the test results are as follows. Figure 8 As shown. Figure 8 The voltage diagrams for the P / C3P20 flexible triboelectric material of Example 4 at different temperatures are shown.

[0088] Depend on Figure 8 It can be seen that as the temperature increases, the voltage of the P / C3P20 flexible triboelectric material gradually decreases due to the thermionic emission effect. Subsequent cyclic heating resulted in a relatively constant voltage, demonstrating excellent cycling performance under high-temperature conditions.

[0089] (vi) Electrical performance testing after combustion

[0090] The P / C3P20 flexible triboelectric material and FEP prepared in Example 4 were cut into 2cm × 2cm squares. The P / C3P20 flexible triboelectric material prepared in Example 4 was burned for 20 seconds. Then, the burned P / C3P20 flexible triboelectric material and FEP were attached to an acrylic plate coated with conductive adhesive as positive and negative electrode materials. The positive and negative electrode plates were respectively mounted on a TENGs electrical test bench, forming a TENGs in a vertical-contact separation mode. Testing was performed at a frequency of 2Hz, and the test results are as follows. Figure 9 As shown. Figure 9 The image shows the physical picture, voltage, and charge diagram of the P / C3P20 flexible triboelectric material of Example 4 after 20 seconds of combustion.

[0091] Depend on Figure 9 It can be seen that even when burning, the P / C3P20 flexible triboelectric material can still output an open-circuit voltage of 9.81V and a transferred charge of 3.22nC, exhibiting excellent triboelectric properties after being attacked by fire.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing PLA-based flexible triboelectric materials with enhanced flame retardancy and high-temperature resistance through a core-shell structure, characterized in that, Includes the following steps: (1) Carboxylated multi-walled carbon nanotubes were added to dichloromethane and N,N dimethylformamide solvents and ultrasonically dispersed to obtain a dispersion; (2) Polylactic acid was added to the above dispersion and magnetically stirred to obtain a polylactic acid / carboxylated multi-walled carbon nanotube core spinning solution; (3) Add calcium phytate and polylactic acid to dichloromethane and NN dimethylformamide solvent and stir magnetically to obtain polylactic acid / calcium phytate shell spinning solution; (4) The two core-shell spinning solutions from steps (2) and (3) are respectively loaded into the injector and coaxial electrospinning is performed to obtain PLA-based nanofiber membranes. (5) The PLA-based nanofiber membrane obtained in step (4) is dried in a drying oven to obtain PLA-based flexible triboelectric material.

2. The method for preparing PLA-based flexible triboelectric material with enhanced flame retardancy and high-temperature resistance according to claim 1, characterized in that, In step (1), 3.0-4.0 g of carboxylated multi-walled carbon nanotubes are added to each liter of solvent.

3. The method for preparing PLA-based flexible triboelectric material with enhanced flame retardancy and high-temperature resistance according to claim 1, characterized in that, In step (1), the volume ratio of dichloromethane to N,N-dimethylformamide is 7:3; the ultrasonic dispersion time is 1.5-2 hours.

4. The method for preparing PLA-based flexible triboelectric material with enhanced flame retardancy and high-temperature resistance according to claim 1, characterized in that, In step (2), the amount of polylactic acid added is 9% of the mass of the dispersion.

5. The method for preparing PLA-based flexible triboelectric material with enhanced flame retardancy and high-temperature resistance according to claim 1, characterized in that, In step (3), the amount of polylactic acid added is 9% of the solvent mass; the calcium phytate accounts for 10-30 wt% of the polylactic acid.

6. The method for preparing PLA-based flexible triboelectric material with enhanced flame retardancy and high-temperature resistance according to claim 1, characterized in that, In step (3), the volume ratio of dichloromethane to N,N-dimethylformamide is 7:

3.

7. The method for preparing PLA-based flexible triboelectric material with enhanced flame retardancy and high-temperature resistance according to claim 1, characterized in that, In steps (2) and (3), the magnetic stirring time is 10-12 hours.

8. The method for preparing PLA-based flexible triboelectric material with enhanced flame retardancy and high-temperature resistance according to claim 1, characterized in that, In step (4), the coaxial needle model is 22G / 17G, and the injection rate of the core spinning solution is set to 1.5 mL·h. -1 The injection rate of the shell spinning solution was set to 2.0 mL / h. -1 The receiving distance was set to 20cm, the spinning voltage was set to 20kV, the ambient temperature was controlled at 25℃, the relative humidity was 40%, and the spinning time was 5h.

9. The method for preparing PLA-based flexible triboelectric material with enhanced flame retardancy and high-temperature resistance according to claim 1, characterized in that, In step (5), the drying temperature is 60°C and the drying time is 20-24 hours.

10. The PLA-based flexible triboelectric material with enhanced flame retardancy and high temperature resistance according to any one of claims 1 to 9 and the preparation method thereof yields a PLA-based flexible triboelectric material with flame retardancy and high temperature resistance.

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