Carboxylated nitrile rubber toughened polyvinylidene fluoride composite material as well as preparation method and application thereof

Abstract

The invention discloses a carboxylated nitrile rubber toughened polyvinylidene fluoride composite material and a preparation method and application thereof, and belongs to the technical field of high polymer material processing, the carboxylated nitrile rubber toughened polyvinylidene fluoride composite material comprises the following components: 40-90 parts of polyvinylidene fluoride resin, 10-40 parts of carboxylated nitrile rubber, and 1-30 parts of a compatibilizer, 0-5 parts of a vulcanizing agent; the compatibilizer is a methyl methacrylate copolymer containing a reactive functional group, the reactive functional group is at least one of an epoxy group, an amino group and a hydroxyl group, and the molecular weight of the compatibilizer is 2000-100000Da. By introducing a methyl methacrylate copolymer compatibilizer containing a reactive functional group and combining a dynamic vulcanization process, high performance of the modified polyvinylidene fluoride composite material is realized, and the super-tough and flexible toughened polyvinylidene fluoride composite material is prepared.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer material processing, and particularly relates to a carboxylated nitrile rubber toughened polyvinylidene fluoride composite material, a preparation method thereof, and an application thereof. Background Art

[0002] Polyvinylidene fluoride (PVDF) plastics have excellent properties such as corrosion resistance, high temperature resistance, low friction, good insulation, non-stickiness, and weather resistance, and are widely used in fields such as chemical industry, electronics, medical treatment, and new energy. However, its inherent high crystallinity results in poor flexibility and toughness, and it is particularly prone to brittle fracture in low-temperature environments, which limits the popularization of PVDF plastics in engineering applications that require good ductility, such as impact-resistant structural materials, flexible films, or highly tough adhesives.

[0003] Rubber-plastic melt blending modification is an effective means for preparing toughened PVDF. At present, there are reports on toughening PVDF with various rubbers including acrylate rubber (ACM), fluororubber (FKM), natural rubber (NR), and thermoplastic polyurethane (TPU). However, the solubility parameters of PVDF plastics and most rubbers / elastomers are quite different, resulting in poor compatibility. If the two components are simply physically blended, there is a tendency for the two components to aggregate and phase separate, and it is difficult to form a super-dispersed and small-particle-size rubber particle dispersed phase with good toughening effect, thus the toughening efficiency of the rubber component cannot be fully exerted, and at the same time, the strength and processing and molding stability of PVDF plastics may be significantly reduced.

[0004] Chinese patent document with publication number CN106854328A discloses a toughened modified polyvinylidene fluoride composite material for injection extrusion molding and a preparation method thereof. In this invention, PVDF is toughened and modified with a thermoplastic resin, and the thermoplastic resin is selected from ethylene-vinyl acetate copolymer (EVA), acrylonitrile-butadiene-styrene terpolymer (ABS), thermoplastic polyurethane (TPU), polyethylene glycol (PEG), polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), or polymethyl methacrylate (PMMA), etc. Chinese patent document with publication number CN105591054A discloses a toughened modified polyvinylidene fluoride-based lithium ion battery separator and a preparation method thereof. In this invention, acrylic rubber (ACM) is used to modify polyvinylidene fluoride (PVDF) to improve its toughness. In the above inventions, there may be problems with component compatibility.

[0005] A Chinese patent document with publication number CN102702404A discloses a method for preparing a polyvinylidene fluoride material, wherein a polybutadiene rubber component is added to the monomer vinylidene fluoride, and then a toughened polyvinylidene fluoride material is prepared by free radical bulk polymerization, wherein the polybutadiene rubber component includes low-cis polybutadiene rubber, or a composite rubber of low-cis polybutadiene and high-cis polybutadiene, and the initiation system uses peroxide thermal initiation polymerization. However, the preparation method of the invention is complicated and has high process requirements.

[0006] In addition, PVDF is chemically inert and it is difficult to introduce reactive groups through a melt grafting method similar to polyolefins, so it cannot form a chemical connection with ordinary rubber dispersed phases. Therefore, it is urgent to develop an ultra-tough and flexible PVDF composite material with simple preparation process and good component compatibility. Summary of the invention

[0007] In order to solve the deficiencies in the above-mentioned prior art, the present invention provides a carboxylated nitrile rubber toughened polyvinylidene fluoride composite material, which realizes the high performance of the modified polyvinylidene fluoride composite material and prepares an ultra-tough and flexible PVDF composite material.

[0008] The specific technical solutions adopted are as follows:

[0009] A carboxylated nitrile rubber toughened polyvinylidene fluoride composite material, comprising the following components in parts by weight:

[0010]

[0011] The compatibilizer is a methyl methacrylate copolymer containing reactive functional groups, the reactive functional groups are at least one of epoxy groups, amino groups and hydroxyl groups, and the molecular weight of the compatibilizer is 5000-100000Da.

[0012] Further preferably, the carboxylated nitrile rubber toughened polyvinylidene fluoride composite material comprises the following components in parts by weight:

[0013]

[0014] On the one hand, carboxylated nitrile rubber (XNBR) is a functional special rubber that has the excellent properties of nitrile rubber (NBR) and contains polar carboxyl functional groups that can react chemically. On the other hand, polymethyl methacrylate (PMMA) has a certain compatibility with PVDF. If epoxy groups that can react with carboxyl groups can be introduced into the PMMA structure, it will have the potential to undergo a grafting reaction with XNBR, and it is expected to generate PMMA-g-NBR macromolecular "surfactant", which can effectively improve the compatibility between PVDF and XNBR and the interfacial bonding strength.

[0015] Therefore, the present invention adopts a methyl methacrylate copolymer containing a reactive functional group, and uses a commercial carboxylated nitrile rubber (XNBR) in combination, and utilizes the reaction of epoxy, amino, hydroxyl and carboxyl groups in the melt blending process to form a PMMA-g-NBR macromolecular "surfactant", thereby improving the dispersion state and interfacial bonding between the PVDF and XNBR phases. In addition, it is preferred to introduce a dynamic vulcanization process in the blending process, form a more stable high-viscosity rubber dispersed phase through a cross-linking reaction rubber phase, improve its dispersion uniformity in the PVDF matrix, enhance the dimensional stability, heat resistance and mechanical properties of the material, and the present invention realizes the high performance of PVDF / XNBR rubber-plastic composite materials, and provides a new technical approach for developing ultra-tough and flexible PVDF composite materials.

[0016] Furthermore, the polyvinylidene fluoride resin is selected from at least one of polyvinylidene fluoride homopolymer, polyvinylidene fluoride-hexafluoropropylene copolymer, and polyvinylidene fluoride-chlorotrifluoroethylene copolymer.

[0017] Preferably, the polyvinylidene fluoride resin is a polyvinylidene fluoride homopolymer.

[0018] Furthermore, the carboxylated nitrile rubber is a nitrile rubber having a carboxyl mass content of 0.01%-5%, and the carboxyl mass content is preferably 0.01%-1%.

[0019] Furthermore, the compatibilizer is a methyl methacrylate-glycidyl methacrylate copolymer, which is formed by copolymerization of methyl methacrylate (MMA) and glycidyl methacrylate (GMA) active monomers, and has a molecular weight of preferably 5000-20000Da.

[0020] Preferably, the compatibilizer is a methyl methacrylate-glycidyl methacrylate copolymer having a molar content of glycidyl methacrylate structural units of 1% to 8%.

[0021] Furthermore, the vulcanizing agent is peroxide, sulfur, a sulfur-containing compound or a phenolic resin.

[0022] Preferably, the peroxide is selected from at least one of peroxydibenzoic acid, diisopropylbenzene peroxide, di-tert-butyl peroxide, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; the sulfur-containing compound is selected from at least one of tetramethylthiuram disulfide, dipentamethylenethiuram tetrasulfide, 4-(2-benzothiazolyldithio)morpholine, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, and tetramethylthiuram tetrasulfide; and the phenolic resin is selected from at least one of p-tert-butylphenol formaldehyde resin, octylphenolformaldehyde vulcanized resin, and halogenated octylphenolformaldehyde vulcanized resin.

[0023] More preferably, the vulcanizing agent is dicumyl peroxide.

[0024] The present invention also provides a method for preparing the carboxylated nitrile rubber toughened polyvinylidene fluoride composite material, comprising the following steps:

[0025] (1) Mixing polyvinylidene fluoride resin, carboxylated nitrile rubber and compatibilizer, or mixing polyvinylidene fluoride resin, carboxylated nitrile rubber, compatibilizer and vulcanizing agent in proportion to obtain a mixture;

[0026] (2) Melting and processing the mixture by a twin-screw extruder, with the screw speed of the twin-screw extruder being 100 - 400 rpm and the processing temperature of each zone being 140 - 280 °C, and forming the carboxylated nitrile rubber toughened polyvinylidene fluoride composite material by extrusion or injection molding process.

[0027] Aiming at the problem that the carboxylated nitrile rubber raw material is in large pieces and is extremely easy to adhere into large pieces after being chopped, which affects the stability of the material during the twin-screw extrusion process, preferably, in step (1), after dividing the polyvinylidene fluoride resin into the first part of polyvinylidene fluoride resin and the second part of polyvinylidene fluoride resin, the carboxylated nitrile rubber and the first part of polyvinylidene fluoride resin are intensively mixed to obtain a toughened masterbatch, and the toughened masterbatch, the second part of polyvinylidene fluoride resin and the compatibilizer, or the toughened masterbatch, the second part of polyvinylidene fluoride resin, the compatibilizer and the vulcanizing agent are mixed evenly to obtain a mixture.

[0028] Preferably, the screw speed of the twin-screw extruder is 200 - 400 rpm.

[0029] Preferably, the processing temperature of each zone of the twin-screw extruder is ±40 °C of the melting point of polyvinylidene fluoride, and more preferably 160 - 240 °C.

[0030] The inventor found in the experiment that the carboxylated nitrile rubber / polyvinylidene fluoride composite material compatibilized by methyl methacrylate-glycidyl methacrylate copolymer has stable production during the twin-screw extrusion water-cooled strand pelletizing process, emits less odor during the production process, has small fluctuations in the test results of the mechanical properties of the sample bars, and has higher melt stability in the processing equipment. This may be because the methyl methacrylate-glycidyl methacrylate copolymer with a number-average molecular weight of 5000 - 20000 Da has both good melt flow and thermal stability and no small molecule residues, and is very suitable for the carboxylated nitrile rubber toughened polyvinylidene fluoride composite material system with a processing temperature > 220 °C. In addition, the methyl methacrylate-glycidyl methacrylate copolymer has good compatibility with polyvinylidene fluoride, and its epoxy group can react with carboxylated nitrile rubber, which can better reduce the interfacial tension between the two phases of polyvinylidene fluoride and carboxylated nitrile rubber, thereby improving the melt uniformity and processing stability of the carboxylated nitrile rubber toughened polyvinylidene fluoride composite material.

[0031] The present invention also provides the application of the carboxylated nitrile rubber toughened polyvinylidene fluoride composite material in the field of new energy or flexible electronic devices, and it can be used as a separator or binder for new energy batteries, etc.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] (1) The present invention uses a methyl methacrylate-glycidyl methacrylate copolymer to compatibilize the polyvinylidene fluoride / carboxylated nitrile rubber composite material, improves the compatibility between the two, reduces the particle size of the rubber dispersed phase, and enhances the interfacial interaction strength between the two phases, thereby improving the tensile strength and elongation at break of the composite material.

[0034] (2) The present invention further uses a dynamic vulcanization process to regulate the phase morphology of the methyl methacrylate-glycidyl methacrylate copolymer compatibilized polyvinylidene fluoride / carboxylated nitrile rubber composite material, and synergistically improves the comprehensive performance of the carboxylated nitrile rubber toughened polyvinylidene fluoride composite material through the compatibilization and dynamic vulcanization processes. Description of the Drawings

[0035] Figure 1 SEM image of the cross-section of the sample of Comparative Example 1 after cryogenic fracture with liquid nitrogen and etching with tetrahydrofuran;

[0036] Figure 2 SEM image of the cross-section of the sample of Example 2 after cryogenic fracture with liquid nitrogen and etching with tetrahydrofuran;

[0037] Figure 3 SEM image of the cross-section of the sample of Example 9 after cryogenic fracture with liquid nitrogen and etching with tetrahydrofuran;

[0038] Figure 4 TEM image of the sample of Example 2 taken after cryosectioning and osmium tetroxide staining;

[0039] Figure 5 TEM image of the sample of Example 9 taken after cryosectioning and osmium tetroxide staining. Detailed Embodiments

[0040] The present invention will be further illustrated below with reference to the embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0041] The information of the raw materials involved in the comparative examples and embodiments of the present invention is as follows:

[0042] Polyvinylidene fluoride (PVDF) was purchased from Zhejiang Fluorocarbon Co., Ltd., and the grade was FL2008.

[0043] Carboxylated nitrile rubber (XNBR) was purchased from Zeon Corporation of Japan, and the commercial model was 1072CGX is a copolymer composed of butadiene and acrylonitrile (with a content of about 27%), having medium oil resistance, and its molecular chain contains 0.07 - 0.08% (mass content) of carboxyl functional groups.

[0044] Table 1. Main performance parameters of the PMG compatibilizer involved in the examples

[0045]

[0046] The methyl methacrylate - glycidyl methacrylate copolymer (PMG) compatibilizer was prepared with reference to the method of Patent CN117024641A, a copolymerization type compatibilizer and its green synthesis method. Using molten caprolactam (CL) as the reaction solvent, it was prepared by free radical copolymerization. The specific synthesis steps are as follows:

[0047] (1) Add 800 g of pre - dehydrated CL solvent, 200 g of MMA / GMA monomer mixture, 4.4 g of azobisisobutyronitrile (AIBN) initiator, and 2 g of dodecyl mercaptan chain transfer agent into a 1 - liter glass reaction kettle (equipped with a mechanical stirrer with a rotation speed set at 100 rpm) in sequence. Continuously introduce nitrogen into the reaction system (flow rate 0.5 L / min), control the reaction temperature at 80 °C, and continuously stir and react for 12 hours.

[0048] (2) Pour the obtained polymer / CL solution into a polyethylene film bag and let it stand at room temperature to solidify into a milky white block. Crush the solidified mixture into particles with a size less than 1 cm, and then use a high - speed mixer (Pribolab, 1 - liter capacity) to wash three times with distilled water according to a solid - liquid mass ratio of 1:5 (10 minutes each time), and then transfer it to a mechanical stirring round - bottom flask (rotation speed 200 rpm) and wash once with 60 °C hot ethanol according to a solid - liquid mass ratio of 1:3 (for 2 hours).

[0049] (3) Collect the washed powder product, place it in a vacuum oven and dry it at 60 °C for 12 hours to obtain the PMG copolymer. The naming rules for the synthesized products are as follows: PMG - 1, PMG - 2, PMG - 4, and PMG - 8 respectively correspond to MMA - GMA copolymers with a molar fraction of GMA structural units of 1%, 2%, 4%, and 8%. The main performance parameters of the PMG compatibilizer synthesized according to the above method are shown in Table 1.

[0050] The equipment, test instruments, and test conditions involved in the comparative examples and examples of the present invention are as follows:

[0051] The PVDF / XNBR composite particles were prepared by a twin-screw extruder, and the equipment model is Nanjing Ke HK26-40D; the mechanical test specimens were injection-molded by an injection molding machine equipped with an ISO standard size mold, and the equipment model is Haitian PL860; the mechanical properties were tested by a universal testing machine in accordance with the ISO standard, and the equipment model is Shenzhen Sansi UTM4304.

[0052] SEM microphase morphology test and solvent resistance performance evaluation: The product materials prepared in the comparative examples and examples of the present invention were quickly brittle fractured after being frozen in liquid nitrogen for 30 minutes, further etched with tetrahydrofuran for 24 hours and dried at 80 °C for 12 hours, and the cross-section was gold-plated and used for observing the microphase morphology with a scanning electron microscope (SEM). The equipment model is (FESEM, Gemini 300), and the test voltage is 20 kV.

[0053] TEM microphase morphology test: The product materials prepared in the comparative examples and examples of the present invention were cut into ultra-thin slices of 80-100 nm under freezing conditions, and then stained with ruthenium tetroxide for 4 hours. The acceleration voltage during the operation of the transmission electron microscope is 80 kV.

[0054] Comparative Examples 1-2 and Examples 1-10

[0055] Prepare the carboxylated nitrile rubber toughened polyvinylidene fluoride composite material of the example or the modified polyvinylidene fluoride composite material of the comparative example according to the feeding ratio in Table 2;

[0056] Regarding that the carboxylated nitrile rubber raw material is a large piece of rubber, which is extremely easy to adhere into a large piece after being chopped, affecting the stability of the material during the twin-screw extrusion process, in the present invention, after dividing the polyvinylidene fluoride resin (polyvinylidene fluoride homopolymer) into the first part of the polyvinylidene fluoride resin and the second part of the polyvinylidene fluoride resin, the carboxylated nitrile rubber and the first part of the polyvinylidene fluoride resin are mixed evenly by a kneader, then transferred to an open mill to be pressed into sheets, cut into particles with a length less than 2 mm, and prefabricated into XNBR / PVDF toughened masterbatch. The preparation method and process parameters of the carboxylated nitrile rubber toughened polyvinylidene fluoride composite material are as follows: Premix the XNBR / PVDF toughened masterbatch, the second part of the polyvinylidene fluoride resin, the PMG compatibilizer prepared in the above steps and the dicumyl peroxide (DCP) powder evenly, and then transfer them to a twin-screw extruder for granulation. The screw speed is set at 300 rpm, and the barrel temperature is set at 170 °C, 180 °C, 185 °C, 190 °C, 200 °C in sequence from the feed inlet to the die. The extruded pellets are the carboxylated nitrile rubber toughened polyvinylidene fluoride composite material. After drying, it is molded into a specimen meeting the ISO test standard by an injection molding machine. The injection molding processing temperature is set at 180 °C, 190 °C, 190 °C, 200 °C respectively from the hopper to the nozzle. Then, the tensile strength and elongation at break of the prepared sample are tested according to the ISO 527 standard.

[0057] Table 2. Mass formula and mechanical properties of comparative examples 1-2 and examples 1-10

[0058]

[0059] Examples 1-4 of the present invention demonstrate the compatibilization effect of PMG with different molar contents of GMA structural units on carboxylated nitrile rubber toughened polyvinylidene fluoride composite materials, and their average elongation at break are 235.0%, 252.5%, 213.0% and 150.0%, respectively, which are significantly higher than 29.7% of Comparative Example 1 (uncompatibilized and unvulcanized), indicating that PMG compatibilizers with a molar content of 1-8% of GMA structural units can effectively improve the compatibility of PVDF and XNBR, wherein the sample of Example 2 is a PMG-2 compatibilizer with a molar content of 2% of GMA structural units added, and its tensile strength (20.9MPa) and elongation at break (252.5%) are the largest. At the same time, in order to compare with Examples 1-4, a control experiment of PMMA is also performed, and the PMG compatibilizer in Examples 1-4 is replaced by PMMA of the same mass. The results show that its tensile strength is 15.2MPa and its elongation at break is 84.8%, which is significantly worse than that of Examples 1-4.

[0060] The samples of Comparative Example 1 and Example 2 were further subjected to liquid nitrogen brittle fracture and tetrahydrofuran etching and then SEM morphology observation was performed. The results are as follows: Figure 1 , Figure 2 As shown. Tetrahydrofuran is a good solvent for XNBR. Figure 1 and Figure 2 The large number of "holes" left behind reflect the morphology and dispersion of the XNBR dispersed phase. The results show that the diameter of the "holes" of the sample of Example 2 after PMG-2 compatibilization is smaller and the hole edges are more blurred, indicating that the compatibilizer can indeed effectively refine and stabilize the XNBR dispersed phase, which is conducive to the smooth transmission of stress and thus shows a higher elongation at break. In addition, Example 2 is significantly better than Comparative Example 1 in terms of the stability of the extrusion granulation process (few broken strips during water-cooled drawing) and the appearance finish of the injection molded strips. These beneficial effects are all attributed to the better microscopic phase distribution brought by the PMG compatibilizer.

[0061] Examples 5-7 of the present invention demonstrate the compatibilization effects of different addition ratios of PMG-2 compatibilizer on the toughened polyvinylidene fluoride composites with carboxylated nitrile rubber. The average elongation at break values are 158.3%, 202.0% and 236.7% respectively, all higher than 29.67% of Comparative Example 1 (uncompatibilized and unvulcanized). This indicates that the PMG compatibilizer, especially PMG-2 compatibilizer, can effectively improve the compatibility between PVDF and XNBR within the corresponding addition ranges. It is worth mentioning that although the elongation at break of Example 7 with 21% PMG-2 added is slightly higher than that of Example 2, its tensile strength is relatively low. Moreover, the structure of PMG-2 is close to that of pure PMMA resin, and the addition of PMG compatibilizer should not be excessive.

[0062] Examples 8-9 of the present invention demonstrate the effect of further adding curing agent DCP for dynamic crosslinking based on the optimal formulation system of 14% PMG-2 compatibilized carboxylated nitrile rubber / polyvinylidene fluoride. Among them, the tensile strength of the sample in Example 9 increased to 21.4 MPa, and the elongation at break decreased but still remained at a relatively high level of 192.2%. This result shows that the dynamic vulcanization process and PMG compatibilization technology can synergistically improve the tensile strength of the toughened polyvinylidene fluoride composites with carboxylated nitrile rubber.

[0063] Furthermore, the samples of Example 2 (compatibilization scheme) and Example 9 (compatibilization + vulcanization synergistic scheme) were cryosectioned and stained with osmium tetroxide, and then subjected to microscopic phase morphology analysis by TEM. The results are shown in Figure 4 and Figure 5 respectively. In the TEM images, the dark phase is the PVDF phase, and the light phase is the XNBR phase. In Example 2, the XNBR did not form a quasi-spherical "island" phase with a regular morphology, while in Example 9, after dynamic vulcanization, the XNBR basically all formed "island" phases with relatively smaller particle sizes. This is because the viscosity of the vulcanized XNBR rubber particles increases sharply (even completely crosslinked, losing the ability of viscous flow) and is more inclined to be the dispersed phase, distributed in the "sea" phase of the low-viscosity PVDF. According to the common knowledge of those skilled in the art, it can be speculated that in the molten state of the sample in Example 9, the crosslinked XNBR rubber particles are less likely to fuse and become larger under low shear, nor will they disperse and become smaller under high shear, and will have better processing stability (the microscopic morphology and physical properties are less affected by processing parameters). This property has certain application advantages in the field of flexible electronic devices with stable performance and high molding accuracy.

[0064] In addition, the applicant observed the SEM morphology of the sample in Example 9 after being brittle fractured by liquid nitrogen and etched with tetrahydrofuran. The results are shown in Figure 3 respectively. Tetrahydrofuran is a good solvent for XNBR. The SEM image of the sample in Example 9 is different from that of the sample in Example 2 ( Figure 2), and its etched cross-section has no obvious holes, indicating that the XNBR phase in the sample of Example 9 is not dissolved in the tetrahydrofuran solvent. This is attributed to the fact that the XNBR dispersed phase forms a three-dimensional cross-linked network after being dynamically vulcanized by DCP, and a higher cross-linking density can effectively resist the dissolution and destruction of organic solvents. This result shows that on the basis of PMG compatibilization, the dynamic vulcanization process can improve the solvent resistance of carboxylated nitrile rubber toughened polyvinylidene fluoride composites, which is crucial for new energy battery binders and separator materials that are long and in contact with complex component electrolytes.

[0065] The above-described embodiments have detailed the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and do not limit the present invention. Any modification, supplement, or substitution in a similar manner within the principle scope of the present invention shall be included within the protection scope of the present invention.

Claims

1. A carboxylated nitrile rubber toughened polyvinylidene fluoride composite material, characterized in that, By weight parts, it comprises the following components: The compatibilizer is a methyl methacrylate copolymer containing reactive functional groups, and the reactive functional groups are at least one of epoxy group, amino group, and hydroxyl group. The molecular weight of the compatibilizer is 2000-100000Da.

2. The carboxylated nitrile rubber toughened polyvinylidene fluoride composite material according to claim 1, characterized in that, The carboxylated nitrile rubber toughened polyvinylidene fluoride composite material, by weight parts, comprises the following components:

3. The carboxylated nitrile rubber toughened polyvinylidene fluoride composite material according to claim 1 or 2, characterized in that The polyvinylidene fluoride resin is selected from at least one of polyvinylidene fluoride homopolymer, polyvinylidene fluoride-hexafluoropropylene copolymer, and vinylidene fluoride-trifluorochloroethylene copolymer.

4. The carboxylated nitrile rubber toughened polyvinylidene fluoride composite material according to claim 1 or 2, characterized in that, The carboxylated nitrile rubber is a nitrile rubber with a carboxyl mass content of 0.01%-5%.

5. The carboxylated nitrile rubber toughened polyvinylidene fluoride composite material according to claim 1 or 2, wherein The compatibilizer is a methyl methacrylate-glycidyl methacrylate copolymer with a molecular weight of 5000-20000Da.

6. The carboxylated nitrile rubber toughened polyvinylidene fluoride composite material according to claim 1 or 2, characterized in that, The vulcanizing agent is peroxide, sulfur, sulfur-containing compound, or phenolic resin.

7. The carboxylated nitrile rubber toughened polyvinylidene fluoride composite material according to claim 6, wherein The peroxide is selected from at least one of diperoxybenzoic acid, dicumyl peroxide, di-tert-butyl peroxide, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; The sulfur-containing compound is selected from at least one of tetramethylthiuram disulfide, tetraethylthiuram disulfide, 4-(2-benzothiazolyldithio)morpholine, tetrabutylthiuram disulfide, and tetramethylthiuram tetrasulfide; The phenolic resin is selected from at least one of p-tert-butylphenol formaldehyde resin, octylphenol formaldehyde curing resin, and halogenated octylphenol formaldehyde curing resin.

8. The preparation method of the carboxylated nitrile rubber toughened polyvinylidene fluoride composite material according to claim 1 or 2, characterized in that, It comprises the following steps: (1) Mix the polyvinylidene fluoride resin, carboxylated nitrile rubber, and compatibilizer, or mix the polyvinylidene fluoride resin, carboxylated nitrile rubber, compatibilizer, and vulcanizing agent evenly according to the ratio to obtain a mixture; (2) Use a twin-screw extruder to melt-process the mixture. The screw speed of the twin-screw extruder is 100-400rpm, and the processing temperature of each zone is 140-280°C. The carboxylated nitrile rubber toughened polyvinylidene fluoride composite material is prepared by extrusion or injection molding.

9. The preparation method of the carboxylated nitrile rubber toughened polyvinylidene fluoride composite material according to claim 8, characterized in that, In step (1), after dividing the polyvinylidene fluoride resin into the first part of polyvinylidene fluoride resin and the second part of polyvinylidene fluoride resin, the carboxylated nitrile rubber and the first part of polyvinylidene fluoride resin are kneaded and processed to obtain a toughened masterbatch. The toughened masterbatch, the second part of polyvinylidene fluoride resin, and the compatibilizer, or the toughened masterbatch, the second part of polyvinylidene fluoride resin, the compatibilizer, and the vulcanizing agent are mixed evenly to obtain a mixture.

10. The application of the carboxylated nitrile rubber toughened polyvinylidene fluoride composite material according to claim 1 in the field of new energy or flexible electronic devices.

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