Preparation method of polyisoprene-acrylonitrile / barium titanate material with reversible cross-linked structure

Abstract

The present invention relates to the technical field of functional polymer composites, in particular to a preparation method of a polyisoprene-acrylonitrile / barium titanate material with a reversible crosslinked structure. First, by using the reaction of boric acid groups with diols, the olefin derivatives are respectively reacted with the corresponding organic molecules to synthesize two functional monomers containing dioxaborolane groups. Secondly, the functional monomers, isoprene and acrylonitrile monomers are subjected to emulsion polymerization by initiating through a redox system to prepare an isoprene-acrylonitrile Vitrimer copolymer with a reversible crosslinked structure. Finally, two kinds of barium titanate containing dioxaborolane groups are selected and heat-blended with the isoprene-acrylonitrile Vitrimer copolymer. Compared with the prior art, the composite material involved in the present invention is innovative, which improves the dielectric properties of the material, has a certain self-healing function, and the synthesis process is simple to implement and requires relatively low reaction conditions, which is very conducive to the industrialization of the product.

Description

Technical Field

[0001] The present invention relates to the technical field of functional polymer composites, and particularly to a polyisoprene-acrylonitrile / barium titanate material with a reversible crosslinked structure. Background Art

[0002] Dielectric materials are insulating materials with excellent dielectric properties. To meet the requirements of miniaturization and flexibility of the new generation of energy storage devices, people combine the advantages of ceramic inorganic materials and polymer organic materials, and use composite means to obtain dielectric flexible composites that not only have high dielectric properties but also have good processability.

[0003] High dielectric ceramic-polymer-based dielectric flexible composites use high dielectric ceramic particles as fillers, and utilize the high dielectric constant of the dielectric ceramic itself and the good processability and organic compatibility of the polymer to obtain composites with a relatively high dielectric constant. There have been a large number of research reports on the dielectric properties and flexibility of this material, mainly focusing on the research of dielectric elastic matrices, filling particles, and composite and modification methods. After a large number of studies, it has also been found that increasing the amount of dielectric ceramic particles can effectively improve the dielectric properties of flexible composites, but a high filling amount will significantly reduce the flexibility and other functions of the material, and even cause the material to crack and break directly. Therefore, strengthening the interaction between inorganic particles and polymers as much as possible to achieve full "compatibility" at the molecular level is the key to solving the above problems.

[0004] In recent years, a class of "supramolecular" materials called "Vitrimers" has emerged in polymers. Due to its multiple response modes and multiple functions such as self-healing, intelligent response, and shape memory, it has now become one of the international research hotspots. Vitrimer materials are essentially a class of dynamic crosslinked polymers with special molecular structures, and the chemical bonds between their molecular chains are not fixed but in a dynamic equilibrium. et al. reported a preparation method of a Vitrimer material containing dioxaborolane groups in the Science journal, modified a polymer with a C-C backbone into a Vitrimer material with a dynamic crosslinked structure, and realized the technological innovation of transforming common C-C backbone plastics into Vitrimer materials with unique functions.

[0005] Currently, Vitrimer materials based on different reversible groups have been continuously developed, and the reports on the excellent mechanical properties, rheological properties, and self-healing properties of such materials have also increased significantly. However, the research on filled Vitrimer-type composites is basically blank, which is mainly due to the need for corresponding crosslinked structures between fillers and polymers. Therefore, carrying out research in this field is of pioneering significance and is urgent.

[0006] In summary, although there are many polymer / barium titanate composites on the market, there are still the following deficiencies:

[0007] (1) By modifying the surface of filler particles with common organic substances such as coupling agents, the modified barium titanate prepared usually cannot form a chemical bonding interaction with polymer molecular chains, resulting in insufficient adhesion between barium titanate and the matrix and affecting the comprehensive properties of the composite material.

[0008] (2) Traditional cross-linked composites, due to irreversible cross-linking, once a cross-linked structure is formed in the polymer and filler system, they do not have reprocessability. Compared with Vitrimer materials with a dynamic cross-linked structure, they lack the structural basis for material functionalization.

[0009] Therefore, we provide a polyisoprene-acrylonitrile / barium titanate material with a reversible cross-linked structure to solve this problem. Summary of the Invention

[0010] The object of the present invention is to solve the disadvantages existing in the prior art, and to propose an innovative composite material, which can improve the dielectric properties of the material, has a certain self-healing function, and has the advantages of simple synthesis process implementation, low reaction condition requirements, and is very conducive to realizing the industrialization of products. A polyisoprene-acrylonitrile / barium titanate material with a reversible cross-linked structure is used to solve this problem.

[0011] To achieve the above object, the present invention adopts the following technical solutions:

[0012] Design a polyisoprene-acrylonitrile / barium titanate material with a reversible cross-linked structure,

[0013] A preparation method of a polyisoprene-acrylonitrile / barium titanate material with a reversible cross-linked structure, which is characterized in that it specifically includes the following steps:

[0014] S1. First, by using the reaction of boronic acid groups with diols, the olefin derivatives (3-allyloxy-1,2-propanediol and 4-vinylphenylboronic acid) are respectively reacted with the corresponding organic molecules (phenylboronic acid and 1,2-propanediol) to synthesize two functional monomers containing dioxaborolane groups (monomer A and monomer B);

[0015] S2. Secondly, the functional monomers, isoprene and acrylonitrile monomers are subjected to emulsion polymerization by an oxidation-reduction system to prepare an isoprene-acrylonitrile Vitrimer copolymer with a reversible cross-linked structure;

[0016] S3. Finally, two kinds of barium titanates containing dioxaborolane groups and isoprene-acrylonitrile Vitrimer copolymer are selected and heated and blended to prepare a polyisoprene-acrylonitrile / barium titanate composite material with a reversible cross-linked structure.

[0017] Furthermore, in S1 when preparing monomer A, 3-allyloxy-1,2-propanediol, phenylboronic acid, anhydrous magnesium sulfate and tetrahydrofuran are mixed according to a mass ratio of 1:(0.5-2):(2-5):(7-30), and the reaction temperature is room temperature, and the stirring time is 3-8 h.

[0018] Furthermore, in S1 when preparing monomer B, 4-vinylphenylboronic acid, 1,2-propanediol, anhydrous magnesium sulfate and tetrahydrofuran are mixed according to a mass ratio of 1:(1-3):(2-5):(7-30), and the reaction temperature is room temperature, and the stirring time is 3-8 h.

[0019] Furthermore, when preparing the isoprene-acrylonitrile Vitrimer copolymer in S2, isoprene, acrylonitrile, monomer A, monomer B, deionized water, sodium dodecylbenzenesulfonate, potassium oleate, tert-dodecyl mercaptan, ferrous sulfate heptahydrate, sodium ethylenediaminetetraacetate, and sodium formaldehyde sulfoxylate are mixed evenly according to a mass ratio of 1:(0.5-1.5):(0.5-1.5):(0.5-1.5):(5-8):(0.08-0.15):(0.05-0.1):(0.03-0.05):(0.01-0.02):(0.1-0.2):(0.2-0.5).

[0020] Furthermore, when preparing the isoprene-acrylonitrile Vitrimer copolymer in S2, after mixing isoprene, acrylonitrile, monomer A, monomer B, deionized water, sodium dodecylbenzenesulfonate, potassium oleate, tert-dodecyl mercaptan, ferrous sulfate heptahydrate, sodium ethylenediaminetetraacetate, and sodium formaldehyde sulfoxylate evenly, 0.01-0.03 of cumene hydroperoxide is added to the polymerization kettle under nitrogen protection.

[0021] Furthermore, when preparing the isoprene-acrylonitrile Vitrimer copolymer in S2, the reaction temperature in the polymerization kettle is 5 °C, and the reaction time is 5-8 h.

[0022] Furthermore, when preparing the polyisoprene-acrylonitrile / barium titanate composite material in S3, two kinds of barium titanates containing dioxaborolane groups are evenly mixed according to a mass ratio of 1:(0.8-1.2), and added to the isoprene-acrylonitrile Vitrimer copolymer at 110-130 °C for mixing reaction.

[0023] The beneficial effects of a polyisoprene-acrylonitrile / barium titanate material with a reversible cross-linked structure proposed by the present invention are as follows:

[0024] 1. The polyisoprene-acrylonitrile / barium titanate composite material with a reversible cross-linked structure involved in the present invention is innovative. It has a certain temperature response itself, can form a dynamic cross-linked structure at about 70 - 80 °C, significantly improves the compatibility between barium titanate particles and the polymer matrix, increases the interfacial adhesion force, improves the dielectric properties of the material, and has a certain self-healing function. In addition, the polyisoprene-acrylonitrile / barium titanate composite material with this reversible cross-linked structure fills the gap of filled Vitrimer-type composite materials at home and abroad;

[0025] 2. In terms of the method and process, the present invention first uses a method of introducing dioxaborolane groups into monomers by reacting specific olefin monomers with organic molecules. The principle is clear and the method is original. The raw materials used, such as 3-allyloxy-1,2-propanediol and phenylboronic acid, etc., are relatively inexpensive, the synthesis process is simple to implement, and the reaction conditions require less, which is very conducive to the industrialization of products. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the preparation process of the polyisoprene-acrylonitrile / barium titanate composite material with a reversible cross-linked structure proposed by the present invention;

[0027] Figure 2 It is an infrared spectrum diagram of two monomers containing dioxaborolane groups and their synthesis raw materials proposed by the present invention;

[0028] Figure 3 It is an infrared spectrum diagram of the polyisoprene-acrylonitrile / barium titanate composite material and its synthesis raw materials proposed by the present invention;

[0029] Figure 4 It is a thermogravimetric curve of the isoprene-acrylonitrile Vitrimer copolymer and the polyisoprene-acrylonitrile / barium titanate composite material proposed by the present invention;

[0030] Figure 5 It is a scanning electron microscope image of the isoprene-acrylonitrile Vitrimer copolymer (a, ×5K times; d, ×10K times), the polyisoprene-acrylonitrile / barium titanate composite material (b, ×5K times; e, ×10K), and two pieces of composite materials after hot pressing for 3 h (c, surface ×10 times; f, cross-section ×50 times) proposed by the present invention;

[0031] Figure 6 It is a curve of the dielectric constant (a) and dielectric loss (b) of the isoprene-acrylonitrile Vitrimer copolymer and the polyisoprene-acrylonitrile / barium titanate composite material proposed by the present invention at different frequencies;

[0032] Figure 7The storage modulus-frequency curve (a) and loss angle-frequency curve (b) of the isoprene-acrylonitrile Vitrimer copolymer and polyisoprene-acrylonitrile / barium titanate composite material proposed by the present invention. Detailed implementation manners

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0034] Example 1

[0035] In this example, 3-allyloxy-1,2-propanediol (≥99%), phenylboronic acid (≥98%), 1,2-propanediol (≥99%), anhydrous magnesium sulfate (≥98%), tetrahydrofuran (≥99.9%), n-heptane (≥98%), 4-vinylphenylboronic acid (≥95%), isoprene (≥99%), acrylonitrile (≥99%), sodium dodecylbenzenesulfonate (≥95%), potassium oleate (≥87%), tert-dodecyl mercaptan (≥98.5%), ferrous sulfate heptahydrate (≥99.9%), sodium ethylenediaminetetraacetate (98%), sodium formaldehyde sulfoxylate (≥95%) and cumene hydroperoxide (≥97%) were all purchased from Sigma-Aldrich Chemical Technology (Shanghai) Co., Ltd. Two barium titanates containing dioxaborolane groups were prepared according to the method in Patent ZL202110646175.X.

[0036] As Figure 1 shown, in this example, a polyisoprene-acrylonitrile / barium titanate composite material with a reversible cross-linked structure was prepared by a three-step method. First, by using the reaction of boronic acid groups with diols, the olefin derivatives (3-allyloxy-1,2-propanediol and 4-vinylphenylboronic acid) were respectively reacted with the corresponding organic molecules (phenylboronic acid and 1,2-propanediol) to synthesize two functional monomers containing dioxaborolane groups (Monomer A and Monomer B). Secondly, the functional monomers, isoprene and acrylonitrile monomers were subjected to emulsion polymerization by initiating with a redox system to prepare an isoprene-acrylonitrile Vitrimer copolymer with a reversible cross-linked structure. Finally, two barium titanates containing dioxaborolane groups were selected and heat-blended with the isoprene-acrylonitrile Vitrimer copolymer to prepare a polyisoprene-acrylonitrile / barium titanate composite material with a reversible cross-linked structure.

[0037] The specific preparation method is as follows:

[0038] I. Preparation of two monomers containing dioxaborolane groups:

[0039] Monomer A: Mix 3-allyloxy-1,2-propanediol (10 ml), phenylboronic acid (10 g), anhydrous magnesium sulfate (30 g) and tetrahydrofuran (100 ml), and stir at room temperature for 6 h. Then filter and concentrate under reduced pressure using a rotary evaporator. Pour the concentrated solution into 100 ml of n-heptane at room temperature, stir, and let stand for 30 min. Filter and concentrate under reduced pressure to obtain a colorless oil, denoted as monomer-A.

[0040] Monomer B: Mix 4-vinylphenylboronic acid (10 g), 1,2-propanediol (20 ml), anhydrous magnesium sulfate (30 g) and tetrahydrofuran (100 ml), and stir at room temperature for 6 h. Then filter and concentrate under reduced pressure using a rotary evaporator. Pour the suspension into 100 ml of n-heptane at room temperature, stir, and let stand for 30 min. Filter and concentrate under reduced pressure to obtain a colorless oil, denoted as monomer-B.

[0041] II. Preparation of polyisoprene-acrylonitrile Vitrimer copolymer containing dioxaborolane groups:

[0042] Isoprene (7 ml), acrylonitrile (6 ml), monomer-A (6 ml) and monomer-B (6 ml), deionized water (40 mg), sodium dodecylbenzenesulfonate (0.75 g), potassium oleate (0.5 g), tert-dodecyl mercaptan (0.25 g), ferrous sulfate heptahydrate (0.1 g), sodium ethylenediaminetetraacetate (1 g), sodium formaldehyde sulfoxylate (2.1 g). Under nitrogen protection, add cumene hydroperoxide (0.125 ml) to a 250 ml polymerization kettle, and then react at 5 °C for 7 h. After degassing, coagulation, washing and drying, a polyisoprene-acrylonitrile Vitrimer copolymer containing dioxaborolane groups is obtained.

[0043] III. Preparation of polyisoprene-acrylonitrile / barium titanate composite material: According to the principle of dioxaborolane metathesis, mix two kinds of barium titanate containing dioxaborolane groups in a mass ratio of 1:1 uniformly, and react at 85 °C for 2 h to obtain reversibly crosslinked barium titanate. Then, add it to the polyisoprene-acrylonitrile Vitrimer copolymer containing dioxaborolane groups at 120 °C, mix evenly, and prepare a polyisoprene-acrylonitrile / barium titanate composite material with a content of 10 wt%.

[0044] The two synthesized monomers and the polyisoprene-acrylonitrile / barium titanate composite material were characterized by infrared spectroscopy. Tested with a Nicolet Avatar 370 Fourier transform infrared spectrometer in the United States, the resolution is 2 cm -1 , the number of scans is 32 times, and their infrared curves are respectively as Figure 2 and Figure 3 shown, which confirmed the formation of the monomers containing dioxaborolane groups and the polyisoprene-acrylonitrile / barium titanate composite material.

[0045] The above-mentioned polyisoprene-acrylonitrile Vitrimer copolymer and isoprene-acrylonitrile / barium titanate composite material were characterized by thermogravimetric analysis. The test was carried out using a TGA55 thermogravimetric analyzer from TA Instruments, USA. The initial temperature was 30 °C, and the temperature was raised to 600 °C at a heating rate of 10 °C / min. The thermogravimetric curves of both are as Figure 4 shown. The results show that the addition of modified barium titanate has little effect on the thermal stability of the isoprene-acrylonitrile Vitrimer copolymer.

[0046] The surface morphologies of the above-mentioned polyisoprene-acrylonitrile Vitrimer copolymer and isoprene-acrylonitrile / barium titanate composite material were analyzed by scanning electron microscopy. After drying the sample, gold was sprayed. The gold spraying current was 5-6 mA, and the gold spraying time was 30 s. The scanning electron micrograph of the surface of barium titanate was observed using a Zeiss SIGMA300 field emission scanning electron microscope, as Figure 5 shown. The results show that the isoprene-acrylonitrile / barium titanate composite material has a dynamic cross-linked structure, and the composite material has a certain self-healing function at a certain temperature.

[0047] The dielectric properties of the above-mentioned polyisoprene-acrylonitrile Vitrimer copolymer and isoprene-acrylonitrile / barium titanate composite material were tested. At room temperature, the sample was analyzed and tested using an Agilent 4294A impedance analyzer from Agilent Technologies. The test frequency was 2×10 2 -10 7 Hz. The frequency-dielectric constant and frequency-dielectric loss curves of the material are as Figure 6 shown.

[0048] The above-mentioned polyisoprene-acrylonitrile Vitrimer copolymer and isoprene-acrylonitrile / barium titanate composite material were subjected to dynamic mechanical analysis (DMA). The test was carried out using a TA Q800 type DMA instrument produced by TA Instruments, USA. The tensile mode was adopted. The temperature scanning test conditions were: temperature range -110-150 °C, frequency 5 Hz, heating rate 5 °C / min. The storage modulus-frequency curve and loss angle-frequency curve are as Figure 7 shown.

[0049] Through infrared spectrum analysis, the characteristic absorption peaks of the two synthesized monomers and the isoprene-acrylonitrile / barium titanate composite material were compared, as Figure 2 and Figure 3 shown. It can be seen from Figure 2 that monomer A shows an absorption peak corresponding to the B-O stretching vibration in dioxaborane at 1306 cm -1 -1, similar to phenylboronic acid, and at 2856 cm -1A characteristic absorption peak of C-H in the methylene group was also shown at this position, similar to 3-allyloxy-1,2-propanediol, confirming the formation of monomer A containing a dioxaborolane group. Monomer B was prepared from 4-vinylphenylboronic acid and 1,2-propanediol. Infrared spectra of monomer B and 4-vinylphenylboronic acid both showed an absorption peak corresponding to the B-O stretching vibration in dioxaborolane at 1306 cm -1 An absorption peak corresponding to the B-O stretching vibration in dioxaborolane appeared at this position. In addition, monomer B showed two characteristic absorption peaks at 2964 cm -1 and 2873 cm -1 These are attributed to the C-H stretching vibration in the methyl group, confirming the formation of monomer B containing a dioxaborolane group.

[0050] The infrared spectra of two modified barium titanates (BT-A and BT-B), isoprene-acrylonitrile Vitrimer copolymer (Ploy(IP-co-AN)), and polyisoprene-acrylonitrile / barium titanate composite (Ploy(IP-co-AN) / BT) are as Figure 3 shown. Both Ploy(IP-co-AN) and Ploy(IP-co-AN) / BT showed a characteristic absorption peak of the C=C bond at 1631 cm -1 In addition, it can be seen that Figure 3 all samples showed an absorption peak of the B-O stretching vibration in the dioxaborolane group at 1306 cm -1 This proves the presence of the dioxaborolane group in the modified barium titanate, isoprene-acrylonitrile Vitrimer copolymer, and polyisoprene-acrylonitrile / barium titanate composite.

[0051] Through thermogravimetric analysis, the thermogravimetric curves of the isoprene-acrylonitrile Vitrimer copolymer (Ploy(IP-co-AN)) and the polyisoprene-acrylonitrile / barium titanate composite (Ploy(IP-co-AN) / BT) were studied comparatively. As Figure 4 shown, it can be seen from the figure that the isoprene-acrylonitrile Vitrimer copolymer and the polyisoprene-acrylonitrile / barium titanate composite showed similar thermogravimetric curves below 200 °C, and the initial decomposition temperature was around 123 °C, indicating that the addition of the modified barium titanate had little effect on the thermal stability of the isoprene-acrylonitrile Vitrimer copolymer.

[0052] To study the morphology of the crosslinked structure of the polyisoprene-acrylonitrile / barium titanate composite, the surface morphology characteristics of different barium titanates were observed by scanning electron microscopy in this invention. As Figure 5 shown, as Figure 5 seen in a and 5d, the surface of the polyisoprene-acrylonitrile / barium titanate composite was smooth and flat. As Figure 5As can be seen from Fig. 5d, the surface of the polyisoprene-acrylonitrile / barium titanate composite material is relatively smooth, with particles evenly distributed on the surface and no agglomeration phenomenon, indicating that the modified barium titanate has good compatibility with the matrix and good dispersibility.

[0053] To further study the dynamic cross-linking structure of the polyisoprene-acrylonitrile / barium titanate composite material, two pieces of the composite material were hot-pressed at 80 °C for 3 h and then observed by SEM, as Figure 5 shown in Fig. 5c and 5f. It can be seen from the figure that after 3 h of hot pressing, from the surface observation, the edges of the two materials are still visible, but from the cross-section of the two materials, the contact surfaces in the middle part of the two materials have adhered together and the interface is relatively blurred, indicating that the polyisoprene-acrylonitrile / barium titanate composite material has a dynamic cross-linking structure and the composite material has a certain self-healing function at a certain temperature.

[0054] To study the change of the dielectric properties of the material, the dielectric constant and dielectric loss curves of the isoprene-acrylonitrile Vitrimer copolymer (Ploy(IP-co-AN)) and the polyisoprene-acrylonitrile / barium titanate composite material (Ploy(IP-co-AN) / BT) at different frequencies were compared, as Figure 6 shown. As Figure 5 shown in Fig. 6a, the dielectric constant of the polyisoprene-acrylonitrile / barium titanate composite material is higher than that of the isoprene-acrylonitrile Vitrimer copolymer in the range of 2×10 2 -10 7 Hz. This is attributed to the high dielectric constant of barium titanate itself and the enhancement of the interfacial polarization in the material due to the addition of barium titanate. As Figure 5 shown in Fig. 6b, the dielectric loss of the isoprene-acrylonitrile Vitrimer copolymer decreases with the decrease of frequency in the lower frequency range and increases with the increase of frequency above 6×10 6 Hz, which can be attributed to conductance or relaxation. The dielectric loss of the polyisoprene-acrylonitrile / barium titanate composite material gradually decreases with the increase of frequency.

[0055] To further study the effect of dynamic cross-linking on the dynamic mechanical properties of the material, the dynamic mechanical analysis (DMA) curves of the isoprene-acrylonitrile Vitrimer copolymer (Ploy(IP-co-AN)) and the polyisoprene-acrylonitrile / barium titanate composite material (Ploy(IP-co-AN) / BT) were compared, as Figure 7 shown. As Figure 7 shown in Fig. 7a, the storage modulus M' of the polyisoprene-acrylonitrile / barium titanate composite material is higher than that of the isoprene-acrylonitrile Vitrimer copolymer without the addition of modified barium titanate. This is because the modified barium titanate forms a bonding effect with the copolymer, thus producing an enhancement effect. As Figure 7b It can be seen that the peak value of the loss peak of the polyisoprene-acrylonitrile / barium titanate composite material is smaller and wider, indicating that the addition of modified barium titanate increases the crosslinking degree of the material to a certain extent.

[0056] In summary, by means of the above technical solutions of the present invention, the polyisoprene-acrylonitrile / barium titanate composite material with a reversible crosslinking structure involved in the present invention is innovative. It has a certain temperature response itself, can form a dynamic crosslinking structure at about 70-80 °C. The compatibility between barium titanate particles and the polymer matrix is significantly improved, and the interfacial adhesion force increases, which improves the dielectric properties of the material and has a certain self-healing function. In addition, the polyisoprene-acrylonitrile / barium titanate composite material with a reversible crosslinking structure fills the gap of filled Vitrimer-type composite materials at home and abroad. Moreover, the present invention first uses the method of introducing dioxaborolane groups into monomers by reacting specific olefin monomers with organic molecules. The principle is clear and the method is original. The raw materials used, such as 3-allyloxy-1,2-propanediol and phenylboric acid, etc., are relatively inexpensive, the synthesis process is simple to implement, and the reaction conditions are relatively low, which is very conducive to the industrialization of products.

[0057] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A preparation method of a polyisoprene-acrylonitrile / barium titanate material with a reversible cross-linked structure, characterized in that Specifically, it includes the following steps: S1. By utilizing the reaction between boronic acid groups and diols, the olefin derivatives 3-allyloxy-1,2-propanediol and 4-vinylphenylboronic acid are respectively reacted with the corresponding organic molecules phenylboronic acid and 1,2-propanediol to synthesize monomers A and B containing dioxaborolane groups. When preparing monomer A, 3-allyloxy-1,2-propanediol, phenylboronic acid, anhydrous magnesium sulfate, and tetrahydrofuran are mixed in a mass ratio of 1:(0.5 - 2):(2 - 5):(7 - 30), the reaction temperature is room temperature, and the stirring time is 3 - 8 h. When preparing monomer B, 4-vinylphenylboronic acid, 1,2-propanediol, anhydrous magnesium sulfate, and tetrahydrofuran are mixed in a mass ratio of 1:(1 - 3):(2 - 5):(7 - 30), the reaction temperature is room temperature, and the stirring time is 3 - 8 h. S2. Monomers A, B, isoprene, and acrylonitrile monomers are subjected to emulsion polymerization through an oxidation-reduction system to prepare an isoprene-acrylonitrile Vitrimer copolymer with a reversible cross-linked structure. S3. Two kinds of barium titanate containing dioxaborolane groups are selected and melt-blended with the isoprene-acrylonitrile Vitrimer copolymer through heating to prepare a polyisoprene-acrylonitrile / barium titanate composite material with a reversible cross-linked structure.

2. The polyisoprene-acrylonitrile / barium titanate material with a reversible crosslinked structure according to claim 1, characterized in that, When preparing the isoprene-acrylonitrile Vitrimer copolymer in S2, isoprene, acrylonitrile, monomer A, monomer B, deionized water, sodium dodecylbenzenesulfonate, potassium oleate, tert-dodecyl mercaptan, ferrous sulfate heptahydrate, sodium ethylenediaminetetraacetate, and sodium formaldehyde sulfoxylate are mixed evenly in a mass ratio of 1:(0.5 - 1.5):(0.5 - 1.5):(0.5 - 1.5):(5 - 8):(0.08 - 0.15):(0.05 - 0.1):(0.03 - 0.05):(0.01 - 0.02):(0.1 - 0.2):(0.2 - 0.5).

3. A polyisoprene-acrylonitrile / barium titanate material with a reversible crosslinked structure according to claim 2, characterized in that, When preparing the isoprene-acrylonitrile Vitrimer copolymer in S2, after mixing isoprene, acrylonitrile, monomer A, monomer B, deionized water, sodium dodecylbenzenesulfonate, potassium oleate, tert-dodecyl mercaptan, ferrous sulfate heptahydrate, sodium ethylenediaminetetraacetate, and sodium formaldehyde sulfoxylate evenly, 0.01 - 0.03 of cumene hydroperoxide is added to the polymerization kettle under nitrogen protection.

4. A polyisoprene-acrylonitrile / barium titanate material with a reversible crosslinked structure according to claim 3, characterized in that, When preparing the isoprene-acrylonitrile Vitrimer copolymer in S2, the reaction temperature in the polymerization kettle is 5°C, and the reaction time is 5 - 8 h.

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