PBO fiber, preparation method thereof and PBO fiber composite material
By acid treating PBO fibers and constructing a rigid-flexible copolymer interface layer using LBL technology, the problem of weak interfacial bonding strength between PBO fibers and the resin matrix was solved, significantly improving the mechanical properties and stability of the composite material.
Patent Information
- Application Number
- CN202511607839.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-05
- Publication Date
- 2025-12-19
AI Technical Summary
PBO fibers have a highly chemically inert and smooth surface, resulting in extremely weak interfacial bonding strength with the resin matrix, which limits their reinforcing effect. Furthermore, existing surface coating methods have poor stability and make it difficult to achieve uniform bonding.
By acid treatment of PBO fibers to generate active functional groups, and then using LBL technology to construct a rigid-flexible alternating copolymer interface layer layer by layer, an interface layer with mechanical interlocking and chemical bonding is formed, which enhances the interfacial adhesion between the fiber and the resin matrix.
The dynamic mechanical properties and performance stability of PBO fiber composites were significantly improved, with tensile modulus and flexural modulus increasing by 49.35% and 31.68% respectively. The interfacial bonding force was significantly enhanced, and the crack propagation resistance and fracture toughness of the material were improved.
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Figure CN121161594A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of PBO fibers, and particularly relates to a PBO fiber, a preparation method thereof, and a PBO fiber composite material. BACKGROUND
[0002] Insulators are key components in power systems to ensure reliable power transmission. Among them, composite insulators are gradually replacing traditional ceramic insulators due to their light weight, easy maintenance, and excellent external insulation performance. As the core structural unit of the insulator, the insulating core not only needs to bear mechanical load, but also must provide stable electrical insulation strength. Composite foam material SF shows great potential as a new type of core material. SF is a two-phase material composed of epoxy resin as the matrix and physically closed hollow polymer microspheres (such as PMMA) as the filling phase. Its unique structure endows it with low density, high specific strength, extremely low water absorption, and high electrical insulation strength. However, due to the lack of toughness, the internal stress of SF material is difficult to release, which may lead to debonding of microspheres and resin matrix, forming micro cracks, which restricts its application in high reliability field. For the performance improvement of SF material, the existing technical paths mainly include nano filler modification, resin modification and fiber reinforcement modification. Compared with the above, fiber reinforcement is proved to be an effective method that can significantly improve the mechanical properties and thermal stability of polymer materials, and is feasible for large-scale production.
[0003] Among many fiber materials, poly-p-phenylene benzobisoxazole fiber (PBO) has excellent specific strength, specific modulus, heat resistance, water resistance and insulation. However, the high chemical inertness and smoothness of the PBO fiber surface result in extremely weak interfacial adhesion strength between the PBO fiber and the resin matrix, which seriously limits the play of its reinforcing effect.
[0004] At present, methods such as plasma treatment, high-energy ray treatment, surface coating and chemical grafting have been widely used in the surface functional modification of PBO fibers. Plasma treatment and high-energy ray treatment usually reduce the mechanical properties. The coating or grafted interface layer with active groups can effectively enhance the chemical activity and roughness of the PBO fiber surface. However, the above surface coating method has poor stability and is difficult to achieve uniform adhesion to the PBO fiber surface.
[0005] In view of this, the present patent application is proposed. SUMMARY
[0006] In order to solve the above problems, the purpose of the present patent application is to provide a PBO fiber, a preparation method thereof, and a PBO fiber composite material. By constructing a polymer interface layer on the surface of the PBO fiber, a rigid-flexible transition structure is formed, and the interface layer has strong mechanical interlocking and chemical bonding, which improves the interfacial adhesion between the PBO fiber and the resin matrix, thereby significantly improving the dynamic mechanical properties and performance stability of the PBO fiber composite material.
[0007] The present application is realized by the following technical solutions:
[0008] The first object of the present application is to provide a preparation method of PBO fiber, comprising:
[0009] The PBO fiber is subjected to acid treatment to obtain a first product;
[0010] A polymer interface layer is constructed on the surface of the first product layer by layer using LBL technology;
[0011] The polymer interface layer is a copolymer interface material layer with rigid segments and flexible segments alternately;
[0012] The rigid segments have benzene ring structures, and the flexible segments have polyether segments.
[0013] In the present application, the PBO fiber is first pretreated, the surface of the PBO is oxidized by acid treatment to generate active functional groups on the surface of the fiber, such as carboxyl (-COOH) and hydroxyl (-OH), which provide chemical reaction sites for subsequent interface construction. Subsequently, a comb-shaped polymer interface is constructed on the surface of the PBO fiber layer by layer using LBL technology, and the construction (i.e. the modifier mentioned later) in LBL technology is reasonably selected to form a copolymer with rigid and flexible segments alternately as the interface material layer. These copolymers have rigid parts (such as benzene ring structures) and flexible parts (such as polyether segments), forming a rigid-flexible transition structure. Thus, the copolymer molecules are deposited on the surface of the PBO fiber layer by layer through a reactive solution, forming an interface layer with strong mechanical interlocking and chemical bonding, significantly increasing the interface contact area, optimizing the load transfer path, and improving the interface bonding force, mechanical properties and stability.
[0014] As a preferred design, the process of constructing a polymer interface layer on the surface of the first product layer by layer using LBL technology is as follows:
[0015] The first product is immersed in a first modifier to obtain a second product;
[0016] The second product is immersed in a second modifier to obtain the copolymer interface material layer;
[0017] The first modifier contains benzene ring and two or more amino groups, and the second modifier contains polyether segments and amino groups.
[0018] In the present application, by reasonably selecting the modifier, a copolymer interface material layer with rigid segments (benzene ring structure in the first modifier) and flexible segments (polyether segment in the second modifier) is obtained, and the amino group in the first modifier and the amino group in the second modifier are used to interact with the carboxyl and hydroxyl groups on the surface of the oxidized PBO fiber, thereby synergistically enhancing the adhesion of the first modifier and the second modifier to the surface of the PBO fiber and improving the interfacial bonding force.
[0019] As a preferred design, the acid treatment is performed using an acid treatment agent, and the acid treatment agent is any one of nitric acid, hydrochloric acid, sulfuric acid, formic acid, acetic acid, and methyl sulfonic acid. More preferably, methyl sulfonic acid is selected as the acid treatment agent.
[0020] As a preferred design, the acid treatment process is as follows:
[0021] The PBO fiber is treated with an acid treatment agent with a concentration of 40% to 50% for 2 hours.
[0022] As a preferred design, the first modifier is selected from any one of phenyl diamine and its derivatives, and phenyl triamine and its derivatives; more preferably, p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, nitro-substituted p-phenylenediamine, o-phenyl triamine, and m-phenyl triamine are selected; and most preferably, p-phenylenediamine is selected as the first modifier.
[0023] In the impregnation process of the first product, the first modifier is dissolved in solvent A to form a mixed solution, and the mixed solution is used as a reactive solution.
[0024] As a preferred design, the solvent A is selected from any one of DMF, dichloromethane, ethyl acetate, methanol, and ethanol.
[0025] The concentration of the first modifier in the mixed solution is 0.1 mol / L to 0.5 mol / L.
[0026] As a preferred design, the second modifier is selected from any one of polyether amine and its derivatives; more preferably, polyether amine is selected as the second modifier.
[0027] In the impregnation process of the second product, the second modifier is dissolved in solvent B to form a mixed solution, and the mixed solution is used as a reactive solution.
[0028] The concentration of the second modifier in the mixed solution is 5 wt%.
[0029] And / or, the solvent B is selected from any one of DMF, dichloromethane, ethyl acetate, methanol, and ethanol.
[0030] The second object of the present application is to provide a PBO fiber obtained by the preparation method according to any one of the above.
[0031] A third object of the present application is to provide a PBO fiber composite material, which contains the PBO fiber as described above, and further contains an epoxy resin, a curing agent and an accelerator, and PMMA hollow microspheres.
[0032] As a preferred design, the curing agent and the accelerator are MHHPA and DMP-30, respectively.
[0033] Compared with the prior art, the present application has the following advantages and beneficial effects:
[0034] 1. The present application grafts a comb-shaped polymer to the surface of the PBO fiber by LBL, and designs and constructs an interface with a rigid-flexible transition structure. The customized comb-shaped molecular structure provides stronger physical and chemical interactions for the interface adhesion of the composite material. The main chain is a rigid segment (such as a structure containing a benzene ring), which plays the role of a "comb back" to provide structural support and rigidity. The side chain is a flexible segment (such as a polyether segment) extending from the main chain, which is arranged like a "comb tooth" to provide flexibility and mobility to form a rigid-flexible alternating multilayer structure, i.e. a "comb-shaped molecular structure". In addition, the rigid-flexible transition structure of the interface can promote the effective transmission of the load near the interface and the absorption / dissipation of the fracture energy.
[0035] 2. The experimental results show that the tensile modulus of the composite material containing the PBO fiber of the present application is increased from 1.56 GPa to 2.33 GPa, which is increased by 49.35% compared with the original PBO sample. The bending modulus is increased from 2.02 GPa to 2.66 GPa, which is increased by 31.68% compared with the original PBO sample. In addition, due to the improvement of the interface adhesion, the dynamic mechanical properties and performance stability of the composite material are also significantly improved.
[0036] 3. The present application obtains PBO-MSA-PPDA-PEA by reasonably selecting an acid treatment agent (such as methyl sulfonic acid MSA), a first modifier (p-phenylenediamine PPDA), and a second modifier (polyether amine PEA), which is a copolymer of rigid and flexible segments, and realizes the precise control of the interface structure and composition. BRIEF DESCRIPTION OF DRAWINGS
[0037] In order to more clearly illustrate the technical solutions of the example embodiments of the present application, the following will briefly introduce the drawings needed to be used in the examples. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be considered as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor. In the drawings:
[0038] Figure 1 The schematic diagram for preparing PBO of the present application.
[0039] Figure 2 Comparison chart of breakdown strength test of each embodiment and comparative example.
[0040] Figure 3 Comparison chart of leakage current test of each embodiment and comparative example.
[0041] Figure 4 Comparison chart of water absorption test of each embodiment and comparative example.
[0042] Figure 5 Comparison chart of tensile strength, bending strength test of each embodiment and comparative example.
[0043] Figure 6 Comparison chart of tensile modulus, bending modulus test of each embodiment and comparative example. DETAILED DESCRIPTION
[0044] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to embodiments. The illustrative embodiments of the present application and their descriptions are only used to explain the present application and not as a limitation of the present application.
[0045] The ranges disclosed in the present application are limited by the lower and upper limits in the form of a range, and the given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The range defined in this way can include or not include the end value, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if the ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that the ranges of 60-110 and 80-120 are also anticipated. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4 and 5 are listed, the following ranges are all anticipated: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise stated, the numerical range "a-b" represents a shorthand notation for any real combination between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed herein, and "0-5" is only a shorthand notation for these numerical combinations. In addition, when a parameter is stated to be ≥2 integers, it is equivalent to disclose that the parameter is, for example, integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.
[0046] If not specifically stated, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions.
[0047] If not particularly specified, all the technical features of the present application and the optional technical features can be combined with each other to form new technical solutions.
[0048] If not particularly specified, all the steps of the present application can be performed in sequence or randomly, preferably in sequence.
[0049] For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) performed in sequence.
[0050] For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) performed in sequence.
[0051] For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) performed in sequence.
[0052] For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) performed in sequence.
[0053] If not particularly specified, the "comprise" and "include" mentioned in the present application mean open type, and can also be closed type. For example, the "comprise" and "include" can mean that other components not listed can also be included or contained, or only the listed components can be included or contained.
[0054] Although PBO fibers have excellent mechanical strength and thermal stability, their surface characteristics are relatively smooth and chemically inert, resulting in weak interfacial adhesion between the fibers and the matrix. Due to the limited physical and chemical bonding between the fibers and the matrix, this interfacial property hinders the effective load transfer, resulting in interfacial debonding of the composite material under stress, thereby significantly reducing the mechanical properties of the composite material, especially under tensile and compressive stress, which easily leads to interfacial failure. The low surface energy of PBO fibers limits the effective contact with the matrix material, especially when the liquid matrix (such as epoxy resin) infiltrates the fiber surface, it is difficult to form sufficient physical adsorption force or interfacial compatibility. PBO fibers without surface treatment lack functional groups that can react with the matrix material. Due to the lack of effective chemical reactivity, the fiber and the matrix can only rely on weak van der Waals force or physical adsorption force for bonding, which makes the interfacial bonding force insufficient to provide sufficient support under stress, thereby limiting the overall performance of the composite material. Although some great achievements have been made in the aspect of interface adjustment, precise control of the interface structure and composition is still a major challenge for composite design and manufacturing.
[0055] To solve the above problems, the application prepares a PBO fiber, which is gradually deposited with copolymer molecules on the surface layer by layer through LBL technology, to form an interface layer with strong mechanical interlocking and chemical bonding.
[0056] The application will be described in more detail through specific examples below.
[0057] Example 1:
[0058] (2) A preparation method of a PBO fiber, the preparation process being as follows:
[0059] First, PBO fibers with a mass fraction of 1% are added to a 40% methyl sulfonic acid aqueous solution (MSA) for pretreatment for 2 hours to obtain PBO-MSA, to generate active functional groups on the surface of the fiber, such as carboxyl groups (-COOH) or hydroxyl groups (-OH) as shown in formula (1). Figure 1
[0060] Then, a comb-shaped polymer interface with a rigid-flexible transition structure is constructed on the surface of the obtained PBO-MSA by using Layer-by-layer (LBL) technology (a thin film technology of electrostatic self-assembly layer by layer). To achieve this process, different types of polymer solutions are used for layer-by-layer deposition.
[0061] Specifically, the obtained PBO-MSA is first immersed in a 1L DMF solution containing 0.1 mol / L p-phenylenediamine (PPDA) for 3 hours, and then washed and dried to obtain PBO-MSA-PPDA (as shown in formula (2)). Figure 1 Then, the PBO-MSA-PPDA is immersed in a 1L DMF solution containing polyetheramine (PEA) (concentration 5 wt%) to obtain PBO-MSA-PPDA-PEA (as shown in formula (3)). The PBO-MSA-PPDA-PEA is the PBO fiber obtained by the application (after modification). Figure 1
[0062] (2) A PBO fiber composite material, the preparation process being as follows:
[0063] First, an epoxy resin matrix is prepared: E51 type epoxy resin, curing agent methylhexahydrophthalic anhydride (MHHPA), and accelerator 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30) are mixed in a mass ratio of 100:80:0.5, and then hollow microspheres accounting for 1% of the mass fraction of the PBO fiber composite material are added.
[0064] Then, 1% of the modified PBO fiber by weight of the PBO fiber composite is added to the epoxy resin matrix. The mixture is stirred uniformly at a speed of 500 r / min using a vacuum planetary mixer to ensure that the fiber and the matrix material are fully mixed. The mixed material is poured into a mold and left to stand in a vacuum environment at 90°C for 10 hours to complete debubbling and curing, and finally a PBO composite is obtained. The sample after curing is cut into a corresponding shape and size for performance testing.
[0065] Example 2:
[0066] (1) A method for preparing PBO fiber, the preparation process being as follows:
[0067] First, the PBO fiber is pretreated with a 40% sulfuric acid solution for 2 hours to obtain PBO-MSA.
[0068] Then, the obtained PBO-MSA is immersed in a 1L DMF solution containing 0.1 mol / L m-phenylenediamine for 3 hours, washed and dried. The product obtained in the previous step is immersed in a 1L DMF solution containing polyetheramine (concentration 5 wt%) to obtain the PBO fiber (modified).
[0069] (2) A PBO fiber composite, the preparation process being the same as that of Example 1.
[0070] Example 3:
[0071] (1) A method for preparing PBO fiber, the preparation process being as follows:
[0072] First, the PBO fiber is pretreated with a 50% methyl sulfonic acid solution for 2 hours to obtain PBO-MSA.
[0073] Then, the obtained PBO-MSA is immersed in a DMF solution containing 0.1 mol / L nitro-substituted p-phenylenediamine for 3 hours, washed and dried. The product obtained in the previous step is immersed in a DMF solution of polyethylene glycol diamine (concentration 5 wt%) to obtain the PBO fiber (modified).
[0074] (2) A PBO fiber composite, the preparation process being the same as that of Example 1.
[0075] Example 4:
[0076] A method for preparing PBO fiber, the preparation process being the same as that of Example 1.
[0077] A PBO fiber composite, the preparation process being the same as that of Example 1, except that 2% of the modified PBO fiber by weight of the PBO fiber composite is added to the epoxy resin matrix.
[0078] Example 5:
[0079] A method for preparing PBO fibers, the preparation process being the same as that of Example 1.
[0080] A PBO fiber composite material, the preparation process being the same as that of Example 1, except that 3% of the modified PBO fibers by mass ratio of the PBO fiber composite material are added to the epoxy resin matrix.
[0081] Example 6:
[0082] A method for preparing PBO fibers, the preparation process being the same as that of Example 1.
[0083] A PBO fiber composite material, the preparation process being the same as that of Example 1, except that 4% of the modified PBO fibers by mass ratio of the PBO fiber composite material are added to the epoxy resin matrix.
[0084] The test items include breakdown strength, leakage current, water absorption, tensile strength, bending strength, tensile modulus, bending modulus, etc.
[0085] Breakdown strength: The breakdown field strength is used to characterize the electrical resistance of the material. The breakdown strength test electrode is a ball-ball electrode. The sample thickness is 1 mm, and the electrode and the sample need to be immersed in dimethyl silicone oil to prevent surface flashover. The test procedure is carried out in accordance with GB / T 1408.1-2016. The voltage rising rate is 2 kV / s. At least 20 samples of each type are tested, and the average value is obtained by statistical analysis.
[0086] Leakage current: The test is carried out in accordance with IEC 62217-2012 standard. In order to more effectively characterize the leakage current flowing through the interface between the fiber and the resin, and the microsphere and the resin, a copper foil is pasted on the surface of the sample as a shielding outer surface current electrode. During the test, an effective value of 12 kV of power frequency alternating voltage is applied, and the current is recorded by a digital multimeter (DM-3068, Puyuan Precision Technology Co., Ltd.). The current accuracy is ±0.1 μA, and the sampling frequency is 20 Hz.
[0087] Mechanical properties: Tensile failure test and bending failure test are carried out on the material to evaluate the strength limit of the material. The test is carried out in accordance with the standard ISO527-4 "Plastics - Tensile properties testing" and the standard ISO14125 "Bending properties of fiber reinforced plastics composites" using an ETM-104C universal testing machine. The bending sample thickness is 1 mm, the width is 15 mm, the length is 40 mm, and the loading span is 20 mm. The tensile sample thickness is 1 mm, the gauge length is 50 mm, and the width of the middle parallel section is 10 mm. When the sample is loaded, it is ensured that the center line of the sample is consistent with the center line of the clamp, and the load loading speed is 10 mm / min.
[0088] Comparative Example 1:
[0089] The matrix resin was prepared according to the ratio of E51 type epoxy resin: methyl hexahydrophthalic anhydride: 2,4,6-tris(dimethylaminomethyl) phenol = 100:80:0.5, and 1% by mass of hollow microspheres was added. Then, the PBO fiber before modification was added, and then the fiber- added matrix was stirred uniformly using a vacuum planetary stirrer at 500 r / min. The uniformly stirred mixture was poured into a mold, and the vacuum environment at 90°C was maintained for 10 h to complete the debubbling and curing. The cured sample was cut into the corresponding shape and size for performance testing.
[0090] Test results:
[0091] Breakdown strength test: As shown in Figure 2 , the breakdown strength of the PBO fiber composite material obtained in Example 1 was 24.06 V / mm; that of Example 2 was 21.43 kV / mm; that of Example 3 was 22.20 kV / mm; that of Example 4 was 24.63 kV / mm; that of Example 5 was 25.98 kV / mm; that of Example 6 was 27.60 kV / mm; and that of Comparative Example 1 was 20.43 kV / mm, which was significantly lower than that of each of the examples.
[0092] Leakage current test: As shown in Figure 3 , Example 1 was 21.57 μA; Example 2 was 20.29 μA; Example 3 was 20.97 μA; Example 4 was 22.15 μA; Example 5 was 22.85 μA; Example 6 was 22.96 μA; and Comparative Example was 19.88 μA, which was significantly lower than that of each of the examples.
[0093] Water absorption test: As shown in Figure 4 , Example 1 was 0.98%; Example 2 was 1.13%; Example 3 was 1.16%; Example 4 was 0.77%; Example 5 was 0.58%; Example 6 was 0.39%; and Comparative Example 1 was 1.16%.
[0094] As shown in Figure 5 , the tensile strength test: Example 1 was 49.96 MPa; Example 2 was 42.38 MPa; Example 3 was 43.96 MPa; Example 4 was 50.25 MPa; Example 5 was 52.72 MPa; Example 6 was 53.78 MPa; and Comparative Example 1 was 34.98 MPa.
[0095] Flexural strength test: Example 1 was 70.42 MPa; Example 2 was 62.22 MPa; Example 3 was 65.00 MPa; Example 4 was 73.96 MPa; Example 5 was 75.57 MPa; Example 6 was 75.54 MPa; Comparative Example 1 was 58.39 MPa.
[0096] As shown in Figure 6 Tensile modulus test: Example 1 was 2.26 GPa; Example 2 was 2.15 GPa; Example 3 was 2.23 GPa; Example 4 was 2.33 GPa; Example 5 was 2.35 GPa; Example 6 was 2.37 GPa; Comparative Example 1 was 1.56 GPa.
[0097] Flexural modulus test: Example 1 was 2.54 GPa; Example 2 was 2.51 GPa; Example 3 was 2.52 GPa; Example 4 was 2.66 GPa; Example 5 was 2.72 GPa; Example 6 was 2.75 GPa; Comparative Example 1 was 2.02 GPa.
[0098] In the present application, during the treatment of PBO fibers, the LBL technique builds a comb-shaped polymer interface with a rigid-flexible transition structure through layer-by-layer construction, effectively improving the interfacial adhesion between the fibers and the matrix. The interface constructed by LBL enhances the physical-chemical bonding force of the interface through mechanical interlocking and chemical bonding effects, thereby improving the overall strength of the interface; the rigid-flexible transition structure helps to effectively absorb and dissipate external stress, slowing down the stress concentration during crack propagation, thereby improving the crack propagation resistance and fracture toughness of the composite material; the rough structure introduced on the surface of the PBO fiber significantly increases the interface contact area, thereby optimizing the load transfer path and further improving the mechanical properties and stability of the material.
[0099] The above detailed description further illustrates the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above is only a specific embodiment of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.
Claims
1. A method for producing PBO fibers, characterized by, The preparation method comprises the following steps: acid treating PBO fibers to obtain a first product; constructing a polymer interfacial layer on the surface of the first product layer by layer (LBL) technology; the polymer interfacial layer is a copolymer interfacial material layer with rigid segments and flexible segments alternately arranged; the rigid segments have benzene ring structures, and the flexible segments have polyether segments.
2. The method for preparing PBO fiber according to claim 1, characterized in that, The process of constructing the polymer interfacial layer on the surface of the first product layer by layer (LBL) technology comprises the following steps: immersing the first product in a first modifier to obtain a second product; immersing the second product in a second modifier to obtain the copolymer interfacial material layer; the first modifier contains benzene rings and two or more amino groups, and the second modifier contains polyether segments and amino groups.
3. The method for preparing PBO fiber according to claim 1, characterized in that, The acid treatment is performed by using an acid treatment agent, and the acid treatment agent is any one of nitric acid, hydrochloric acid, sulfuric acid, formic acid, acetic acid and methyl sulfonic acid.
4. The method for preparing PBO fiber according to claim 1, characterized in that, The process of the acid treatment comprises the following steps: acid treating the PBO fibers by using an acid treatment agent with a concentration of 40% to 50% for 2 hours.
5. The method for preparing PBO fiber according to claim 1, characterized in that, The first modifier is any one of phenyl diamine and derivatives thereof and phenyl triamine and derivatives thereof; In the process of immersing the first product, the first modifier is dissolved in a solvent A to form a mixed solution.
6. The method of claim 5, wherein the PBO fiber is prepared by the process of claim 1, wherein the step of polymerizing the monomers is performed in the presence of a solvent. The solvent A is any one of DMF, dichloromethane, ethyl acetate, methanol and ethanol; the concentration of the first modifier in the mixed solution is 0.1 mol / L to 0.5 mol / L.
7. The method for preparing PBO fiber according to claim 1, characterized in that, The second modifier is any one of polyether amine and derivatives thereof; In the process of immersing the second product, the second modifier is dissolved in a solvent B to form a mixed solution; the concentration of the second modifier in the mixed solution is 5 wt%; and / or, the solvent B is any one of DMF, dichloromethane, ethyl acetate, methanol and ethanol.
8. A PBO fiber characterized by, The preparation method is obtained by using any one of claims 1 to 7.
9. A PBO fiber composite material, characterized by, The PBO fibers contain epoxy resin, a curing agent and an accelerator, and PMMA hollow microspheres.
10. A PBO fiber composite material according to claim 9, wherein The curing agent and the accelerator are MHHPA and DMP-30, respectively.