Wave-absorbing-damping dual-functional glass fiber reinforced composite material and preparation method and application thereof

Abstract

This invention provides a glass fiber reinforced composite material with dual functions of wave absorption and damping, its preparation method, and its application. The composite material is prepared from raw material components including 100 parts by weight of syndiotactic polystyrene, 15-30 parts by weight of glass fiber, 5-25 parts by weight of magnetic particles, and 0.3-2.0 parts by weight of carbon nanotube aerogel particles. It has both high-frequency electromagnetic wave absorption and broadband mechanical vibration damping functions, and can be used in electronic appliances, 5G communication equipment, and automotive parts that require wave absorption, damping, and heat resistance.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials technology, and more specifically, to a glass fiber reinforced composite material with dual functions of wave absorption and damping, its preparation method, and its application. Background Technology

[0002] Syntactic polystyrene (sPS), an engineering plastic with high heat resistance (melting point up to 270°C), excellent dimensional stability, and unique high-frequency dielectric properties (dielectric constant of approximately 2.6 at 1 GHz), has become a key matrix material in high-tech fields such as aerospace and 5G communications. sPS exhibits strong crystallinity and high crystallinity, giving it good high-temperature and chemical resistance, as well as excellent dimensional stability and electrical properties—qualities crucial for high-performance applications. Furthermore, annealing treatment can increase the breakdown strength of sPS films by approximately 19.6% at 120°C, while simultaneously improving dielectric loss.

[0003] However, the inherent properties of sPS also bring some functional limitations, restricting its application in certain specific scenarios. First, the high crystallinity of sPS restricts the movement of its molecular chain segments, resulting in insufficient damping performance. At a frequency of 1 kHz, its loss factor (tanδ) is only 0.03~0.05, making it difficult for sPS to meet the noise, vibration, and harshness (NVH) requirements in vibration scenarios. Second, due to the extremely low dielectric loss of sPS, the reflectivity of incident electromagnetic waves often exceeds 90%, making it perform poorly in the field of electromagnetic wave absorption. Although traditional modification methods, such as adding magnetic fillers, can attempt to improve electromagnetic wave absorption performance, this usually severely degrades the mechanical strength of the material. In terms of nanoporous structure, sPS also exhibits a complex polymorphism, with multiple crystal forms (such as δ and ε types). These crystal forms have unique dielectric, thermal, and acoustic properties due to the different ways in which polymer chains are stacked within the lattice, but their intrinsic dielectric loss remains very low.

[0004] Current functional modification techniques for sPS face numerous challenges. For example, in terms of microwave absorption modification, although some studies have successfully increased electromagnetic wave absorption to 85% (at 12 GHz) by incorporating aerogel into sPS, this modification method leads to a decrease in the flexural strength of the composite material of more than 35%, and the performance of the aerogel degrades by more than 20% after moisture absorption. This contradiction between strength and microwave absorption performance is common in the development of high-performance microwave absorbing materials. Regarding damping modification, although toughening treatment with styrene-ethylene / butene-styrene (SEBS) block copolymers can increase the damping factor to 0.07, this improvement is still insufficient to effectively suppress electromagnetic reflection. Furthermore, while composites of sPS with nickel nanoparticle-modified reduced graphene oxide can be used for electromagnetic wave shielding applications, their compatibility with the sPS matrix and final damping performance still require further optimization. For glass fiber reinforced sPS composites, the traditional silane coupling agent treatment of glass fibers is prone to interface failure under high-frequency vibration, resulting in an acoustic transmission loss of less than 8dB (500Hz), which limits its application effect in high-frequency vibration environments.

[0005] In the field of electromagnetic wave absorption, researchers have explored various materials and strategies to overcome the limitations of existing materials. Gai et al., through compositional and structural engineering, designed SiC / C hollow microspheres and added them to carbon materials at a mass ratio of 35.4%, achieving excellent microwave absorption performance, including broadband absorption at 5.1 GHz and absorption at 10.4 GHz. The hollow microspheres exhibit a high microwave absorption efficiency of 60.8 dB, but their mechanical strength is limited, relying mainly on the matrix in composite materials and making them susceptible to stress damage. Nickel-carbon (Ni@C) composites also demonstrate high microwave absorption efficiency through mechanisms such as multiple reflections, conductive networks, interfacial polarization, and magnetic coupling, but require MOFs as precursors, resulting in high costs.

[0006] Furthermore, carbon-based materials possess immense potential for electromagnetic wave absorption due to their tunable dielectric properties. Defect-rich heterostructured sulfide / carbon composites can achieve robust electromagnetic wave absorption capabilities by enhancing polarization coupling, with reflection losses as low as [missing value]. 48.3 dB. Biomass-derived carbon materials, due to their unique microstructure and interface control, are also used to develop electromagnetic shielding materials, improving absorption performance through mechanisms such as conductive loss, magnetic loss, and dipole polarization. Nanoporous crystalline sPS aerogels have also attracted attention; by adjusting the crystal structure and porosity, their dielectric properties can be used for low dielectric constant applications, but further modification is still needed for electromagnetic wave absorption.

[0007] In summary, in demanding applications involving high temperatures, vibration, and electromagnetic multi-field coupling, such as hypersonic vehicle resonant cavities or 5G base station power amplifier housings, there is an urgent need to develop an sPS composite material that simultaneously possesses high heat resistance, excellent electromagnetic wave absorption, and damping capabilities. However, existing technologies often suffer from phase separation due to simple blending of functional components, or rely on materials with low mechanical strength such as aerogels, making it difficult to effectively solve these mutually restrictive performance challenges.

[0008] Therefore, there is an urgent need for an innovative strategy to design and prepare high-performance sPS composites to meet the needs of these cutting-edge applications. Summary of the Invention

[0009] To address the aforementioned problems, this invention provides a glass fiber reinforced composite material with dual functions of wave absorption and damping, which not only possesses excellent comprehensive performance but also combines high-frequency electromagnetic wave absorption with broadband mechanical vibration damping.

[0010] Firstly, one of the objectives of this invention is to provide a glass fiber reinforced composite material with dual functions of absorbing and damping waves.

[0011] Specifically, the composite material is made from raw materials comprising the following components, with the following weight parts per 100 parts by weight of syndiotactic polystyrene: 100 parts by weight of syndiotactic polystyrene resin; 15-30 parts by weight of glass fiber; preferably 20-30 parts by weight; Magnetic particles: 5-25 parts by weight; preferably 8-20 parts by weight; The carbon nanotube aerogel particles are 0.3 to 2.0 parts by weight; preferably 0.5 to 1.0 parts by weight.

[0012] Furthermore, the molecular weight of the syndiotactic polystyrene resin is 150,000 to 300,000, preferably 250,000 to 300,000; and it is selected from one or a combination of α-crystalline, β-crystalline, γ-crystalline, and δ-crystalline forms.

[0013] Furthermore, the glass fiber is selected from glass fiber with hollow SiC nanowires embedded in its surface; it can be prepared by melt coating method.

[0014] Preferably, the preparation method of glass fibers with surface-embedded hollow SiC nanowires includes the following steps: Step 1: Hollow SiC nanowires and silane coupling agent A are mixed in a solvent and stirred to obtain a suspension. The suspension is then passed through an airflow and spray-dried to obtain surface-modified dispersed SiC nanowires. Preferably, the solvent is selected from one or more of ethanol, isopropanol, and acetone.

[0015] Step 2: First, mix the alkali-free chopped glass fiber and compatibilizer, then add the surface-modified dispersed SiC nanowires and mix again to obtain glass fiber with surface-embedded hollow SiC nanowires.

[0016] More preferably, the method for preparing glass fibers with surface-embedded hollow SiC nanowires includes the following steps: Step 1: Hollow SiC nanowires and silane coupling agent A are mixed in an anhydrous solvent and stirred at high speed in an air jet mill to form a suspension at a stirring speed of 600~800 rpm. Then, a high-pressure air flow of 2~7 bar is introduced to crush and agglomerate the nanowires. At the same time, the nanowires are spray-dried to obtain surface-modified dispersed SiC nanowires. Step 2: First, mix the alkali-free chopped glass fiber and compatibilizer for 3-15 minutes, then add the surface-modified dispersed SiC nanowires in batches and mix for 10-40 minutes to obtain glass fiber with a surface-embedded hollow SiC nanowires in an interface structure of "glass fiber-compatibilizer-SiC".

[0017] Preferably, the mass ratio of hollow SiC nanowires to silane coupling agent A is 1:(0.1~1.5); more preferably, it is 1:(0.3~1.0); wherein, silane coupling agent A is selected from silane coupling agents with special functional groups, preferably silane coupling agents containing one or more functional groups of epoxy, phenyl, and amino groups.

[0018] Preferably, the mass ratio of alkali-free chopped glass fiber, hollow SiC nanowires, and compatibilizer is 1:(0.5~5):(0.1~2); more preferably, it is 1:(0.5~2):(0.1~1.5); wherein the alkali-free chopped glass fiber has a cylindrical microstructure with an average diameter of 3~20μm, preferably 10~15μm; and an average length of 1~5mm, preferably 3~4mm.

[0019] Preferably, the compatibilizer is selected from a compound system of polymer A having anhydride groups and polymer B having epoxy groups; and in the above compound system, the molar ratio of anhydride groups in polymer A to epoxy groups in polymer B is 1:(0.3~1.2); more preferably 1:(0.6~0.8). Polymer A is selected from maleic anhydride-grafted elastomer polymers, preferably one or a combination of SEBS-g-MAH, POE-g-MAH, and EPDM-g-MAH, with an anhydride group grafting rate of 0.5~2.0 wt%, preferably 1.0~1.5 wt%; the weight-average molecular weight (Mw) of polymer A is 100,000~300,000, preferably 200,000~300,000; it is commercially available, such as Kraton's FG1901 and FG1924, and Asahi Kasei's M1913. The epoxy polymer B is selected from alicyclic epoxy polymers and glycidyl ether type polymers, preferably from one or a combination of 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate and polypropylene glycol diglycidyl ether, and its epoxy equivalent is 50~200 g / eq, preferably 180~200 g / eq.

[0020] It is worth mentioning that the aforementioned hollow SiC nanowires embedded in the biomimetic glass fiber surface mimic the biological structure of plant roots anchoring to the soil in nature. The hollow SiC nanowires are embedded at an inclined angle on the glass fiber surface, forming a mechanical interlock to enhance interfacial bonding, while the hollow structure provides resonant dissipation cavities, simultaneously improving mechanical strength and interfacial dissipation. Furthermore, the Si-OH groups on the glass fiber surface undergo esterification with the anhydride groups of polymer A, and the hydroxyl groups on the SiC surface undergo ring-opening reactions with the epoxy groups of polymer B. These two reactions simultaneously achieve covalent bonding between the two phases, enabling interfacial chemical regulation and improving stress and energy transfer efficiency. At the same time, the flexible segments of the compatibilizer become entangled with the molecular chains of the sPS matrix, and the polar groups chemically bond with the filler surface, eliminating interfacial voids; thus achieving both reinforcement and dissipation functions.

[0021] Furthermore, the magnetic particles are selected from FeSiAl@BaTiO3 core-shell magnetic particles, wherein the diameter of the FeSiAl magnetic core is 50~300nm, preferably 50~200nm; and the thickness of the BaTiO3 piezoelectric shell layer is 5~45nm, preferably 5~30nm.

[0022] Preferably, the FeSiAl@BaTiO3 core-shell magnetic particles are prepared by a solvothermal method, and the specific preparation method includes the following steps: Step 1: Immerse FeSiAl in acid solution and sonicate to remove the Fe2O3 layer on the surface, thus obtaining powder; Step 2: Mix silane coupling agent B with the powder from Step 1, and heat-treat to obtain FeSiAl; Step 3: Mix tetrabutyl titanate solution and Ba(OH)2 solution evenly to obtain precursor mixture, then add FeSiAl from step 2, sonicate and heat to obtain FeSiAl@BaTiO3 core-shell magnetic particles.

[0023] More preferably, the preparation method of FeSiAl@BaTiO3 core-shell magnetic particles includes the following steps: Step 1: Immerse the FeSiAl powder in an acid solution and sonicate it at 60-80°C for 15-30 minutes to remove the Fe2O3 layer on the surface and obtain the powder. Step 2: Treat the acid-etched powder with an ethanol solution of silane coupling agent B, reflux at 70-80°C for 2-3 hours, and wash the resulting powder sequentially with anhydrous ethanol and deionized water 3-5 times, at 60-80°C. o Vacuum drying at C yields FeSiAl; Step 3: Add tetrabutyl titanate / anhydrous ethanol solution dropwise to Ba(OH)₂·8H₂O aqueous solution, stir until homogeneous, then transfer to a polytetrafluoroethylene liner. Disperse the FeSiAl obtained in Step 2 into the precursor mixture, and sonicate for 15-30 minutes. The FeSiAl feed rate is 5-30 g / L. Assemble the reactor and place it in a 50 mL container. o The oven is heated to 150-250℃, preferably 180-200℃, at a heating rate of 1-2. o The reaction mixture was kept at 60-80 °C / min for 12-18 hours. The reaction product was then centrifuged and washed three times sequentially with anhydrous ethanol, dilute acetic acid, and deionized water. o Vacuum drying at C yielded FeSiAl@BaTiO3 core-shell magnetic particles.

[0024] Preferably, in step one, the acid is selected from one or a combination of citric acid, oxalic acid, and acetic acid; its molar concentration is 0.1~2M, preferably 0.5~1M.

[0025] Preferably, in step two, the silane coupling agent B is selected from one or a combination of γ-aminopropyltriethoxysilane coupling agent, γ-glycidoxypropyltrimethoxysilane coupling agent, γ-methacryloyloxypropyltrimethoxysilane coupling agent, and anilinemethyltriethoxysilane coupling agent; the mass ratio of silane coupling agent B to powder is (0.2~2.0):1, preferably (0.5~1.0):1.

[0026] Preferably, in step three, the molar concentration of the tetrabutyl titanate solution is 0.1~2M, more preferably 0.5~1M; the molar concentration of the Ba(OH)2 solution is 0.1~2M, more preferably 0.5~1M; and the molar ratio of tetrabutyl titanate, Ba(OH)2, and FeSiAl is 1:(0.5~1.0):(1.0~2.0), more preferably 1:(0.6~0.8):(1.1~1.3).

[0027] It is worth mentioning that, in this invention, the FeSiAl magnetic core, after being modified with a silane coupling agent, can react in situ with the BaTiO3 precursor to form Ti-O-Fe covalent bonds, rather than the physical adsorption bonding of the traditional process. This chemical bonding interface not only avoids shell detachment, but also directly realizes the interfacial magnetic-electric coupling between the magnetic core and the piezoelectric shell, significantly improving energy transfer and dissipation efficiency.

[0028] Furthermore, the average diameter of the carbon nanotube aerogel particles ranges from 30 to 50 μm, preferably from 35 to 50 μm.

[0029] Furthermore, the composite material also includes components such as toughening agents, nucleating agents, antioxidants, and lubricants. Based on 100 parts by weight of syndiotactic polystyrene, the weight parts of each component are as follows: 100 parts by weight of syndiotactic polystyrene; Toughening agent: 1-8 parts by weight; preferably 4-8 parts by weight; Nucleating agent: 0.2-1 parts by weight; preferably 0.5-1 parts by weight; Antioxidant: 0.1-0.4 parts by weight; preferably 0.1-0.3 parts by weight; The lubricant is used in amounts of 0.1 to 0.4 parts by weight; preferably 0.1 to 0.3 parts by weight.

[0030] Furthermore, the toughening agent is selected from hydrogenated styrene-ethylene-butene-styrene block copolymers; wherein the molecular weight of the hydrogenated styrene-ethylene-butene-styrene block copolymer is 50,000 to 300,000, preferably 250,000 to 300,000; and the styrene segment accounts for 10% to 35% of the copolymer mass, more preferably 17% to 33%. It can be purchased, such as KETEN G1651, G1652, and Yuehua YH503T.

[0031] Furthermore, the nucleating agent is selected from one or more of the following: sodium benzoate, saline resin, aluminum hydroxyl p-tert-butylbenzoate, 2,2'-methylene-bis(4,6-di-tert-butylphenoxy) phosphate, 2,2'-methylene-bis(4,6-di-tert-butylphenyl phosphate) basic aluminum, sodium 2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate, calcium tetrahydrophthalate, and talc.

[0032] Furthermore, the antioxidant is selected from one or more of antioxidant 1098, antioxidant 626, antioxidant S9228, and antioxidant DSTP.

[0033] Furthermore, the lubricant is selected from one or more of calcium stearate, ethylene bis-stearamide, and polysiloxane.

[0034] Secondly, another objective of this invention is to provide a method for preparing a glass fiber reinforced composite material with dual functions of wave absorption and damping, which is one of the objectives of this invention.

[0035] Specifically, the preparation method includes the following steps: The components, including syndiotactic polystyrene resin, magnetic particles, carbon nanotube aerogel particles, and additives, are mixed to obtain a mixture. The components, including the mixture and glass fiber, are then co-extruded to obtain a glass fiber reinforced composite material with dual functions of wave absorption and damping.

[0036] More specifically, the preparation method includes the following steps: The components, including syndiotactic polystyrene resin, magnetic particles, carbon nanotube aerogel microparticles, and additives, are added to a high-speed mixer and mixed evenly to obtain a mixture. The mixture is then fed through a main feed loss-in-weight scale, while the glass fiber is fed through a side feed loss-in-weight scale. All materials are then co-extruded through a twin-screw extruder, drawn into strands, water-cooled, and pelletized to obtain a glass fiber reinforced composite material with both wave absorption and damping functions.

[0037] Preferably, the process parameters for co-extrusion using a twin-screw extruder are as follows: the twin-screw extruder is divided into ten temperature zones, with zones one to three being pre-melting zones at a temperature of 240~270°C. o C; Zones four to six are the cross-linking reaction zones, with a temperature of 270~285°C. o C, Zones 7 to 10 are homogenization zones with temperatures ranging from 260 to 270°C. o C; The head temperature is 275~280°C. o C; The speed of the twin-screw extruder is 300~380 rpm.

[0038] Finally, a third objective of this invention is to provide the application of the glass fiber reinforced composite material with dual functions of absorbing and damping, which is used in electronic appliances, 5G communication equipment, automotive parts, etc., that require absorbing, damping, and heat resistance.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention abandons low-strength components such as aerogel. Through original core-shell particle design, biomimetic structure construction of glass fiber, and interfacial chemical regulation, while retaining the high heat resistance of sPS material (heat distortion temperature (HDT) can reach 255℃ or higher, and the full formula maintains ≥235℃), it achieves for the first time the synergistic effect of wave absorption and damping, providing a breakthrough solution for the protection of high-end equipment in multi-physical field (such as high temperature, vibration and electromagnetic) environments.

[0040] 2. This invention proposes a method for the first time to achieve efficient integration of microwave absorption and damping functions in an SPS / glass fiber system through multi-level structural design and interface synergy mechanism. Specifically, the Ti-O-Fe covalent bonds at the core-shell interface realize the magneto-electric coupling between the magnetic core and the piezoelectric shell; the tilted embedding and chemical bonding at the glass fiber-SiC interface simultaneously improve mechanical strength and interface dissipation; and the compound compatibilizing double-reaction bonding at the filler-matrix interface improves stress and energy transfer efficiency. The synergy of these three factors achieves the simultaneous improvement of microwave absorption and damping functions, fundamentally avoiding the problem of the traditional material functions being at odds with each other.

[0041] 3. This invention features a groundbreaking design of a magnetic-electric coupled core-shell filler. Through the synergistic effect of the hysteresis loss of FeSiAl and the mechanical-to-electrical energy conversion of BaTiO3, this composite material can achieve an absorption rate of ≥90% in the 8-12GHz X-band frequency range, while increasing the damping factor to over 0.13 (at 1kHz frequency), effectively solving the limitation of the single function of traditional fillers.

[0042] 4. This invention introduces a BaTiO3 piezoelectric shell for the first time, realizing multi-field coupling of mechanical, electrical, and magnetic fields. FeSiAl converts the energy of incident electromagnetic waves into heat energy through hysteresis loss, while the heat generated by hysteresis enhances the piezoelectric activity of BaTiO3, further promoting mechanical energy conversion. BaTiO3 converts the mechanical energy of mechanical vibrations / sound waves into electrical energy through the piezoelectric effect, and then dissipates it as heat energy through interface loss. Simultaneously, the insulating shell of BaTiO3 blocks the conductive path between FeSiAl, reducing eddy current loss and improving absorption efficiency. The SiC / glass fiber structure scatters sound wave energy through Helmholtz resonance, enhancing acoustic damping, and dissipates electromagnetic wave energy through interface polarization, providing structural support for multi-field coupling.

[0043] 5. This invention innovatively constructs a hollow SiC nanowire biomimetic structure. Hollow SiC nanowires inclined to the glass fiber surface are constructed on the glass fiber surface through airflow pulverization-melt embedding method. This structure enhances sound wave dissipation through Helmholtz resonance and enhances electromagnetic wave absorption through interface polarization, simultaneously improving acoustic damping and electromagnetic wave absorption performance. This results in a sound transmission loss of ≥13dB in the 100-1000Hz frequency range of the composite material, while maintaining a bending strength of ≥140MPa. This avoids the defects of aerogels, which, when improving damping through porous structures, will simultaneously lead to a decrease in interface bonding strength and limited improvement in acoustic damping.

[0044] 6. This invention employs a dual-network chemical compatibilization technology, which uses a composite system of anhydride-based polymers and epoxy-based polymers to form a chemically bonded cross-linked network during the melting process. This results in the composite material exhibiting less than 6% degradation in performance relative to its initial properties after aging at 200°C for 500 hours, while maintaining an interfacial shear strength of ≥20MPa after aging. This achieves low degradation while maintaining high strength, thus overcoming the problem of interfacial failure under high strength and high temperature conditions.

[0045] 7. The preparation method of the glass fiber reinforced composite material with dual functions of wave absorption and damping disclosed in this invention is simple, easy to control, and uses general polymer processing equipment, which is highly efficient and conducive to industrial production. Detailed Implementation

[0046] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0047] The raw materials and reagents used in this application are all commercially available products. Among them, the alkali-free chopped glass fibers are cylindrical with an average diameter of 3~20μm and an average length of 1~5mm.

[0048] Example 1 This embodiment illustrates the preparation of glass fibers with surface-embedded hollow SiC nanowires. The specific preparation method is as follows: Hollow SiC nanowires and a silane coupling agent (KH-DN42) were added to anhydrous ethanol at a mass ratio of 1:0.5 and stirred at high speed using an air jet mill (600 rpm) to form a suspension. The suspension was then deagglomerated by passing a 6 bar high-pressure air jet and simultaneously spray-dried to obtain surface-modified dispersed SiC nanowires.

[0049] Alkali-free chopped glass fiber (Taishan ECS10-3.0-T435N) and compatibilizer were added to a high-speed hot mixer at a mass ratio of 1:2 and mixed at 800 rpm for 5 min. Then, pre-dispersed SiC nanowires were added in batches at a mass ratio of glass fiber to SiC of 1:1 and mixed for 15 min. This yields a surface-embedded hollow SiC nanowire glass fiber with an interface structure of "glass fiber-compatibilizer-SiC". The compatibilizers include anhydride-based polymers (SEBS-g-MAH KETEN FG1901, with a weight-average molecular weight of approximately 100,000 g / mol and a grafting rate of approximately 1 wt%) and epoxy-based polymers (polypropylene glycol diglycidyl ether, with an epoxy equivalent of 180-200 g / eq); the molar ratio of the anhydride groups in SEBS-g-MAH to the epoxy groups in polypropylene glycol diglycidyl ether is 1:0.6.

[0050] Example 2 This embodiment illustrates the preparation of FeSiAl@BaTiO3 core-shell magnetic particles. The specific preparation method is as follows: Step 1: Immerse 40g of FeSiAl powder in 500mL of 0.5M oxalic acid solution for 60 minutes. o C-ultrasound treatment for 30 minutes to remove the surface Fe2O3 layer.

[0051] Step 2: Treat the acid-etched powder with a 2wt% silane coupling agent (KH-550) ethanol solution (silane coupling agent to powder mass ratio is 0.2:1), 70 o Reflux at 80°C for 2 hours. The resulting powder was washed three times successively with anhydrous ethanol and deionized water. o Vacuum drying at C yields FeSiAl.

[0052] Step 3: 200 mL of 0.1 M tetrabutyl titanate / anhydrous ethanol solution was added dropwise to 200 mL of 0.1 M Ba(OH)₂·8H₂O aqueous solution. After stirring evenly, the solution was transferred to a polytetrafluoroethylene liner. The FeSiAl obtained in Step 2 was then dispersed in the precursor mixture. The mixture was sonicated for 30 minutes. The reactor was then assembled and placed in a 50 °C oven for programmed temperature increase to 200 °C at a rate of 1 °C / min, and maintained for 12 hours. The reaction product was centrifuged and washed three times sequentially with anhydrous ethanol, dilute acetic acid, and deionized water, and then vacuum dried at 80 °C. This yielded FeSiAl@BaTiO₃ core-shell magnetic particles. The FeSiAl magnetic core diameter was 100–200 nm, and the BaTiO₃ piezoelectric shell thickness was 10–20 nm.

[0053] Example 3 This embodiment illustrates the preparation of a glass fiber reinforced composite material with dual functions of wave absorption and damping. The raw material components and their weight parts are as follows: 100 parts of SPS resin (Idemitsu SPS 90ZC, α-crystal form, molecular weight approximately 230,000 g / mol). 20 portions of glass fiber with surface-embedded hollow SiC nanowires (prepared in Example 1); Eight portions of FeSiAl@BaTiO3 core-shell magnetic particles (prepared in Example 2); 0.5 parts of carbon nanotube aerogel particles (average diameter 30~50μm); 8 parts of hydrogenated styrene-ethylene-butene-styrene block copolymer toughening agent (Yuehua YH503T); 0.5 parts nucleating agent (calcium tetrahydrophthalate); 0.2 parts antioxidant (0.1 parts antioxidant 1098, 0.1 parts antioxidant 626); 0.2 parts lubricant (0.1 parts ethylene bis-stearamide, 0.1 parts polysiloxane); The specific preparation steps are as follows: Syndiotactic polystyrene resin, magnetic particles, carbon nanotube aerogel microparticles, and additives are added to a high-speed mixer in parts by weight and mixed evenly to obtain a mixture. The mixture is then fed through a main feed loss-in-weight scale, while short-cut glass fibers with hollow SiC nanowires embedded on their surface are fed through a side feed loss-in-weight scale. All materials are co-extruded through a twin-screw extruder, and after being drawn, water-cooled, and pelletized, a glass fiber reinforced SPS composite material with both high-frequency electromagnetic wave absorption and broadband mechanical vibration damping functions is obtained.

[0054] The specific process parameters for co-extrusion using a twin-screw extruder are as follows: the twin-screw extruder is divided into ten temperature zones, with zones one to three being pre-melting zones at a temperature of 260°C. o C; Zones four to six are the cross-linking reaction zones, with a temperature of 270°C. o C, Zones 7 to 10 are homogenized zones with a temperature of 265°C. o C; The head temperature is 275°C. o C; The twin-screw extruder operates at a speed of 320 rpm.

[0055] Example 4 This embodiment illustrates the preparation of a glass fiber reinforced composite material with dual functions of wave absorption and damping. The raw material components and weight parts used are the same as in Example 3, except that: 15 parts of FeSiAl@BaTiO3 core-shell magnetic particles were added.

[0056] Example 5 This embodiment illustrates the preparation of a glass fiber reinforced composite material with dual functions of wave absorption and damping. The raw material components and weight parts used are the same as in Example 3, except that: 20 parts of FeSiAl@BaTiO3 core-shell magnetic particles were added.

[0057] Example 6 This embodiment illustrates the preparation of a glass fiber reinforced composite material with dual functions of wave absorption and damping. The raw material components and weight parts used are the same as in Example 3, except that: In the glass fibers with added surface-embedded hollow SiC nanowires, the mass ratio of glass fiber to SiC is 1:2.

[0058] Example 7 This embodiment illustrates the preparation of a glass fiber reinforced composite material with dual functions of wave absorption and damping. The raw material components and weight parts used are the same as in Example 3, except that: When preparing glass fibers with surface-embedded hollow SiC nanowires, the molar ratio of anhydride groups in SEBS-g-MAH to epoxy groups in polypropylene glycol diglycidyl ether is 1:0.8.

[0059] Example 8 This embodiment illustrates the preparation of a glass fiber reinforced composite material with dual functions of wave absorption and damping. The raw material components and weight parts used are the same as in Example 3, except that: sPS resin is β-crystalline syndiotactic polystyrene (obtained by direct twin-screw extrusion of sPS90ZC followed by rapid cooling with supercooling water). When preparing FeSiAl@BaTiO3 core-shell magnetic particles, KH-560 was used as the silane coupling agent.

[0060] Example 9 This embodiment illustrates the preparation of a glass fiber reinforced composite material with dual functions of wave absorption and damping. The raw material components and weight parts used are the same as in Example 3, except that: The amount of glass fiber used for surface-embedded hollow SiC nanowires is 15 parts by weight; The amount of FeSiAl@BaTiO3 core-shell magnetic particles used is 5 parts by weight.

[0061] Example 10 This embodiment illustrates the preparation of a glass fiber reinforced composite material with dual functions of wave absorption and damping. The raw material components and weight parts used are the same as in Example 3, except that: The amount of glass fiber used for surface-embedded hollow SiC nanowires is 30 parts by weight; The amount of FeSiAl@BaTiO3 core-shell magnetic particles used is 25 parts by weight.

[0062] Example 11 This embodiment illustrates the preparation of a glass fiber reinforced composite material with dual functions of wave absorption and damping. The raw material components and weight parts used are the same as in Example 3, except that: When preparing surface-embedded hollow SiC nanowires, the mass ratio of glass fiber to SiC is 1:0.5. The molar ratio of the anhydride group to the polypropylene glycol diglycidyl ether epoxy group in SEBS-g-MAH is 1:1.0.

[0063] Comparative Example 1 This comparative example illustrates the preparation of glass fiber reinforced composite material with dual functions of wave absorption and damping. The raw material components and weight parts used are the same as in Example 3, except that 108 parts of sPS resin are added and FeSiAl@BaTiO3 core-shell magnetic particles are not added.

[0064] Comparative Example 2 This comparative example illustrates the preparation of glass fiber reinforced composite material with dual functions of wave absorption and damping. The raw material components and weight parts used are the same as in Example 3. The difference is that the glass fiber is not modified with SiC nanowires, that is, alkali-free short-cut glass fiber is added.

[0065] Comparative Example 3 This comparative example illustrates the preparation of glass fiber reinforced composite material with dual functions of wave absorption and damping. The raw material components and weight parts used are the same as in Example 3. The difference is that when preparing glass fibers with hollow SiC nanowires embedded in the surface, the compatibilizer is only a polymer with an anhydride group (SEBS-g-MAH).

[0066] Comparative Example 4 This comparative example illustrates the preparation of glass fiber reinforced composite material with dual functions of absorbing and damping. The raw material components and weight parts used are the same as in Example 3. The difference is that 8 parts of FeSiAl@BaTiO3 core-shell magnetic particles are replaced with an equal amount of silicon-based aerogel absorbing filler (purchased from Langfang Kenuo Building Materials).

[0067] Comparative Example 5 This comparative example illustrates the preparation of a glass fiber reinforced composite material with dual functions of wave absorption and damping. The raw material components and weight parts used are the same as in Example 3, except that 100.5 parts of sPS resin are added and carbon nanotube aerogel particles are not added.

[0068] The composite materials of the above embodiments and comparative examples were subjected to performance tests, and the test methods are as follows: (1) Absorption performance: The electromagnetic wave absorption rate in the 8GHz and 12GHz frequency bands was measured according to IEEE 1128. The arched frame method or bow method was used, and the sample size was ≥300×300mm.

[0069] (2) Damping performance: The loss factor (tanδ) was measured at 500 Hz, 1 kHz, and 2 kHz using a dynamic thermomechanical analyzer, with reference to ASTM D4065. The three-point bending mode was used, with a frequency of 1 kHz and a heating rate of 3 ℃ / min. tanδ = E'' / E' (loss modulus / storage modulus), which characterizes the energy dissipation capacity of internal friction.

[0070] (3) Acoustic damping: The impedance tube method was used to test according to ISO 10534-2 standard. A four-microphone system was used, the sample diameter was ≥100mm, and the acoustic transmission loss STL value in the 100-1000Hz frequency band was measured.

[0071] (4) Mechanical properties: Bending strength was tested according to ISO 178:2019E, with a specimen size of 80mm×10mm×4mm, a test speed of 2mm / min, and a span of 64mm. Tensile strength was tested according to ISO 527-2-2012, with a specimen size of 150mm×10mm×4mm and a tensile speed of 5mm / min.

[0072] (5) 1.82 MPa heat distortion temperature test: The 1.82 MPa heat distortion temperature test was conducted using an RV-300A heat distortion Vicat temperature measuring instrument. The test standard was GB / T1634-2001, and the test sample was 80 mm × 10 mm × 4 mm.

[0073] (6) Interface shear strength: The short beam shear test (SBS) was conducted according to ISO 14130. High shear stress was generated in the specimen by three-point bending loading and using a small span-to-thickness ratio (span / thickness). The span was 8 mm, the thickness was 2 mm, and the test sample size was 20 mm × 6 mm × 2 mm.

[0074] (7) Resistance to damp heat aging: Each product was placed at 200°C. o C. After 500 hours in an environment with a relative humidity of 85%, cool to room temperature and test the tensile strength of the aged product again. Calculate the retention rate of tensile strength. The higher the value, the better the resistance to damp heat aging. The test method for tensile strength is the same as the test method for tensile properties in (4).

[0075] The performance test results of the composite materials of the above embodiments and comparative examples are detailed in Tables 1 and 2: Table 1: Wave Absorption and Damping Performance

[0076] Table 2: Mechanical properties, heat resistance, and aging resistance

[0077] As shown in Tables 1 and 2, the composite materials of Examples 3-11 exhibit excellent, efficient, and stable multifunctional characteristics in both high-frequency (8-12 GHz) and wide-frequency (100-1000 Hz) ranges, displaying typical broad peak characteristics rather than single-frequency characteristics, effectively covering the target high-frequency and wide-frequency range. This indicates that the FeSiAl@BaTiO3 core-shell filler, combined with the hollow SiC nanowire biomimetic structure and dual-network compatibilization system, successfully achieved synergistic optimization of microwave absorption, damping, mechanical properties, and heat resistance.

[0078] Furthermore, as shown in Example 3 and Comparative Example 1, the absorption rate of Example 3 (94.0%@8GHz) is significantly higher than that of Comparative Example 1 (40.0%@8GHz, without core-shell filler), proving that a single sPS / glass fiber matrix has almost no absorption capability. In contrast, this invention, by introducing FeSiAl@BaTiO3 core-shell particles, achieves synergy between magnetic and dielectric losses, forming an effective electromagnetic loss network.

[0079] Furthermore, as shown in Example 3 and Comparative Example 4, although the absorption rate of Comparative Example 4 (94.2%@8GHz) is close to that of Example 3, its damping performance (tanδ at 1kHz) is only 0.09 and its acoustic damping STL is only 7.8dB, which are far lower than those of Example 3 (0.15 and 14.5dB), respectively, thus failing to achieve synergistic absorption and damping functions. This indicates that the FeSiAl@BaTiO3 core-shell filler has a much higher electromagnetic energy conversion efficiency than traditional porous absorbing materials that rely on pore scattering (such as silicon-based aerogels with large addition amounts).

[0080] Furthermore, as shown in Example 3 and Comparative Example 2, the damping factor of Example 3 (0.15 @ 1 kHz) is higher than that of Comparative Example 2 (0.112 @ 1 kHz, using unmodified glass fiber). This indicates that the hollow SiC nanowire biomimetic structure obliquely embedded on the glass fiber surface can effectively dissipate vibrational energy through interfacial friction and mechanical interlocking. Furthermore, the acoustic damping of Example 6 (glass fiber:SiC = 1:2, STL 15.8) is significantly higher than that of Example 3 with the basic formulation (glass fiber:SiC = 1:1, STL 14.5), indicating that increasing the SiC content increases the number of Helmholtz resonant cavities per unit volume, which enhances the resonant scattering energy dissipation of low-frequency sound waves. Even further, the flexural strength (160 MPa) and interfacial shear strength (23.7 MPa) of Example 3 are both higher than those of Comparative Example 2 (156 MPa, 17.2 MPa). This indicates that the mechanical interlocking structure formed by the tilted embedded SiC nanowires greatly improves the stress transfer efficiency between the glass fiber and the resin matrix.

[0081] Furthermore, as shown in Example 3 and Comparative Example 3, when Comparative Example 3 uses a single SEBS-g-MAH without epoxy compound crosslinking, the initial interfacial shear strength is only 17.3 MPa, far lower than the shear strength of 23.7 MPa in Example 3. This indicates that the present invention employs a dual-network chemical compatibilization technology to form a chemically bonded crosslinked network during the melting process. Its thermal stability is superior to physical entanglement, resulting in a composite material that, after aging at 200°C for 500 hours, exhibits less than 6% degradation relative to its initial properties, and the interfacial shear strength remains ≥23 MPa after aging. This demonstrates better maintenance of interfacial integrity under high-strength, high-temperature, and long-term use.

[0082] Furthermore, as can be seen from Example 3 and Comparative Example 5, Comparative Example 5 (without adding trace amounts of carbon nanotube aerogel particles, absorption 87.5%@8GHz, damping 0.13@1kHz) has lower absorption and damping performance than Example 3, proving that the trace amounts of carbon nanotube aerogel particles added in this invention can improve interfacial polarization and micropore energy dissipation without deteriorating mechanical properties, and further optimize absorption and damping performance.

[0083] Furthermore, the heat distortion temperature and interfacial shear strength of Example 7 (anhydride / epoxy molar ratio 1:0.8) are both better than those of Example 3 (1:0.6), indicating that optimizing the compatibilizer functional group ratio can further improve the crosslinking density and interfacial strength.

[0084] Furthermore, Example 6, by increasing the glass fiber / SiC ratio to 1:2, further improved the microwave absorption performance (96.5%@8GHz), acoustic damping (STL 15.8dB), and interfacial shear strength (24.5MPa), demonstrating the significant advantages of high-SiC content biomimetic structures in multifunctional integration. Simultaneously, due to the introduction of more interfacial stress concentration points by the high-content rigid SiC nanowires, the bending strength exhibited a controllable decrease (140MPa). This illustrates that the multi-level structural design method provided by this invention possesses high flexibility, allowing for customization of the final product's overall performance by optimizing the component ratio (such as the glass fiber to SiC ratio) according to different emphases on "mechanical strength, broadband microwave absorption, and efficient damping" in practical applications.

[0085] Furthermore, even with a reduction in the amount of core-shell filler (5 parts) and glass fiber (15 parts), Example 9 still exhibits superior overall performance.

[0086] Furthermore, when the amount of filler is increased in Example 10, the absorption (97%@8GHz), damping (0.19@1kHz), and heat distortion temperature (258°C) are improved. o C) Further improvements were made. The tensile strength decreased slightly to 108 MPa due to the increased filler content, but still meets the engineering requirements.

[0087] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A glass fiber reinforced composite material with dual functions of wave absorption and damping, made from raw materials comprising the following components, wherein the weight parts of each component are as follows, based on 100 parts by weight of syndiotactic polystyrene: 100 parts by weight of syndiotactic polystyrene resin; 15-30 parts by weight of glass fiber; preferably 20-30 parts by weight; Magnetic particles: 5-25 parts by weight; preferably 8-20 parts by weight; The carbon nanotube aerogel particles are 0.3 to 2.0 parts by weight; preferably 0.5 to 1.0 parts by weight.

2. The glass fiber reinforced composite material with dual functions of absorbing and damping as described in claim 1, characterized in that, The molecular weight of the syndiotactic polystyrene resin is 150,000 to 300,000, preferably 250,000 to 300,000; and / or, The syndiotactic polystyrene resin is selected from one or a combination of α-crystalline, β-crystalline, γ-crystalline, and δ-crystalline forms.

3. The glass fiber reinforced composite material with dual functions of absorbing and damping as described in claim 1, characterized in that, The glass fiber is selected from glass fibers with surface-embedded hollow SiC nanowires; Preferably, the glass fiber with surface-embedded hollow SiC nanowires is prepared by melt coating method; More preferably, the method for preparing the glass fiber with surface-embedded hollow SiC nanowires includes the following steps: Step 1: Hollow SiC nanowires and silane coupling agent A are mixed in a solvent and stirred to obtain a suspension. The suspension is then dried by airflow and spray to obtain surface-modified dispersed SiC nanowires. Step 2: First, mix the alkali-free chopped glass fiber and compatibilizer, then add the surface-modified dispersed SiC nanowires and mix again to obtain glass fiber with surface-embedded hollow SiC nanowires.

4. The glass fiber reinforced composite material with dual functions of absorbing and damping as described in claim 3, characterized in that, The mass ratio of the hollow SiC nanowires to silane coupling agent A is 1:(0.1~1.5); preferably 1:(0.3~1.0); and / or, The mass ratio of the alkali-free chopped glass fiber, hollow SiC nanowires, and compatibilizer is 1:(0.5~5):(0.1~2); preferably 1:(0.5~2):(0.1~1.5); and / or, The alkali-free chopped glass fibers have a cylindrical microstructure with an average diameter of 3-20 μm, preferably 10-15 μm; an average length of 1-5 mm, preferably 3-4 mm; and / or, The silane coupling agent A is selected from silane coupling agents with one or more functional groups selected from epoxy, phenyl, and amino groups; and / or, The compatibilizer is selected from a compound system of polymer A with an anhydride group and polymer B with an epoxy group; Preferably, the molar ratio of the anhydride groups in the anhydride-based polymer A to the epoxy groups in the epoxy-based polymer B is 1:(0.3~1.2); more preferably 1:(0.6~0.8); and / or, Preferably, the anhydride-based polymer A is selected from maleic anhydride-grafted elastomer polymers, more preferably from one or a combination of SEBS-g-MAH, POE-g-MAH, and EPDM-g-MAH; and / or, Preferably, the grafting rate of the anhydride groups in the polymer A with anhydride groups is 0.5~2.0 wt%, more preferably 1.0~1.5 wt%; and / or, Preferably, the weight-average molecular weight of the anhydride-based polymer A is 100,000 to 300,000, more preferably 200,000 to 300,000; and / or, Preferably, the epoxy-containing polymer B is selected from alicyclic epoxy polymers, glycidyl ether type polymers, more preferably from one or a combination of 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate and polypropylene glycol diglycidyl ether; and / or, Preferably, the epoxy equivalent of the epoxy polymer B is 50~200 g / eq, more preferably 180~200 g / eq.

5. The glass fiber reinforced composite material with dual functions of absorbing and damping as described in claim 1, characterized in that, The magnetic particles are selected from FeSiAl@BaTiO3 core-shell magnetic particles; wherein, the diameter of the FeSiAl magnetic core is 50~300nm, preferably 50~200nm; and the thickness of the BaTiO3 piezoelectric shell layer is 5~45nm, preferably 5~30nm. Preferably, the preparation method of the FeSiAl@BaTiO3 core-shell magnetic particles includes the following steps: Step 1: Immerse FeSiAl in acid solution and sonicate to remove the Fe2O3 layer on the surface, thus obtaining powder; Step 2: Mix silane coupling agent B with the powder from Step 1, and heat-treat to obtain FeSiAl; Step 3: Mix tetrabutyl titanate solution and Ba(OH)2 solution evenly to obtain precursor mixture, then add FeSiAl from step 2, sonicate and heat to obtain FeSiAl@BaTiO3 core-shell magnetic particles. More preferably, in step one, The acid is selected from one or a combination of citric acid, oxalic acid, and acetic acid; and / or, The molar concentration of the acid solution is 0.1~2M, preferably 0.5~1M; and / or, The ultrasonic treatment temperature is 60~80℃; the treatment time is 10~30 minutes; and / or, More preferably, in step two, The silane coupling agent B is selected from one or a combination of γ-aminopropyltriethoxysilane coupling agent, γ-glycidoxypropyltrimethoxysilane coupling agent, γ-methacryloyloxypropyltrimethoxysilane coupling agent, and anilinemethyltriethoxysilane coupling agent; and / or, The mass ratio of the silane coupling agent B to the powder is (0.2~2.0):1, preferably (0.5~1.0):1; and / or, The heating temperature is 70~80℃; the processing time is 2~3 hours; and / or, More preferably, in step three, The molar concentration of the tetrabutyl titanate solution is 0.1~2M, preferably 0.5~1M; and / or, The molar concentration of the Ba(OH)₂ solution is 0.1~2M, preferably 0.5~1M; and / or, The molar ratio of tetrabutyl titanate, Ba(OH)₂, and FeSiAl is 1:(0.5~1.0):(1.0~2.0), preferably 1:(0.6~0.8):(1.1~1.3); and / or, The ultrasonic treatment time is 15-30 minutes; and / or, The heating temperature is 150~250℃, preferably 180~200℃; the heating time is 12~18 hours.

6. The glass fiber reinforced composite material with dual functions of absorbing and damping as described in claim 1, characterized in that, The average diameter of the carbon nanotube aerogel particles ranges from 30 to 50 μm, preferably from 35 to 50 μm.

7. The glass fiber reinforced composite material with dual functions of absorbing and damping as described in claim 1, characterized in that, It also includes components such as toughening agents, nucleating agents, antioxidants, and lubricants. Based on 100 parts by weight of syndiotactic polystyrene, the weight parts of each component are as follows: 100 parts by weight of syndiotactic polystyrene; Toughening agent: 1-8 parts by weight; preferably 4-8 parts by weight; Nucleating agent: 0.2-1 parts by weight; preferably 0.5-1 parts by weight; Antioxidant: 0.1-0.4 parts by weight; preferably 0.1-0.3 parts by weight; The lubricant is used in amounts of 0.1 to 0.4 parts by weight; preferably 0.1 to 0.3 parts by weight.

8. The glass fiber reinforced composite material with dual functions of absorbing and damping as described in claim 7, characterized in that, The toughening agent is selected from hydrogenated styrene-ethylene-butene-styrene block copolymer; Preferably, the hydrogenated styrene-ethylene-butene-styrene block copolymer has a molecular weight of 50,000 to 300,000, more preferably 250,000 to 300,000; the styrene segments account for 10% to 35% of the copolymer mass, more preferably 17% to 33%; and / or, The nucleating agent is selected from one or more of the following: sodium benzoate, saline resin, aluminum hydroxyl p-tert-butylbenzoate, 2,2'-methylene-bis(4,6-di-tert-butylphenoxy) phosphate, 2,2'-methylene-bis(4,6-di-tert-butylphenyl phosphate) basic aluminum, sodium 2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate, calcium tetrahydrophthalate, and talc; and / or... The antioxidant is selected from one or more of antioxidant 1098, antioxidant 626, antioxidant S9228, and antioxidant DSTP; and / or, The lubricant is selected from one or more of calcium stearate, ethylene bis-stearamide, and polysiloxane.

9. A method for preparing a glass fiber reinforced composite material with dual functions of absorbing and damping according to any one of claims 1 to 8, comprising the following steps: The components, including syndiotactic polystyrene resin, magnetic particles, carbon nanotube aerogel particles, and additives, are mixed to obtain a mixture. The components, including the mixture and glass fiber, are then co-extruded to obtain a glass fiber reinforced composite material with dual functions of wave absorption and damping.

10. The application of the glass fiber reinforced composite material with dual functions of absorbing and damping as described in any one of claims 1 to 8, for use in electronic appliances, 5G communication equipment, and automotive parts.

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