Broadband rubber wave-absorbing material and preparation method thereof
By using a composite absorber composed of Fe3O4 nanoparticles loaded on the surface of polypyrrole nanotubes in a rubber-based absorbing material, the balance between dielectric loss and magnetic loss is regulated, solving the problem of difficult coordinated optimization of impedance matching and strong absorption performance in the existing technology, and achieving broadband absorption performance and cost advantages.
Patent Information
- Application Number
- CN202510801581.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-16
- Publication Date
- 2025-09-16
AI Technical Summary
Existing rubber-based absorbing materials are difficult to synergistically optimize in terms of impedance matching and strong absorption performance, and the absorbing frequency band is relatively narrow.
A composite absorber with Fe3O4 nanoparticles uniformly loaded on the surface of polypyrrole nanotubes is used. By precisely controlling the mass ratio of polypyrrole nanotubes and Fe3O4, the balance between dielectric loss and magnetic loss is optimized, thereby improving the impedance matching characteristics.
It achieves broadband absorption performance, and can cover the entire X-band with an effective absorption bandwidth of reflection loss (RL) ≤ -10dB at a thickness of 3.1mm. It has significant cost advantages and is easy to mass-produce.
Smart Images
Figure CN120648043A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of functional composite materials, and in particular to a broadband rubber absorbing material and a preparation method thereof. Background Art
[0002] With the rapid development of modern electronic technology, electromagnetic wave pollution has become the fourth largest environmental hazard after noise pollution, water pollution, and air pollution. Electromagnetic interference not only seriously affects the normal operation of electronic equipment and threatens the security of information transmission, but also poses potential risks to human health. Absorbing materials, which can effectively dissipate incident electromagnetic wave energy by converting it into heat or other forms of energy, have become a key technological solution to electromagnetic pollution and radar detection issues. Ideal absorbing materials should be lightweight, have a wide bandwidth, strong absorption properties, and good environmental adaptability.
[0003] Rubber-based absorbing materials have attracted much attention due to their excellent electromagnetic wave absorption performance and good mechanical properties. They also have advantages such as corrosion resistance, good flexibility, easy processing and molding, strong adhesion, and tailorability, which can meet the coating requirements of complex-shaped devices. Currently, rubber-based absorbing materials mainly achieve electromagnetic wave absorption performance by adding functional absorbing fillers. Commonly used absorbers include magnetic loss-type materials such as ferrite and carbonyl iron, as well as dielectric loss-type materials such as carbon nanotubes, graphene, and conductive polymers. However, existing technologies still have problems such as difficulty in synergistically optimizing impedance matching and strong absorption performance, and a narrow absorption bandwidth. Summary of the Invention In view of the above problems, the present invention provides a broadband rubber absorbing composite material and a preparation method thereof. To achieve the above objectives, the present invention adopts the following technical solutions: The present invention provides a broadband rubber wave-absorbing composite material, comprising the following components in parts by weight: 50-70 parts natural rubber Nitrile rubber 50-30 parts 12-15 parts of absorbent 1 part accelerator 3 parts zinc oxide 1 part stearic acid 1.5 parts antioxidant 2 parts sulfur The total weight fraction of the natural rubber and the nitrile rubber is 100 parts; The wave absorbing agent is a composite wave absorbing agent in which Fe3O4 nanoparticles are uniformly loaded on the surface of polypyrrole nanotubes.
[0004] Preferably, the conductivity of the composite absorber is 0.161 S / cm and the saturation magnetization is 20.5 emu*g -1The mass ratio of polypyrrole nanotubes to Fe3O4 in the composite absorber is 1.7:1, the diameter of the polypyrrole nanotubes in the composite absorber is 50-100 nm, and the particle size of the Fe3O4 nanoparticles is 20-30 nm.
[0005] Preferably, the preparation method of the composite absorber is as follows: Under a nitrogen atmosphere, 0.015 mol of pyrrole monomer and 0.00075 mol of methyl orange were dissolved in 50 ml of deionized water. Then, 50 ml of 0.3 MFeCl₃ aqueous solution was added to the mixture at a rate of 1.5 ml / min using a syringe pump. After 1 hour of reaction, 4.5 ml of triethylamine was added to the reaction system. The mixture was then magnetically stirred at room temperature for 12 hours to ensure sufficient reaction. After the reaction, the product was alternately filtered and washed with anhydrous ethanol and deionized water until the filtrate reached a neutral pH. The resulting solid product was then transferred to a vacuum oven and dried at 60°C for 12 hours to obtain a composite absorber.
[0006] Preferably, the accelerator is selected from any one of N-tert-butyl-2-benzothiazole sulfenamide (NS), N,N-dicyclohexyl-2-benzothiazole sulfenamide (DZ), N-oxydiethylene-2-benzothiazole sulfenamide (NOBS) or N-cyclohexyl-2-benzothiazole sulfenamide (CZ).
[0007] Preferably, the antioxidant is selected from any one of 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD), N-phenyl-2-naphthylamine (D) or N,N'-diphenyl-p-phenylenediamine (DPPD).
[0008] The present invention also provides a method for preparing the above-mentioned X-band full-frequency absorption rubber absorbing composite material, comprising the following steps: Step (1), setting the initial temperature of the open mill roller to 45 ° C, the roller gap distance to 1.0 mm, and the speed ratio to 30 / 20, adding natural rubber and nitrile rubber to the open mill and wrapping the rollers, and achieving uniform blending by multiple tapping; adding antioxidant, stearic acid, and zinc oxide in sequence, and continuing to tap to ensure that the additives are fully dispersed; adding composite absorber and repeatedly refining to ensure that the filler is dispersed, and finally adding sulfur and accelerator at the same time, repeatedly refining until the mixture is uniform, and then thinly sheeting to obtain a mixed rubber; Step (2), vulcanizing and molding the rubber mixture obtained in step (1) on a flat vulcanizer to obtain a rubber absorbing material with full-frequency absorption in the X-band.
[0009] Preferably, the vulcanization temperature in step (2) is 175°C.
[0010] Compared with the prior art, the present invention has the following advantages: This invention achieves synergistic control of electromagnetic properties through an innovative composite structure of polypyrrole nanotubes and Fe₃O₄ nanoparticles. By precisely controlling the mass ratio of polypyrrole nanotubes to Fe₃O₄, the composite achieves an ideal balance between dielectric and magnetic losses, thereby optimizing impedance matching. Furthermore, the composite structure avoids the agglomeration of the absorber in the rubber matrix caused by physical mixing. Simultaneously, the controlled blending ratio of the rubber matrix further optimizes the dispersion and interfacial interactions of the composite absorber. This dual-scale control strategy (component ratio control and matrix compatibility design) effectively establishes multiple loss mechanisms: the polypyrrole nanotubes provide dielectric loss, the uniformly distributed Fe₃O₄ particles enhance magnetic loss, and the interface between the two enhances polarization relaxation. This synergistic effect gives the composite broadband absorption, enabling full-band absorption from 8.2 to 12.4 GHz. At a thickness of 3.1 mm, the effective absorption bandwidth, with a reflection loss (RL) ≤ -10 dB, covers the entire X-band.
[0011] The preparation process of the present invention is simple, has significant cost advantages, and is easy to achieve large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 This is a scanning electron microscope image of the composite absorber in Example 1 of the present invention; Figure 2 This is a transmission electron microscope image of the composite absorber in Example 1 of the present invention; Figure 3 This is an infrared spectrum of the composite absorber in Example 1 of the present invention; Figure 4 is the XRD pattern of the composite absorber in Example 1 of the present invention; Figure 5 This is a thermogravimetric diagram of the composite absorber in Example 1 of the present invention; Figure 6 1-2 and 1-3 are reflection loss curves of the rubber absorbing materials in Examples 1-2 of the present invention and Comparative Example 1. DETAILED DESCRIPTION
[0013] The present invention will be further described below in conjunction with specific embodiments, and the advantages and features of the present invention will become clearer as the description proceeds. However, the embodiments are merely exemplary and do not limit the scope of the present invention in any way. It should be understood by those skilled in the art that the details and forms of the technical solutions of the present invention may be modified or replaced without departing from the spirit and scope of the present invention, and such modifications and replacements fall within the scope of protection of the present invention.
[0014] Example 1 This embodiment provides a broadband rubber absorbing composite material, which includes the following components in parts by weight: 50 parts of natural rubber; 50 parts of nitrile rubber; 15 parts of a composite absorber having Fe3O4 nanoparticles uniformly loaded on the surface of polypyrrole nanotubes; 1.5 parts of an antioxidant RD; 3 parts of zinc oxide; 1 part of stearic acid; 1 part of an accelerator NS; and 2 parts of sulfur.
[0015] The composite absorber with Fe3O4 nanoparticles uniformly loaded on the surface of polypyrrole nanotubes is prepared by the following method: Under a nitrogen atmosphere, 0.015 mol of pyrrole monomer and 0.00075 mol of methyl orange were dissolved in 50 ml of deionized water. Then, 50 mL of 0.3 M FeCl₃ aqueous solution was added to the mixed solution at a rate of 1.5 ml / min using a syringe pump. After 1 hour of reaction, 4.5 ml of triethylamine was added to the reaction system. The mixed solution was then magnetically stirred at room temperature for 12 hours to ensure sufficient reaction. After the reaction, the product was alternately filtered and washed with anhydrous ethanol and deionized water until the filtrate reached a neutral pH. The resulting solid product was then transferred to a vacuum oven and dried at 60°C for 12 hours to obtain the composite absorber with Fe₃O₄ nanoparticles uniformly loaded on the surface of polypyrrole nanotubes.
[0016] The morphology, phase and composition of the obtained product were measured by scanning electron microscopy, transmission electron microscopy, XRD, infrared spectroscopy and thermal gravimetric analysis. Figure 1-5 As shown. According to the results of scanning electron microscopy and transmission electron microscopy analysis, the diameter of the prepared polypyrrole nanotubes is 50-100 nm, and its surface has a rough structural feature. Ferroferric oxide nanoparticles with a particle size of 20-30 nm are evenly distributed on the surface of the polypyrrole nanotubes. XRD and infrared spectroscopy tests confirmed that the composite absorber is composed of polypyrrole and ferroferric oxide. According to the thermal gravimetric results, it was calculated that the mass ratio of polypyrrole nanotubes to Fe3O4 is 1.7:1. The conductivity and saturation magnetization of the composite absorber were measured by four probes and hysteresis loops, which were 0.161 S / cm and 20.5 emu*g respectively. -1 .
[0017] The method for preparing the broadband rubber absorbing composite material comprises the following steps: Step (1): Set the initial temperature of the open mill roller to 45°C, the roller gap distance to 1.0 mm, and the speed ratio to 30 / 20, add natural rubber and nitrile rubber to the open mill and roll them, and achieve uniform blending by multiple tapping; add antioxidant, stearic acid, and zinc oxide in sequence, and continue tapping to ensure that the additives are fully dispersed; add composite absorber and ensure filler dispersion through multiple refining; finally, add sulfur and accelerator at the same time, repeatedly refining until the mixture is uniform, and then thinly slice it to obtain a mixed rubber.
[0018] Step (2): vulcanizing the rubber compound obtained in step (1) at 175° C. on a flat vulcanizing machine to obtain a rubber absorbing material.
[0019] Example 2 Compared with Example 1, the difference is that the formula of the broadband rubber absorbing material of this embodiment includes the following components in parts by weight: 70 parts of natural rubber; 30 parts of nitrile rubber; 15 parts of a composite absorber having Fe3O4 nanoparticles uniformly loaded on the surface of polypyrrole nanotubes; 1.5 parts of an antioxidant RD; 3 parts of zinc oxide; 1 part of stearic acid; 1 part of an accelerator NS; and 2 parts of sulfur.
[0020] The preparation method of the composite absorber with Fe3O4 nanoparticles uniformly loaded on the surface of polypyrrole nanotubes and the preparation method of the rubber absorbing material are the same as those in Example 1.
[0021] Comparative Example 1 This comparative example provides a rubber absorbing material, which is a wave absorbing agent formed by physically mixing polypyrrole nanotubes and Fe3O4 nanoparticles at a mass ratio of 1.7:1. The composition of the rubber absorbing material is shown below in parts by weight: 50 parts of natural rubber; 50 parts of nitrile rubber; 9.4 parts of polypyrrole nanotubes; 5.6 parts of Fe3O4 nanoparticles; 1.5 parts of antioxidant RD; 3 parts of zinc oxide; 1 part of stearic acid; 1 part of accelerator NS; and 2 parts of sulfur.
[0022] The preparation method of the rubber absorbing material in this comparative example is the same as that in Example 1.
[0023] The wave absorbing properties of the rubber absorbing materials in Examples 1-2 and Comparative Example 1 were tested by a waveguide method. Figure 6 The reflection loss of the rubber absorbing materials of Examples 1-2 and Comparative Example 1 within the 8.2-12.4 GHz frequency range is shown for samples with a thickness of 3.1 mm. Compared to Comparative Example 1, the reflection losses of the rubber absorbing materials of Examples 1-2 within the 8.2-12.4 GHz frequency range are all less than -10 dB, and the effective absorption frequency band covers the entire X-band.
[0024] The present invention will be further described below in conjunction with specific embodiments. The advantages and features of the present invention will be more clearly reflected in the description. However, the embodiments are merely exemplary and do not limit the scope of the present invention in any way. It should be understood by those skilled in the art that the details and forms of the technical solutions may be modified or replaced without departing from the spirit and scope of the present invention, and such modifications and replacements all fall within the scope of protection of the present invention.
Claims
1. A broadband rubber absorbing composite material, characterized in that: It comprises the following components in parts by weight: 50-70 parts natural rubber Nitrile rubber 50-30 parts 12-15 parts of absorbent 1 part accelerator 3 parts zinc oxide 1 part stearic acid 1.5 parts antioxidant 2 parts sulfur The total weight parts of the natural rubber and the nitrile rubber is 100 parts; The wave absorbing agent is a composite wave absorbing agent in which Fe3O4 nanoparticles are uniformly loaded on the surface of polypyrrole nanotubes.
2. The broadband rubber absorbing composite material according to claim 1, characterized in that: The conductivity of the composite absorber is 0.161 S / cm and the saturation magnetization is 20.5 emu*g -1 The mass ratio of polypyrrole nanotubes to Fe3O4 in the composite absorber is 1.7:1, the diameter of the polypyrrole nanotubes in the composite absorber is 50-100 nm, and the particle size of the Fe3O4 nanoparticles is 20-30 nm.
3. The broadband rubber absorbing composite material according to claim 1, characterized in that: The preparation method of the composite absorber is as follows: Under a nitrogen atmosphere, 0.015 mol of pyrrole monomer and 0.00075 mol of methyl orange were dissolved in 50 ml of deionized water. Then, 50 ml of 0.3M FeCl3 aqueous solution was added to the mixed solution at a drop rate of 1.5 ml / min using a syringe pump. After reacting for 1 hour, 4.5 ml of triethylamine was added to the reaction system. The mixed solution was then placed at room temperature and continuously magnetically stirred for 12 hours to ensure sufficient reaction. After the reaction, the product was alternately filtered and washed with anhydrous ethanol and deionized water until the pH value of the filtrate reached neutral. Then, the obtained solid product was transferred to a vacuum oven and dried at 60°C for 12 hours to obtain a composite absorber.
4. The broadband rubber absorbing composite material according to claim 1, characterized in that: The accelerator is selected from any one of N-tert-butyl-2-benzothiazole sulfenamide, N,N-dicyclohexyl-2-benzothiazole sulfenamide, N-oxydiethylene-2-benzothiazole sulfenamide or N-cyclohexyl-2-benzothiazole sulfenamide.
5. The broadband rubber absorbing composite material according to claim 1, characterized in that: The antioxidant is selected from any one of 2,2,4-trimethyl-1,2-dihydroquinoline polymer, N-phenyl-2-naphthylamine or N,N'-diphenyl-p-phenylenediamine.
6. The method for preparing a broadband rubber wave-absorbing composite material according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step (1), setting the initial temperature of the open mill roller to 45 ° C, the roller gap distance to 1.0 mm, and the speed ratio to 30 / 20, adding natural rubber and nitrile rubber to the open mill and wrapping the rollers, and achieving uniform blending by multiple tapping; adding antioxidant, stearic acid, and zinc oxide in sequence, and continuing to tap to ensure that the additives are fully dispersed; adding composite absorber and repeatedly refining to ensure that the filler is dispersed, and finally adding sulfur and accelerator at the same time, repeatedly refining until the mixture is uniform, and then thinly sheeting to obtain a mixed rubber; Step (2), vulcanizing and molding the rubber mixture obtained in step (1) on a flat vulcanizer to obtain a broadband rubber absorbing composite material.
7. The method for preparing a broadband rubber absorbing composite material according to claim 6, characterized in that: The vulcanization temperature in step (2) is 175°C.