CN114517015A - Wave-absorbing composition, wave-absorbing material and preparation method thereof - Google Patents
Wave-absorbing composition, wave-absorbing material and preparation method thereof Download PDFInfo
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Abstract
The invention provides a wave-absorbing composition, a wave-absorbing material and a preparation method thereof. The wave-absorbing composition comprises silicon rubber, polyurethane, a grafting agent, alloy magnetic powder, a conductive agent and a vulcanizing agent, wherein the grafting agent is used for grafting the polyurethane on a molecular chain of the silicon rubber. Different from simple physical blending, the polyurethane is grafted on a silicon rubber molecular chain by using a grafting agent, so that the polyurethane and the silicon rubber molecular chain are distributed more uniformly, and the formed wave-absorbing material has better comprehensive properties such as sealing property, mechanical strength and the like. In addition, alloy magnetic powder, conductive agent and vulcanizing agent are added into the wave-absorbing composition, the crosslinking reaction density of the wave-absorbing material is further enhanced by the vulcanizing agent, and the wave-absorbing performance of the material is further improved by the alloy magnetic powder and the conductive agent. Therefore, the wave-absorbing composition solves the problems of poor mechanical strength and poor flexibility of the wave-absorbing material in the prior art, and has the advantages of easily available raw materials and low cost.
Description
Technical Field
The invention relates to the technical field of wave-absorbing materials, in particular to a wave-absorbing composition, a wave-absorbing material and a preparation method thereof.
Background
The radar wave-absorbing material is widely applied to various parts of an aircraft such as a fuselage, wings and the like, in modern war, the electromagnetic interference can also influence the operation and the operation of a top weapon, and a communication command system can also generate a great obstacle due to the electromagnetic interference.
In the prior art, researchers prepare a blending rubber material into an interpenetrating network structure by adopting a compatilizer or mix two rubber materials by a physical blending method, so that the mechanical property of the wave-absorbing material is improved under the condition of not losing any material, but the obtained electromagnetic shielding silicone rubber often has the problems of high density, poor mechanical strength, poor flexibility and the like.
Disclosure of Invention
The invention mainly aims to provide a wave-absorbing composition, a wave-absorbing material and a preparation method thereof, and aims to solve the problems of poor mechanical strength and poor flexibility of the wave-absorbing material in the prior art.
In order to achieve the above object, according to one aspect of the present invention, there is provided a wave absorbing composition, which includes silicone rubber, polyurethane, a grafting agent, alloy magnetic powder, a conductive agent, and a vulcanizing agent, wherein the grafting agent is used for grafting the polyurethane on a molecular chain of the silicone rubber.
Further, the wave absorbing composition comprises 70-100 parts by weight of silicone rubber, 10-30 parts by weight of polyurethane, 2-4 parts by weight of grafting agent, 100-300 parts by weight of alloy magnetic powder, 50-100 parts by weight of conductive agent and 2-4 parts by weight of vulcanizing agent; preferably, the grafting agent is selected from one or more of aminopropyltriethoxysilane, vinyltriethoxysilane, trimethoxysilane and epoxy silane, the alloy magnetic powder is selected from one or more of iron-silicon-aluminum alloy powder, iron-silicon-chromium alloy powder and iron-cobalt alloy powder, and the conductive agent is nickel-plated fiber and/or silver powder.
Further, the weight ratio of the silicone rubber, the polyurethane and the grafting agent is 40-50: 10-15: 1-2.
According to one aspect of the invention, the wave absorbing material comprises a polymer base material, alloy magnetic powder and a conductive agent, wherein the alloy magnetic powder and the conductive agent are dispersed in the polymer base material, the polymer base material is cross-linked graft modified silicone rubber, the graft modified silicone rubber comprises a silicone rubber main chain and a polyurethane molecular chain grafted on the silicone rubber main chain, and the polyurethane molecular chain is grafted on the silicone rubber main chain by adopting the grafting agent.
Further, the wave-absorbing material comprises 70-100 parts by weight of a silicone rubber main chain, 10-30 parts by weight of a polyurethane molecular chain, 100-300 parts by weight of alloy magnetic powder and 50-100 parts by weight of a conductive agent, wherein the conductive agent is preferably nickel-plated fiber and/or silver powder.
Further, the weight part of the grafting agent is 2-4, the weight ratio of the silicone rubber main chain, the polyurethane molecular chain and the grafting agent is preferably 40-50: 10-15: 1-2, and the grafting agent is preferably selected from one or more of aminopropyltriethoxysilane, vinyltriethoxysilane, trimethoxysilane and epoxy silane.
Further, the alloy magnetic powder is selected from one or more of iron-silicon-aluminum alloy powder, iron-silicon-chromium alloy powder and iron-cobalt alloy powder.
According to another aspect of the invention, a preparation method of the wave-absorbing material is provided, and the preparation method comprises the following steps: step S1, reacting the silicone rubber with a grafting agent to obtain modified silicone rubber; step S2, mixing raw materials including modified silicone rubber, polyurethane, alloy magnetic powder and a conductive agent to obtain a mixture; and step S3, carrying out vulcanization reaction on the mixture and a vulcanizing agent, and grafting polyurethane on the modified silicone rubber to obtain the wave-absorbing material.
Further, the step S1 includes: the silicone rubber, the grafting agent and the crosslinking agent are reacted to obtain the modified silicone rubber, the reaction temperature is preferably 160-180 ℃, the stirring speed of the reaction is preferably 30-60 r/min, and the reaction time is preferably 3-5 min.
Further, the magnetic alloy powder is lamellar, and the preparation process of the magnetic alloy powder comprises the following steps: performing ball milling on the alloy magnetic particles to obtain flaky alloy magnetic powder; oxidizing the flaky alloy magnetic powder to obtain oxidized alloy magnetic powder; and (2) performing circulating treatment on the oxidized alloy magnetic powder by using an inductive coupling plasma to obtain the alloy magnetic powder, wherein the inductive coupling plasma treatment is performed in an inert gas atmosphere or nitrogen, the particle size of the alloy magnetic powder is preferably 10-50 microns, the temperature of the oxidation treatment is preferably 500-800 ℃, the time of the oxidation treatment is preferably 6-10 h, the temperature of the inductive coupling plasma treatment is preferably 750-850 ℃, the frequency of the circulating treatment is preferably 30-50 times, and the time of each circulating treatment is preferably 60-120 s.
By applying the technical scheme of the invention, the wave absorbing composition simultaneously comprises silicon rubber, polyurethane and a grafting agent, and the grafting agent is used for grafting the polyurethane on a silicon rubber molecular chain. Therefore, in the actually formed wave-absorbing material, the polymer matrix is the silicon rubber grafted with polyurethane, the silicon rubber is nonpolar rubber, has no reaction functional group, and has good sealing property and high and low temperature resistance, and the polyurethane rubber is strong polar rubber, contains N-H bonds, and has the advantages of high hardness, good elasticity, high wear resistance and the like, so that the formed wave-absorbing material combines the characteristics of the two polymer materials. Particularly, different from simple physical blending, the polyurethane is grafted on a silicon rubber molecular chain by using a grafting agent, so that the polyurethane and the silicon rubber molecular chain are distributed more uniformly, and the formed wave-absorbing material has better comprehensive properties such as sealing property, mechanical strength and the like. In addition, alloy magnetic powder, conductive agent and vulcanizing agent are added into the wave-absorbing composition, the crosslinking reaction density of the wave-absorbing material is further enhanced by the vulcanizing agent, and the wave-absorbing performance of the material is further improved by the alloy magnetic powder and the conductive agent.
Therefore, the wave-absorbing composition effectively solves the problems of poor mechanical strength and poor flexibility of the wave-absorbing material in the prior art, the obtained wave-absorbing material has good sealing performance and high mechanical strength, and is good in flexibility, and can be cut into different shapes according to the requirements of different parts on an aircraft, so that the wave-absorbing material is more tightly attached to the required parts, and the wave-absorbing composition is easy to obtain raw materials and low in cost.
Detailed Description
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail with reference to examples.
As analyzed by the background art, the wave-absorbing material in the prior art has the problems of poor mechanical strength and poor flexibility, and in order to solve the problems, the invention provides a wave-absorbing composition, a wave-absorbing material and a preparation method thereof.
In an exemplary embodiment of the present application, a wave-absorbing composition is provided, where the wave-absorbing composition includes silicone rubber, polyurethane, a grafting agent, alloy magnetic powder, a conductive agent, and a vulcanizing agent, where the grafting agent is used to graft the polyurethane on a molecular chain of the silicone rubber.
The wave absorbing composition simultaneously comprises silicon rubber, polyurethane and a grafting agent, wherein the grafting agent is used for grafting the polyurethane on a silicon rubber molecular chain. Therefore, in the actually formed wave-absorbing material, the polymer matrix is the silicon rubber grafted with polyurethane, the silicon rubber is nonpolar rubber, has no reaction functional group, and has good sealing property and high and low temperature resistance, and the polyurethane rubber is strong polar rubber, contains N-H bonds, and has the advantages of high hardness, good elasticity, high wear resistance and the like, so that the formed wave-absorbing material combines the characteristics of the two high polymer materials. Particularly, unlike simple physical blending, the invention grafts polyurethane on a silicon rubber molecular chain by using a grafting agent, so that the polyurethane and the silicon rubber molecular chain are distributed more uniformly, and the formed wave-absorbing material has better comprehensive properties such as sealing property, mechanical strength and the like. In addition, alloy magnetic powder, conductive agent and vulcanizing agent are added into the wave-absorbing composition, the crosslinking reaction density of the wave-absorbing material is further enhanced by the vulcanizing agent, and the wave-absorbing performance of the material is further improved by the alloy magnetic powder and the conductive agent.
Therefore, the wave-absorbing composition effectively solves the problems of poor mechanical strength and poor flexibility of the wave-absorbing material in the prior art, the obtained wave-absorbing material has good sealing performance and high mechanical strength, and is good in flexibility, and can be cut into different shapes according to the requirements of different parts on an aircraft, so that the wave-absorbing material is more tightly attached to the required parts, and the wave-absorbing composition is easy to obtain raw materials and low in cost.
The silicone rubber of the present application is 110 series, and the polyurethane is 101L series, etc.
In order to improve the matching effect of the components in the wave-absorbing composition, so as to obtain the wave-absorbing material with strong flexibility, high crosslinking density, strong mechanical property and strong sealing property, the wave-absorbing composition preferably comprises 70-100 parts by weight of silicone rubber, 10-30 parts by weight of polyurethane, 2-4 parts by weight of grafting agent, 100-300 parts by weight of alloy magnetic powder, 50-100 parts by weight of conductive agent and 2-4 parts by weight of vulcanizing agent. In order to improve the modification effect of the grafting agent on the silicone rubber, the grafting agent is preferably selected from any one or more of aminopropyltriethoxysilane, vinyltriethoxysilane, trimethoxysilane and epoxy silane. In order to enable the wave-absorbing material to have higher magnetic conductivity so as to improve the demagnetization performance of the wave-absorbing material, the preferred alloy magnetic powder is selected from any one or more of iron-silicon-aluminum alloy powder, iron-silicon-chromium alloy powder and iron-cobalt alloy powder. The conductive agent can improve the conductivity of the wave-absorbing material, thereby being more beneficial to improving the absorption of magnetic waves and shielding magnetism, and preferably being nickel-plated fibers and/or silver powder. And the conductive agent can be more fully and uniformly mixed with other components in the wave-absorbing composition.
In one embodiment of the present application, the weight ratio of the silicone rubber, the polyurethane and the grafting agent is 40-50: 10-15: 1-2.
The proportion is favorable for the grafting agent to fully modify the silicon rubber, so that modified silicon rubber as much as possible is obtained, and the silicon rubber and polyurethane are fully reacted to obtain fully crosslinked silicon rubber.
In order to further improve the performance of the wave-absorbing material, the wave-absorbing composition preferably further comprises 0.3-0.5 part by weight of a cross-linking agent, and the cross-linking agent is preferably DCP and/or a bis-25 cross-linking agent. Preferably, the wave-absorbing composition further comprises 0.3-0.5 part by weight of an auxiliary agent, and the preferable auxiliary agent comprises 5-15 parts by weight of white carbon black and 3-5 parts by weight of hydroxyl silicone oil. Of course, those skilled in the art can also use the cross-linking agent and the auxiliary agent commonly used in the wave-absorbing material in the prior art, and details are not described herein.
In another exemplary embodiment of the present application, a wave-absorbing material is provided, where the wave-absorbing material includes a polymer base material, and alloy magnetic powder and a conductive agent dispersed in the polymer base material, the polymer base material is a cross-linked graft modified silicone rubber, the graft modified silicone rubber includes a silicone rubber main chain and a polyurethane molecular chain grafted on the silicone rubber main chain, and the polyurethane molecular chain is grafted on the silicone rubber main chain by using a grafting agent.
The polymer base material in the wave-absorbing material is graft modified silicon rubber in a cross-linking state, and the graft modified silicon rubber comprises a silicon rubber main chain and a polyurethane molecular chain grafted on the silicon rubber main chain. The main chain of the silicon rubber is nonpolar, has good sealing property and high and low temperature resistance, but has poor mechanical property; the polyurethane molecular chain is strong-polarity rubber, contains N-H bonds, and has the advantages of high hardness, good elasticity, high wear resistance and the like. Therefore, the wave-absorbing material can be cut into different shapes according to the requirements of different parts on the aircraft, so that the wave-absorbing material is tightly attached to the required parts, and the wave-absorbing composition is easy to obtain raw materials and low in cost.
In an embodiment of the present application, the wave-absorbing material includes 70 to 100 parts by weight of a silicone rubber main chain, 10 to 30 parts by weight of a polyurethane molecular chain, 100 to 300 parts by weight of alloy magnetic powder, and 50 to 100 parts by weight of a conductive agent, and preferably, the conductive agent is nickel-plated fiber and/or silver powder.
The main chain of the silicone rubber is associated with the molecular chain of polyurethane, the main chain and the molecular chain of polyurethane are connected through chemical bonds, and the weight parts of the main chain and the molecular chain of polyurethane are used for limiting the content distribution of the main chain and the molecular chain of the graft modified silicone rubber. And the advantages of the silicone rubber main chain and the polyurethane molecular chain can be fully exerted, and the wave-absorbing material with strong flexibility, high crosslinking density, strong mechanical property and strong sealing property can be further obtained by combining the alloy magnetic powder and the conductive agent with the above contents. The conductive agent can better improve the conductivity of the wave-absorbing material. In order to further improve the performance of the wave-absorbing material, the wave-absorbing composition preferably further comprises 0.3-0.5 part by weight of a cross-linking agent, and the cross-linking agent is preferably DCP and/or a bis-25 cross-linking agent. Preferably, the wave-absorbing composition further comprises 0.3-0.5 part by weight of an auxiliary agent, and the preferable auxiliary agent comprises 5-15 parts by weight of white carbon black and 3-5 parts by weight of hydroxyl silicone oil. Of course, those skilled in the art can also use the cross-linking agent and the auxiliary agent commonly used in the wave-absorbing material in the prior art, and details are not described herein.
In one embodiment of the present application, the grafting agent is 2 to 4 parts by weight, preferably, the weight ratio of the silicone rubber backbone, the polyurethane molecular chain and the grafting agent is 40 to 50:10 to 15:1 to 2, and preferably, the grafting agent is selected from any one or more of aminopropyltriethoxysilane, vinyltriethoxysilane, trimethoxysilane and epoxysilane.
The grafting agent and the weight ratio of the silicone rubber main chain to the polyurethane molecular chain to the grafting agent are favorable for fully exerting the respective advantages of the silicone rubber main chain and the polyurethane molecular chain, so that the properties of the silicone rubber main chain and the polyurethane molecular chain are cooperated on the whole, and the wave-absorbing material with excellent comprehensive properties is obtained.
In order to make the wave-absorbing material have higher magnetic conductivity and thus improve the demagnetization performance of the wave-absorbing material, the alloy magnetic conductive powder is preferably selected from any one or more of iron-silicon-aluminum alloy powder, iron-silicon-chromium alloy powder and iron-cobalt alloy powder.
In another exemplary embodiment of the present application, there is provided a method for preparing the wave-absorbing material, the method includes: step S1, reacting the silicone rubber with a grafting agent to obtain modified silicone rubber; step S2, mixing raw materials including modified silicone rubber, polyurethane, alloy magnetic powder and a conductive agent to obtain a mixture; and step S3, carrying out vulcanization reaction on the mixture and a vulcanizing agent, and grafting polyurethane on the modified silicone rubber to obtain the wave-absorbing material.
The silicon rubber is non-polar rubber, has no reaction functional group, has good sealing property and high and low temperature resistance, but has poor mechanical property. The polyurethane rubber is strong polar rubber, contains N-H bonds, and has the advantages of high hardness, good elasticity, high wear resistance and the like. According to the application, the silicon rubber is modified through the grafting agent, and the obtained modified silicon rubber can be grafted with the polyurethane, so that the silicon rubber and the polyurethane are uniformly mixed, the integral crosslinking reaction density of the wave-absorbing material is enhanced, the advantages of the silicon rubber and the polyurethane rubber are further integrated, and the wave-absorbing material with excellent performances such as sealing performance, mechanical strength and the like is obtained. The crosslinking reaction density of the wave-absorbing material is further enhanced by adding the alloy magnetic powder and the conductive agent and carrying out vulcanization reaction, so that the wave-absorbing material with strong flexibility, high crosslinking density, strong mechanical property and strong sealing property is obtained, the wave-absorbing material can meet the cutting requirements of any shape, and the method is simple and has low cost.
In addition, in order to improve the mixing efficiency, the mixing temperature is preferably 40-50 ℃, and the mixing time is preferably 1-1.5 h. In order to improve the efficiency of the vulcanization reaction, the temperature of the vulcanization reaction is preferably 165-170 ℃, and the time of the vulcanization reaction is preferably 10-30 min.
In an embodiment of the present application, the step S1 further includes: the silicone rubber, the grafting agent and the crosslinking agent are reacted to obtain the modified silicone rubber, the reaction temperature is preferably 160-180 ℃, the stirring speed of the reaction is preferably 30-60 r/min, and the reaction time is preferably 3-5 min.
The control of the temperature, the time and the stirring speed of the reaction is beneficial to fully modifying the silicon rubber and further expanding the branching degree of the main chain of the silicon rubber, so that the silicon rubber is better mixed with the polyurethane rubber.
In an embodiment of the present application, the alloy magnetic powder is in a sheet shape, and a preparation process of the alloy magnetic powder includes: performing ball milling on the alloy magnetic particles to obtain flaky alloy magnetic powder; oxidizing the flaky alloy magnetic powder to obtain oxidized alloy magnetic powder; and carrying out circulating treatment on the oxidized alloy magnetic powder by using an inductive coupling plasma to obtain the alloy magnetic powder, wherein the inductive coupling plasma treatment is carried out in an inert gas atmosphere or nitrogen, the particle size of the alloy magnetic powder is preferably 10-50 microns, the temperature of the oxidation treatment is preferably 500-800 ℃, the time of the oxidation treatment is preferably 6-10 h, the temperature of the inductive coupling plasma treatment is preferably 750-850 ℃, the frequency of the circulating treatment is preferably 30-50 times, and the time of each circulating treatment is preferably 60-120 s.
The scheme carries out flakiness treatment on the alloy powder, so that the alloy powder obtains higher magnetic conductivity and is beneficial to high-performance absorption of low-frequency materials. The metal element in the alloy powder magnetic metal micro powder reacts with oxygen at high temperature to form metal oxide. The high-energy plasma enables the metal oxide to have the same growth condition in all directions, so that the consistency of thickness and uniformity can be realized, and the oxide layers are changed into ordered gradient arrangement from disordered arrangement on the surface of the magnetic alloy powder. The multilayer composite structure on the surface of the alloy powder is prepared by utilizing a plasma induction technology, a plurality of interface layers are introduced on the basis of meeting the performance and the bonding strength among the layers, the absorption effect of the alloy powder on low-frequency high-strength electromagnetic waves is ensured, and the prepared absorbent has a certain antioxidation effect. The composite interface layer structure provides abundant transmission and scattering channels for electromagnetic waves, contributes to a large number of interfaces on the premise of realizing good impedance matching between the sheet alloy magnetic powder and a free space, and enhances the polarization loss capability of the interfaces.
The advantageous effects of the present application will be described below with reference to specific examples and comparative examples.
Example 1
The wave-absorbing composition comprises 70 parts by weight of methyl vinyl silicone rubber, 30 parts by weight of UR101L-2 polyurethane, 2 parts by weight of aminopropyltriethoxysilane and 100 parts by weight of FSA @ SiO2@Al2O350 parts by weight of nickel-plated fibers, 20 parts by weight of silver powder, 0.3 part by weight of DCP, and 15 parts by weight of gas-phase SiO24 parts by weight of a hydroxy silicone oil and 4 parts by weight of bis 25.
And (2) placing the methyl vinyl silicone rubber and the DCP into a stirring reaction kettle, setting the temperature at 170 ℃, stirring at the speed of 30r/min, adding aminopropyltriethoxysilane into the reaction kettle, and stirring for 5min to obtain the modified methyl vinyl silicone rubber.
Adopting planetary ball mill to carry out FSA @ SiO2@Al2O3And (3) carrying out ball milling on the particles, wherein the grinding balls are zirconium balls (the particle size is 5mm), and the ball-to-material ratio is 10: 1, ball milling for 24 hours by using ethanol as a ball milling solvent to obtain sheet FSA @ SiO2@Al2O3And (3) powder. The sheet FSA @ SiO2@Al2O3Oxidizing the powder in air at 500 deg.C for 8h to obtain oxidized FSA @ SiO2@Al2O3And (3) powder. Adopting inductively coupled plasma to carry out oxidation on the oxidized FSA @ SiO2@Al2O3The powder is circularly treated in nitrogen at 850 ℃, the number of the circular treatments is 30, the time of each circular treatment is 120s, and finally the FSA @ SiO is obtained2@Al2O3The particle size was 50 μm.
Mixing the above modified methyl vinyl silicone rubber and UR101L-2 polyurethaneEster, FSA @ SiO2@Al2O3Nickel-plated fiber, silver powder, gas phase SiO2And hydroxyl silicone oil are mixed at 40 ℃ to obtain a mixture, and bis-25 is added into the mixture to carry out vulcanization reaction to obtain the wave-absorbing material 1.
Example 2
Example 2 differs from example 1 in that,
the wave-absorbing composition comprises 80 parts by weight of methyl vinyl silicone rubber, 20 parts by weight of UR101L-2 polyurethane and 3 parts by weight of aminopropyltriethoxysilane, and finally the wave-absorbing material 2 is obtained.
Example 3
Example 3 differs from example 1 in that,
the wave-absorbing composition comprises 100 parts by weight of methyl vinyl silicone rubber, 10 parts by weight of UR101L-2 polyurethane and 4 parts by weight of aminopropyltriethoxysilane, and finally the wave-absorbing material 3 is obtained.
Example 4
Example 4 differs from example 1 in that,
the wave absorbing composition comprises 100 parts by weight of methyl vinyl silicone rubber, 30 parts by weight of UR101L-2 polyurethane, 4 parts by weight of aminopropyltriethoxysilane and 200 parts by weight of FSA @ SiO2@Al2O370 parts by weight of nickel-plated fiber, 30 parts by weight of silver powder, 0.4 part by weight of DCP, and 10 parts by weight of gas-phase SiO23 parts of hydroxyl silicone oil and 3 parts of bis-25 to finally obtain the wave-absorbing material 4.
Example 5
Example 5 differs from example 1 in that,
the wave absorbing composition comprises 100 parts by weight of methyl vinyl silicone rubber, 30 parts by weight of UR101L-2 polyurethane, 5 parts by weight of aminopropyltriethoxysilane and 300 parts by weight of FSA @ SiO2@Al2O340 parts by weight of nickel-plated fiber, 10 parts by weight of silver powder, 0.5 part by weight of DCP, and 5 parts by weight of gas-phase SiO25 parts of hydroxyl silicone oil and 5 parts of bis-25 to finally obtain the wave-absorbing material 5.
Example 6
Example 6 differs from example 1 in that,
and epoxy silane is used as a grafting agent to finally obtain the wave-absorbing material 6.
Example 7
Example 7 differs from example 1 in that,
FeSiCr is adopted as alloy magnetic powder, and the wave-absorbing material 7 is finally obtained.
Example 8
Example 8 differs from example 1 in that,
and (3) placing the methyl vinyl silicone rubber and the DCP in a stirring reaction kettle, setting the temperature to be 160 ℃, obtaining the modified methyl vinyl silicone rubber, and finally obtaining the wave-absorbing material 8.
Example 9
Example 9 differs from example 1 in that,
and (3) placing the methyl vinyl silicone rubber and the DCP in a stirring reaction kettle, setting the temperature to be 180 ℃ to obtain modified methyl vinyl silicone rubber, and finally obtaining the wave-absorbing material 9.
Example 10
Example 10 differs from example 1 in that,
and (3) placing the methyl vinyl silicone rubber and the DCP in a stirring reaction kettle for reaction, setting the temperature to be 155 ℃, obtaining modified methyl vinyl silicone rubber, and finally obtaining the wave-absorbing material 10.
Example 11
Example 11 differs from example 1 in that,
and (3) placing the methyl vinyl silicone rubber and the DCP in a stirring reaction kettle for reaction, wherein the stirring speed of the reaction is 45r/min, obtaining the modified methyl vinyl silicone rubber, and finally obtaining the wave-absorbing material 11.
Example 12
Example 12 differs from example 1 in that,
and (3) placing the methyl vinyl silicone rubber and the DCP in a stirring reaction kettle for reaction, wherein the stirring rotation speed of the reaction is 60r/min, obtaining the modified methyl vinyl silicone rubber, and finally obtaining the wave-absorbing material 12.
Example 13
Example 13 differs from example 1 in that,
and (3) placing the methyl vinyl silicone rubber and the DCP in a stirring reaction kettle for reaction, wherein the stirring rotation speed of the reaction is 25r/min, obtaining the modified methyl vinyl silicone rubber, and finally obtaining the wave-absorbing material 13.
Example 14
Example 14 differs from example 1 in that,
and (3) placing the methyl vinyl silicone rubber and the DCP in a stirring reaction kettle for reaction for 5min to obtain modified methyl vinyl silicone rubber, and finally obtaining the wave-absorbing material 14.
Example 15
Example 15 differs from example 1 in that,
FSA@SiO2@Al2O3the particle size of the composite material is 10 mu m, and the wave-absorbing material 15 is finally obtained.
Example 16
Example 16 differs from example 1 in that,
the sheet FSA @ SiO2@Al2O3The temperature for oxidation treatment is 800 ℃ and the time is 6h, and the oxidized FSA @ SiO is obtained2@Al2O3And (5) powder to finally obtain the wave-absorbing material 16.
Example 17
Example 17 differs from example 1 in that,
the sheet FSA @ SiO2@Al2O3The temperature for oxidation treatment is 700 ℃, the time is 10h, and the oxidized FSA @ SiO is obtained2@Al2O3And (5) obtaining the wave-absorbing material 17 finally.
Example 18
Example 18 differs from example 1 in that,
adopting inductively coupled plasma to carry out oxidation on the oxidized FSA @ SiO2@Al2O3The powder is circularly processed at 750 ℃ to obtain FSA @ SiO2@Al2O3And finally obtaining the wave-absorbing material 18.
Example 19
Example 19 differs from example 1 in that,
adopting inductively coupled plasma to carry out oxidation on the oxidized FSA @ SiO2@Al2O3The powder is recycled at 700 ℃ to obtain FSA @ SiO2@Al2O3And finally obtaining the wave-absorbing material 19.
Example 20
Example 20 differs from example 1 in that,
adopting inductively coupled plasma to carry out oxidation on the oxidized FSA @ SiO2@Al2O3The powder is recycled at 600 ℃ to obtain FSA @ SiO2@Al2O3And finally obtaining the wave-absorbing material 20.
Example 21
Example 21 differs from example 1 in that,
the number of times of the circulating treatment is 40, and the FSA @ SiO is obtained2@Al2O3And finally obtaining the wave-absorbing material 21.
Example 22
Example 22 differs from example 1 in that,
the number of the circulating treatment is 50 to obtain FSA @ SiO2@Al2O3And finally obtaining the wave-absorbing material 22.
Example 23
Example 23 differs from example 1 in that,
the number of the circulating treatment is 20, and FSA @ SiO is obtained2@Al2O3And finally obtaining the wave-absorbing material 23.
Example 24
Example 24 differs from example 1 in that,
the time of each circulation treatment is 60s, and FSA @ SiO is obtained2@Al2O3And finally obtaining the wave-absorbing material 24.
Example 25
Example 25 differs from example 1 in that,
each treatment cycleThe time is 80s, and FSA @ SiO is obtained2@Al2O3And finally obtaining the wave-absorbing material 25.
Example 26
Example 26 differs from example 1 in that,
the time of each circulation treatment is 50s, and FSA @ SiO is obtained2@Al2O3And finally obtaining the wave-absorbing material 26.
Comparative example 1
Comparative example 1 is different from example 1 in that,
the wave absorbing composition comprises 100 parts by weight of methyl vinyl silicone rubber, 2 parts by weight of aminopropyl triethoxysilane and 100 parts by weight of FSA @ SiO2@Al2O350 parts by weight of nickel-plated fibers, 20 parts by weight of silver powder, 0.3 part by weight of DCP, 15 parts by weight of gas-phase SiO24 parts of hydroxyl silicone oil and 4 parts of bis-25, and finally obtaining the wave-absorbing material 27.
Comparative example 2
Comparative example 2 differs from example 1 in that,
the wave absorbing composition comprises 100 parts by weight of UR101L-2 polyurethane, 2 parts by weight of aminopropyltriethoxysilane and 100 parts by weight of FSA @ SiO2@Al2O350 parts by weight of nickel-plated fibers, 20 parts by weight of silver powder, 0.3 part by weight of DCP, and 15 parts by weight of gas-phase SiO24 parts of hydroxyl silicone oil and 4 parts of bis-25, and finally obtaining the wave-absorbing material 28.
Comparative example 3
Comparative example 3 differs from example 1 in that,
the wave absorbing composition comprises 70 parts by weight of methyl vinyl silicone rubber, 30 parts by weight of UR101L-2 polyurethane and 100 parts by weight of FSA @ SiO2@Al2O350 parts by weight of nickel-plated fibers, 20 parts by weight of silver powder, 0.3 part by weight of DCP, and 15 parts by weight of gas-phase SiO24 parts of hydroxyl silicone oil and 4 parts of bis-25, and finally obtaining the wave-absorbing material 29.
The volume resistivity of the wave-absorbing material 1-29 is measured according to GB/T2439-2001: the test sample is 10cm in length, 2-3 mm in thickness and 1cm in width. And (3) testing the mechanical properties (elongation at break and tensile strength) of the wave-absorbing materials 1-29 according to GBT528-2009 respectively. Electromagnetic performance parameters (frequency point, bandwidth and absorption peak) of the double-layer flat wave-absorbing material are tested in a microwave darkroom by adopting an arch reflection method according to the GJB2038 standard, the thickness of the darkroom material is 1.5mm, and the test results are listed in Table 1.
TABLE 1
From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects:
the wave absorbing composition simultaneously comprises silicon rubber, polyurethane and a grafting agent, wherein the grafting agent is used for grafting the polyurethane on a silicon rubber molecular chain. Therefore, in the actually formed wave-absorbing material, the polymer matrix is the silicon rubber grafted with polyurethane, the silicon rubber is nonpolar rubber, has no reaction functional group, and has good sealing property and high and low temperature resistance, and the polyurethane rubber is strong polar rubber, contains N-H bonds, and has the advantages of high hardness, good elasticity, high wear resistance and the like, so that the formed wave-absorbing material combines the characteristics of the two high polymer materials. Particularly, different from simple physical blending, the polyurethane is grafted on a silicon rubber molecular chain by using a grafting agent, so that the polyurethane and the silicon rubber molecular chain are distributed more uniformly, and the formed wave-absorbing material has better comprehensive properties such as sealing property, mechanical strength and the like. In addition, alloy magnetic powder, conductive agent and vulcanizing agent are added into the wave-absorbing composition, the crosslinking reaction density of the wave-absorbing material is further enhanced by the vulcanizing agent, and the wave-absorbing performance of the material is further improved by the alloy magnetic powder and the conductive agent.
Therefore, the wave-absorbing composition effectively solves the problems of poor mechanical strength and poor flexibility of the wave-absorbing material in the prior art, the obtained wave-absorbing material has good sealing performance and high mechanical strength, and is good in flexibility, and can be cut into different shapes according to the requirements of different parts on an aircraft, so that the wave-absorbing material is more tightly attached to the required parts, and the wave-absorbing composition is easy to obtain raw materials and low in cost.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. The wave absorbing composition is characterized by comprising silicon rubber, polyurethane, a grafting agent, alloy magnetic powder, a conductive agent and a vulcanizing agent, wherein the grafting agent is used for grafting the polyurethane on a molecular chain of the silicon rubber.
2. The wave absorbing composition according to claim 1, wherein the wave absorbing composition comprises 70-100 parts by weight of the silicone rubber, 10-30 parts by weight of the polyurethane, 2-4 parts by weight of the grafting agent, 100-300 parts by weight of the alloy magnetic powder, 50-100 parts by weight of the conductive agent and 2-4 parts by weight of the vulcanizing agent; preferably, the grafting agent is selected from one or more of aminopropyltriethoxysilane, vinyltriethoxysilane, trimethoxysilane and epoxy silane, the alloy magnetic powder is selected from one or more of iron-silicon-aluminum alloy powder, iron-silicon-chromium alloy powder and iron-cobalt alloy powder, and the conductive agent is nickel-plated fiber and/or silver powder.
3. The wave absorbing composition according to claim 2, wherein the weight ratio of the silicone rubber, the polyurethane and the grafting agent is 40-50: 10-15: 1-2.
4. The wave-absorbing material is characterized by comprising a polymer base material, alloy magnetic powder and a conductive agent, wherein the alloy magnetic powder and the conductive agent are dispersed in the polymer base material, the polymer base material is cross-linked graft modified silicone rubber, the graft modified silicone rubber comprises a silicone rubber main chain and polyurethane molecular chains grafted on the silicone rubber main chain, and the polyurethane molecular chains are grafted on the silicone rubber main chain by adopting a grafting agent.
5. The wave-absorbing material according to claim 4, wherein the wave-absorbing material comprises 70-100 parts by weight of the silicone rubber main chain, 10-30 parts by weight of the polyurethane molecular chain, 100-300 parts by weight of the alloy magnetic powder and 50-100 parts by weight of the conductive agent, and preferably the conductive agent is nickel-plated fiber and/or silver powder.
6. The wave absorbing material according to claim 4, wherein the grafting agent is 2-4 parts by weight, preferably, the weight ratio of the silicone rubber main chain, the polyurethane molecular chain and the grafting agent is 40-50: 10-15: 1-2, and preferably, the grafting agent is selected from any one or more of aminopropyltriethoxysilane, vinyltriethoxysilane, trimethoxysilane and epoxy silane.
7. The wave-absorbing material of claim 4, wherein the alloy magnetic powder is selected from any one or more of iron-silicon-aluminum alloy powder, iron-silicon-chromium alloy powder and iron-cobalt alloy powder.
8. A method for preparing the wave-absorbing material of any one of claims 4 to 7, wherein the method comprises the following steps:
step S1, reacting the silicone rubber with a grafting agent to obtain modified silicone rubber;
step S2, mixing the raw materials including the modified silicone rubber, polyurethane, alloy magnetic powder and conductive agent to obtain a mixture; and
and step S3, carrying out vulcanization reaction on the mixture and a vulcanizing agent, and grafting the polyurethane on the modified silicone rubber to obtain the wave-absorbing material.
9. The method for preparing as claimed in claim 8, wherein the step S1 further comprises:
and carrying out the reaction on the silicone rubber, the grafting agent and the cross-linking agent to obtain the modified silicone rubber, wherein the reaction temperature is preferably 160-180 ℃, the reaction stirring speed is preferably 30-60 r/min, and the reaction time is preferably 3-5 min.
10. The preparation method of claim 8, wherein the alloy magnetic powder is in a sheet shape, and the preparation process of the alloy magnetic powder comprises:
performing ball milling on the alloy magnetic particles to obtain flaky alloy magnetic powder;
oxidizing the flaky alloy magnetic powder to obtain oxidized alloy magnetic powder;
and carrying out circulating treatment on the oxidized alloy magnetic powder by using an inductive coupling plasma to obtain the alloy magnetic powder, wherein the inductive coupling plasma treatment is carried out in an inert gas atmosphere or nitrogen, the particle size of the alloy magnetic powder is preferably 10-50 μm, the temperature of the oxidation treatment is preferably 500-800 ℃, the time of the oxidation treatment is preferably 6-10 h, the temperature of the inductive coupling plasma treatment is preferably 750-850 ℃, the number of the circulating treatment is preferably 30-50, and the time of each circulating treatment is preferably 60-120 s.
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