Preparation method of carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material
Technical Field
The invention belongs to the technical field of preparation of polymer composite materials, and particularly relates to a preparation method of a carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material.
Background
In recent years, conductive polymer composite materials such as graphene, carbon nanotubes, transition metal oxides/carbonitrides and the like embedded in conductive fillers have attracted much attention due to their advantages of light weight, easy manufacturing, good corrosion resistance, excellent performance of absorbing and reflecting electromagnetic radiation in a wide frequency range, and the like, but conductive polymer composite materials containing conductive fillers generally require a large shielding layer thickness and have a good shielding effect, which will limit their practical applications in aerospace, small portable electronic devices and highly integrated circuit communication devices.
In order to solve various problems caused by electromagnetic interference, polymer-based, metal-based, and carbon-based materials have been studied. However, most metals and metal compounds have high density, poor toughness, difficult processing, easy corrosion and poor designability, which greatly limits their application in electromagnetic shielding.
The carbon-based material has the advantages of low density, high conductivity, good thermal property and the like, and is considered as an ideal choice of the electromagnetic interference shielding material, however, the pure carbon material is easy to oxidize under aerobic conditions, and a simple solution coating method is adopted for solving the problems and obtaining the electromagnetic shielding material with larger thickness; the flexible carbon fiber felt is used as a base material, the silver nanowires are selected as the conductive elements, the flexible carbon fiber felt is used as the flexible base material due to the roughness and the good porosity of the flexible carbon fiber felt, the silver nanowires are easily deposited and adhered, and the compact silver nanowire layer is favorable for improving the electromagnetic shielding performance. In order to further stabilize the silver nanowire network structure on the surface of the flexible carbon fiber felt, a polyvinylidene fluoride layer is synthesized on the surface of the silver nanowire layer. The preparation of the composite material with ultrahigh electromagnetic shielding performance is simple to process, and the product has high cost performance, so that the composite material is considered as a new hotspot for research in the application of ultrahigh electromagnetic shielding performance.
Disclosure of Invention
The invention aims to provide a preparation method of a carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material, which solves the problem of low electromagnetic shielding performance of the composite material in the prior art.
The invention adopts the technical scheme that the preparation method of the carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material is implemented according to the following steps:
step 1, mixing an ethylene-propylene alcohol solution with a silver nanowire solution, and stirring the mixed solution by using a vortex mixer to obtain a silver nanowire/ethylene-propylene alcohol solution with the mass concentration of 2 mg/ml;
step 2, dissolving polyvinylidene fluoride particles in N, N-dimethylformamide, and carrying out water bath reaction to obtain a polyvinylidene fluoride/N, N-dimethylformamide solution with the mass concentration of 100 mg/ml;
step 3, soaking the flexible carbon fiber felt in a silver nanowire/ethylene-propylene alcohol solution, then placing the flexible carbon fiber felt in a culture dish attached with a polytetrafluoroethylene membrane, drying, and repeatedly soaking and drying for nine times to obtain nine layers of carbon fiber felt fabrics coated with silver nanowires;
and 4, soaking the nine layers of carbon fiber felt fabrics coated with the silver nanowires in a polyvinylidene fluoride/N, N-dimethylformamide solution, then placing the soaked fabric in a culture dish attached with a polytetrafluoroethylene membrane, and drying to obtain the carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material.
The present invention is also characterized in that,
in the step 1, the stirring time is 0.5-1 h.
In the step 2, the reaction temperature is 80-90 ℃, and the reaction time is 1-2 h.
In the step 3, the soaking time is 1-3 s, the drying temperature is 40-60 ℃, and the drying time is 30-60 min.
In the step 4, the soaking time is 1-3 s.
In the step 4, the drying temperature is 40-60 ℃, and the drying time is 2-3 h.
The invention has the beneficial effects that:
the method of the invention has simple process and high safety, can meet the application requirements of various electronic products, and simultaneously realizes low filler content, larger shielding layer thickness and high electromagnetic shielding performance.
Drawings
FIG. 1 is a graph of the electromagnetic shielding effectiveness of a carbon fiber mat/silver nanowire/polyvinylidene fluoride composite prepared by the method of the present invention;
fig. 2 is a graph of electromagnetic shielding effectiveness of a carbon fiber felt/silver nanowire/polyvinylidene fluoride composite of a pure flexible carbon nanofiber felt and a single layer of silver nanowires.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
The invention relates to a preparation method of a carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material, which is implemented according to the following steps:
step 1, mixing an ethylene-propylene alcohol solution and a silver nanowire solution, stirring the mixed solution for 0.5-1 h by using a vortex mixer, and uniformly mixing the solutions to obtain a silver nanowire/ethylene-propylene alcohol solution with the mass concentration of 2 mg/ml;
the silver nanowire solution consists of silver nanowires and ethylene glycol, and the mass concentration of the silver nanowire solution is 1%;
step 2, dissolving polyvinylidene fluoride particles in N, N-dimethylformamide, and carrying out water bath reaction for 1-2 h at the temperature of 80-90 ℃ to obtain a polyvinylidene fluoride/N, N-dimethylformamide solution with the mass concentration of 100 mg/ml;
step 3, soaking the flexible carbon fiber felt in a silver nanowire/ethylene-propylene alcohol solution, taking out the flexible carbon fiber felt with a pair of tweezers, placing the flexible carbon fiber felt in a culture dish attached with a polytetrafluoroethylene membrane, and drying the flexible carbon fiber felt to obtain a single-layer silver nanowire coated carbon fiber felt fabric; then soaking the carbon fiber felt fabric coated by the single layer of silver nanowires in a silver nanowire/ethylene-propylene alcohol solution, taking out the carbon fiber felt fabric by using tweezers, placing the carbon fiber felt fabric in a culture dish attached with a polytetrafluoroethylene membrane, and drying the carbon fiber felt fabric; soaking and drying are carried out repeatedly for nine times to obtain nine layers of carbon fiber felt fabrics coated by the silver nanowires;
the soaking time is 1-3 s; the drying temperature is 40-60 ℃, and the drying time is 30-60 min;
the culture dish is a circular culture dish with the diameter of 60 mm;
the size of the flexible carbon fiber felt is 13mm multiplied by 2 mm; the production manufacturer of the flexible carbon fiber felt is Shanghai Lingbang environmental protection science and technology company;
and 4, soaking the nine-layer silver nanowire-coated carbon fiber felt fabric in a polyvinylidene fluoride/N, N-dimethylformamide solution for 1-3 s, then taking out the fabric by using a pair of tweezers, placing the fabric in a culture dish attached with a polytetrafluoroethylene membrane, and drying the fabric for 2-3 h at the temperature of 40-60 ℃ to obtain the carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material.
Example 1
A preparation method of a carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material comprises the following specific steps:
step 1, weighing 12ml of ethylene-propylene alcohol solution, mixing with 3ml of silver nanowire solution, stirring the mixed solution for 0.5h by using a vortex mixer, and uniformly mixing the solution to obtain silver nanowire/ethylene-propylene alcohol solution with the mass concentration of 2 mg/ml;
step 2, weighing 10g of polyvinylidene fluoride, dissolving the polyvinylidene fluoride in 90ml of N, N-dimethylformamide, stirring the mixture in a water bath kettle at the temperature of 80 ℃ for 80min to completely dissolve the polyvinylidene fluoride in the N, N-dimethylformamide to obtain a polyvinylidene fluoride/N, N-dimethylformamide solution with the concentration of 100 mg/ml;
step 3, soaking the flexible carbon fiber felt in the silver nanowire/ethylene-propylene alcohol solution for 1s, then taking out the flexible carbon fiber felt with tweezers, placing the flexible carbon fiber felt in a culture dish attached with a polytetrafluoroethylene membrane, drying the flexible carbon fiber felt at 40 ℃ for 30min, and repeating the operation nine times to obtain nine layers of silver nanowire coated carbon fiber felt fabrics;
and 4, taking the sample prepared in the step 3, respectively soaking the sample in a polyvinylidene fluoride/N, N-dimethylformamide solution for 1s, then taking out the sample with a pair of tweezers, placing the sample in a culture dish attached with a polytetrafluoroethylene membrane, and drying the sample at 40 ℃ for 2h to obtain the carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material.
Compared with a commercial electromagnetic shielding material (20dB), the electromagnetic shielding effectiveness of the carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material prepared in example 1 is 64.1dB, and is improved by 220.5% correspondingly.
Example 2
A preparation method of a carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material comprises the following specific steps:
step 1, weighing 12ml of ethylene-propylene alcohol solution, mixing with 3ml of silver nanowire solution, stirring the mixed solution for 1 hour by using a vortex mixer, and uniformly mixing the solutions to obtain silver nanowire/ethylene-propylene alcohol solution with the mass concentration of 2 mg/ml;
step 2, weighing 10g of polyvinylidene fluoride, dissolving the polyvinylidene fluoride in 90ml of N, N-dimethylformamide, stirring the mixture in a water bath kettle at the temperature of 90 ℃ for 90min to completely dissolve the polyvinylidene fluoride in the N, N-dimethylformamide to obtain a polyvinylidene fluoride/N, N-dimethylformamide solution with the concentration of 100 mg/ml;
step 3, soaking the flexible carbon fiber felt in a silver nanowire/ethylene-propylene alcohol solution for 3s, then taking out the flexible carbon fiber felt with a pair of tweezers, placing the flexible carbon fiber felt in a culture dish attached with a polytetrafluoroethylene membrane, drying the flexible carbon fiber felt for 60min at the temperature of 60 ℃, and repeating the operation for nine times to obtain nine layers of carbon fiber felt fabrics coated with silver nanowires;
and 4, taking the sample prepared in the step 3, respectively soaking in a polyvinylidene fluoride/N, N-dimethylformamide solution for 3s, then taking out the sample with a pair of tweezers, placing the sample in a culture dish attached with a polytetrafluoroethylene membrane, and drying the sample at 60 ℃ for 3h to obtain the carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material.
Compared with a commercial electromagnetic shielding material (20dB), the electromagnetic shielding effectiveness of the carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material prepared in example 2 is 69.2dB, and is correspondingly improved by 246%.
Example 3
A preparation method of a carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material comprises the following specific steps:
step 1, weighing 12ml of ethylene-propylene alcohol solution, mixing with 3ml of silver nanowire solution, stirring the mixed solution for 45min by using a vortex mixer, and uniformly mixing the solutions to obtain silver nanowire/ethylene-propylene alcohol solution with the mass concentration of 2 mg/ml;
step 2, weighing 10g of polyvinylidene fluoride, dissolving the polyvinylidene fluoride in 90ml of N, N-dimethylformamide, stirring for 85min in a water bath kettle at 85 ℃ to completely dissolve the polyvinylidene fluoride in the N, N-dimethylformamide to obtain a polyvinylidene fluoride/N, N-dimethylformamide solution with the concentration of 100 mg/ml;
step 3, soaking the flexible carbon fiber felt in a silver nanowire/ethylene-propylene alcohol solution for 1-3 s, then taking out the flexible carbon fiber felt with a pair of tweezers, placing the flexible carbon fiber felt in a culture dish attached with a polytetrafluoroethylene membrane, drying the flexible carbon fiber felt for 50min at the temperature of 50 ℃, and repeating the operation for nine times to obtain nine layers of carbon fiber felt fabrics coated with silver nanowires;
and 4, taking the sample prepared in the step 3, respectively soaking in a polyvinylidene fluoride/N, N-dimethylformamide solution for 2s, then taking out the sample with a pair of tweezers, placing the sample in a mould attached with a polytetrafluoroethylene membrane, putting the mould in an oven, and drying the mould at 50 ℃ for 2.5h to obtain the carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material.
Compared with a commercial electromagnetic shielding material (20dB), the electromagnetic shielding effectiveness of the carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material prepared in example 3 is 73.4dB, which is correspondingly improved by 267%.
Fig. 2 is a graph of electromagnetic shielding effectiveness of a carbon fiber felt/silver nanowire/polyvinylidene fluoride composite of a pure flexible carbon nanofiber felt and a single layer silver nanowire, the average electromagnetic shielding effectiveness of the pure flexible carbon nanofiber felt is 47.3dB, and the average electromagnetic shielding effectiveness of the flexible carbon nanofiber felt is 65.7dB when a silver nanowire layer is impregnated on the surface of the flexible carbon nanofiber felt; the electromagnetic shielding effect of the carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material prepared by the method is shown in figure 1, and the composite material has high electromagnetic shielding performance and total Shielding Effect (SE) of the composite materialT) Absorption by Shielding (SE)A) And shield reflection (SE)R) Composition, SE of composite MaterialAAnd SETThe variation trends are consistent; however, with SEAIn contrast, SERThe value of (a) is almost constant. The results fully prove that the microwave absorption of the carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material is more contributed to the overall shielding effect than the microwave reflection, which indicates that the microwave absorption is the dominant action of the shielding mechanism. In addition, the composite material causes less secondary electromagnetic pollution than the metallic material, which is important for applications in high-precision electronic devices.
The invention relates to a preparation method of a carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material, which mainly adopts a solution soaking layer-by-layer self-assembly technology to soak a flexible carbon fiber felt in a silver nanowire/ethylene-propylene alcohol solution for repeated multiple times to prepare the composite material with a multilayer structure. The prepared carbon fiber felt/silver nanowire/polyvinylidene fluoride composite material is simple in process, high in safety, easy to produce in batch, and ultrahigh in electromagnetic shielding performance, and has great practical and popularization values in the fields of various electronic and electrical equipment, aerospace and next-generation flexible electronics.