CN103554530A - Electric conductive continuous fiber-reinforced fabric or prepreg and electric conductive treatment method - Google Patents

Abstract

The invention belongs to the technical field of structural composite materials, and relates to a conductive continuous fiber reinforced fabric or prepreg and a conductive treatment method. In the present invention, the continuous fiber reinforced fabric and/or the reinforced fabric prepreg is used as a mechanical carrier, and the nano-conductive component is directly loaded on its surface to obtain a conductive functionalized continuous fiber reinforced fabric or prepreg, and then the fabrics or prepregs, single or multilayer, interspersed with untreated fabrics and prepregs; or entirely of such fabrics or prepregs, in different ways, to lay-up composite prefabricated structures, including sandwich structures, Then, according to the preparation process of the original conventional composite material, a continuous fiber-reinforced structural composite material or sandwich composite material with adjustable electrical and thermal conductivity is prepared. This electrically conductive and thermally conductive composite material completely maintains the structure and mechanical properties of the original composite material. .

Description

Conductive continuous fiber reinforced fabric or prepreg and conductive treatment method

technical field

The invention belongs to the technical field of structural composite materials, and relates to a conductive continuous fiber reinforced fabric or prepreg and a conductive treatment method.

Background technique

It is well known in the art that continuous fiber reinforced resin matrix structural composites are generally electrically insulating, whether these reinforcing fibers are glass fibers, aramid fibers, ultra-high molecular weight polyethylene fibers, ceramic fibers, basalt fibers, or better axial conductivity carbon fiber etc. Therefore, for the purpose of antistatic, electromagnetic shielding, lightning protection, etc., such structural composite materials usually must be conductively treated. For the same reason, the thermal conductivity of this composite material is generally relatively low.

There are two main methods to improve the conductivity of this type of structural composite material. One is to mix conductive components, such as various metal particles, into the resin matrix of the composite material to improve the conductivity of the composite material. In recent years, it has become more popular. It is to add conductive components such as carbon nanotubes to the matrix resin, such as the reference patent US2009140098-A1, etc.; the second is to add continuous reinforcing fiber bundles within bundles, between bundles, within layers, between layers, or in the thickness direction of the composite material Mixing metal fibers, metal strips, etc., including laying metal mesh on the surface and inside of the composite material (refer to patent WO2005032812-A2, US2005181203-A1), etc., or replacing metal strips with hybrid conductive materials such as carbon nanotube paper in order to reduce weight , Metal mesh, such as reference patents CN102001448A, EP2289803-A2 and US2011049292-A1, etc.

The main disadvantage of the method of filling conductive particles in contact with electrical conduction is that the conductive efficiency is low. It is often difficult to obtain a good conductive effect when a large amount of conductive particles are filled, and it also leads to increased costs; , and its preparation technology and mixing process are generally more complicated. The main disadvantages of hybrid metal fibers and metal strips are the increase in weight of composite materials and the mismatch of scales, while the disadvantages of the hybrid carbon nanotube paper conductive method are that it is difficult to obtain raw materials, high cost, and the process preparation technology is difficult, and its industrial scale is also comparatively large. Difficult, so the technology is currently only in the exploratory stage.

Contents of the invention

Purpose of the present invention: In view of the deficiencies of the above technologies, the purpose of the present invention is to propose a conductive continuous fiber reinforced fabric or prepreg and a conductive treatment method. The traditional continuous fiber reinforced fabrics and prepregs are modified by nano-conductive media to make them have better conductivity, and then structural composite materials with excellent conductivity can be prepared to solve the shortcomings of the above-mentioned technologies.

The object of the present invention is achieved through the following technical solutions:

The material is composed of a continuous fiber reinforced fabric or a prepreg formed by a continuous fiber reinforced fabric prepreg resin and a conductive medium attached to the fabric or prepreg; the conductive medium is silver nanowires, or silver nanowires and carbon nanotubes, A mixture of one or more of silver nanowires and graphene, silver nanowires and conductive microfibers; the method of attaching the conductive medium to the continuous fiber reinforced fabric or the prepreg formed by the continuous fiber reinforced fabric prepreg resin is as follows One of three methods:

(1) Disperse the conductive medium into a solvent that does not damage and dissolve the continuous fiber reinforced fabric or prepreg and does not destroy the conductive medium to form a dispersion liquid, spray the dispersion liquid directly on the carrier, and then dry the fabric with the conductive medium ;

(2) Disperse the conductive medium into a solvent that does not damage and dissolve the continuous fiber reinforced fabric or prepreg and does not destroy the conductive medium to form a dispersion liquid, then soak the continuous fiber reinforced fabric or prepreg in the dispersion liquid, take it out, subsequent drying;

(3) For the conductive continuous fiber reinforced fabric, the conductive medium is dispersed into a solvent that does not dissolve the continuous fiber reinforced fabric and does not destroy the conductive medium to form a dispersion liquid, and the dispersion liquid is passed through the continuous fiber reinforced fabric under negative pressure, The fabric loaded with the conductive medium is then dried.

The continuous fiber reinforced fabric refers to glass fiber, aramid fiber, basalt fiber, carbon fiber, ultra-high molecular weight polyethylene fiber or ceramic fiber, and its weaving mode is unidirectional, plain weave, twill weave or satin weave.

The continuous fiber reinforced fabric of the prepreg includes glass fiber, aramid fiber, basalt fiber, carbon fiber, ultra-high molecular weight polyethylene fiber or ceramic fiber, and the weaving mode of the fabric is unidirectional, plain weave, twill weave or satin weave. The impregnated resin is epoxy resin, unsaturated polyester, benzoxazine resin, bismaleimide resin or polyimide resin.

Application of conductive continuous fiber reinforced fabrics or prepregs, the above-mentioned conductive continuous fiber reinforced fabrics or prepregs are laminated as a single layer or mixed with continuous fiber reinforced fabrics or prepregs without conductive treatment to form composite material prefabrication Body, the number of layers of conductive continuous fiber reinforced fabric or prepreg in the prefabricated body is one or more layers or equal to the total number of layers, and after curing and molding according to the curing molding process of composite materials, it is made into a composite material with improved electrical or thermal conductivity. Material parts.

The curing molding process is autoclave molding, resin transfer molding, molding, vacuum assist or vacuum bag molding.

Advantages and characteristics of the present invention are:

In the present invention, the continuous fiber reinforced fabric and/or the reinforced fabric prepreg are used as the mechanical carrier, and the nano-conductive components are directly loaded on the surface, which simplifies the material preparation process, greatly improves the utilization rate of the materials used, and obtains Intermediate materials such as higher conductivity continuous fiber reinforced fabrics and/or higher conductivity reinforced fabric prepregs, only need to load 1-2% silver nanowires to increase the conductivity of fabrics or prepregs About 100 times, while the literature (Ha M S, Kwon O Y, Choi H S. Improved Electrical Conductivity of CFRP by Conductive Silver Nano-particles Coating for Lightning Strike Protection[J].) reported that the loading of 10% colloidal silver can make the The conductivity of the impregnated material is increased by four times; and the preparation technology of these intermediate state materials is low-cost, and the process can be easily scaled up.

By using one layer, or multiple layers, or all of these intermediate materials, the prefabricated structure of the composite material is paved, and according to the preparation process of the original conventional composite material, the continuous fiber-reinforced composite material with adjustable conductivity for different applications is prepared. Structural composite materials, or sandwich composite materials, this conductive composite material completely maintains the structure and mechanical properties of its original composite material, and its electrical conductivity is significantly improved. When the unidirectional composite material plate is loaded with 1 to 2% silver nanowires, The out-of-plane conductivity increases by about 200 times, the in-plane 90° direction conductivity increases by about 330 times, and the in-plane 0° direction conductivity does not change much; while the literature (H.S.Kim.Journal of Composite Materials2011,45(10):1109 –1120) reported that when the composite material was loaded with 2% unidirectional carbon nanotubes, the out-of-plane conductivity increased by 2.44 times, and the in-plane conductivity did not change.

Since the main component of the preferred conductive loading material is silver nanowires, the conductively treated structural composite material of the present invention also has good thermal conductivity.

And in terms of processing and molding technology, the conductive treatment technology of the composite material proposed by the present invention is fully compatible with the preparation technology of the original conventional structure composite material.

Detailed ways

The design and preparation technology of the present invention will be described in further detail below through examples.

Conductive treated continuous fiber reinforced fabric and prepreg are composed of continuous fiber reinforced fabric or continuous fiber reinforced fabric prepreg formed by prepreg and conductive medium attached to the fabric or prepreg; the conductive medium is silver nanometer wire, or one or more mixtures of silver nanowires and carbon nanotubes, silver nanowires and graphene, silver nanowires and conductive microfibers.

Continuous fiber reinforced fabric refers to the fabric of glass fiber, aramid fiber, basalt fiber, carbon fiber, ultra-high molecular weight polyethylene fiber or ceramic fiber, and its weaving method can be unidirectional, plain weave, twill weave, satin weave.

The continuous fiber reinforced fabric of the prepreg contains glass fiber, aramid fiber, basalt fiber, carbon fiber, ultra-high molecular weight polyethylene fiber or ceramic fiber, and the weaving method of the fabric is unidirectional, plain weave, twill weave, satin weave. The pre-impregnated resin is epoxy resin, unsaturated polyester, benzoxazine resin, bismaleimide resin and polyimide resin.

The method of attaching the conductive medium to the continuous fiber reinforced fabric and prepreg is one of the following methods:

(1) Disperse the conductive component into a solvent that does not destroy and dissolve the continuous fiber reinforced fabric or prepreg and does not destroy the conductive medium to form a dispersion liquid, spray the dispersion liquid directly on the carrier, and then apply the conductive medium to the fabric dry;

(2) Disperse the conductive component into a solvent that does not destroy and dissolve the continuous fiber reinforced fabric or prepreg and does not destroy the conductive medium to form a dispersion, and then soak the continuous fiber reinforced fabric or prepreg in this dispersion , taken out, and then dried;

(3) For the conductive continuous fiber reinforced fabric, the conductive component is dispersed into a solvent that does not dissolve the continuous fiber reinforced fabric and does not destroy the conductive medium to form a dispersion liquid, and the dispersion liquid is passed through the continuous fiber reinforced fabric under negative pressure , followed by drying of the fabric loaded with the conductive medium.

The above-mentioned conductive continuous fiber reinforced fabric or prepreg is laid up as a single layer or mixed with continuous fiber reinforced fabric or prepreg without conductive treatment to form a composite material preform, and the conductive continuous fiber in the preform The number of layers of reinforced fabrics and prepregs is one or more layers or equal to the total number of layers, and after curing and molding according to the curing molding process of composite materials, composite materials with layer-selective electrical conductivity, thermal conductivity or overall electrical conductivity and thermal conductivity are made Parts, or sandwich composite parts whose panels are selectively conductive and thermally conductive.

The curing molding process of the composite material can be autoclave molding, resin transfer molding (RTM), compression molding, vacuum assist or vacuum bag molding. The specific operation is carried out according to the original molding conditions of the matrix resin.

Example 1:

The implementation process of the technical solution of the present invention is as follows:

(1-1) Disperse silver nanowires in ethanol or isopropanol or acetone or ethylene glycol or water to form a dispersion with a concentration of 5 mg/mL or 10 mg/mL;

(1-2) Immerse a piece of carbon fiber fabric, carbon fiber T800, 12K or CCF300, 3K, into the dispersion of silver nanowires obtained in the above step (1-1) with a content of 5 mg/mL or 10 mg/mL, and pull out liquid surface and dry or dry; turn it upside down and impregnate again, and determine the number of impregnations according to the requirements of the loading capacity, and finally obtain a conductive carbon fiber fabric uniformly loaded with silver nanowires. Repeat this step to obtain a plurality of conductive enhanced fabric materials in this intermediate state;

(1-3) Lay the conductive intermediate fabric obtained in the above (1-2) one by one according to the order and principle of conventional composite material layup design to obtain a conductive carbon fiber fabric prefabricated body;

(1-4) Using the resin transfer molding (RTM) process, liquid epoxy resin 3266 (product of Beijing Institute of Aeronautical Materials) or liquid benzoxazine (BOZ) resin (Epsilon, product of Henkel, Germany), according to the resin RTM The molding process requires injecting the conductive fabric prefabricated body obtained in the above (1-3), and then curing and molding according to the process specified by the selected resin, and finally obtains a structural composite product reinforced by carbon fiber fabric attached to the surface of the silver nanowire. Composite materials have high electrical conductivity, and at the same time, they have excellent thermal conductivity. Compared with the composite material without silver nanowires, the in-plane conductivity of the carbon fiber fabric reinforced structural composite material loaded on the surface of silver nanowires increased by 330 times in the vertical fiber direction, and the conductivity in the thickness direction increased by nearly 200 times, effectively improving the electrical conductivity of the composite material.

(1-5) If necessary, the intermediate-state conductive material prepared in step (1-2) can also be laid on only one or both front and back surfaces of the carbon fiber fabric prefabricated body, instead of the one in step (1-3). All the above-mentioned materials are prefabricated one by one by lamination of this intermediate state material, and then, the prefabricated body is formed and cured according to the steps (1-4) to obtain a carbon fiber structure composite material with a conductive surface layer. This composite material has excellent Surface conductive properties, but the use of conductive components is reduced, so the cost is lower, suitable for electromagnetic shielding and lightning strike protection of composite materials;

(1-6) Replace the carbon fiber fabric in this implementation example with glass fiber fabric, aramid fiber fabric, basalt fiber fabric or ceramic fabric such as silicon carbide fiber fabric, and repeat the above steps (1-1) to (1-5) A structural composite material reinforced with glass fiber fabric, aramid fiber fabric, basalt fiber fabric, or silicon carbide fiber fabric that is both conductive and thermally conductive is prepared.

Example 2:

The implementation process of the technical solution of the present invention is as follows:

(2-1) Disperse silver nanowires in a 2:1 (V:V) mixture of methanol or isopropanol or acetone or ethanol and water or water to form a dispersion with a concentration of 2 mg/mL or 4 mg/mL;

(2-2) Spread 3233 epoxy resin prepreg (product of Beijing Aeronautical Materials Research Institute) or QY9611 epoxy resin prepreg (product of Beijing Aeronautical Manufacturing Engineering Research Institute), prepared by step (2-1) The silver nanowire dispersion liquid is uniformly sprayed onto one or both front and back surfaces, and the spraying times are determined according to the requirements of the loaded amount, so as to obtain a conductive 3233 or QY9611 prepreg intermediate material uniformly loaded with silver nanowires;

(2-3) Lay the intermediate state conductive prepregs obtained above according to the lay-up design of the original composite material one by one to form a composite material prefabricated body;

(2-4) According to the curing process specified by the epoxy resin prepreg used, the autoclave method or the hot molding method is used for curing and molding to obtain conductive and thermally conductive structural composite products loaded with silver nanowires;

(2-5) Replace the silver nanowire dispersion in step (2-1) with a carbon nanotube dispersion, using butanol or methanol or tetrahydrofuran as the medium; or replace the silver nanowire in (2-1) with Ternary co-dispersion of silver nanowires, graphene and carbon nanotubes in butanol or methanol or tetrahydrofuran medium, the concentrations of the three are: silver nanowires 4mg/mL, graphene concentration 1mg/mL, carbon nano The tube concentration is 4mg/mL, and the total concentration of the conductive medium is 9mg/mL;

(2-6) The carbon nanotube dispersion in the above step (2-5), or the ternary co-dispersion of silver nanowires, graphene, and carbon nanotubes, is also attached to the The surface of 3233 or QY9611 prepreg can be used to obtain carbon nanotubes, or 3233 or QY9611 conductive intermediate materials loaded with silver nanowires, graphene, and carbon nanotubes;

(2-7) The above-mentioned (2-6) surface is loaded with carbon nanotube dispersion liquid, or the 3233 or QY9611 prepreg intermediate state materials loaded with silver nanowires, graphene, and carbon nanotubes are respectively laid on the A panel is formed on one or both sides of the aramid paper honeycomb. According to the curing process specified by the epoxy resin prepreg and its original honeycomb sandwich composite material, the autoclave method or hot pressing molding method is used for curing and molding to obtain carbon Nanotube-loaded, or silver nanowire, graphene, carbon nanotube ternary co-loaded honeycomb sandwich composite material, one panel or upper and lower panels of this sandwich composite material conduct electricity.

Example 3:

The implementation process of the technical solution of the present invention is as follows:

(3-1) Disperse the silver nanowires in ethanol to form a 5 mg/mL dispersion, and disperse the carboxy-modified carbon nanotubes in water or acetone or DMF to form a 2 mg/mL or 10 mg/mL dispersion;

(3-2) The above-mentioned dispersion of carboxy-modified carbon nanotubes (CNTs) with a solid content of 2 mg/mL or 10 mg/mL is attached to the glass fiber fabric by passing the dispersion through the carrier under negative pressure. After drying, immerse the glass fiber fabric that this CNT attaches load again in the ethanol dispersion liquid that silver nanowire content is 5mg/mL, pull out liquid surface and dry, obtain the conductive glass fiber that silver nanowire and carbon nanotube double attach. fabric intermediate state materials;

(3-3) Lay up the conductive glass fiber fabric intermediate materials obtained by the above-mentioned double loading one by one to obtain a conductive glass fiber composite material prefabricated body;

(3-4) Using this prefabricated body, repeat the steps (1-4) to (1-5) in the above-mentioned Example 1 or the vacuum forming method, and solidify and form to obtain double-loaded silver nanowires and carbon nanotubes with high conductivity. , heat-conducting glass fiber composite products;

(3-5) Lay the above-mentioned (3-2) double-loaded glass fiber intermediate state material on one or both upper and lower surfaces of the aramid paper honeycomb to form a panel, and use the RTM forming method or vacuum forming method to 3266 or Epsilon liquid resin is inhaled according to the molding requirements of the resin, and then cured according to the process specified by the selected resin, and finally a honeycomb sandwich composite product with silver nanowires and carbon nanotubes loaded and highly conductive is obtained.

Example 4:

The implementation process of the technical solution of the present invention is as follows:

(4-1) Co-disperse silver nanowires and nickel-plated carbon nanofibers in isopropanol or water to form a dispersion. The total concentration is 11mg/mL; then the silver nanowires are dispersed in isopropanol to form a 5mg/mL dispersion;

(4-2) Spray the above-mentioned co-dispersion of silver nanowires and nickel-plated carbon nanofibers onto the front and back sides of the aramid fiber fabric by spraying the dispersion, and then dry the pre-loaded fabric. Immersed into the dispersion of silver nanowires to obtain a double-loaded conductive intermediate state material;

(4-3) Using this intermediate state material, repeat the steps (1-3) to (1-5) in the above Example 1 or the vacuum forming method, and solidify and form to obtain silver nanowires and nickel-plated carbon nanofibers. Highly conductive and thermally conductive aramid fiber composite products;

(4-4) Lay the aramid fiber intermediate material with double loading on the surface of (4-2) on one or both upper and lower surfaces of the polymethacrylimide (PMI) foam material to form a panel, and use RTM molding method or vacuum molding method, inhale 3266 or Epsilon liquid resin according to the molding requirements of the resin, and then cure according to the process specified by the selected resin, and finally obtain silver nanowires and nickel-plated nano-carbon fibers with dual loading and high surface conductivity. PMI foam sandwich composite parts.

Claims (5)

1. A conductive continuous fiber reinforced fabric or prepreg and conductive treatment method, characterized in that: the material is formed by continuous fiber reinforced fabric or continuous fiber reinforced fabric prepreg resin and attached to the fabric or prepreg The conductive medium on the surface; the conductive medium is silver nanowires, or a mixture of one or more of silver nanowires and carbon nanotubes, silver nanowires and graphene, silver nanowires and conductive microfibers; the conductive medium is attached The method of prepreg formed by continuous fiber reinforced fabric or continuous fiber reinforced fabric pre-impregnated resin is one of the following three methods: (1) Disperse the conductive medium into a solvent that does not destroy and dissolve the continuous fiber reinforced fabric or prepreg and does not destroy the conductive medium to form a dispersion liquid. The concentration of the solution is 1-20mg/mL, and the dispersion liquid is directly sprayed on the carrier. The fabric loaded with the conductive medium is then dried; (2) Disperse the conductive medium into a solvent that does not damage and dissolve the continuous fiber reinforced fabric or prepreg and does not destroy the conductive medium to form a dispersion liquid. The concentration of the solution is 1-20mg/mL, and then the continuous fiber reinforced fabric or prepreg The material is soaked in the dispersion liquid, taken out, and then dried; (3) For the conductive continuous fiber reinforced fabric, disperse the conductive medium into a solvent that does not dissolve the continuous fiber reinforced fabric and does not destroy the conductive medium to form a dispersion liquid. The concentration of the solution is 1-20mg/mL, and the dispersion liquid is The fabric is reinforced by continuous fibers under negative pressure, and the fabric loaded with the conductive medium is subsequently dried. 2. The conductive continuous fiber reinforced fabric or prepreg and conductive treatment method according to claim 1, characterized in that: said continuous fiber reinforced fabric refers to glass fiber, aramid fiber, basalt fiber, carbon fiber, ultra-high Molecular weight polyethylene fiber or ceramic fiber, the weaving method is unidirectional, plain weave, twill weave or satin weave. 3. The conductive continuous fiber reinforced fabric or prepreg and conductive treatment method according to claim 1, characterized in that: the continuous fiber reinforced fabric of the prepreg comprises glass fiber, aramid fiber, basalt fiber, carbon fiber , ultra-high molecular weight polyethylene fiber or ceramic fiber, the weaving method of the fabric is unidirectional, plain weave, twill weave or satin weave, and the pre-impregnated resin is epoxy resin, unsaturated polyester, benzoxazine resin, bismaleyl imide resin or polyimide resin. 4. The conductive continuous fiber reinforced fabric or prepreg and conductive treatment method according to claim 1, characterized in that: the application of the conductive continuous fiber reinforced fabric or the prepreg, the above-mentioned conductive continuous fiber reinforced fabric Or a single layer of prepreg or a mixed layer of continuous fiber reinforced fabric or prepreg without conductive treatment to form a composite material prefabricated body, the number of layers of conductive continuous fiber reinforced fabric or prepreg in the prefabricated body is one One or more layers or equal to the total number of layers, and after curing and molding according to the curing molding process of composite materials, composite parts with improved electrical or thermal conductivity are made. 5. The conductive continuous fiber reinforced fabric or prepreg and conductive treatment method according to claim 4, characterized in that: the curing molding process is autoclave molding, resin transfer molding, molding, vacuum assisted or Vacuum bag forming.