CN115895000B - Self-lubricating fiber fabric composite material and forming method - Google Patents

Abstract

The invention provides a self-lubricating fiber fabric composite material and a forming method, wherein a self-lubricating dynamic polymer network is formed by carbon fiber fabric and polymer prepolymer loaded on the surface of the carbon fiber fabric, and layer-by-layer welding and forming of complex shapes of the self-lubricating dynamic polymer network material can be realized by means of dynamic covalent action of a thermosetting polymer composite material. Therefore, the thermosetting polymer composite material with dynamic covalent exchange reaction is synthesized by introducing the embodiment of the invention, the self-lubricating fiber fabric composite material can also have reworking performance on the premise of not influencing the integral lubricating performance of the self-lubricating fiber fabric composite material, and the self-lubricating fiber fabric composite material has the capability of being repeatedly and repeatedly bonded, so that the reusability of the material is greatly improved.

Description

Self-lubricating fiber fabric composite material and forming method

Technical Field

The invention relates to the technical field of carbon composite materials, and in particular to a self-lubricating fiber fabric composite material and a molding method thereof.

Background Art

With the continuous development of polymer chemistry and materials science, the development of new self-lubricating composite materials, the development of new molding methods and the realization of reprocessing have become new directions in the development of materials science. Traditional fiber fabric self-lubricating composite materials can obtain good lubrication properties, but they are generally difficult to bond and process after being solidified by impregnation, and self-lubricating components with complex shapes require complex molds or processes, which greatly limits the application of self-lubricating fiber fabric composite materials. In recent years, there have been reports on methods of constructing polymer reprocessing and recyclable properties through dynamic covalent chemistry, but there are few reports on introducing it into the field of polymer lubrication to construct multifunctional self-lubricating polymer materials.

In addition, once the traditional resin-impregnated self-lubricating fabric composites are cured and formed, it is difficult to perform secondary processing and bonding, which greatly limits the acquisition and reprocessing of complex shapes of self-lubricating fiber fabric composites; therefore, how to achieve the bonding and reprocessing of self-lubricating fiber fabric composites has become an important challenge faced in the field of lubrication.

Summary of the invention

The present invention aims to solve one of the technical problems in the related art to a certain extent at least, and proposes a method for forming a self-lubricating fiber fabric composite material, wherein a carbon fiber fabric and a polymer prepolymer loaded on the surface of the carbon fiber fabric form a self-lubricating dynamic polymer network, and by means of the dynamic covalent action of the thermosetting polymer composite material, the layer-by-layer welding and complex shape forming of the self-lubricating dynamic polymer network material can be achieved. Therefore, the introduction of the synthesis of a thermosetting polymer composite material with a dynamic covalent exchange reaction in the embodiment of the present invention can achieve the reprocessing performance without affecting the overall lubrication performance of the self-lubricating fiber fabric composite material, and the self-lubricating fiber fabric composite material has a good ability to be repeatedly re-bonded, which greatly improves the reusability of the material.

To this end, the object of the present invention is to provide a method for forming a self-lubricating fiber fabric composite material, comprising the following steps:

Dispersing a two-dimensional layered functional filler in an organic solvent to obtain a first mixed material; the functional filler includes 0.5-5 μm amine-modified graphene or 1-20 μm transition metal carbide;

Synthesizing a thermosetting polymer composite material with a dynamic covalent exchange reaction and mixing it with the first mixed material to form a polymer prepolymer solution; wherein the mass percentage of the functional filler is 0.5-2% based on the mass of the polymer composite material;

The polymer prepolymer solution is impregnated into several layers of carbon fiber fabrics respectively for curing and forming; the cured layers of carbon fiber fabrics are stacked and attached to the mold surface for hot pressing for 10s-120min; wherein the temperature of the hot pressing treatment is higher than the temperature of the dynamic covalent bond exchange reaction of the polymer.

In some embodiments, the type of the dynamic covalent bond of the polymer composite is a dynamic ester bond or a dynamic disulfide bond.

In some embodiments, the polymer composite material includes a resin and a curing agent; the polymer composite material can be obtained by dissolving the resin and the curing agent in the organic solvent.

In some embodiments, the resin includes at least one of epoxy resin E-51, epoxy resin E-44, and bisphenol A diglycidyl ether; the curing agent includes at least one of 4,4'-diaminodiphenyl disulfide, 4,4'-dihydroxydiphenyl disulfide, 4,4'-dithiodibutyric acid, 2,2'-dithiodibenzoic acid, and 4,4'-dithiodibenzoic acid.

In some embodiments, the carbon fiber fabric 1K has a thickness of 0.1-0.2 mm, a warp density of 10 strands/10 mm, a weft density of 10 strands/10 mm, and a gram weight of 120-130 g/m ² .

In some embodiments, the polymer prepolymer solution is impregnated into several layers of carbon fiber fabrics for curing and molding at 50-90° C. for 30-120 min, and then at 100-140° C. for 30-120 min.

In some embodiments, the conditions for hot pressing after stacking several layers of cured carbon fiber fabrics and attaching them to the mold surface are 150-200° C., 0.5 MPa-5 MPa, and a heating rate of 10-12° C./min.

In some embodiments, the method of respectively impregnating the polymer prepolymer solution into several layers of the carbon fiber fabric is: repeatedly immersing the carbon fiber fabric in the polymer prepolymer solution for 5-7 minutes each time; until the carbon fiber fabric increases in weight by 20%.

According to a second aspect of the present invention, a self-lubricating fiber fabric composite material is provided, which comprises a composite material prepared by the method in any one of the above embodiments.

Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

FIG1 is a flow chart of the preparation of a self-lubricating fiber fabric composite material according to an embodiment of the present invention;

FIG. 2 is a morphological diagram of the self-lubricating fiber fabric composite material proposed in Example 1 of the present invention.

DETAILED DESCRIPTION

In order to make the purpose, technical scheme, and advantages of the present invention more clearly understood, the present invention is further described in detail with reference to the embodiments below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other technical schemes obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

To this end, as shown in FIG1 , the present invention provides a method for forming a self-lubricating fiber fabric composite material, comprising the following steps:

S1: dispersing a two-dimensional layered functional filler into an organic solvent to obtain a first mixed material; the functional filler includes 0.5-5 μm amine-modified graphene or 1-20 μm transition metal carbide;

S2: synthesizing a thermosetting polymer composite material having a dynamic covalent exchange reaction and mixing the first mixed material thereof to form a polymer prepolymer solution; wherein the mass percentage of the functional filler is 0.5-2% based on the mass of the polymer composite material;

S3: impregnating the polymer prepolymer solution into several layers of carbon fiber fabrics respectively for curing and forming; stacking the cured layers of carbon fiber fabrics and attaching them to the mold surface for hot pressing for 10s-120min; wherein the temperature of the hot pressing treatment is higher than the temperature of the dynamic covalent bond exchange reaction of the polymer.

Exemplarily, the two-dimensional layered functional filler in this embodiment includes a first solution including only 0.5-5μm amine-modified graphene; and a second solution including only 1-20μm transition metal carbide; wherein the two-dimensional layered graphene can be selected from Xianfeng Nano XF005-4, and its size can be exemplified as 0.5μm, 1μm, 2μm, 3μm, 4μm, 5μm or any range therebetween. The graphene selected in the embodiment of the present invention is amine-modified, and can participate in chemical reactions in the polymer matrix to form strong interfacial bonding, and no sedimentation and uneven dispersion will occur. The transition metal carbide in this embodiment is MXene-TiTaAlC (can be selected from Xianfeng Nano XFK27); its sheet diameter can be exemplified as 1μm, 2μm, 3μm, 4μm, 5μm, 10μm, 12μm, 15μm, 18μm, 20μm or any range therebetween. The surface of the MXene-TiTaAlC selected in the embodiment of the present invention contains a large number of hydroxyl groups which can also participate in the chemical reaction during the polymer curing process, maintaining high adhesion and dispersibility.

Without being limited to any theory, the mass percentage of the functional filler is 0.5-2% based on the mass of the polymer composite material, and the mass percentage of the functional filler is 0.5%, 1%, 1.5%, 2% or any range therebetween. Under the action of friction shear stress, the two-dimensional layered material is very easy to slide, which can reduce the interface shear strength and thus reduce the friction coefficient; the amount of functional filler added has a great influence on the self-lubricating fiber fabric composite material, and when the mass percentage of the functional filler is low, such as less than 0.5%, the self-lubricating fiber fabric composite material cannot form an ordered structure and does not have a good lubrication effect; but when the mass percentage of the functional filler is high, such as higher than 0.5%, it is easy to agglomerate.

In some embodiments, the two-dimensional layered functional filler is dispersed in an organic solvent to obtain a first mixture, wherein the organic solvent can be selected from ethanol, that is, the two-dimensional layered functional filler is dispersed in ethanol, and the dispersion method is to use ultrasound for 15-60 minutes, preferably 30 minutes to make it dispersed evenly.

In some embodiments, the polymer composite material includes a resin and a curing agent. The polymer composite material can be obtained by dissolving the resin and the curing agent in an organic solvent. Preferably, the ratio of the resin to the curing agent in the polymer composite material is 1-2 mmol:1 mmol.

Specifically, the type of dynamic covalent bond of the polymer composite material is a dynamic ester bond or a dynamic disulfide bond. The resin includes at least one of epoxy resin E-51, epoxy resin E-44, and bisphenol A diglycidyl ether; the curing agent includes at least one of 4,4'-diaminodiphenyl disulfide, 4,4'-dihydroxydiphenyl disulfide, 4,4'-dithiodibutyric acid, 2,2'-dithiodibenzoic acid, and 4,4'-dithiodibenzoic acid.

In some embodiments, the carbon fiber fabric 1K has a thickness of 0.1-0.2 mm, a warp density of 10 strands/10 mm, a weft density of 10 strands/10 mm, and a gram weight of 120-130 g/m ² . In this embodiment, the carbon fiber fabric is defined so that the polymer prepolymer solution can easily penetrate the carbon fiber fabric, and the formed composite material is dense and uniform.

Specifically, several layers of carbon fiber fabrics are immersed in the polymer prepolymer solution for multiple times, each time for 5-7 minutes, and then the excess glue flows out naturally at room temperature, that is, the excess glue is removed, and the dipping process is repeated until each carbon fiber fabric increases by 20%, and then heated in an oven to complete the curing process. The curing molding conditions are 50-90°C, 30-120min, and then 100-140°C, 30-120min curing; that is, the curing temperature is 50°C, 60°C, 70°C, 80°C, 90°C or When the curing time is within any range therebetween, the curing time is 30-120min, that is, the curing time is 30min, 50min, 90min, 100min, 120min or any range therebetween; after the first curing process is completed, the curing temperature is 100°C, 110°C, 120°C, 130°C, 140°C or any range therebetween, and the curing time is again 30-120min, that is, 30min, 50min, 90min, 100min, 120min or any range therebetween.

In the embodiment of the present invention, the carbon fiber fabric and the polymer prepolymer loaded on the surface of the carbon fiber fabric form a self-lubricating dynamic polymer network. With the help of the dynamic covalent action of the thermosetting polymer composite material, the layer-by-layer welding and complex shape forming of the self-lubricating dynamic polymer network material can be achieved. Therefore, the introduction of the synthesis of the thermosetting polymer composite material with a dynamic covalent exchange reaction in the embodiment of the present invention can achieve the reprocessing performance without affecting the overall lubrication performance of the self-lubricating fiber fabric composite material, and the self-lubricating fiber fabric composite material has a good ability to be repeatedly re-bonded, which greatly improves the reusability of the material.

In some embodiments, the conditions for hot pressing after stacking several layers of cured carbon fiber fabrics and attaching them to the mold surface are 150-200° C., 0.5 MPa-5 MPa, and a heating rate of 10-12° C./min.

Exemplarily, several layers of cured carbon fiber fabrics are stacked and attached to the mold surface, and a pressure of 0.5MPa-5Mpa is applied, preferably a pressure of 1.2MPa is applied, and the temperature is raised from room temperature to 150-200°C at a heating rate of 10-12°C/min, and a bonded self-lubricating fiber fabric composite material is obtained after hot pressing for 10s-120min, preferably 10s-60min. The hot pressing temperature in this embodiment is higher than the temperature of the dynamic covalent bond exchange reaction of the polymer. During the hot pressing process, the traditional thermosetting polymer composite material forms a stable three-dimensional network due to cross-linking, and the network topology will not change even above the deformation temperature and under pressure, so it is difficult to achieve the re-bonding and further processing of the cured composite material. In the present invention, external force is continuously applied to the thermosetting polymer composite material at a temperature above the dynamic covalent bond temperature, and reversible exchange and recombination occur between the dynamic reversible exchange bonds in the thermosetting polymer composite material, so that the thermosetting polymer composite material can be re-bonded together at the interface to form stable covalent bonds. In addition, the carbon fiber fabric composite material can also form a complex shape through dynamic exchange reaction according to the needs of the shape. Therefore, a self-lubricating multifunctional carbon fiber fabric composite material can be prepared by this method.

Example 1

Based on the mass of the polymer composite material, 1% of graphene is dispersed in an ethanol solution, and ultrasonicated for 30 minutes to obtain a first mixed material;

Dissolving epoxy resin E-51 (10 mmol) and 4,4'-dithiodibutyric acid (10 mmol) in 20 mL of ethanol, stirring thoroughly to synthesize a thermosetting polymer composite material having a dynamic covalent exchange reaction, and adding the first mixed material to the thermosetting polymer composite material to obtain a polymer prepolymer solution;

Several carbon fiber fabrics with specifications of 1K, warp density of 10 strands/10mm, weft density of 10 strands/10mm, and unit area mass of 125g/ ^m2 were immersed in the above polymer prepolymer solution for 5 minutes, and then the excess polymer prepolymer solution was naturally discharged at room temperature. The dipping process was repeated until the carbon fiber fabric gained 20% in weight, and then heated in an oven to complete the curing process. The curing conditions were 80°C for 1 hour and then 120°C for 2 hours;

The fiber fabric composite material obtained above was stacked layer by layer and attached to the mold surface, a pressure of 1 MPa was applied, and the temperature was increased from room temperature to 180°C at a rate of 10°C/min. After pressing for 1 hour, a bonded self-lubricating fiber fabric composite material was obtained, and its morphology is shown in Figure 2. From the figure, it can be seen that the thermosetting polymer composite material with dynamic covalent exchange reaction is evenly and fully impregnated in the carbon fiber fabric.

Example 2

Based on the mass of the polymer composite material, 2% of MXene-TiTaAlC was dispersed in an ethanol solution, and ultrasonicated for 30 minutes to obtain a first mixed material;

Dissolving bisphenol A diglycidyl ether (20 mmol) and 4,4'-diaminodiphenyl disulfide (10 mmol) in 20 mL of ethanol to synthesize a thermosetting polymer composite material having a dynamic covalent exchange reaction, and adding the first mixed material to the thermosetting polymer composite material to obtain a polymer prepolymer solution;

A carbon fiber fabric with a specification of 1K, a warp density of 10 strands/10mm, a weft density of 10 strands/10mm, and a unit area mass of 125g/ ^m2 is immersed in the above-mentioned polymer prepolymer solution for 5 minutes, and then the excess polymer prepolymer solution is naturally discharged at room temperature, and the dipping process is repeated until the fiber cloth gains 20% in weight, and then heated in an oven to complete the curing process. The curing conditions are curing at 80°C for 1 hour and then curing at 120°C for another 2 hours;

The fiber fabric composite material obtained above was stacked layer by layer, attached to the mold surface, and a pressure of 0.5 MPa was applied. The temperature was raised from room temperature to 200° C. at a rate of 10° C./min. After pressing for 1 hour, a bonded self-lubricating composite material was obtained.

Example 3

Based on the mass of the polymer composite material, 0.8% of MXene-TiTaAlC was dispersed in an ethanol solution, and ultrasonicated for 30 minutes to obtain a first mixed material;

Dissolving epoxy resin E-44 (20 mmol) and 4,4'-diaminodiphenyl disulfide (10 mmol) in 20 mL of ethanol to synthesize a thermosetting polymer composite material having a dynamic covalent exchange reaction, and adding the first mixed material to the thermosetting polymer composite material to obtain a polymer prepolymer solution;

A carbon fiber fabric with a specification of 1K, a warp density of 10 strands/10mm, a weft density of 10 strands/10mm, and a unit area mass of 125g/ ^m2 is immersed in the above-mentioned polymer prepolymer solution for 5 minutes, and then the excess polymer prepolymer solution is naturally discharged at room temperature, and the immersion process is repeated until the fiber fabric increases in weight by 20%, and then heated in an oven to complete the curing process. The curing conditions are curing at 80°C for 1 hour and curing at 120°C for another 2 hours;

The fiber fabric composite material obtained above was stacked layer by layer and attached to the mold surface, a pressure of 1.2 MPa was applied, the temperature was raised from room temperature to 180°C at a rate of 10°C/min, and pressed for 1 hour to obtain a bonded self-lubricating fiber fabric composite material.

Example 4

Based on the mass of the polymer composite material, 1.5% of graphene is dispersed in an ethanol solution, and ultrasonicated for 30 minutes to obtain a first mixed material;

Dissolving epoxy resin E-51 (10 mmol) and 4,4'-dithiodibutyric acid (10 mmol) in 20 mL of ethanol, stirring thoroughly to synthesize a thermosetting polymer composite material having a dynamic covalent exchange reaction, and adding the first mixed material to the thermosetting polymer composite material to obtain a polymer prepolymer solution;

A carbon fiber fabric with a specification of 1K, a warp density of 10 strands/10mm, a weft density of 10 strands/10mm, and a unit area mass of 125g/ ^m2 is immersed in a polymer prepolymer solution for 5 minutes, and then the excess polymer prepolymer solution is naturally discharged at room temperature for 5 minutes. The immersion process is repeated until the carbon fiber fabric increases in weight by 20%, and then heated in an oven to complete the curing process. The curing conditions are curing at 80°C for 1 hour and then curing at 120°C for 2 hours;

The fiber fabric composite material obtained above was stacked layer by layer and attached to the mold surface, a pressure of 1 MPa was applied, the temperature was raised from room temperature to 180° C. at a rate of 10° C./min, and pressed for 1 hour to obtain a bonded self-lubricating fiber fabric composite material.

Comparative Example 1

Dissolve bisphenol A diglycidyl ether (20 mmol) and 4,4'-diaminodiphenyl disulfide (10 mmol) in 20 mL of ethanol and stir thoroughly to obtain a polymer prepolymer solution. The remaining technical features are exactly the same as those in Example 2 and will not be repeated here.

Comparative Example 2

Based on the mass of the polymer composite material, 5% by mass of MXene (TiTaAlC) was dispersed in an ethanol solution, and ultrasonicated for 30 minutes to obtain a first mixed material; the remaining technical features were exactly the same as those in Example 2.

Comparative Example 3

Dissolve bisphenol A diglycidyl ether (20 mmol) and 4,4'-diaminobiphenyl (10 mmol) in 20 mL of ethanol, stir thoroughly and then add the first mixed material to obtain a polymer prepolymer solution; the remaining technical features are exactly the same as those in Example 2.

Performance Testing

The self-lubricating fiber fabric composite materials obtained in Examples 1-4 and Comparative Examples 1-3 were tested respectively, wherein the friction coefficient was tested by a CSM friction machine, and the calculation formula of the friction coefficient was μ=F/N; wherein μ is the friction coefficient, F is the friction force, and N is the normal pressure;

One side of the self-lubricating fiber fabric composite material obtained in Examples 1-4 and Comparative Examples 1-3 was ground against a steel ball with a diameter of 3 mm, with a test load of 5 N, a rotation speed of 3 cm/s, and a running time of 1 h. The friction coefficient was the average value of 5 tests. The results are listed in Table 1.

Table 1 Performance data of lubricated fiber fabric composites

From the comparison between Examples 1-4 and Comparative Example 1, it can be seen that the carbon fiber fabrics in Examples 1-4 are impregnated into a polymer prepolymer solution with two-dimensional functional fillers added, which can achieve a reduction in the friction coefficient compared to the carbon fiber fabrics in Comparative Example 1 that are impregnated into a polymer prepolymer solution without the introduction of two-dimensional functional fillers. And the carbon fiber fabrics in Comparative Example 2 are impregnated into a polymer prepolymer solution with an excessive amount of two-dimensional functional fillers, which can still achieve a reduction in the friction coefficient compared to Comparative Document 1. At the same time, the thermosetting polymer composite material with a dynamic covalent exchange reaction also has a great influence on the performance of the polymer prepolymer solution. In Comparative Example 3, the type of curing agent is replaced. Although it can reduce the friction coefficient of the self-lubricating fiber fabric composite material to a certain extent, it causes the self-lubricating fiber fabric composite material in Comparative Example 3 to be unprocessable. Therefore, the thermosetting polymer composite material and functional filler with a dynamic covalent exchange reaction introduced into the carbon fiber fabric in the embodiment of the present invention can achieve the reprocessing of the carbon fiber composite material without affecting the overall lubrication performance of the material.

In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims (7)

1. The forming method of the self-lubricating fiber fabric composite material is characterized by comprising the following steps of:

dispersing the two-dimensional lamellar functional filler into an organic solvent to obtain a first mixed material; the functional filler comprises 0.5-5 mu m of amino modified graphene or 1-20 mu m of transition metal carbide;

Synthesizing a thermoset polymer composite material having a dynamic covalent exchange reaction and mixing said first blend thereof to produce a polymer prepolymer solution; wherein the mass percentage of the functional filler is 0.5-2% based on the mass of the polymer composite material; the polymer composite material comprises resin and a curing agent, and the polymer composite material can be obtained by dissolving the resin and the curing agent into the organic solvent; the resin comprises at least one of epoxy resin E-51, epoxy resin E-44 and bisphenol A diglycidyl ether; the curing agent comprises at least one of 4,4' -diaminodiphenyl disulfide, 4' -dihydroxydiphenyl disulfide, 4' -dithiodibutyric acid, 2' -dithiodibenzoic acid and 4,4' -dithiodibenzoic acid;

Respectively dipping the polymer prepolymer solution on a plurality of layers of carbon fiber fabrics for curing and forming; overlapping the solidified carbon fiber fabrics and then attaching the carbon fiber fabrics to the surface of a die for hot pressing for 10s-120min; wherein the temperature of the autoclave treatment is higher than the temperature of the dynamic covalent bond exchange reaction of the polymer.

2. The method of claim 1, wherein the dynamic covalent bonds of the polymer composite are dynamic ester bonds or dynamic disulfide bonds.

3. The method of claim 1, wherein the carbon fiber fabric has a gauge of 1K, a thickness of 0.1-0.2mm, a warp density of 10 pieces/10 mm, a weft density of 10 pieces/10 mm, and a grammage of 120-130g/m ².

4. The method according to claim 1, wherein the conditions for curing and forming the polymer prepolymer solution respectively impregnated on the carbon fiber fabrics are 50-90 ℃ for 30-120min; and then 100-140 ℃ for 30-120min.

5. The method according to claim 1, wherein the condition of hot pressing the solidified carbon fiber fabrics after being overlaid on the surface of the die is 150-200 ℃, 0.5-5 MPa, and the heating rate is 10-12 ℃/min.

6. The method according to claim 1, wherein the method of impregnating the polymer prepolymer solution onto the several layers of the carbon fiber fabric respectively is: repeatedly dipping the carbon fiber fabric into the polymer prepolymer solution for 5-7min each time; until the weight of the carbon fiber fabric is increased by 20%.

7. A self-lubricating fibrous web composite material prepared by the method of any one of claims 1 to 6.