Preparation method of microchip piezoelectric yarn reinforced resin-based composite material and microchip piezoelectric yarn reinforced resin-based composite material

Abstract

The invention relates to the technical field of composite material preparation, and particularly discloses a preparation method of a microchip piezoelectric yarn reinforced resin-based composite material and the material. Preparing a piezoelectric polymer fiber net on the surface of the silver-plated aramid fiber core layer by taking a piezoelectric polymer as a spinning raw material to obtain a piezoelectric core-spun yarn; coating the surface of the piezoelectric core-spun yarn with silver-plated aramid fiber in a weaving manner to obtain initial piezoelectric yarn; melting polypropylene, and uniformly coating the surface of the initial piezoelectric yarn with the molten polypropylene to obtain a target piezoelectric yarn; the target piezoelectric yarn is connected with a microchip, and microchip fibers are obtained; the microchip fibers and the resin matrix are integrated through a three-dimensional weaving technology, and the microchip piezoelectric yarn reinforced resin matrix composite material is obtained. Based on the scheme, the prepared microchip piezoelectric yarn reinforced resin-based composite material has the characteristics of high strength, no external power supply, long-distance identification and wireless communication.

Description

Technical Field

[0001] This application relates to the field of composite material preparation technology, specifically to a method and material for preparing a microchip piezoelectric yarn reinforced resin-based composite material. Background Technology

[0002] Resin-based composite materials have become commonly used structural materials in modern engineering due to their advantages such as high specific strength, corrosion resistance, and strong structural designability. However, current resin-based composite materials can only meet the basic structural load-bearing requirements and cannot meet the integrated needs of modern engineering for real-time monitoring of structural health and wireless transmission of monitoring signals.

[0003] Current intelligent resin-based composite materials mostly use external sensors spliced ​​with resin-based structural materials to achieve sensing functions. This has problems such as poor compatibility between sensors and resin matrix, low reliability of connection interface, need for external power supply for sensors, short signal recognition distance, and insufficient stability of wireless communication. Furthermore, it is difficult to achieve integrated "load-bearing, sensing, and communication", which limits its long-term stable application under complex working conditions.

[0004] Piezoelectric materials have the inherent property of converting mechanical energy into electrical energy. However, existing piezoelectric yarns have defects such as poor structural stability and insufficient mechanical strength, making it difficult to balance load-bearing performance with sensing and communication performance in resin-based composite materials. This makes it impossible to achieve real-time online monitoring of the structural health of composite materials and wireless signal transmission.

[0005] Therefore, how to solve the above-mentioned technical problems and prepare a composite material that can integrate "load bearing, sensing and communication" is an urgent technical problem to be solved. Summary of the Invention

[0006] This application provides a method for preparing a microchip piezoelectric yarn reinforced resin matrix composite material and the material itself, which can prepare a microchip piezoelectric yarn reinforced resin matrix composite material that integrates "load bearing, sensing and communication". This composite material has the characteristics of high strength, no external power supply, long-distance identification and wireless communication.

[0007] To achieve the above objectives, this application provides the following technical solution:

[0008] In a first aspect, embodiments of this application provide a method for preparing a microchip piezoelectric yarn-reinforced resin-based composite material, the method comprising:

[0009] Using piezoelectric polymers as spinning raw materials, piezoelectric polymer fiber webs are prepared on the surface of silver-plated aramid core layers to obtain piezoelectric core-spun yarns.

[0010] Silver-plated aramid is braided and wrapped around the surface of piezoelectric core-spun yarn to obtain the initial piezoelectric yarn;

[0011] Polypropylene is melted and uniformly coated onto the surface of the initial piezoelectric yarn to obtain the target piezoelectric yarn.

[0012] Connect the target piezoelectric yarn to the microchip to obtain microchip fibers;

[0013] By integrating microchip fibers and resin matrix through a three-dimensional weaving process, a microchip piezoelectric yarn-reinforced resin matrix composite material is obtained.

[0014] In some embodiments of this application, a piezoelectric polymer fiber web is prepared on the surface of a silver-plated aramid core layer to obtain a piezoelectric core-spun yarn, comprising:

[0015] Piezoelectric polymer fiber webs were prepared on the surface of a silver-plated aramid core layer by electrospinning parallel electrode method to obtain piezoelectric core-spun yarn.

[0016] Among them, the electrospinning parallel electrode method is used to form a jet of spinning solution by applying a high voltage electric field, which is deposited on the surface of the silver-plated aramid core layer between the receiving electrodes.

[0017] The piezoelectric polymer is polyvinylidene fluoride and / or polyvinylidene fluoride trifluoroethylene copolymer.

[0018] In some embodiments of this application, the electrospinning parallel electrode method uses a spinning voltage of 15-25 kV, a spinning distance of 8-15 cm, a spinning rate of 0.5-2 mL / h, a receiving electrode spacing of 5-10 cm, an ambient temperature of 20-30 °C, and an ambient humidity of 30%-50%.

[0019] In some embodiments of this application, silver-plated aramid is braided and wrapped around the surface of piezoelectric core-spun yarn to obtain an initial piezoelectric yarn, comprising:

[0020] The initial piezoelectric yarn is obtained by weaving silver-plated aramid yarn onto the surface of piezoelectric core-spun yarn using a two-dimensional weaving process.

[0021] Among them, the silver-plated aramid and the silver-plated aramid used in the silver-plated aramid core layer have the same diameter, which is 50~200μm;

[0022] The weaving density of the two-dimensional weaving process is 20~40 threads / 10cm, and the weaving angle is 30~60°.

[0023] In some embodiments of this application, polypropylene is melted and uniformly coated onto the surface of an initial piezoelectric yarn to obtain a target piezoelectric yarn, including:

[0024] By using a melt spinning process, polypropylene is melted and uniformly coated onto the surface of the initial piezoelectric yarn to obtain the target piezoelectric yarn;

[0025] The melting temperature of the melt spinning process is 170~200℃, and the spinning rate is 1~3m / min;

[0026] The target piezoelectric yarn has a polypropylene coating thickness of 10~50μm, a melting point of 160~170℃, and a tensile strength greater than or equal to 20MPa.

[0027] In some embodiments of this application, the target piezoelectric yarn is connected to a microchip to obtain microchip fibers, including:

[0028] The target piezoelectric yarn is connected to the microchip by laser welding or ultrasonic welding to obtain microchip fiber;

[0029] The temperature for laser welding or ultrasonic welding is 80~120℃, the welding pressure is 0.1~0.5MPa, and the welding time is 10~30s.

[0030] In some embodiments of this application, the microchip is a wireless radio frequency microchip with an identification distance greater than or equal to 5m and an operating frequency of 860~960MHz.

[0031] In some embodiments of this application, the resin of the resin matrix is ​​epoxy resin or phenolic resin;

[0032] The weaving density of the three-dimensional weaving process is 30~50 threads / 10cm, and the weaving thickness is 2~10mm;

[0033] The microchip piezoelectric yarn reinforced resin matrix composite material has a tensile strength greater than or equal to 300 MPa, a flexural strength greater than or equal to 250 MPa, a sensing sensitivity greater than or equal to 0.5 mV / MPa, and a wireless transmission distance greater than or equal to 5 m.

[0034] Secondly, embodiments of this application provide a microchip piezoelectric yarn reinforced resin matrix composite material, comprising: a resin matrix and microchip fibers uniformly distributed in the resin matrix;

[0035] The microchip fiber includes interconnected target piezoelectric yarns and microchips; the target piezoelectric yarn includes an initial piezoelectric yarn and a polypropylene covering layer covering the surface of the initial piezoelectric yarn; the initial piezoelectric yarn includes a piezoelectric core-spun yarn and a silver-plated aramid braided layer covering the surface of the piezoelectric core-spun yarn; the piezoelectric core-spun yarn includes a silver-plated aramid core layer and a piezoelectric polymer fiber web covering the surface of the silver-plated aramid core layer.

[0036] In some embodiments of this application, the raw material for the piezoelectric polymer fiber web is polyvinylidene fluoride and / or polyvinylidene fluoride trifluoroethylene copolymer;

[0037] The silver-plated aramid core layer and the silver-plated aramid braided layer have the same diameter, which is 50~200μm.

[0038] The thickness of the polypropylene coating is 10~50μm;

[0039] The microchip is a wireless radio frequency microchip;

[0040] The resin matrix is ​​made of epoxy resin or phenolic resin. Attached Figure Description

[0041] To more intuitively illustrate the prior art and this application, exemplary drawings are provided below. It should be understood that the specific shapes and structures shown in the drawings should not generally be regarded as limiting conditions for implementing this application; for example, based on the technical concept disclosed in this application and the exemplary drawings, those skilled in the art are able to easily make conventional adjustments or further optimizations to the addition / reduction / classification, specific shapes, positional relationships, connection methods, size ratios, etc. of certain units (components).

[0042] Figure 1 This is a schematic diagram illustrating the implementation process of the preparation method of the microchip piezoelectric yarn reinforced resin matrix composite material provided in the embodiments of this application. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. Any combination of different embodiments is possible.

[0044] In the description of this application: unless otherwise stated, "a plurality of" means two or more. The terms "first," "second," "third," etc., in this application are intended to distinguish the objects referred to and do not have any special meaning in terms of technical connotation (e.g., they should not be construed as an emphasis on importance or order). Expressions such as "including," "comprising," and "having" also mean "not limited to" (certain units, components, materials, steps, etc.).

[0045] This application provides a method for preparing a microchip piezoelectric yarn-reinforced resin-based composite material, aiming to solve the problems of poor compatibility between current intelligent resin-based composite material sensors and the matrix, the need for an external power supply, short signal recognition distance, and the inability to achieve "load-bearing, sensing, and communication" integration. It also addresses the shortcomings of current piezoelectric yarns, such as insufficient mechanical strength and easy detachment at the interface with the microchip. The method produces a microchip piezoelectric yarn-reinforced resin-based composite material that combines high strength, no external power supply required, long-distance recognition, and wireless communication characteristics, enabling real-time online monitoring of structural health and wireless signal transmission. Figure 1As shown, the preparation method of microchip piezoelectric yarn reinforced resin matrix composite material may include the following steps:

[0046] Step 101: Using piezoelectric polymer as the spinning raw material, a piezoelectric polymer fiber web is prepared on the surface of the silver-plated aramid core layer to obtain piezoelectric core-spun yarn.

[0047] In the embodiments of this application, piezoelectric polymer can be used as the spinning raw material to prepare a piezoelectric polymer fiber web on the surface of the silver-plated aramid core layer to obtain piezoelectric core-spun yarn.

[0048] In the embodiments of this application, piezoelectric polymer refers to a polymer with a piezoelectric effect, which can realize the mutual conversion of mechanical energy and electrical energy.

[0049] In the embodiments of this application, the silver-plated aramid core layer refers to the core basic support layer of the composite yarn formed by using silver-plated aramid as raw material. The silver-plated aramid combines the high strength characteristics of aramid with the conductive characteristics of silver.

[0050] In the embodiments of this application, the piezoelectric polymer fiber web refers to a mesh fiber layer formed by a piezoelectric polymer spinning process, which can provide piezoelectric sensing function for the yarn.

[0051] It is understood that, in the embodiments of this application, piezoelectric core-spun yarn refers to a core-skin structure composite yarn with silver-plated aramid as the core layer and piezoelectric polymer fiber web as the skin layer.

[0052] In some embodiments of this application, when preparing a piezoelectric polymer fiber web on the surface of a silver-plated aramid core layer to obtain piezoelectric core-spun yarn, the piezoelectric polymer fiber web can be prepared on the surface of the silver-plated aramid core layer by electrospinning parallel electrode method to obtain piezoelectric core-spun yarn.

[0053] Among them, the electrospinning parallel electrode method is used to form a jet of spinning solution by applying a high voltage electric field, which is then deposited on the surface of the silver-plated aramid core layer between the receiving electrodes.

[0054] In the embodiments of this application, the electrospinning parallel electrode method is a sub-process of electrospinning. Specifically, it can be achieved by applying a high voltage electric field to the spinning solution to form a charged jet. The jet is stretched and refined under the action of the electric field force, and finally deposited on the surface of the silver-plated aramid core layer between the parallel receiving electrodes to form a continuous and uniform piezoelectric polymer fiber web.

[0055] In the embodiments of this application, the piezoelectric polymer is polyvinylidene fluoride and / or polyvinylidene fluoride trifluoroethylene copolymer; "and / or" means that polyvinylidene fluoride can be used alone, polyvinylidene fluoride trifluoroethylene copolymer can be used alone, or the two can be mixed.

[0056] In the embodiments of this application, a uniform and dense piezoelectric polymer fiber web can be formed on the surface of the silver-plated aramid core layer by electrospinning parallel electrode method, ensuring the piezoelectric sensing performance of the yarn; at the same time, the above-mentioned piezoelectric polymers have good bonding with the silver-plated aramid core layer and stable piezoelectric effect, which can solve the problem of poor sensing performance of piezoelectric yarns in the current related technologies.

[0057] In the embodiments of this application, the electrospinning parallel electrode method uses a spinning voltage of 15~25kV, a spinning distance of 8~15cm, a spinning rate of 0.5~2mL / h, a receiving electrode spacing of 5~10cm, an ambient temperature of 20~30℃, and an ambient humidity of 30%~50%.

[0058] In the embodiments of this application, the spinning voltage refers to the high-voltage electric field voltage applied to the spinning solution.

[0059] In the embodiments of this application, the spinning distance refers to the straight-line distance between the spinning nozzle and the receiving electrode.

[0060] In the embodiments of this application, the spinning rate refers to the push rate of the spinning solution.

[0061] In the embodiments of this application, the receiving electrode spacing refers to the distance between two receiving electrodes arranged in parallel.

[0062] It is understood that, in the embodiments of this application, the above process parameters are the optimal parameter range for preparing piezoelectric polymer fiber webs by the electrospinning parallel electrode method, and the ambient temperature and humidity are the basic environmental conditions for implementing the electrospinning parallel electrode method.

[0063] In the embodiments of this application, the specific process parameter range of the above-mentioned electrospinning parallel electrode method can ensure the stability of the spinning process and avoid problems such as jet breakage, uneven fiber web, and weak bonding between fiber and core layer. The prepared piezoelectric polymer fiber web has uniform thickness and is tightly bonded to the silver-plated aramid core layer, which further improves the structural stability and sensing performance of the piezoelectric core-spun yarn. At the same time, the parameter range is highly controllable and suitable for large-scale production.

[0064] Step 102: Weave silver-plated aramid yarn over the surface of the piezoelectric core-spun yarn to obtain the initial piezoelectric yarn.

[0065] In the embodiments of this application, after preparing a piezoelectric polymer fiber web on the surface of a silver-plated aramid core layer using a piezoelectric polymer as the spinning raw material to obtain a piezoelectric core-spun yarn, the silver-plated aramid is woven and wrapped onto the surface of the piezoelectric core-spun yarn to obtain an initial piezoelectric yarn.

[0066] In the embodiments of this application, the initial piezoelectric yarn refers to a three-layer composite yarn formed by adding a silver-plated aramid braiding layer to the outside of the piezoelectric core-spun yarn, which provides a basis for the subsequent polypropylene coating layer.

[0067] In some embodiments of this application, when silver-plated aramid is braided and wrapped around the surface of piezoelectric core-spun yarn to obtain the initial piezoelectric yarn, a two-dimensional braiding process can be used to braid and wrap the silver-plated aramid around the surface of the piezoelectric core-spun yarn to obtain the initial piezoelectric yarn.

[0068] In the embodiments of this application, the two-dimensional weaving process refers to the process of continuously weaving and covering the core material with weaving yarn (silver-plated aramid) in a planar direction at a specific angle and density, which can form a uniform woven protective layer on the surface of the piezoelectric core-spun yarn.

[0069] The silver-plated aramid and the silver-plated aramid core layer have the same diameter, which is 50~200μm.

[0070] In the embodiments of this application, the silver-plated aramid and the silver-plated aramid core layer have the same diameter, which can ensure the structural uniformity of the initial piezoelectric yarn and avoid weaving gaps caused by size differences.

[0071] In the embodiments of this application, the weaving density of the two-dimensional weaving process is 20~40 threads / 10cm, and the weaving angle is 30~60°.

[0072] In the embodiments of this application, a braiding density of 20-40 strands / 10cm means that the number of silver-plated aramid braided loops per 10cm length is 20-40.

[0073] In the embodiments of this application, the weaving angle refers to the angle between the axis of the silver-plated aramid braided yarn and the piezoelectric core-spun yarn.

[0074] In the embodiments of this application, a two-dimensional braiding process is used to coat the piezoelectric core-spun yarn with silver-plated aramid. The silver-plated aramid used for braiding has the same diameter as the silver-plated aramid in the core layer, and the parameter ranges of braiding density and braiding angle are clearly defined. This allows a dense, uniform, and robust silver-plated aramid braided layer to be formed on the outside of the piezoelectric core-spun yarn, resulting in a three-layer structure of the initial piezoelectric yarn: a silver-plated aramid core layer, a piezoelectric polymer fiber web, and a silver-plated aramid braided layer. This not only improves the overall mechanical strength of the piezoelectric yarn but also forms a continuous conductive path through the double-layered silver-plated aramid, providing a structural basis for the transmission of piezoelectric signals and solving the problem of insufficient mechanical strength in current piezoelectric yarns.

[0075] Step 103: Melt polypropylene and uniformly coat it onto the surface of the initial piezoelectric yarn to obtain the target piezoelectric yarn.

[0076] In the embodiments of this application, after the silver-plated aramid is braided and wrapped around the surface of the piezoelectric core-spun yarn to obtain the initial piezoelectric yarn, polypropylene is melted and uniformly wrapped around the surface of the initial piezoelectric yarn to obtain the target piezoelectric yarn.

[0077] In embodiments of this application, the target piezoelectric yarn includes an initial piezoelectric yarn and a polypropylene coating layer covering the surface of the initial piezoelectric yarn; the polypropylene coating layer can provide protection and interface compatibility characteristics for the piezoelectric yarn.

[0078] In some embodiments of this application, when the target piezoelectric yarn is obtained by uniformly coating the surface of the initial piezoelectric yarn with melted polypropylene, the target piezoelectric yarn can be obtained by melt spinning process.

[0079] In the embodiments of this application, melt spinning refers to the process of heating polypropylene polymer material to a molten state, uniformly coating the molten polypropylene onto the surface of the initial piezoelectric yarn through spinning equipment, and forming a continuous polypropylene film coating layer after cooling.

[0080] In the embodiments of this application, the melting temperature of the melt spinning process is 170~200℃ and the spinning rate is 1~3m / min.

[0081] In the embodiments of this application, the melt temperature refers to the optimal melt molding temperature of polypropylene.

[0082] In the embodiments of this application, the spinning rate is the coating rate of the molten polypropylene.

[0083] In the embodiments of this application, the polypropylene coating of the target piezoelectric yarn has a thickness of 10~50μm, a melting point of 160~170℃, and a tensile strength greater than or equal to 20MPa.

[0084] In the embodiments of this application, the polypropylene coating layer refers to the thin film layer formed on the surface of the initial piezoelectric yarn after the molten polypropylene is cooled. Its melting point is the thermal performance parameter of the polypropylene film after molding, and its tensile strength is its mechanical performance parameter.

[0085] In the embodiments of this application, a polypropylene coating layer is prepared using a melt spinning process. Specific melt spinning process parameters and the performance and dimensional parameters of the polypropylene coating layer are determined. This allows for the formation of a uniformly thick and firmly bonded polypropylene film layer on the surface of the initial piezoelectric yarn. This coating layer effectively protects the internal piezoelectric polymer fiber network, preventing mechanical damage during subsequent processing and use. Simultaneously, the polypropylene coating layer improves the interfacial compatibility between the piezoelectric yarn and the resin matrix, enhances the interfacial bonding strength of the composite material, and avoids interfacial detachment problems.

[0086] Step 104: Connect the target piezoelectric yarn to the microchip to obtain microchip fiber.

[0087] In the embodiments of this application, polypropylene can be melted and uniformly coated onto the surface of the initial piezoelectric yarn to obtain the target piezoelectric yarn. Then, the target piezoelectric yarn can be connected to the microchip to obtain the microchip fiber.

[0088] In the embodiments of this application, microchip fiber refers to a functional composite yarn that integrates a microchip, enabling the acquisition and wireless transmission of piezoelectric signals.

[0089] In the embodiments of this application, a microchip refers to a miniature electronic component with signal acquisition and wireless transmission functions.

[0090] In some embodiments of this application, the target piezoelectric yarn can be connected to the microchip using a high-precision bonding technique at a heterogeneous interface to obtain microchip fibers; wherein, the high-precision bonding technique at a heterogeneous interface is mainly achieved through laser welding or ultrasonic welding.

[0091] In some embodiments of this application, the target piezoelectric yarn can be connected to the microchip by laser welding or ultrasonic welding to obtain microchip fibers.

[0092] In the embodiments of this application, laser welding mainly utilizes the localized high-energy beam of a laser to slightly melt the surface of the polypropylene coating layer of the target piezoelectric yarn, achieving a reliable bond with the microchip interface. Ultrasonic welding mainly utilizes the vibrational energy of ultrasound to generate a localized thermal effect at the connection interface between the target piezoelectric yarn and the microchip, achieving interface fusion. Both laser welding and ultrasonic welding are high-precision joining methods for dissimilar materials (polymer materials and electronic components).

[0093] In the embodiments of this application, the temperature of laser welding or ultrasonic welding is 80~120℃, the welding pressure is 0.1~0.5MPa, and the welding time is 10~30s. The above parameters are the optimal process parameters for the two welding methods, which can ensure the connection strength while avoiding damage to the piezoelectric yarn and microchip.

[0094] In the embodiments of this application, by specifying whether the target piezoelectric yarn and the microchip are connected by laser welding or ultrasonic welding, and specifying the welding process parameters, high-precision and reliable bonding of the heterogeneous interface between the piezoelectric yarn and the microchip can be achieved, solving the problem of easy detachment of the connection interface between the piezoelectric yarn and the microchip in current related technologies. At the same time, the welding parameters can avoid damage to the piezoelectric properties of the piezoelectric yarn and the electronic properties of the microchip caused by high temperature and high pressure, ensuring the stability of the sensing and communication functions of the microchip fiber.

[0095] In the embodiments of this application, the microchip is a radio frequency identification (RFID) microchip, which does not require an external power supply and can realize data acquisition and wireless transmission through radio frequency signals.

[0096] In the embodiments of this application, the identification distance of the wireless radio frequency microchip is greater than or equal to 5m, and the operating frequency is 860~960MHz; wherein, the identification distance refers to the distance at which the chip can achieve stable wireless signal transmission, and the operating frequency refers to the radio frequency of the chip for wireless communication.

[0097] In the embodiments of this application, the microchip is a wireless radio frequency microchip, and its identification distance and operating frequency parameters are clearly defined. The microchip does not require an external power supply and can be powered by the piezoelectric energy generated by the piezoelectric yarn, which solves the problem that current related smart composite materials require an external power supply. At the same time, the wireless radio frequency microchip with these parameters has a long identification distance and a stable operating frequency, which can ensure the wireless communication performance of the composite material and solve the problems of short signal identification distance and insufficient wireless communication stability in current related technologies.

[0098] Step 105: Integrate the microchip fiber and resin matrix through a three-dimensional weaving process to obtain a microchip piezoelectric yarn reinforced resin matrix composite material.

[0099] In the embodiments of this application, after connecting the target piezoelectric yarn to the microchip to obtain the microchip fiber, the microchip fiber and the resin matrix can be integrated by a three-dimensional weaving process to obtain a microchip piezoelectric yarn reinforced resin matrix composite material.

[0100] In the embodiments of this application, the three-dimensional weaving process can be used to integrally mold microchip fibers and resin matrix in a three-dimensional spatial interweaving manner.

[0101] In the embodiments of this application, the resin matrix refers to the continuous phase of the composite material formed from resin as raw material, which can provide the basic molding and load-bearing characteristics of the composite material.

[0102] In the embodiments of this application, the microchip piezoelectric yarn reinforced resin matrix composite material refers to a composite structural material with a resin matrix as the continuous phase, microchip fibers as the reinforcing and functional phases, and which has load-bearing, sensing and communication functions.

[0103] In the embodiments of this application, the resin of the resin matrix is ​​epoxy resin or phenolic resin.

[0104] In the embodiments of this application, the weaving density of the three-dimensional weaving process is 30-50 fibers / 10cm, and the weaving thickness is 2-10mm; wherein, the weaving density of 30-50 fibers / 10cm means that the number of fibers interlaced within each 10cm length during the three-dimensional weaving process is 30-50 fibers; the weaving thickness refers to the overall thickness of the prepared composite material.

[0105] In the embodiments of this application, the tensile strength of the microchip piezoelectric yarn reinforced resin matrix composite material is greater than or equal to 300 MPa, the flexural strength is greater than or equal to 250 MPa, the sensing sensitivity is greater than or equal to 0.5 mV / MPa, and the wireless transmission distance is greater than or equal to 5 m. The above parameters are the core performance indicators of the microchip piezoelectric yarn reinforced resin matrix composite material. The tensile strength and flexural strength can reflect its mechanical load-bearing capacity, the sensing sensitivity can reflect its piezoelectric sensing performance, and the wireless transmission distance can reflect its wireless communication performance.

[0106] In the embodiments of this application, the specific resin types of the resin matrix, the parameters of the three-dimensional weaving process, and the core performance indicators of the composite material are clearly defined. Among them, epoxy resin and phenolic resin have good compatibility with microchip fibers. With the optimal parameters of the three-dimensional weaving process, the microchip fibers and the resin matrix can be integrated in three-dimensional space, so that the microchip fibers are evenly distributed in the resin matrix, ensuring the overall mechanical strength of the composite material. At the same time, the composite material prepared by this process achieves the preset performance indicators, and has excellent load-bearing capacity, sensing capacity, and wireless communication capacity, realizing the integration of "load-bearing, sensing, and communication".

[0107] This application provides a method for preparing a microchip piezoelectric yarn-reinforced resin-based composite material. The method involves using a piezoelectric polymer as the spinning raw material to prepare a piezoelectric polymer fiber web on the surface of a silver-plated aramid core layer, obtaining a piezoelectric core-spun yarn. Silver-plated aramid is then woven and wrapped around the surface of the piezoelectric core-spun yarn to obtain an initial piezoelectric yarn. Melted polypropylene is then uniformly wrapped around the surface of the initial piezoelectric yarn to obtain a target piezoelectric yarn. The target piezoelectric yarn is then connected to a microchip to obtain microchip fibers. Finally, the microchip fibers and the resin matrix are integrated using a three-dimensional weaving process to obtain the microchip piezoelectric yarn-reinforced resin-based composite material. Therefore, this application, through stepwise preparation of the core-skin structure and integration of the microchip to obtain microchip fibers, and then integration with the resin matrix through a three-dimensional weaving process, forms a composite material preparation method with smooth process connections and controllable steps. This method achieves layer-by-layer integration of "load-bearing, sensing, and communication" functions at the process level, solving the core problem of poor bonding between piezoelectric yarns and the resin matrix and microchip in current related technologies, and providing basic process support for the preparation of integrated intelligent composite materials.

[0108] Based on the above embodiments, in another embodiment of this application, a method for preparing a microchip piezoelectric yarn-reinforced resin-based composite material is provided, comprising the following steps:

[0109] Step 1: Prepare piezoelectric core-spun yarn.

[0110] Using the parallel electrode electrospinning method, silver-plated aramid with a diameter of 100 μm was used as the core layer, and polyvinylidene fluoride (PVDF) was used as the spinning raw material. A PVDF spinning solution with a mass concentration of 15% was prepared (the solvent was a mixed solution of N,N-dimethylformamide and acetone, with a volume ratio of 7:3). The electrospinning process parameters were set as follows: spinning voltage 20 kV, spinning distance 12 cm, spinning rate 1 mL / h, receiving electrode spacing 8 cm, ambient temperature 25℃, and ambient humidity 40%. A PVDF fiber web was prepared on the surface of the core layer as the sheath layer to obtain a piezoelectric core-spun yarn with a silver-plated aramid core layer and a PVDF fiber web sheath layer.

[0111] Step 2: Prepare piezoelectric yarn.

[0112] Using the piezoelectric core-spun yarn prepared in step 1 as the core material and silver-plated aramid with a diameter of 100μm as the outer layer braided yarn, a two-dimensional braiding process is adopted, with a braiding density of 30 yarns / 10 cm and a braiding angle of 45° to braid and cover the core material, resulting in a three-layer piezoelectric yarn with an outer layer of silver-plated aramid, a middle layer of PVDF fiber web, and a core layer of silver-plated aramid.

[0113] Step 3: Prepare PP-coated piezoelectric yarn.

[0114] Using melt spinning technology, polypropylene (PP) is used as the coating material. The PP is heated to 185°C to melt, and the spinning rate is set to 2 m / min. A PP film (polypropylene coating layer) is uniformly coated on the surface of the piezoelectric yarn prepared in step 2. The coating layer thickness is 30 μm, and a PP-coated PVDF piezoelectric yarn is obtained. The PP film has a melting point of 165°C and a tensile strength of 25 MPa.

[0115] Step 4: Prepare microchip fibers.

[0116] Using high-precision ultrasonic welding technology at heterogeneous interfaces, the PP-wrapped PVDF piezoelectric yarn prepared in step 3 was connected to an RFID microchip. The welding temperature was set at 100℃, the welding pressure at 0.3 MPa, and the welding time at 20 s, achieving reliable bonding between the piezoelectric yarn and the microchip, resulting in a high-strength microchip fiber that supports wireless communication and requires no external power supply. The RFID microchip has a recognition distance of 6 m and an operating frequency of 915 MHz.

[0117] Step 5: Prepare and test the three-dimensional woven composite material.

[0118] The microchip fibers prepared in step 4 were integrated with epoxy resin preforms using a three-dimensional weaving process. The weaving density was set to 40 threads / 10 cm, and the weaving thickness was 5 mm, resulting in a three-dimensional woven composite material integrating load-bearing, sensing, and communication functions. Performance tests were conducted on the composite material, and the results showed that the tensile strength was 350 MPa, the flexural strength was 280 MPa, the sensing sensitivity was 0.6 mV / MPa, and the wireless transmission distance was 6 m. It can stably realize real-time online monitoring of stress and strain of the composite material and wireless signal transmission.

[0119] Based on the above embodiments, in another embodiment of this application, a method for preparing a microchip piezoelectric yarn-reinforced resin-based composite material is provided, comprising the following steps:

[0120] Step 1: Prepare piezoelectric core-spun yarn.

[0121] Using the parallel electrode electrospinning method, silver-plated aramid with a diameter of 50 μm was used as the core layer, and polyvinylidene fluoride-trifluoroethylene copolymer (PVDF-TrFE) was used as the spinning raw material. The molar ratio of PVDF to TrFE was 8:2. A PVDF-TrFE spinning solution with a mass concentration of 12% (solvent: N,N-dimethylacetamide) was prepared. The electrospinning process parameters were set as follows: spinning voltage 15 kV, spinning distance 8 cm, spinning rate 0.5 mL / h, receiving electrode spacing 5 cm, ambient temperature 20℃, and ambient humidity 30%. A PVDF-TrFE fiber web was prepared on the surface of the core layer as a sheath to obtain piezoelectric core-spun yarn.

[0122] Step 2: Prepare piezoelectric yarn.

[0123] Using the piezoelectric core-spun yarn prepared in step 1 as the core material, and silver-plated aramid with a diameter of 50μm as the outer layer braided yarn, a two-dimensional braiding process was adopted, with a braiding density of 20 yarns / 10cm and a braiding angle of 30°. After braiding and covering, a three-layer piezoelectric yarn was obtained.

[0124] Step 3: Prepare PP-coated piezoelectric yarn.

[0125] Using melt spinning technology, PP is heated to 170℃ to melt, and the spinning rate is set to 1m / min. The surface of the piezoelectric yarn prepared in step 2 is coated with a PP film with a coating thickness of 10μm to obtain a PP-coated piezoelectric yarn. The PP film has a melting point of 160℃ and a tensile strength of 20MPa.

[0126] Step 4: Prepare microchip fibers.

[0127] Using high-precision laser welding technology for heterogeneous interfaces, PP-wrapped piezoelectric yarn is connected to an RFID microchip. The welding temperature is set at 80℃, the welding pressure at 0.1MPa, and the welding time at 10s to create the microchip fiber. The RFID microchip has a recognition distance of 5m and an operating frequency of 860MHz.

[0128] Step 5: Prepare and test the three-dimensional woven composite material.

[0129] Microchip fibers were integrated with phenolic resin preforms and a three-dimensional weaving process was used to prepare a three-dimensional woven composite material with a weaving density of 30 threads / 10 cm and a weaving thickness of 2 mm. Performance test results showed that the tensile strength was 300 MPa, the flexural strength was 250 MPa, the sensing sensitivity was 0.5 mV / MPa, and the wireless transmission distance was 5 m, which can realize real-time online monitoring and wireless transmission of structural health.

[0130] Based on the above embodiments, in another embodiment of this application, a method for preparing a microchip piezoelectric yarn-reinforced resin-based composite material is provided, comprising the following steps:

[0131] Step 1: Prepare piezoelectric core-spun yarn.

[0132] Using the parallel electrode electrospinning method, silver-plated aramid with a diameter of 200 μm was used as the core layer, and a mixture of PVDF and PVDF-TrFE (mass ratio of 1:1) was used as the spinning raw material. A spinning solution with a mass concentration of 18% was prepared. The electrospinning process parameters were set as follows: spinning voltage 25 kV, spinning distance 15 cm, spinning rate 2 mL / h, receiving electrode spacing 10 cm, ambient temperature 30℃, and ambient humidity 50%. Piezoelectric core-spun yarn was thus prepared.

[0133] Step 2: Prepare piezoelectric yarn.

[0134] Using the piezoelectric core-spun yarn prepared in step 1 as the core material, and silver-plated aramid with a diameter of 200μm as the outer layer braided yarn, a two-dimensional braiding process was adopted, with a braiding density of 40 yarns / 10cm and a braiding angle of 60°. After braiding and covering, a three-layer piezoelectric yarn was obtained.

[0135] Step 3: Prepare PP-coated piezoelectric yarn.

[0136] Using melt spinning technology, PP is heated to 200℃ to melt, and the spinning rate is set to 3m / min. A PP film is then coated on the surface of the piezoelectric yarn with a coating thickness of 50μm to obtain a PP-coated piezoelectric yarn. The PP film has a melting point of 170℃ and a tensile strength of 30MPa.

[0137] Step 4: Prepare microchip fibers.

[0138] Using high-precision ultrasonic welding technology for heterogeneous interfaces, PP-wrapped piezoelectric yarn is connected to an RFID microchip. The welding temperature is set at 120℃, the welding pressure at 0.5MPa, and the welding time at 30s to create a microchip fiber. The RFID microchip has a recognition distance of 7m and an operating frequency of 960MHz.

[0139] Step 5: Prepare and test the three-dimensional woven composite material.

[0140] Microchip fibers were integrated with epoxy resin preforms and a three-dimensional weaving process was used to prepare a three-dimensional woven composite material with a weaving density of 50 threads / 10cm and a weaving thickness of 10 mm. Performance test results showed that the tensile strength was 380 MPa, the flexural strength was 300 MPa, the sensing sensitivity was 0.7 mV / MPa, the wireless transmission distance was 7 m, and the monitoring and transmission performance was stable.

[0141] Based on the above embodiments, in another embodiment of this application, a microchip piezoelectric yarn reinforced resin matrix composite material is provided, which is prepared by the above-described method for preparing microchip piezoelectric yarn reinforced resin matrix composite material. The microchip piezoelectric yarn reinforced resin matrix composite material includes: a resin matrix and microchip fibers uniformly distributed in the resin matrix.

[0142] In the embodiments of this application, the resin matrix is ​​the continuous phase of the composite material, providing basic molding and load-bearing functions, and the microchip fiber is the reinforcing and functional phase of the composite material, while providing mechanical reinforcement, piezoelectric sensing and wireless communication functions.

[0143] The microchip fiber includes interconnected target piezoelectric yarns and microchips; the target piezoelectric yarn includes an initial piezoelectric yarn and a polypropylene covering layer covering the surface of the initial piezoelectric yarn; the initial piezoelectric yarn includes a piezoelectric core-spun yarn and a silver-plated aramid braided layer covering the surface of the piezoelectric core-spun yarn; the piezoelectric core-spun yarn includes a silver-plated aramid core layer and a piezoelectric polymer fiber web covering the surface of the silver-plated aramid core layer.

[0144] In the embodiments of this application, the target piezoelectric yarn and the microchip are reliably connected by laser welding or ultrasonic welding.

[0145] In the embodiments of this application, the polypropylene coating layer is tightly adhered to the surface of the initial piezoelectric yarn.

[0146] In the embodiments of this application, the silver-plated aramid braided layer is tightly wrapped around the surface of the piezoelectric core-spun yarn through a two-dimensional braiding process.

[0147] In the embodiments of this application, piezoelectric polymer fiber webs are deposited on the surface of a silver-plated aramid core layer by electrospinning parallel electrode method.

[0148] In the embodiments of this application, the core structure of the microchip piezoelectric yarn reinforced resin matrix composite material is a resin matrix and uniformly distributed microchip fibers. Furthermore, the microchip fibers comprise a multi-level composite structure, with each layer having a clearly defined function and strong bonding. Specifically, the silver-plated aramid core layer and the silver-plated aramid braided layer provide mechanical strength and electrical conductivity, the piezoelectric polymer fiber web provides piezoelectric sensing functionality, the polypropylene coating layer provides protection and interface compatibility, and the microchip provides signal acquisition and wireless transmission functionality. This structural design highly integrates the load-bearing, sensing, and communication functions of the microchip piezoelectric yarn reinforced resin matrix composite material, solving the current problems of functional separation and poor structural compatibility in smart composite materials. Simultaneously, the uniform distribution of microchip fibers within the resin matrix ensures the uniformity of the composite material's performance.

[0149] In the embodiments of this application, the raw material of the piezoelectric polymer fiber web is polyvinylidene fluoride and / or polyvinylidene fluoride trifluoroethylene copolymer, which can ensure the piezoelectric sensing performance of the sensing functional layer.

[0150] In the embodiments of this application, the silver-plated aramid core layer and the silver-plated aramid in the silver-plated aramid braided layer have the same diameter, which is 50~200μm, to ensure the structural uniformity of the microchip fiber and the continuity of the conductive path.

[0151] In the embodiments of this application, the thickness of the polypropylene coating layer is 10~50μm, which can provide reliable protection and ensure interfacial bonding performance.

[0152] In the embodiments of this application, the microchip is a wireless radio frequency microchip, which can ensure wireless communication functionality.

[0153] In the embodiments of this application, the resin of the resin matrix is ​​epoxy resin or phenolic resin, which can ensure the basic load-bearing performance and compatibility with microchip fibers.

[0154] This application provides a microchip piezoelectric yarn-reinforced resin-based composite material. The raw materials and dimensional parameters of each component of the composite material are clearly defined, and these parameters are matched to each other, resulting in a tighter bond and more synergistic performance between the various structures of the composite material. This ensures both the overall mechanical load-bearing capacity of the composite material and the stability of its piezoelectric sensing and wireless communication functions. Furthermore, the clearly defined structural parameters provide a clear standard for the large-scale preparation and performance control of the composite material, solving the problem of poor performance caused by the mismatch between piezoelectric yarn and resin matrix / microchip parameters in current related technologies.

[0155] In summary, compared with existing related technologies, the microchip piezoelectric yarn reinforced resin matrix composite material and its preparation method of this application have the following advantages: The piezoelectric yarn adopts a four-layer structure design consisting of a silver-plated aramid core layer, a piezoelectric polymer fiber web, a silver-plated aramid braided layer, and a polypropylene coating layer. Both the core layer and the outer layer are silver-plated aramid, which ensures the high strength of the piezoelectric yarn and improves its piezoelectric sensing performance. At the same time, the two layers of silver-plated aramid form a continuous conductive path, providing a guarantee for signal transmission between the microchip and the piezoelectric yarn, thus solving the defects of insufficient mechanical strength and poor sensing performance of existing piezoelectric yarns. The polypropylene coating layer is prepared on the surface of the piezoelectric yarn using a melt spinning process, which can effectively protect the piezoelectric polymer fiber web and prevent it from being damaged during subsequent processing and use. It also improves the compatibility between the piezoelectric yarn and the resin matrix, enhances the interfacial bonding strength of the composite material, and avoids the problem of interfacial detachment. Laser welding or Ultrasonic welding achieves high-precision bonding of the heterogeneous interface between piezoelectric yarns and wireless RF microchips, resulting in high connection reliability. Furthermore, the wireless RF microchip requires no external power supply, has a recognition distance of ≥5m, and operates at a stable frequency, solving the problems of current smart composite materials requiring external power supplies, poor wireless communication stability, and short recognition distances. A three-dimensional weaving process integrates the microchip fibers with the resin matrix, ensuring uniform distribution of the microchip fibers within the resin matrix. The resulting composite material possesses excellent mechanical load-bearing capacity, piezoelectric sensing performance, and wireless communication performance, achieving integration of "load-bearing, sensing, and communication." This meets the needs of aerospace, rail transportation, and other fields for smart structural materials, expanding the application scope of resin-based composite materials. The preparation method presented in this application has clear process steps, controllable process parameters, smooth transitions between steps, and no complex processing equipment requirements, making it suitable for large-scale production and possessing high industrial application value.

[0156] The above embodiments are merely preferred embodiments provided to fully illustrate this application, and the scope of protection of this application is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on this application are all within the scope of protection of this application.

Claims

1. A method for preparing a microchip piezoelectric yarn-reinforced resin-based composite material, characterized in that, The method includes: Using piezoelectric polymers as spinning raw materials, piezoelectric polymer fiber webs are prepared on the surface of silver-plated aramid core layers to obtain piezoelectric core-spun yarns. Silver-plated aramid is braided and wrapped around the surface of the piezoelectric core-spun yarn to obtain the initial piezoelectric yarn; Polypropylene is melted and uniformly coated onto the surface of the initial piezoelectric yarn to obtain the target piezoelectric yarn. The target piezoelectric yarn is connected to a microchip to obtain microchip fibers; The microchip fibers and resin matrix are integrated by a three-dimensional weaving process to obtain a microchip piezoelectric yarn reinforced resin matrix composite material.

2. The method for preparing the microchip piezoelectric yarn-reinforced resin-based composite material according to claim 1, characterized in that, The process of preparing a piezoelectric polymer fiber web on the surface of a silver-plated aramid core layer to obtain a piezoelectric core-spun yarn includes: The piezoelectric polymer fiber web was prepared on the surface of the silver-plated aramid core layer by electrospinning parallel electrode method to obtain the piezoelectric core-spun yarn; The electrospinning parallel electrode method is used to form a jet of spinning solution by applying a high voltage electric field, which is then deposited on the surface of the silver-plated aramid core layer between the receiving electrodes. The piezoelectric polymer is polyvinylidene fluoride and / or polyvinylidene fluoride trifluoroethylene copolymer.

3. The method for preparing the microchip piezoelectric yarn-reinforced resin-based composite material according to claim 2, characterized in that, The electrospinning parallel electrode method has a spinning voltage of 15~25kV, a spinning distance of 8~15cm, a spinning rate of 0.5~2mL / h, a receiving electrode spacing of 5~10cm, an ambient temperature of 20~30℃, and an ambient humidity of 30%~50%.

4. The method for preparing the microchip piezoelectric yarn-reinforced resin-based composite material according to claim 1, characterized in that, The step of weaving silver-plated aramid fibers onto the surface of the piezoelectric core-spun yarn to obtain the initial piezoelectric yarn includes: The initial piezoelectric yarn is obtained by weaving the silver-plated aramid yarn onto the surface of the piezoelectric core-spun yarn using a two-dimensional weaving process. Wherein, the silver-plated aramid has the same diameter as the silver-plated aramid used in the silver-plated aramid core layer, and the diameter is 50~200μm; The two-dimensional weaving process has a weaving density of 20-40 strands / 10cm and a weaving angle of 30-60°.

5. The method for preparing the microchip piezoelectric yarn-reinforced resin-based composite material according to claim 1, characterized in that, The process of uniformly coating the surface of the initial piezoelectric yarn with melted polypropylene to obtain the target piezoelectric yarn includes: The target piezoelectric yarn is obtained by melting polypropylene and uniformly coating the surface of the initial piezoelectric yarn through a melt spinning process. The melting temperature of the melt spinning process is 170~200℃, and the spinning rate is 1~3m / min; The target piezoelectric yarn has a polypropylene coating layer with a thickness of 10~50μm, a melting point of 160~170℃, and a tensile strength greater than or equal to 20MPa.

6. The method for preparing the microchip piezoelectric yarn-reinforced resin-based composite material according to claim 1, characterized in that, The step of connecting the target piezoelectric yarn to the microchip to obtain microchip fibers includes: The target piezoelectric yarn is connected to the microchip by laser welding or ultrasonic welding to obtain the microchip fiber; The laser welding or ultrasonic welding is performed at a temperature of 80-120℃, a welding pressure of 0.1-0.5MPa, and a welding time of 10-30s.

7. The method for preparing the microchip piezoelectric yarn-reinforced resin-based composite material according to claim 6, characterized in that, The microchip is a wireless radio frequency microchip with a recognition distance greater than or equal to 5m and an operating frequency of 860~960MHz.

8. The method for preparing the microchip piezoelectric yarn-reinforced resin-based composite material according to claim 1, characterized in that, The resin matrix is ​​an epoxy resin or a phenolic resin. The weaving density of the three-dimensional weaving process is 30~50 threads / 10cm, and the weaving thickness is 2~10mm; The microchip piezoelectric yarn reinforced resin matrix composite material has a tensile strength greater than or equal to 300 MPa, a flexural strength greater than or equal to 250 MPa, a sensing sensitivity greater than or equal to 0.5 mV / MPa, and a wireless transmission distance greater than or equal to 5 m.

9. A microchip piezoelectric yarn-reinforced resin-based composite material, characterized in that, include: A resin matrix and microchip fibers uniformly distributed in the resin matrix; The microchip fiber comprises interconnected target piezoelectric yarns and microchips; the target piezoelectric yarn comprises an initial piezoelectric yarn and a polypropylene covering layer covering the surface of the initial piezoelectric yarn; the initial piezoelectric yarn comprises a piezoelectric core-spun yarn and a silver-plated aramid braided layer covering the surface of the piezoelectric core-spun yarn; the piezoelectric core-spun yarn comprises a silver-plated aramid core layer and a piezoelectric polymer fiber web covering the surface of the silver-plated aramid core layer.

10. The microchip piezoelectric yarn-reinforced resin-based composite material according to claim 9, characterized in that, The raw material for the piezoelectric polymer fiber web is polyvinylidene fluoride and / or polyvinylidene fluoride trifluoroethylene copolymer; The silver-plated aramid core layer has the same diameter as the silver-plated aramid in the silver-plated aramid braided layer, which is 50~200μm. The thickness of the polypropylene coating layer is 10~50μm; The microchip is a wireless radio frequency microchip; The resin matrix is ​​made of epoxy resin or phenolic resin.

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