Retreatment method of recycled carbon fibers

A carbon fiber recycling and reprocessing technology, applied in fiber treatment, ultrasonic/sonic fiber treatment, physical treatment, etc., can solve the problems of limiting the comprehensive performance of composite materials, difficult to ensure the stability of quality, disordered fiber shape, etc., to achieve expanded reuse Fields, improved thermal conductivity, and low power consumption

Active Publication Date: 2020-10-09
SHANGHAI JIAO TONG UNIV
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  • Application Information

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Problems solved by technology

Due to the disordered shape and dispersed properties of fibers, it is difficult to ensure stable quality after cutting, which limits the comprehensive performance of composite materials used as reinforcements
In addition, fiber cutting introduces additional operation steps, which is troublesome to implement. At the same time, the cut carbon fiber is not suitable for the processing method of braid forming, which greatly limits its application field. Therefore, a large number of researchers are studying how to deal with recycled carbon fiber , such as Chinese patent CN108586797A discloses a method for recycling and preparing waste carbon fiber PA6 composite materials. Although this partial recycling method can maintain the integrity of carbon fiber tow to a certain extent, the recycling process involves many steps, which is not conducive to large-scale recycling operations

Method used

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  • Retreatment method of recycled carbon fibers
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Experimental program
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Effect test

Embodiment 1

[0029] The bidirectional carbon fiber cloth recovered by pyrolysis was ultrasonically cleaned with ethanol for 1 h. Then the cleaned carbon fiber cloth was placed in a vacuum oven at 60°C and dried for 12 hours. Then the recycled carbon fiber cloth is non-woven and cut into rectangular pieces of 10cm×5cm for later use. Using conductive silver paste, two copper sheet electrodes with a size of 4cm×5cm were bonded to both sides of the cut recycled carbon fiber cloth, placed in a vacuum oven at 70°C, and dried for 3 hours. The dried sample was transferred to a closed box with an argon protective atmosphere, and the positive and negative poles of the regulated DC power supply were connected to the copper sheet electrodes. Use a voltage of 150V to conduct electricity treatment on carbon fiber cloth, and the voltage density is 3V / cm 2 , the power-on time is 1min. After energizing, take out the sample, remove the copper electrode lugs at both ends, use acetone to clean the carbon f...

Embodiment 2

[0032] Ultrasonic cleaning is performed on the carbon fiber precursors obtained by the method of supercritical dissolution of thermosetting composite materials, and the cleaning time is 1 h. Then the cleaned carbon fiber cloth was placed in a vacuum oven at 60°C and dried for 12 hours. Then the recycled carbon fiber cloth is non-woven and cut into 8cm×6cm rectangular pieces for later use. Two pieces of copper foil with a size of 6 cm × 5 cm were bonded on both sides of the cut recycled carbon fiber cloth with conductive adhesive IAC, and placed in a vacuum oven at 70 ° C for 3 h. The dried sample was transferred to a closed box with an argon protective atmosphere, and the positive and negative electrodes of the regulated DC power supply were connected to the copper foil. Use a voltage of 120V to conduct electricity treatment on carbon fiber cloth, and the voltage density is 2.5V / cm 2 , power-on time is 3min. After electrification, take out the sample, remove the copper foil...

Embodiment 3

[0035] During high voltage treatment, the applied voltage density is 1V / cm 2 , the processing time is 300s. All the other are with embodiment 1.

[0036] The carbon fiber cloth before and after electrification treatment was used as reinforcement, and thermosetting resin-based composite materials were prepared respectively. Bisphenol A epoxy resin (E-51) was used as the resin matrix, methyl nadic anhydride was used as the curing agent, and tertiary amine salt was used as the curing agent. Accelerator, mixed uniformly at room temperature, wherein the mass ratio of resin, curing agent and accelerator is 100:98.5:4. The vacuum-assisted molding process is used for molding, and the curing system is 100°C for 1h+130°C for 4h to obtain a carbon fiber reinforced composite material. After mechanical testing, the composite material made of carbon fiber before treatment has a tensile strength of 377.4MPa and a bending strength of 449.3MPa; while the composite material made of carbon fib...

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Abstract

The invention relates to a retreatment method of recycled carbon fibers. The retreatment method comprises the following steps of (1) preparing the recycled carbon fibers into a recycled carbon fiber felt body; (2) cleaning and drying the recovered carbon fiber felt body to remove surface impurities; and (3) connecting lugs to the two ends of the recycled carbon fiber felt body, connecting the recycled carbon fiber felt body with a power supply through the lugs, performing high-voltage treatment, taking down the lugs after treatment, and performing cleaning and drying to obtain a product. Compared with the prior art, the method is wide in application range and can be suitable for carbon fiber products which have different resin residues and are recycled by using different methods. Meanwhile, the treatment time is short, and it can be guaranteed that the performance of the carbon fibers is improved under low energy consumption.

Description

technical field [0001] The invention relates to recovery of carbon fibers, in particular to a reprocessing method for recovered carbon fibers. Background technique [0002] Resin-based carbon fiber composites (referred to as "composites") are based on thermosetting resins or thermoplastic resins, contacting carbon fibers and their fabrics (unidirectional fabrics, two-dimensional woven fabrics, three-dimensional woven preforms, etc.) or chopped dispersed fibers Composite material for reinforcement. It has high specific strength, high specific stiffness, high corrosion resistance, excellent performance and structural design, and flexible formability. It has been widely used in national defense, aerospace, aviation, automobile, energy, construction and other fields, and has become the above-mentioned important One of the pillar materials in the field. With the expansion of the application fields of composite components, the recycling of composite components and waste has beco...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D04H1/4242D06M10/02D01G11/00
CPCD04H1/4242D06M10/025D01G11/00Y02W30/66Y02W30/62
Inventor 李华陈浩昌蔡云丽张舜喆陈玉洁刘河洲丁文江
Owner SHANGHAI JIAO TONG UNIV
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