Carbon fiber bundling performance testing device and testing method based on airflow disturbance

Abstract

The invention relates to a device and a method for testing the bundling property of carbon fibers based on airflow disturbance. An unwinding device in the device provides pre-tension for the running process of fiber bundles; the limiting rollers prevent the fiber tows from swinging in the unwinding process; the airflow generating device generates airflow to disturb the fiber tows, so that the fiber tows are dispersed and unfolded; the winding device pulls the fiber tows to operate and provides power for the unwinding device and the limiting rollers. The testing method comprises the following steps: measuring the initial width of a tow, fixing a sample, setting parameters, carrying out a tow disturbance test, measuring the width of the tow after disturbance, and calculating the change of the width of the tow before and after disturbance. According to the method, mechanical damage to the fibers can be avoided, and the authenticity and accuracy of test results are improved. In the testing method, the width change of the tows is provided as a quantitative evaluation index of the bundling property, and a real and visual quantitative index is provided for evaluating and researching the application manufacturability of the carbon fibers.

Description

Technical Field

[0001] This invention belongs to the field of carbon fiber testing and measurement technology, and relates to a carbon fiber bundle property testing device and testing method based on airflow disturbance. Background Technology

[0002] With the development, progress, and maturity of technology, the research and application level of domestically produced carbon fiber has improved rapidly. The performance of a series of carbon fibers and their composites has reached the world's advanced level, meeting the urgent needs of equipment and achieving complete self-sufficiency and control over key raw materials for various equipment models. However, currently, domestically produced carbon fibers generally meet the overall performance standards, but during use, issues such as broken fibers, fuzz, clumps, and even broken yarns occur, resulting in serious "unusable" conditions. This not only affects the continuity, orientation, and uniformity of fiber quality in the intermediates, ultimately reducing the performance conversion rate of the carbon fiber; furthermore, during the weaving, pre-impregnation, and winding processes, it is necessary to frequently clean fuzz and clumps, and even interrupt the preparation process for yarn replacement and splicing, reducing work efficiency and increasing costs.

[0003] Depending on the molding process requirements, continuous carbon fibers typically need to be processed into two main categories of intermediates / preforms for application: prepreg and dry fabric. According to existing carbon fiber prepreg preparation processes, carbon fiber bundles need to pass through numerous combs and guide rollers under certain tension. However, during the weaving process of dry fabric, the fiber bundles repeatedly interweave, rub, and bend, inevitably causing damage due to friction, resulting in broken filaments, fuzz, clumps, and even broken yarns. If the individual filaments in the fiber bundle have a strong ability to bind and aggregate into bundles, maintaining their original aggregation state during use, or returning to their original state after being forced to unfold (i.e., better bundle cohesion), it can reduce the contact area between the bundle and external objects, better maintain the parallelism and shared load-bearing capacity of the individual filaments, and enhance the wear resistance of the fiber bundle. Furthermore, even after frictional breakage, the broken filaments can still bind within the bundle, reducing the cascading friction and wear caused by the broken ends.

[0004] Sizing agents are the primary source of carbon fiber bundle properties. With the same sizing agent content, stronger intermolecular forces result in better "adhesion" and thus better carbon fiber bundle properties. This primarily depends on the molecular structure of the sizing agent, a chemical intrinsic factor. With the same type of sizing agent, a larger sizing amount leads to better carbon fiber bundle properties, a physical extrinsic factor. Secondly, more uniform sizing results in more balanced cohesion between monofilaments, facilitating simultaneous stress on different monofilaments and further improving carbon fiber bundle properties. Sizing uniformity is also determined by both chemical intrinsic and physical extrinsic factors. The chemical intrinsic factor refers to the consistency of intermolecular forces in the sizing agent, depending on the uniformity of molecular weight distribution and the consistency of the type and quantity of terminal functional groups. The physical extrinsic factor refers to the uniformity of the sizing agent coating on the fiber surface, depending on the rationality of the sizing process and the stability of process parameter control.

[0005] In summary, if the sizing agent is of good quality and the sizing is uniform, the carbon fiber bundle / dispersion will be better, which manifests as: 1) the fiber bundles are tightly bound and not easily dispersed under external force; 2) the fiber bundle width is consistent, with no significant changes in fiber bundle width. Therefore, achieving quantitative testing and characterization of carbon fiber bundle properties can effectively guide the improvement of sizing agent quality and sizing process stability.

[0006] The patent "A Carbon Fiber Bundle Performance Testing Device and Evaluation Method" (ZL202210255106.0) discloses a simple device and method for testing the bundle performance of carbon fibers, and proposes a quantitative evaluation index (springback rate). The testing principle is as follows: A carbon fiber bundle is stretched horizontally from its edge along a direction parallel to the bundle width to a specified width by an external force. After a certain period of stretching, the external force is removed, allowing the fiber bundle to spring back freely. The degree / ratio of free shrinkage of the fiber bundle after the removal of the external force is calculated (springback rate). This method fills a domestic gap and can reflect the processability of carbon fiber applications to a certain extent. However, the test requires applying a lateral tensile force to the fiber, which can easily damage the fiber and cause the test results to deviate from the true value. Secondly, when the fiber bundle size increases (24K and above), the applicability of the method decreases significantly. In particular, for carbon fibers prepared by multi-plate spinneret stranding process, the fiber bundle is split during the test and continues to the fixed end of the sample, making it impossible to obtain the expected mesh structure and causing the test to fail. In addition, the whole process is basically manual, which reduces the stability and comparability of the test results.

[0007] Therefore, establishing a more practical, widely applicable, and mechanized method for testing the bundle properties of carbon fibers, and achieving an objective, effective, and rapid quantitative evaluation of the bundle properties of carbon fibers, is of great significance for guiding the improvement of domestic carbon fiber preparation technology and subsequent applications of composite materials. Summary of the Invention

[0008] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a carbon fiber bundle property testing device and method based on airflow disturbance. This provides a mechanized and universal testing device for carbon fiber bundle property, which can minimize mechanical damage to the sample during the testing process and improve the authenticity of the test results.

[0009] The solution of the present invention is:

[0010] A carbon fiber bundle test device based on airflow disturbance includes an unwinding device, a limiting roller, an airflow generating device, and a winding device.

[0011] The unwinding device provides pre-tension for the fiber bundle during its operation; the limiting roller is a smooth dumbbell-shaped driven roller used to prevent the fiber bundle from swinging during unwinding; the airflow generating device generates airflow to disturb the fiber bundle, causing the fiber bundle to disperse and unfold; the winding device pulls the fiber bundle and provides power for the unwinding device and the limiting roller.

[0012] Preferably, the width and length of the air outlet of the airflow generating device are both greater than 1.5cm to ensure that the fiber bundle is uniformly disturbed; the wind speed is adjustable to meet the unfolding of fiber bundles of various specifications.

[0013] Preferably, the winding device pulls the filament bundle to run, and the filament spacing is adjustable from 5 to 30 mm; the speed of the winding device roller is adjustable from 0 to 20 r / min, and it can automatically record the running length of the filament bundle and has an automatic stop function at the preset length.

[0014] A carbon fiber bundle property testing method based on airflow disturbance, implemented using the aforementioned testing device, includes the following steps:

[0015] Step 1: Measure the initial width of the fiber bundle sample;

[0016] Step 2: Place the sample roll on the unwinding device, pull one end of the filament bundle through the limiting roller, and wind it clockwise onto the winding device. Fix the end to the roller of the winding device.

[0017] Step 3: Set the test parameters, including the winding rate of the winding device, the wire pitch, the sample running length, and the wind speed of the airflow generating device;

[0018] Step 4: Turn on the winding device switch, start the airflow generator, and begin the test; after the filament bundle reaches the preset length, turn off the winding device switch, turn off the airflow, fix the tail end of the test sample on the winding device roller, and then cut the filament bundle from behind the fixed end position.

[0019] Step 5: Measure the width of the fiber bundle after disturbance;

[0020] Step Six: Clean the testing device;

[0021] Step 7: Based on the initial width of the fiber bundle sample in Step 1 and the width of the fiber bundle after disturbance in Step 5, calculate the change in fiber bundle width, and use the change in fiber bundle width to quantitatively evaluate the bundle properties of carbon fibers.

[0022] Preferably, in step one, the initial width of the fiber bundle sample is measured using the following method:

[0023] Take a 100cm test specimen every 10 meters from the fiber bundle sample, for a total of n test specimens; place the n test specimens straight on a flat surface, and measure the bundle width using a steel ruler with a minimum scale of 0.5mm. Measure one point every 20cm on each test specimen, for a total of 5 points per test specimen, with the measurement result accurate to 0.1mm; take the average of the 20 individual fiber bundle width values ​​as the initial width of the carbon fiber bundle, denoted as d0, accurate to 0.01mm; n is not less than 4.

[0024] Preferably, during sample fixation in step two, the entire process must ensure that the carbon fiber bundles do not flip, knot, or twist.

[0025] Preferably, in step five, the width of the fiber bundle after disturbance is measured using the following method:

[0026] The width of the carbon fiber bundle after being disturbed by airflow is measured using a steel ruler, accurate to 0.1 mm. N measurement points are used, and the average of the N individual values ​​is taken as the width of the carbon fiber bundle after disturbance, denoted as d. n Accurate to 0.01mm, N not less than 40.

[0027] Preferably, when the diameter of the winding device roller is greater than 700mm, measurement points are evenly selected per turn, and the maximum number of measurement points is 4; when the diameter of the winding device roller is less than 300mm, measurement points are evenly selected per turn, and the maximum number of measurement points is 2; when the diameter of the winding device roller is between 300mm and 700mm, measurement points are evenly selected per turn, and the maximum number of measurement points is 3.

[0028] Preferably, in step six, if there are visible lint or clumps of lint remaining on the surface of the limiting roller or the winding device roller, they need to be cleaned before testing the next sample.

[0029] Preferably, the fiber bundle width change = initial fiber bundle width - fiber bundle width after disturbance.

[0030] The advantages of this invention compared to the prior art are:

[0031] (1) This invention provides a device for testing the bundle properties of carbon fibers, including key components such as an unwinding device, a limiting roller, an airflow generating device, and a winding device, filling a gap in the domestic market. This mechanized device effectively avoids the problems of the flat stretching method, which is basically manual, has a high proportion of human factors, and reduces the stability and comparability of test results.

[0032] (2) This invention innovatively proposes a test method for the bundle properties of carbon fibers based on airflow disturbance. This method uses an airflow generating device to provide external force for the fiber bundle unfolding, without direct contact with the fibers, thus avoiding mechanical damage to the fibers and improving the authenticity and accuracy of the test results. The test parameters involved in this method, such as sample running speed, running length, airflow intensity, and number of data points, have been verified and confirmed through systematic and extensive comparative experiments. While ensuring the stability and representativeness of the test results, the method also takes into account the principle of minimizing the costs of samples, power, and time during the testing process.

[0033] (3) This invention also proposes a quantitative evaluation index for the bundle properties of carbon fibers—the "width change" of the fiber bundle before and after airflow disturbance. This index provides a real and intuitive quantitative indicator for evaluating and studying the application processability of carbon fibers. The test results are quantifiable, repeatable, and have low dispersion, with high temporal and spatial stability. The test results are objective, real, and stable, which is conducive to the performance comparison and analysis of multiple samples. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the composition and testing process of the carbon fiber bundle testing device of the present invention. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0036] like Figure 1 As shown, a carbon fiber abrasion resistance testing device includes an unwinding device 1, a limiting roller 2, an airflow generating device 3, and a winding device 4. The unwinding device 1 provides pre-tension for the fiber bundle winding process; the limiting roller 2 is a smooth-surfaced, silk-smooth rotating dumbbell-shaped driven roller to prevent frictional damage to the fiber bundle; the winding device 4 provides power for the testing process; the airflow generating device 3 generates airflow to disturb the fiber bundle, causing it to disperse and unfold; the winding device 4 pulls the fiber bundle along, providing power for the testing process.

[0037] The unwinding device 1 provides pre-tension for the filament winding process, with the tension continuously adjustable from (2 to 10) N. Rubber or similar materials can be used to provide unwinding friction, thus generating the pre-tension. The airflow generating device 3 has an outlet width and length greater than 1.5 cm to ensure uniform disturbance of the filament; the air velocity is adjustable from (0 to 20) m / s to accommodate the unfolding of filaments of various specifications. The winding device 4 pulls the filament, with a filament pitch adjustable from (5 to 30) mm to adapt to sample testing of different filament widths; the roller speed is adjustable from (0 to 20) r / min, automatically records the filament's running length, and has an automatic stop function at a preset length; the total winding length of the winding roller is not less than 30 meters under the condition of a maximum filament pitch of 30 mm, meeting the sample testing requirements.

[0038] A method for testing the bundle properties of carbon fibers, implemented using the aforementioned testing apparatus, comprises the following specific testing steps:

[0039] Step 1: Initial width measurement of fiber bundle. Take a 100cm test specimen every 10 meters from the fiber bundle sample, for a total of n test specimens. Place the n test specimens straight on a flat surface and measure the bundle width using a steel ruler with a minimum scale of 0.5mm. Measure at 20cm intervals on each test specimen, for a total of 5 measurements per test specimen. The measurement result should be accurate to 0.1mm. Take the average of the 20 individual fiber bundle width values ​​as the initial width of the carbon fiber bundle, denoted as d0, accurate to 0.01mm; n should not be less than 4.

[0040] Step 2: Sample Fixation. Place the sample roll on the unwinding device 1, pull one end of the fiber bundle through the limiting roller 2, and wind it clockwise onto the winding device 4. Secure the end to the winding roller with tape or adhesive tape. Throughout the process, ensure that the carbon fiber bundle does not flip, knot, or twist.

[0041] Step 3, test parameter setting: including the winding rate of the winding device (2.5m / min), the wire pitch (ensuring the wire bundle spacing is ≥5mm), the sample running length (≥20m); and the wind speed of the airflow generating device (5m / s, calibrated using an anemometer).

[0042] Step 4: Disturbance Test. Turn on the winding device switch and start the airflow generator to begin the test. After the filament bundle reaches the preset length (generally ≥20m), turn off the winding device switch and the airflow generator. Secure the end of the test sample to the winding roller with adhesive tape, and then cut the filament bundle from behind the fixed end.

[0043] Step 5: Measurement of fiber bundle width after disturbance. Use a steel ruler to measure the width of the fiber bundle after airflow disturbance, accurate to 0.1 mm. Take N measurement points and record the average of these N values ​​as the width of the carbon fiber bundle after disturbance, denoted as d. n The accuracy should be to 0.01mm, and N should not be less than 40. Recommended measurement points and the number of measurement points per revolution are shown in Table 1. When the diameter of the winding device roller is greater than 700mm, measurement points should be evenly selected per revolution, with a maximum of 4 measurement points; when the diameter of the winding device roller is less than 300mm, measurement points should be evenly selected per revolution, with a maximum of 2 measurement points; when the diameter of the winding device roller is between 300mm and 700mm, measurement points should be evenly selected per revolution, with a maximum of 3 measurement points.

[0044] Table 1. Recommended locations and number of measurement points for filament width after airflow disturbance.

[0045]

[0046] Step Six: Instrument Cleaning. If visible lint or clumps remain on the surface of the limiting roller or the winding device roller, they must be cleaned before testing the next sample.

[0047] Step 7: Based on the initial fiber bundle width in Step 1 and the fiber bundle width after disturbance in Step 5, calculate the change in fiber bundle width to determine the carbon fiber bundle properties. The smaller the change in bundle width before and after airflow disturbance, the better the carbon fiber bundle properties.

[0048] The width change Δd of the filament bundle before and after airflow disturbance is calculated using formula (1):

[0049] Width change (Δd) = Initial width (d0) - Width after disturbance (d) n (Equation 1)

[0050] Example 1:

[0051] 1) Cut four T800HB-12K carbon fiber (Toray Industries, Japan, wet process) samples with a length of 100cm ± 0.5cm using sharp scissors or a utility knife, and leave them in a free state overnight. Place the samples straight on a flat surface, and use a steel ruler perpendicular to the fiber bundle width direction to measure the bundle width. Measure one point every 20cm, for a total of 5 points for each sample, accurate to 0.1mm, obtaining a total of 20 individual values.

[0052] 2) Place the sample roll on the unwinding device, pull one end of the fiber bundle through the bottom of the limiting roller, and wind it clockwise onto the winding device. Secure the end to the winding roller with tape or adhesive tape. Ensure that the carbon fiber bundle does not flip, knot, or twist throughout the entire process.

[0053] 3) Set the winding device roller running speed (winding rate) to 2.5m / min, running length to 30m, wire pitch to 10mm, and airflow disturbance wind speed to 5m / s (calibrated using a gas flow meter).

[0054] 4) Turn on the winding device switch, start the airflow generator, and begin the test. After the filament bundle reaches the preset length, turn off the winding device switch and shut off the airflow. Secure the end of the test sample to the winding roller with adhesive tape, and then cut the filament bundle from behind the fixed end.

[0055] 5) Directly above the winding device rollers and perpendicular to the fiber bundle width direction, use a steel ruler to measure the width d of the fiber bundle after it has been disturbed by the airflow. n The data was recorded with an accuracy of 0.1 mm. Four measurement points were used for each lap, resulting in a total of 40 data points and 40 individual values.

[0056] 6) Calculate the average of 20 initial width values ​​as the initial width d0 of the carbon fiber bundle, accurate to 0.01 mm. Calculate the average of 40 perturbed width values ​​as the perturbed width of the carbon fiber bundle, denoted as d. n The change in fiber bundle width Δd of T800HB-12K carbon fiber before and after airflow disturbance was calculated using formula (1), as shown in Table 2.

[0057] Table 2. Changes in fiber bundle width before and after airflow disturbance of T800HB-12K carbon fiber (unit: mm)

[0058]

[0059]

[0060] Example 2:

[0061] 1) Cut four T800SC-24K carbon fiber (Toray Industries, Japan, dry process) samples with a length of 100cm ± 0.5cm using sharp scissors or a utility knife, and leave them in a free state overnight. Place the samples straight on a flat surface, and use a steel ruler perpendicular to the fiber bundle width direction to measure the bundle width. Measure one point every 20cm, for a total of 5 points for each sample, accurate to 0.1mm, obtaining a total of 20 individual values.

[0062] 2) Place the sample roll on the unwinding device, pull one end of the fiber bundle through the bottom of the limiting roller, and wind it clockwise onto the winding device 4. Secure the end to the winding roller with tape or adhesive tape. Ensure that the carbon fiber bundle does not flip, knot, or twist throughout the process.

[0063] 3) Set the winding device operating speed (winding rate) to 2.5m / min, the operating length to 30m, the wire pitch to 10mm, and the airflow disturbance wind speed to 5m / s (calibrated using a gas flow meter).

[0064] 4) Turn on the winding device switch, start the airflow generator, and begin the test. After the filament bundle reaches the preset length, turn off the test device switch and shut off the airflow. Fix the end of the test sample to the winding roller with adhesive tape, and then cut the filament bundle from behind the fixed end.

[0065] 5) Directly above the take-up roller, perpendicular to the fiber bundle width direction, use a steel ruler to measure and record the width dn of the fiber bundle after it has been disturbed by the airflow, accurate to 0.1 mm. There are 4 measurement points per turn, for a total of 40 data points, obtaining 40 individual values.

[0066] 6) Calculate the average of 20 initial width values ​​as the initial width d0 of the carbon fiber bundle, accurate to 0.01 mm. Calculate the average of 40 perturbed width values ​​as the perturbed width of the carbon fiber bundle, denoted as d. n The change in fiber bundle width Δd of T800SC-24K carbon fiber before and after airflow disturbance, calculated using formula (1), is shown in Table 3.

[0067] Table 3. Width variation of T800HB-24K carbon fiber after airflow disturbance (unit: mm)

[0068]

[0069]

[0070] Example 3:

[0071] 1) Cut four TG800HXC-12K (domestic 1, wet preparation process) carbon fiber samples with a length of 100cm ± 0.5cm using sharp scissors or a utility knife, and leave them in a free state overnight. Place the samples straight on a flat table, and use a steel ruler perpendicular to the fiber bundle width direction to measure the fiber bundle width. Measure one point every 20cm, and measure 5 points for each sample, accurate to 0.1mm, to obtain a total of 20 individual values.

[0072] 2) Place the sample roll on the unwinding device, pull one end of the fiber bundle under the limiting roller, and wind it clockwise onto the winding device. Secure the end to the winding roller with tape or adhesive tape. Ensure that the carbon fiber bundle does not flip, knot, or twist throughout the process.

[0073] 3) Set the winding device operating speed (winding rate) to 2.5m / min, the operating length to 30m, the wire pitch to 10mm, and the airflow disturbance wind speed to 5m / s (calibrated using a gas flow meter).

[0074] 4) Turn on the winding device switch, start the airflow generator, and begin the test. After the filament bundle reaches the preset length, turn off the test device switch and shut off the airflow. Fix the end of the test sample to the winding roller with adhesive tape, and then cut the filament bundle from behind the fixed end.

[0075] 5) Directly above the take-up roller, perpendicular to the fiber bundle width direction, use a steel ruler to measure and record the width dn of the fiber bundle after it has been disturbed by the airflow, accurate to 0.1 mm. There are 4 measurement points per turn, for a total of 40 data points, obtaining 40 individual values.

[0076] 6) Calculate the average of 20 initial width values ​​as the initial width d0 of the carbon fiber bundle, accurate to 0.01 mm. Calculate the average of 40 perturbed width values ​​as the perturbed width of the carbon fiber bundle, denoted as d. n The change in fiber bundle width Δd before and after airflow disturbance of TG800HXC-12K carbon fiber, calculated using formula (1), is shown in Table 4.

[0077] Table 4. Width variation of TG800HXC-12K carbon fiber after airflow disturbance (unit: mm)

[0078]

[0079]

[0080] Example 4:

[0081] 1) Cut four HF40S-12K (domestic product 2, dry preparation process) carbon fiber samples with a length of 100cm ± 0.5cm using sharp scissors or a utility knife, and leave them in a free state overnight. Place the samples straight on a flat surface, and use a steel ruler perpendicular to the fiber bundle width direction to measure the fiber bundle width. Measure one point every 20cm, and measure 5 points for each sample, accurate to 0.1mm, obtaining a total of 20 individual values.

[0082] 2) Place the sample roll on the unwinding device, pull one end of the fiber bundle under the limiting roller, and wind it clockwise onto the winding device. Secure the end to the winding roller with tape or adhesive tape. Ensure that the carbon fiber bundle does not flip, knot, or twist throughout the process.

[0083] 3) Set the winding device operating speed (winding rate) to 2.5m / min, the operating length to 30m, the wire pitch to 10mm, and the airflow disturbance wind speed to 5m / s (calibrated using a gas flow meter).

[0084] 4) Turn on the winding device switch, start the airflow generator, and begin the test. After the filament bundle reaches the preset length, turn off the winding device switch and shut off the airflow. Secure the end of the test sample to the winding roller with adhesive tape, and then cut the filament bundle from behind the fixed end.

[0085] 5) Directly above the take-up roller, perpendicular to the fiber bundle width direction, use a steel ruler to measure and record the width dn of the fiber bundle after it has been disturbed by the airflow, accurate to 0.1 mm. There are 4 measurement points per turn, for a total of 40 data points, obtaining 40 individual values.

[0086] 6) Calculate the average of 20 initial width values ​​as the initial width d0 of the carbon fiber bundle, accurate to 0.01 mm. Calculate the average of 40 perturbed width values ​​as the perturbed width of the carbon fiber bundle, denoted as d. n The change in fiber bundle width Δd before and after airflow disturbance of HF40S-12K carbon fiber, calculated using formula (1), is shown in Table 5.

[0087] Table 5. Width variation of HF40S-12K carbon fiber after airflow disturbance (unit: mm)

[0088]

[0089]

[0090] From the test process of the four typical examples above, the test process is smooth and unobstructed, with no obvious abnormalities, and can proceed normally. In addition, as can be seen from the test result summary table 6, the coefficient of variation Cv of the carbon fiber bundle width test value remains basically the same before and after the airflow disturbance, indicating that the airflow disturbance did not have a significant impact on the stability of the fiber bundle processability, indicating that the equipment and test method are operable.

[0091] Table 6. Statistical Table of Test Results for Width Changes of Carbon Fiber After Airflow Disturbance (Unit: mm)

[0092]

[0093] The test results show that the variation pattern of Δd data basically matches the actual process state (unfolding and filamentation) of the fiber in actual application, indicating that the test method and parameters established in this invention can be used to evaluate the bundle performance of carbon fibers.

[0094] In terms of the applicability of the testing method, the testing device and testing method built in this invention have a wide range of applications and high stability, and can be used for quantitative testing and evaluation of the bundle properties of polyacrylonitrile-based carbon fibers of multiple grades and specifications.

[0095] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A carbon fiber bundle property testing device based on airflow disturbance, characterized in that: Includes unwinding device, limiting roller, airflow generating device, and winding device; The unwinding device provides pre-tension for the fiber bundle during its operation; the limiting roller is a smooth dumbbell-shaped driven roller used to prevent the fiber bundle from swinging during unwinding; the airflow generating device generates airflow to disturb the fiber bundle, causing the fiber bundle to disperse and unfold; the winding device pulls the fiber bundle and provides power for the unwinding device and the limiting roller.

2. The carbon fiber bundle property testing device based on airflow disturbance according to claim 1, characterized in that: The airflow generating device has an outlet width and length greater than 1.5cm to ensure that the fiber bundles are uniformly disturbed; the wind speed is adjustable to meet the needs of unfolding fiber bundles of various specifications.

3. The carbon fiber bundle property testing device based on airflow disturbance according to claim 1, characterized in that: The winding device pulls the filament bundle and the filament pitch is adjustable from 5 to 30 mm; the speed of the winding device roller is adjustable from 0 to 20 r / min, and it can automatically record the running length of the filament bundle and has an automatic stop function at the preset length.

4. A method for testing the bundle properties of carbon fibers based on airflow disturbance, implemented using the testing apparatus described in any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Measure the initial width of the fiber bundle sample; Step 2: Place the sample roll on the unwinding device, pull one end of the filament bundle through the limiting roller, and wind it clockwise onto the winding device. Fix the end to the roller of the winding device. Step 3: Set the test parameters, including the winding rate of the winding device, the wire pitch, the sample running length, and the wind speed of the airflow generating device; Step 4: Turn on the winding device switch, start the airflow generator, and begin the test; after the filament bundle reaches the preset length, turn off the winding device switch, turn off the airflow, fix the tail end of the test sample on the winding device roller, and then cut the filament bundle from behind the fixed end position. Step 5: Measure the width of the fiber bundle after disturbance; Step Six: Clean the testing device; Step 7: Based on the initial width of the fiber bundle sample in Step 1 and the width of the fiber bundle after disturbance in Step 5, calculate the change in fiber bundle width, and use the change in fiber bundle width to quantitatively evaluate the bundle properties of carbon fibers.

5. The carbon fiber bundle property testing method based on airflow disturbance according to claim 4, characterized in that, In step one, the initial width of the fiber bundle sample is measured using the following method: Take a 100cm test specimen every 10 meters from the fiber bundle sample, for a total of n test specimens; place the n test specimens straight on a flat surface, and measure the bundle width using a steel ruler with a minimum scale of 0.5mm. Measure one point every 20cm on each test specimen, for a total of 5 points per test specimen, with the measurement result accurate to 0.1mm; take the average of the 20 individual fiber bundle width values ​​as the initial width of the carbon fiber bundle, denoted as d0, accurate to 0.01mm; n is not less than 4.

6. The carbon fiber bundle property testing method based on airflow disturbance according to claim 4, characterized in that, In step two, when fixing the sample, the carbon fiber bundle must be kept from flipping, knotting, or twisting throughout the entire process.

7. The carbon fiber bundle property testing method based on airflow disturbance according to claim 4, characterized in that, In step five, the width of the fiber bundle after disturbance is measured, as follows: The width of the carbon fiber bundle after being disturbed by airflow is measured using a steel ruler, accurate to 0.1 mm. N measurement points are used, and the average of the N individual values ​​is taken as the width of the carbon fiber bundle after disturbance, denoted as d. n Accurate to 0.01mm, N not less than 40.

8. The carbon fiber bundle property testing method based on airflow disturbance according to claim 7, characterized in that, When the diameter of the winding device roller is greater than 700mm, measurement points are evenly selected per turn, with a maximum of 4 measurement points; when the diameter of the winding device roller is less than 300mm, measurement points are evenly selected per turn, with a maximum of 2 measurement points; when the diameter of the winding device roller is between 300mm and 700mm, measurement points are evenly selected per turn, with a maximum of 3 measurement points.

9. The carbon fiber bundle property testing method based on airflow disturbance according to claim 4, characterized in that, In step six, if there are visible lint or clumps of lint remaining on the surface of the limiting roller or the winding device roller, they must be cleaned before testing the next sample.

10. The carbon fiber bundle property testing method based on airflow disturbance according to claim 4, characterized in that, Change in fiber bundle width = Initial width of fiber bundle - Width of fiber bundle after disturbance.

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