Method and apparatus for testing carbon fiber wettability
By recording the reciprocating motion and widening of carbon fiber bundles in the impregnating agent, the inaccuracy of carbon fiber wettability evaluation in the prior art is solved, and a simple and intuitive test method is provided to guide the bonding effect between carbon fiber and resin.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHONGFU SHENYING CARBON FIBER
- Filing Date
- 2023-12-12
- Publication Date
- 2026-06-26
AI Technical Summary
Existing methods for evaluating the wettability of carbon fibers are sensitive to sample thickness and width, and have low evaluation timeliness, making it difficult to accurately quantify the bonding effect between carbon fibers and resins.
A method for testing the wettability of carbon fiber is provided. By adjusting the position of the carbon fiber bundle and making it move vertically within the field of view of the camera device, and using a wetting agent to make it move up and down reciprocally, the wetting factor R=(BA)/A is calculated by combining the width recorded by the camera device.
It enables a simple and intuitive test of the wettability of carbon fibers, and provides rapid and accurate guidance for the development of carbon fiber sizing agents and the adjustment of resin system compatibility.
Smart Images
Figure CN117723444B_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of carbon fiber performance testing, and more specifically, to a method and apparatus for testing the wettability of carbon fiber. Background Technology
[0002] As the application scenarios and fields of carbon fiber continue to expand and become more refined, downstream customers are increasingly demanding more professional and customized carbon fiber. In downstream applications, carbon fiber is gradually shifting from simply being "usable" to being "highly usable." The performance of different types and models of carbon fiber in different resin systems is closely related to the degree of bonding between carbon fiber and resin. Good wettability is a prerequisite for the bonding effect between carbon fiber and resin. Therefore, how to quantitatively evaluate the wettability of carbon fiber is becoming increasingly important. Summary of the Invention
[0003] The purpose of this disclosure is to overcome the above-mentioned deficiencies in the prior art and to provide a method and apparatus for testing the wettability of carbon fibers.
[0004] A first aspect of the exemplary embodiments of this disclosure provides a method for testing the wettability of carbon fiber, the method comprising:
[0005] The bottom preset area of the carbon fiber bundle is adjusted to be located in the preset area of the image captured by the camera device, and the position of the carbon fiber bundle is recorded as the lowest point; wherein, the carbon fiber bundle is fixed on the movable bracket, the carbon fiber bundle hangs down and is perpendicular to the horizontal plane, and the carbon fiber bundle has a shape with parallel sides and connected at the bottom.
[0006] Move the movable support upwards so that it pulls the carbon fiber bundle to a preset position and record the position of the carbon fiber bundle as the highest point. Place a container filled with sizing agent below the carbon fiber bundle. The liquid level of the sizing agent in the container is higher than the height of the camera device. The bottom connection of the carbon fiber bundle is higher than the liquid level of the sizing agent in the container.
[0007] The movable support is pulled so that the carbon fiber bundle moves up and down at a preset speed between the highest point and the lowest point. Each time the carbon fiber bundle moves to the lowest point, it stays for a first preset time so that the camera device can acquire and record the spread width of the bottom preset area of the carbon fiber bundle. When the carbon fiber bundle moves to the lowest point for the first time, the spread width of the bottom preset area of the carbon fiber bundle is recorded as the initial width.
[0008] The wettability of the carbon fiber is determined based on the initial width and the spread width.
[0009] In some exemplary embodiments, the testing method further includes:
[0010] When the carbon fiber bundle moves to the lowest point, and the difference between the width of the bottom preset region of the carbon fiber bundle and the width of the bottom preset region of the carbon fiber bundle when the carbon fiber bundle moved to the lowest point last time is less than or equal to a preset value, the carbon fiber bundle stops moving up and down.
[0011] In some exemplary embodiments, determining the wettability of the carbon fiber based on the initial width and the spread width includes:
[0012] The wettability of the carbon fiber is determined based on the initial width and the width of the bottom preset region of the carbon fiber bundle when the carbon fiber bundle last moves to the lowest point.
[0013] In some exemplary embodiments, the wettability factor of the carbon fiber tow is calculated according to the following formula:
[0014] R = (BA) / A;
[0015] Wherein, R represents the wettability factor of the carbon fiber bundle, B represents the width of the bottom preset region of the carbon fiber bundle when the carbon fiber bundle last moves to the lowest point, and A represents the initial width.
[0016] In some exemplary embodiments, the preset value is determined according to the type of carbon fiber.
[0017] In some exemplary embodiments, the testing method further includes:
[0018] The carbon fiber bundle is fixed to the movable bracket in a preset manner, so that the carbon fiber bundle hangs down;
[0019] A shaping structure is suspended at the bottom of the carbon fiber bundle, with the center of the shaping structure located at the center of the image captured by the camera device. After remaining stationary for a second preset time, the carbon fiber bundle is stretched straight and perpendicular to the horizontal plane, forming a shape with parallel sides and connected bottom. The shaping structure is then removed.
[0020] In some exemplary embodiments, the shaping structure includes a structure with a circular outer perimeter or a structure with a rectangular outer perimeter; the outer perimeter width of the shaping structure is equal to the width of the carbon fiber bundle fixed on the movable support, so that the carbon fiber bundle is stretched straight and perpendicular to the horizontal plane, forming a shape with parallel sides and connected bottom.
[0021] In some exemplary embodiments, the first preset duration is 2-4 seconds;
[0022] The second preset duration is 20-40 minutes;
[0023] The preset speed is 1-5 meters per minute.
[0024] A second aspect of the exemplary embodiments of this disclosure provides a carbon fiber wettability testing apparatus, the testing apparatus being used to implement the above-described carbon fiber wettability testing method; the testing apparatus includes:
[0025] A container filled with a wetting agent is used to immerse and widen the predetermined bottom region of the carbon fiber tow;
[0026] A movable support is used to pull the carbon fiber bundle to move up and down reciprocally.
[0027] A camera device is used to acquire and record the spread width of the bottom preset region of the carbon fiber tow.
[0028] In some exemplary embodiments, the testing apparatus further includes:
[0029] Fixed bracket;
[0030] A slide rail is mounted on the fixed bracket and is perpendicular to the horizontal plane; one end of the movable bracket is slidably connected to the slide rail, and the movable bracket moves up and down along the slide rail.
[0031] A driving device is used to drive the movable support to move up and down reciprocally at a preset speed.
[0032] The beneficial effects of this disclosure include, but are not limited to: the carbon fiber wettability test method provided by the exemplary embodiments of this disclosure can intuitively and easily test the wettability of carbon fibers of different specifications, and quickly and accurately provide guidance and reference for the development of carbon fiber sizing agents and the adjustment of compatibility with different resin systems. Attached Figure Description
[0033] To more clearly illustrate the technical solutions of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0034] Figure 1 This is a schematic diagram of a carbon fiber wettability testing apparatus according to an exemplary embodiment of the present disclosure;
[0035] Figure 2 This is a schematic diagram of a carbon fiber tow stretched straight and perpendicular to the horizontal plane, representing an exemplary embodiment of this disclosure.
[0036] Figure 3This is a schematic diagram of an upward movable support, which is an exemplary embodiment of the present disclosure, in which a container containing acetone is placed below a carbon fiber bundle.
[0037] Figure 4a This is a schematic diagram of the widening of a carbon fiber bundle when it first moves to the lowest point, which is an exemplary embodiment of the present disclosure.
[0038] Figure 4b This is a schematic diagram of the widening of a carbon fiber bundle when it moves to its lowest point for the last time, which is an exemplary embodiment of this disclosure. Detailed Implementation
[0039] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the protection scope of this disclosure.
[0040] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0041] In related technologies, contact angle and other test methods are often used to evaluate the wettability of carbon fibers. However, factors such as sample thickness and width have a great influence on the test results during the test process, which requires high sample preparation and has low evaluation timeliness.
[0042] Based on this, an exemplary embodiment of this disclosure provides a method for testing the wettability of carbon fiber, the method comprising:
[0043] S100: Adjust the bottom preset area of the carbon fiber bundle to be located in the preset area of the image captured by the camera device, and record the position of the carbon fiber bundle as the lowest point; wherein, the carbon fiber bundle is fixed on the movable bracket, the carbon fiber bundle hangs down and is perpendicular to the horizontal plane, and the carbon fiber bundle has a shape with parallel sides and connected at the bottom.
[0044] In an embodiment of this disclosure, a slide rail can be provided on a fixed bracket, wherein the extension direction of the slide rail is perpendicular to the horizontal plane. One end of a movable bracket is slidably connected to the slide rail, and the movable bracket is slid to a given position on the slide rail, such as the lowest point of the slide rail. A carbon fiber bundle is fixed to the movable bracket in a shape with parallel sides and connected bottoms. For example, both ends of the carbon fiber bundle can be clamped and fixed to the other end of the movable bracket away from the slide rail, so that the carbon fiber bundle hangs down perpendicular to the horizontal plane. The length of the hanging carbon fiber bundle is adjusted by adjusting the clamping part of the carbon fiber bundle, so that the bottom preset area of the carbon fiber bundle is located in the preset area of the image captured by the camera device, and the position of the carbon fiber bundle at this time is recorded as the lowest point. At this time, the movable bracket is located at the given position on the slide rail, and the given position is the lowest point of the subsequent up-and-down reciprocating movement path of the carbon fiber bundle.
[0045] For ease of operation, the given position can be set to the lowest point of the slider. The preset area for the image captured by the camera can be any area that is convenient for the camera to capture the image, such as the center area of the image captured by the camera.
[0046] The bottom preset area of the carbon fiber tow can be the portion of the carbon fiber tow below the container containing the sizing agent when the carbon fiber tow is at the lowest point of the up-and-down reciprocating movement path, which is the part of the carbon fiber tow below the surface of the sizing agent in the container.
[0047] S200: Move the movable support upwards to guide the carbon fiber bundle to a preset position and record the position of the carbon fiber bundle as the highest point. Place a container filled with sizing agent below the carbon fiber bundle. The liquid level of the sizing agent in the container is higher than the height of the camera equipment, and the bottom connection of the carbon fiber bundle is higher than the liquid level of the sizing agent in the container.
[0048] After securing the carbon fiber tow to the moving support and determining the lowest point of its reciprocating movement path, place a container filled with a transparent liquid (the wetting agent) on the test surface. Move the moving support along the slide rail to guide the carbon fiber tow upwards to a preset position. This preset position can be the point where the bottom of the hanging carbon fiber tow is higher than the container filled with the wetting agent. Record this position as the highest point, which will also be the highest point of the subsequent reciprocating movement path. For example, this preset position could be 3-5 cm above the container filled with the wetting agent. Place the container filled with the wetting agent below the carbon fiber tow, ensuring the liquid level is higher than the camera equipment. This allows the wetting agent to further wet and expand the carbon fiber tow, and the camera equipment will capture the expansion of the preset area at the bottom of the carbon fiber tow.
[0049] It should be noted that after placing the container containing the sizing agent below the carbon fiber bundle, the moving support can be moved down to pull the carbon fiber bundle downwards until the bottom connection of the hanging carbon fiber bundle is higher than the level of the sizing agent in the container. The position of the carbon fiber bundle at this time is taken as the highest point of the subsequent up-and-down reciprocating movement path.
[0050] In the exemplary embodiments provided in this disclosure, the wetting agent includes at least one of acetone, ethanol, and resin.
[0051] Acetone and ethanol are both good solvents. Using acetone or ethanol as a wetting agent to broaden carbon fiber tows can effectively reflect the degree of wetting of carbon fiber tows with liquid solvents. Furthermore, using transparent resin as a wetting agent can simulate the degree of wetting of carbon fiber tows with resin in practical applications, providing guidance for actual production. When using transparent resin as a wetting agent, the viscosity of the resin system must be controlled below 100 mPa·s using acetone or ethanol as a solvent.
[0052] S300: The traction moving bracket causes the carbon fiber bundle to move up and down at a preset speed between the highest and lowest points of the reciprocating movement path. Each time the carbon fiber bundle moves to the lowest point, it stays for a first preset duration so that the camera device can acquire and record the width of the preset area at the bottom of the carbon fiber bundle. When the carbon fiber bundle moves to the lowest point for the first time, the width of the preset area at the bottom of the carbon fiber bundle is recorded as the initial width.
[0053] The carbon fiber bundle is pulled by a moving support to move up and down between the highest and lowest points at a preset speed. Each time the preset area at the bottom of the carbon fiber bundle moves below the surface of the sizing agent, it will be wetted and widened under the wetting effect of the sizing agent. The degree of widening of the preset area at the bottom of the carbon fiber bundle can reflect the wettability of the carbon fiber.
[0054] In the exemplary embodiments provided in this disclosure, the first preset duration is 2-4 seconds.
[0055] The traction support moves the carbon fiber bundle back and forth between the highest and lowest points at a preset speed. Each time the carbon fiber bundle reaches the lowest point, it stays for a first preset duration of 2-4 seconds, allowing the preset area at the bottom of the carbon fiber bundle to be fully impregnated and widened by the sizing agent, so that the camera device can acquire and record the width of the preset area at the bottom of the carbon fiber bundle.
[0056] In the exemplary embodiments provided in this disclosure, the preset speed is 1-5 meters per minute.
[0057] The preset speed at which the carbon fiber tow moves up and down between the highest and lowest points of its reciprocating path can be selected based on the type of carbon fiber tow being tested. For example, when the tested carbon fiber tow is model T700-12K, the number of individual filaments is large. When the carbon fiber tow moves downward into the sizing agent, the degree of deformation caused by the impact of the sizing agent surface is relatively small. Therefore, the preset speed can be appropriately increased to improve the testing speed of carbon fiber wettability. For example, the carbon fiber tow can move up and down at a preset speed of 4.5 m / min between the highest and lowest points of the reciprocating movement path. When the tested carbon fiber tow is model T700-8K, the number of individual filaments is small. When the carbon fiber tow moves downward into the sizing agent, the degree of deformation caused by the impact of the sizing agent surface is relatively large. Therefore, the preset speed of the carbon fiber tow moving up and down should be reduced to minimize the degree of deformation caused by the impact of the sizing agent surface when the carbon fiber tow moves downward into the sizing agent. For example, the carbon fiber tow can move up and down at a preset speed of 2.5 m / min between the highest and lowest points of the reciprocating movement path.
[0058] S400: Determine the wettability of the carbon fiber based on the initial width and spread width.
[0059] Each time the carbon fiber tow moves to the lowest point, the camera device acquires and records the spread width of the preset area at the bottom of the carbon fiber tow. The spread width of the preset area at the bottom of the carbon fiber tow when it first moves to the lowest point is the initial width. After the up-and-down reciprocating movement stops, the wettability of the carbon fiber is determined based on the initial width and the spread width.
[0060] The carbon fiber wettability test method provided by the exemplary embodiments of this disclosure can intuitively and easily test the wettability of carbon fibers of different specifications, and quickly and accurately provide guidance and reference for the development of carbon fiber sizing agents and the adjustment of compatibility with different resin systems.
[0061] In the exemplary embodiments provided in this disclosure, the testing method further includes: when the difference between the expansion width of the bottom preset region of the carbon fiber bundle when it moves to the lowest point and the expansion width of the bottom preset region of the carbon fiber bundle when it moved to the lowest point last time is less than or equal to a preset value, the carbon fiber bundle stops moving up and down.
[0062] When the carbon fiber tow moves up and down, each time the carbon fiber tow reaches the lowest point, the preset area at the bottom of the carbon fiber tow will widen to a certain extent. When the difference between the width of the preset area at the bottom of the carbon fiber tow when it reaches the lowest point and the width of the preset area at the bottom of the carbon fiber tow when it reached the lowest point before the last time it moved to the lowest point is less than or equal to a preset value, it indicates that the width of the preset area at the bottom of the carbon fiber tow is close to the peak value, and the up and down reciprocating movement can be stopped. Then, the wettability of the carbon fiber is determined based on the width of the expansion and the initial width of the preset area at the bottom of the carbon fiber tow when it first moves to the lowest point.
[0063] In the exemplary embodiments provided in this disclosure, determining the wettability of carbon fibers based on the initial width and the spread width includes: determining the wettability of carbon fibers based on the initial width and the spread width of the bottom preset region of the carbon fiber bundle when the carbon fiber bundle last moves to the lowest point.
[0064] When the carbon fiber tow reaches its lowest point for the last time, if the difference between the width of the preset area at the bottom of the carbon fiber tow and the width at the bottom of the carbon fiber tow when it reached its lowest point for the last time is less than or equal to the preset value, it indicates that the width of the preset area at the bottom of the carbon fiber tow is close to the peak value, and the up-and-down reciprocating movement can be stopped. The width of the preset area at the bottom of the carbon fiber tow when it reached its lowest point for the last time is taken as the final width. Based on the final width and the initial width of the preset area at the bottom of the carbon fiber tow when it first reached its lowest point, the wettability of the carbon fiber is determined.
[0065] In the exemplary embodiments provided in this disclosure, the wettability factor of the carbon fiber tow is calculated according to the following formula:
[0066] R = (BA) / A; where R represents the wettability factor of the carbon fiber bundle, B represents the width of the bottom preset area of the carbon fiber bundle when the carbon fiber bundle moves to the lowest point for the last time, and A represents the initial width.
[0067] When the bottom preset region of the carbon fiber bundle moves to its lowest point for the last time, the difference between the expansion width of the bottom preset region of the carbon fiber bundle and the initial width, and the ratio of the expansion width to the initial width, yields the wettability factor. The wettability factor reflects the wettability of the carbon fiber; the larger the wettability factor, the better the wettability of the carbon fiber.
[0068] The following six specific examples illustrate the method for calculating the wettability factor of carbon fiber bundles based on R = (BA) / A. It should be noted that, except for the variables in Table 1, the test conditions are the same in Examples 1-6.
[0069] Table 1
[0070]
[0071] The wettability factor values in Table 1 reflect the magnitude of wettability. A larger wettability factor indicates better wettability, and vice versa. A comparison of Examples 1 and 3 in Table 1 shows that when the sizing agent is the same, the smaller the number of single filaments in the carbon fiber bundle, the better the wettability. A comparison of Examples 1 and 2 in Table 1 shows that when the type of carbon fiber bundle is the same, the greater the wetting effect of the sizing agent on the carbon fiber bundle, the better the wettability.
[0072] In the exemplary embodiments provided in this disclosure, the preset value is determined according to the type of carbon fiber.
[0073] The carbon fiber tow moves up and down repeatedly. Each time the tow reaches its lowest point, it widens to a certain extent. When the width of the pre-set area at the bottom of the carbon fiber tow at the lowest point is less than or equal to the width at the previous lowest point, it indicates that the width of the pre-set area at the bottom of the carbon fiber tow is close to its peak. If the up-and-down movement continues and the change in the width of the pre-set area at the bottom of the carbon fiber tow is not significant, the up-and-down movement can be stopped. Then, the wettability of the carbon fiber is determined based on the width of the tow and the initial width of the pre-set area at the bottom of the carbon fiber tow when it first reaches the lowest point. For example, when the tested carbon fiber tow is model T700-12K, the preset value can be 1.5cm; when the tested carbon fiber tow is model T700-8K, the preset value can be 1cm.
[0074] In the exemplary embodiments provided in this disclosure, the testing method further includes:
[0075] The carbon fiber bundles are fixed to the movable support in a preset manner, so that the carbon fiber bundles hang down.
[0076] A shaping structure is suspended at the bottom of the carbon fiber bundle, with the center of the shaping structure located at the center of the image captured by the camera device. After remaining still for a second preset time, the carbon fiber bundle is stretched straight and perpendicular to the horizontal plane, forming a shape with parallel sides and connected bottom. The shaping structure is then removed.
[0077] The carbon fiber bundle is fixed to the movable support in a preset manner. For example, the two ends of the carbon fiber bundle are fixed to the movable support with a fixing clamp, so that the carbon fiber bundle hangs down. The shaping structure is suspended at the bottom of the hanging carbon fiber bundle. After a second preset time, the carbon fiber bundle is stretched straight and perpendicular to the horizontal plane under the gravity of the shaping structure, forming a shape with parallel sides and connected bottom.
[0078] In the exemplary embodiments provided in this disclosure, the shaping structure includes a structure with a circular outer perimeter or a structure with a rectangular outer perimeter; the outer perimeter width of the shaping structure is equal to the width of the carbon fiber bundle fixed on the movable support, so that the carbon fiber bundle is stretched straight and perpendicular to the horizontal plane, forming a shape with parallel sides and connected bottom.
[0079] The carbon fiber tow is fixed to the movable support in a predetermined manner. After the carbon fiber tow hangs down, a shaping structure is suspended at the bottom of the hanging carbon fiber tow. The shaping structure can be circular or rectangular in shape. When the shaping structure is circular, its diameter is equal to the width of the carbon fiber tow fixed on the movable support; for example, the diameter of the circular shaping structure is 2-5 cm, such as 2cm, 3cm, or 5cm. When the shaping structure is rectangular, its length is equal to the width of the carbon fiber tow fixed on the movable support; for example, the length of the rectangular shaping structure is 2-5 cm, such as 2cm, 3cm, or 5cm. Under the weight of the shaping structure, the carbon fiber tow stretches straight and becomes perpendicular to the horizontal plane, forming a shape with parallel sides and a connected bottom.
[0080] In the exemplary embodiments provided in this disclosure, the weight of the shaping structure is 50-200g. The shape of the shaping structure can be, for example, a circular ring structure with a circular outer perimeter. The size of the central hole in the ring can be determined according to the counterweight, i.e., different ring sizes with different central hole sizes are selected based on the type of carbon fiber tow being tested. For example, when the tested carbon fiber tow is of type T700-12K, the number of individual filaments is large, the overall mass of the carbon fiber tow is large, and the strength is high. A relatively heavy shaping structure can be suspended to straighten it, for example, a 150g shaping structure can be suspended. When the tested carbon fiber tow is of type T700-8K, the number of individual filaments is small, the overall mass of the carbon fiber tow is small, and the strength is low. A relatively light shaping structure can be suspended to straighten it, to avoid excessive weight of the shaping structure, overstretching of the carbon fiber tow, damaging the strength of the carbon fiber tow, and affecting the test results of carbon fiber wettability. For example, a 50g shaping structure can be suspended. With a weight of 50-200g, the sizing structure can straighten the carbon fiber bundles and make them perpendicular to the horizontal plane, forming a shape with parallel sides and connected bottom, and the performance of the carbon fiber will not be affected by the excessive weight of the sizing structure.
[0081] In the exemplary embodiments provided in this disclosure, the second preset duration is 20-40 minutes.
[0082] The carbon fiber bundle is fixed to the movable support in a preset manner, for example, by fixing the two ends of the carbon fiber bundle to the movable support with a fixing clamp, so that the carbon fiber bundle hangs down; the shaping structure is suspended at the bottom of the hanging carbon fiber bundle, and after a second preset time of 20-40 minutes, for example, after 20 minutes, 30 minutes or 40 minutes, the carbon fiber bundle is stretched straight and perpendicular to the horizontal plane under the gravity of the shaping structure, forming a shape with parallel sides and connected bottom.
[0083] This exemplary embodiment provides a carbon fiber wettability testing apparatus for implementing the carbon fiber wettability testing method provided in this exemplary embodiment; such as Figure 1As shown, the testing device 100 includes: a container 20 containing a wetting agent, used to immerse and widen a preset bottom area of the carbon fiber bundle; a movable support 10, used to pull the carbon fiber bundle to move back and forth between the highest and lowest points of a reciprocating movement path, wherein the highest point can be the position of the carbon fiber bundle when the bottom connection of the hanging carbon fiber bundle is 3-5 cm above the surface of the wetting agent in the container 20; the lowest point can be the position of the carbon fiber bundle when the preset bottom area of the carbon fiber bundle is located in a preset area of the image captured by the camera device; wherein the preset bottom area of the carbon fiber bundle can be the part of the carbon fiber bundle below the surface of the wetting agent in the container when the carbon fiber bundle is at the lowest point; and the bottom connection of the carbon fiber bundle is within 3-10 cm below the surface of the wetting agent when the carbon fiber bundle is at the lowest point; and a camera device 30, used to acquire and record the widening width of the preset bottom area of the carbon fiber bundle when the carbon fiber bundle moves to the lowest point.
[0084] In the exemplary embodiments provided in this disclosure, such as Figure 1 As shown, the testing device 100 also includes: a fixed bracket 40; a slide rail 50, which is mounted on the fixed bracket 40 and is perpendicular to the horizontal plane; one end of a movable bracket 10 is slidably connected to the slide rail 50, and the movable bracket 10 moves up and down along the slide rail 50 to pull the carbon fiber bundle to move up and down between the highest and lowest points of the up and down reciprocating movement path; and a drive device 60, which drives the movable bracket 10 to move up and down at a preset speed. For example, the drive device 60 can be a drive motor, wherein the drive motor is equipped with two movement modes: manual and automatic control.
[0085] To more clearly explain the technical solution of this disclosure, a specific example is given by implementing the carbon fiber wettability testing method provided by the exemplary embodiment of this disclosure using the carbon fiber wettability testing apparatus provided by the exemplary embodiment of this disclosure.
[0086] like Figure 2 As shown, a carbon fiber tow sample 80 about 40cm long is fixed on the movable bracket 10, allowing the carbon fiber tow 80 to hang down. A circular ring made of 304 stainless steel with a circular outer circumference is suspended at the bottom of the carbon fiber tow 80 as a shaping structure 70. By adjusting the length of the hanging carbon fiber tow sample, the center of the shaping structure 70 is located at the center of the image captured by the camera device 30. The position of the carbon fiber tow 80 at this time is recorded as the lowest point. After standing for 20-40 minutes, the carbon fiber tow 80 is stretched straight and perpendicular to the horizontal plane, forming a shape with parallel sides and connected bottom. The shaping structure 70 is then removed.
[0087] like Figure 3As shown, the drive motor is activated to move the support 10 upwards, so that the bottom connection of the hanging carbon fiber bundle 80 is 3-5 cm higher than the surface of the impregnating agent in the container 20. The position of the carbon fiber bundle 80 at this time is recorded as the highest point. A container 20 containing acetone is placed below the carbon fiber bundle 80, with the acetone level in the container 20 higher than the height of the camera device 30. The container 20 is a transparent container.
[0088] It should be noted that the camera device 30 can be installed on the outside of the container 20, or it can be installed inside the container 20 with a waterproof structure attached directly. Figure 3 The image only shows the case where the camera device 30 is located outside the container 20.
[0089] The drive motor is activated to pull the moving support, causing the carbon fiber bundle to move up and down at a preset speed of 1-5 meters per minute between the highest and lowest points. Each time the carbon fiber bundle reaches the lowest point, it pauses for a preset duration of 2-4 seconds to allow the camera to capture and record the width of the preset area at the bottom of the carbon fiber bundle. The width of the preset area at the bottom of the carbon fiber bundle when it first reaches the lowest point is recorded as the initial width. Figure 4a A in the middle.
[0090] When the carbon fiber tow reaches its lowest point, if the difference between the width of the preset area at the bottom of the carbon fiber tow and the width of the preset area at the bottom of the carbon fiber tow when it last reached its lowest point is less than or equal to 1.5 cm, the carbon fiber tow stops its up-and-down reciprocating movement. Record the width of the preset area at the bottom of the carbon fiber tow when it last reaches its lowest point. Figure 4b B in the middle.
[0091] The wettability of the carbon fiber is determined by the expansion width B of the bottom preset region of the carbon fiber bundle when it last moves to the lowest point and the initial width A of the bottom preset region of the carbon fiber bundle when it first moves to the lowest point. That is, the wettability factor of the carbon fiber bundle to be tested is determined by the formula R=(BA) / A.
[0092] Using the carbon fiber wettability testing apparatus provided in the exemplary embodiments of this disclosure above, and implementing the carbon fiber wettability testing method provided in the exemplary embodiments of this disclosure, two embodiments are given.
[0093] Example 7
[0094] The first group of T700-12K carbon fiber tow was selected, with a tensile strength of 5267MPa, a modulus of 233GPa, a linear density of 802g / km, and a shear strength of 98MPa.
[0095] The wettability factor of the carbon fiber tow obtained according to the above test method is: R = (BA) / A = (26.3-7.2) / 7.2 = 2.65.
[0096] Example 8
[0097] The second group of T700-12K carbon fiber tow was selected, with a tensile strength of 5267MPa, a modulus of 233GPa, a linear density of 802g / km, and a shear strength of 76MPa.
[0098] The wettability factor of the carbon fiber tow obtained according to the above test method is: R = (BA) / A = (24.6-7.3) / 7.3 = 2.37.
[0099] The carbon fiber wettability test method provided by the exemplary embodiments of this disclosure can intuitively and easily test the wettability of carbon fibers of different specifications, and quickly and accurately provide guidance and reference for the development of carbon fiber sizing agents and the adjustment of compatibility with different resin systems.
[0100] The above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit it. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this disclosure.
Claims
1. A method for testing the wettability of carbon fiber, characterized in that, The testing method includes: The bottom preset area of the carbon fiber bundle is adjusted to be located in the preset area of the image captured by the camera device, and the position of the carbon fiber bundle is recorded as the lowest point; wherein, the carbon fiber bundle is fixed on the movable bracket, the carbon fiber bundle hangs down and is perpendicular to the horizontal plane, and the carbon fiber bundle has a shape with parallel sides and connected at the bottom. Move the movable support upwards so that it pulls the carbon fiber bundle to a preset position and record the position of the carbon fiber bundle as the highest point. Place a container filled with sizing agent below the carbon fiber bundle. The liquid level of the sizing agent in the container is higher than the height of the camera device. The bottom connection of the carbon fiber bundle is higher than the liquid level of the sizing agent in the container. The movable support is pulled so that the carbon fiber bundle moves up and down at a preset speed between the highest point and the lowest point. Each time the carbon fiber bundle moves to the lowest point, it stays for a first preset time so that the camera device can acquire and record the spread width of the bottom preset area of the carbon fiber bundle. When the carbon fiber bundle moves to the lowest point for the first time, the spread width of the bottom preset area of the carbon fiber bundle is recorded as the initial width. The wettability of the carbon fiber is determined based on the initial width and the spread width.
2. The method for testing the wettability of carbon fiber according to claim 1, characterized in that, The testing method also includes: When the carbon fiber bundle moves to the lowest point, and the difference between the width of the bottom preset region of the carbon fiber bundle and the width of the bottom preset region of the carbon fiber bundle when the carbon fiber bundle moved to the lowest point last time is less than or equal to a preset value, the carbon fiber bundle stops moving up and down.
3. The method for testing the wettability of carbon fiber according to claim 2, characterized in that, Determining the wettability of the carbon fiber based on the initial width and the spread width includes: The wettability of the carbon fiber is determined based on the initial width and the width of the bottom preset region of the carbon fiber bundle when the carbon fiber bundle last moves to the lowest point.
4. The method for testing the wettability of carbon fiber according to claim 3, characterized in that, The wettability factor of carbon fiber bundles is calculated using the following formula: R = (BA) / A; Wherein, R represents the wettability factor of the carbon fiber bundle, B represents the width of the bottom preset region of the carbon fiber bundle when the carbon fiber bundle last moves to the lowest point, and A represents the initial width.
5. The method for testing the wettability of carbon fiber according to claim 2, characterized in that, The preset value is determined based on the type of carbon fiber.
6. The method for testing the wettability of carbon fiber according to claim 1, characterized in that, The testing method also includes: The carbon fiber bundle is fixed to the movable bracket in a preset manner, so that the carbon fiber bundle hangs down; A shaping structure is suspended at the bottom of the carbon fiber bundle, with the center of the shaping structure located at the center of the image captured by the camera device. After remaining stationary for a second preset time, the carbon fiber bundle is stretched straight and perpendicular to the horizontal plane, forming a shape with parallel sides and connected bottom. The shaping structure is then removed.
7. The method for testing the wettability of carbon fiber according to claim 6, characterized in that, The shaping structure includes a circular outer perimeter or a rectangular outer perimeter; the outer perimeter width of the shaping structure is equal to the width of the carbon fiber bundle fixed on the movable support, so that the carbon fiber bundle is stretched straight and perpendicular to the horizontal plane, forming a shape with parallel sides and connected bottom.
8. The method for testing the wettability of carbon fiber according to claim 6, characterized in that, The first preset duration is 2-4 seconds; The second preset duration is 20-40 minutes; The preset speed is 1-5 meters per minute.
9. A device for testing the wettability of carbon fiber, characterized in that, The testing apparatus is used to implement the carbon fiber wettability testing method according to any one of claims 1-8; the testing apparatus includes: A container filled with a wetting agent is used to immerse and widen the predetermined bottom region of the carbon fiber tow; A movable support is used to pull the carbon fiber bundle to move up and down reciprocally. A camera device is used to acquire and record the spread width of the bottom preset region of the carbon fiber tow.
10. The carbon fiber wettability testing apparatus according to claim 9, characterized in that, The testing apparatus also includes: Fixed bracket; A slide rail is mounted on the fixed bracket and is perpendicular to the horizontal plane; one end of the movable bracket is slidably connected to the slide rail, and the movable bracket moves up and down along the slide rail. A driving device is used to drive the movable support to move up and down reciprocally at a preset speed.