Sample preparation device and method for testing the interfacial shear strength of fibers and thermoplastic resins

Abstract

The application relates to the technical field of mechanical property testing, and discloses a sample preparation device and a sample preparation method for testing the interfacial shear strength of fibers and thermoplastic resins, which comprises a forming assembly, a monofilament fiber connected to the forming assembly, and a monofilament fixing assembly for fixing the monofilament fiber, wherein the forming assembly comprises a heating mechanism for containing and heating the thermoplastic resin and a forming die connected to the heating mechanism; the monofilament fiber is fixed to extend through the forming die, so that the thermoplastic resin droplets can be formed on the monofilament fiber by the forming assembly. The heating function of the heating mechanism is used to heat the thermoplastic resin to be detected, so that the thermoplastic resin can be in a molten state and drop along the heating mechanism to flow into the forming die, without manual sample preparation, thereby guaranteeing the accuracy of sample preparation and facilitating the operation; meanwhile, the monofilament fiber is fixed to extend through the forming die, so that the thermoplastic resin in the molten state can be in contact with the monofilament fiber, thereby facilitating subsequent shear strength testing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical property testing, in particular to a sample preparation device and method for testing the interfacial shear strength of fibers and thermoplastic resins. BACKGROUND

[0002] Fiber-reinforced thermoplastic resin composites have attracted more and more attention due to their high damage tolerance, recyclability, and rapid and efficient molding. However, compared with thermosetting resin composites, the interfacial compatibility between the reinforcing phase and the continuous phase of thermoplastic resin composites is more complex, and multiple characterization methods are needed for analysis.

[0003] Currently, the commonly used method for testing the shear strength between fibers and resins is the micro-debonding method. Compared with the macroscopic test method which lacks precision, the micro-test method can more directly and accurately obtain the interfacial bonding strength of the material. Among them, the micro-drop debonding method forms a small symmetrical resin droplet on the fiber monofilament, then fixes the resin droplet behind the card, and calculates the interfacial shear strength of the material by applying the size of the external force and the bonding length and using the standardized consensus. However, this method is only suitable for thermosetting resins. For thermoplastic resins which are solid at room temperature and have a melting point generally > 100℃, this method does not have a heating and melting process. Even if an external oven is used, the accuracy of the sample preparation cannot be guaranteed during the dropping process, resulting in large data dispersion.

[0004] Therefore, there is an urgent need to propose a corresponding solution to the problem of large manual error and high data dispersion in the micro-debonding test sample preparation for thermoplastic resins in the prior art. SUMMARY

[0005] The purpose of the present application is to overcome the problem of large manual error and high data dispersion in the micro-debonding test sample preparation for thermoplastic resins in the prior art.

[0006] In order to achieve the above-mentioned purpose, the present application provides a sample preparation device for testing the interfacial shear strength of fibers and thermoplastic resins, comprising a forming assembly, a monofilament fiber connected to the forming assembly, and a monofilament fixing assembly for fixing the monofilament fiber, wherein the forming assembly comprises a heating mechanism for containing and heating a thermoplastic resin and a forming mold connected to the heating mechanism, and the monofilament fiber is fixed to extend through the forming mold, so that the forming assembly can form a thermoplastic resin droplet on the monofilament fiber.

[0007] In some embodiments, a sealing plug is installed in the heating mechanism, and the sealing plug is connected to a hydraulic device to control the sealing plug to extrude the molten thermoplastic resin in the heating mechanism towards the forming mold.

[0008] In some embodiments, an outlet end of the heating mechanism is provided with a metal sheet for controlling the on-off relationship between the heating mechanism and the forming mold.

[0009] In some embodiments, the forming mold comprises two half-circle molds which are spliced together, and a through hole is formed in the center of the spliced surface of the half-circle molds along the extension direction of the monofilament fiber, the diameter of the through hole being matched with the diameter of the monofilament fiber.

[0010] In some embodiments, the outer side of the half-circle mold is sleeved with a hoop along the circumferential direction, the hoop comprising an upper clamping plate and a lower clamping plate which are arc-shaped and matched with the forming mold, and the upper clamping plate and the lower clamping plate are hinged at one end and connected by bolts at the other end.

[0011] In some embodiments, the monofilament fixing assembly comprises a fixing plate connected to both ends of the monofilament fiber, and a supporting rod supported at the bottom of the fixing plate, the fixing plate comprising a first fixing plate and a second fixing plate which are screwed together, and the monofilament fiber is connected to the connection between the first fixing plate and the second fixing plate by an adhesive.

[0012] The second aspect of the present application provides a sample preparation method, comprising the following steps: S1, passing a monofilament fiber through a forming mold for forming thermoplastic resin droplets, and fixing both ends of the monofilament fiber by a monofilament fixing assembly; S2, cutting off the passage between a heating mechanism and the forming mold, adding a thermoplastic resin to be tested into the heating mechanism, heating the thermoplastic resin by the heating mechanism, and melting the thermoplastic resin; S3, opening the passage between the heating mechanism and the forming mold, and making the molten thermoplastic resin flow into the forming mold, and then cutting off the passage between the heating mechanism and the forming mold after the thermoplastic resin has completely flowed in.

[0013] In some embodiments, the forming mold is formed by splicing two half circles, and in step S1, the inner surface of the forming mold is wiped by a soft cloth before the monofilament fiber is passed through the forming mold, and the forming mold is fastened by bolts; both ends of the monofilament fiber are fixedly connected to the monofilament fixing assembly by an adhesive.

[0014] In some embodiments, in step S2, the passage between the heating mechanism and the forming mold is cut off by inserting the metal sheet at the communication between the heating mechanism and the forming mold.

[0015] In some embodiments, a sealing plug is installed in the heating mechanism, the sealing plug is connected to a hydraulic device, and in step S3, the hydraulic device is controlled to pressurize the sealing plug to extrude the molten thermoplastic resin to smoothly flow into the forming mold.

[0016] In the above technical solution, by connecting the heating mechanism with the forming mold, the heating function of the heating mechanism is used to heat the thermoplastic resin to be detected, so that it can be in a molten state and flow into the forming mold along the heating mechanism to form thermoplastic resin droplets. No manual operation is required for sample preparation, and the accuracy of sample preparation is ensured by heating and melting the thermoplastic resin to form droplets, which is convenient to operate. At the same time, the single-fiber fiber is fixed through the forming mold, so that the thermoplastic resin in a molten state can be in contact with the single-fiber fiber, which is convenient for subsequent shear strength test. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a structural schematic diagram of a sample preparation device for testing the interfacial shear strength of fibers and thermoplastic resins according to the present disclosure.

[0018] BRIEF DESCRIPTION OF DRAWINGS

[0019] 1 forming assembly 11 heating mechanism

[0020] 12 forming mold 13 metal sheet

[0021] 14 sealing plug 2 single-fiber fiber

[0022] 3 single-fiber fixing assembly 31 first fixing plate

[0023] 32 second fixing plate 33 support rod DETAILED DESCRIPTION

[0024] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the embodiments described herein are only a part of the embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0025] In the present application, unless otherwise stated, the orientation words such as "up", "down", etc. indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the design and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the design.

[0026] In the description of the present design, it should be noted that, unless otherwise explicitly specified and limited, the terms "provided with", "connected" and the like should be understood broadly, for example, "connected" can be fixedly connected, or detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present design can be understood according to the specific circumstances.

[0027] In addition, the terms "first", "second", "third" and the like are only for descriptive purposes and should not be understood as indicating or implying relative importance.

[0028] In order to overcome the problem of large manual error and high data dispersion in the sample preparation for the micro-debonding test of thermoplastic resin in the prior art.

[0029] As shown in Figure 1 , the present application provides a sample preparation device for testing the interfacial shear strength of fibers and thermoplastic resin.

[0030] Embodiment one

[0031] The sample preparation device for testing the interfacial shear strength of fibers and thermoplastic resin comprises a forming assembly 1, a monofilament fiber 2 connected to the forming assembly 1, and a monofilament fixing assembly 3 for fixing the monofilament fiber 2, wherein the forming assembly 1 comprises a heating mechanism 11 for accommodating and heating thermoplastic resin and a forming mold 12 communicated with the heating mechanism 11, and the monofilament fiber 2 is fixed to extend through the forming mold 12, so that the thermoplastic resin micro-droplets can be formed on the monofilament fiber 2 by the forming assembly 1.

[0032] Specifically, by communicating the heating mechanism 11 with the forming mold 12, the heating function of the heating mechanism 11 is used to heat the thermoplastic resin to be tested to a molten state and flow into the forming mold 12 along the heating mechanism 11 to form thermoplastic resin micro-droplets, without manual sample preparation. The molten thermoplastic resin is heated to form micro-droplets, which ensures the accuracy of the sample preparation and is convenient to operate. At the same time, the monofilament fiber is fixed to pass through the forming mold 12, so that the molten thermoplastic resin can contact the monofilament fiber 2, which is convenient for subsequent shear strength test.

[0033] Further, the forming mold 12 can also have a heating function, so as to heat the molten thermoplastic resin flowing into the forming mold 12.

[0034] Embodiment two

[0035] This embodiment contains all the contents of embodiment one. In this embodiment, refer to Figure 1As shown, the heating mechanism 11 can be provided with a sealing plug 14, which is connected to a hydraulic device to control the sealing plug 14 to extrude the molten thermoplastic resin in the heating mechanism 11 to flow towards the molding die 12. It can be understood that the thermoplastic resin heated by the heating mechanism 11 can flow in a molten state, but due to the different melting points and viscosities of the components of the thermoplastic resin, bubbles can appear in the molten thermoplastic resin. Therefore, the hydraulic device can be used to pressurize the sealing plug 14, so that the sealing plug 14 moves towards the molding die 12, and then extrudes the molten thermoplastic resin in the heating mechanism 11 that has reached a temperature towards the molding die 12, avoiding bubbles in the molten thermoplastic resin.

[0036] Embodiment Three

[0037] This embodiment includes all the contents of Embodiment One. In this embodiment, the outlet end of the heating mechanism 11 is provided with a metal sheet 13 for controlling the on-off relationship between the heating mechanism 11 and the molding die 12. Referring to Figure 1 As shown, the metal sheet 13 can be inserted between the heating mechanism 11 and the molding die 12 to cut off the passage between the heating mechanism 11 and the molding die 12; or the metal sheet 13 can be pulled out to form a passage between the heating mechanism 11 and the molding die 12, so that the molten thermoplastic resin in the heating mechanism 11 can flow into the molding die 12. The metal sheet 13 can be controlled by a telescopic device, as long as it can be inserted or pulled out in time to control the on-off relationship between the heating mechanism 11 and the molding die 12.

[0038] Embodiment Four

[0039] This embodiment includes all the contents of Embodiment One. In this embodiment, the molding die 12 includes two semicircular dies that are spliced together, and a through hole is formed in the center of the spliced surface of the semicircular dies along the extension direction of the monofilament fiber 2, and the diameter of the through hole is matched with the diameter of the monofilament fiber 2.

[0040] Specifically, the molding die 12 can be formed by splicing two semicircular dies, and a through hole matched with the diameter of the monofilament fiber 2 is formed at the spliced surface of the two semicircular dies, so that the monofilament fiber 2 can extend through the through hole, avoiding gaps between the monofilament fiber 2 and the molding die 12, which can cause inaccurate shear strength test of the fiber and the thermoplastic resin.

[0041] Further, the outer side of the semicircular mold is sleeved with a hoop in the circumferential direction, the hoop includes an upper clamping plate and a lower clamping plate which are arc-shaped and matched with the forming mold 12, one end of the upper clamping plate and the lower clamping plate is hinged, and the other end is connected by a bolt. It can be understood that the outer surface of the forming mold 12 can be sleeved with a hoop in the circumferential direction, the hoop can be composed of two circular clamping plates, one end of which is hinged to each other, and the other end is connected by a bolt, so that it can clamp and fix the forming mold 12 to form a sealed structure, preventing cracks between the two semicircular molds spliced into the forming mold 12, causing the molten thermoplastic resin to leak out.

[0042] Example five

[0043] This embodiment includes all the contents of example one. And in this embodiment, as shown in Figure 1 The monofilament fixing assembly 3 includes a fixing plate connected to both ends of the monofilament fiber 2, and a support rod 33 supported at the bottom of the fixing plate, the fixing plate includes a first fixing plate 31 and a second fixing plate 32 which are screwed to each other, and the monofilament fiber 2 is connected to the connection between the first fixing plate 31 and the second fixing plate 32 by an adhesive.

[0044] Specifically, the connection between the first fixing plate 31 and the second fixing plate 32 and both ends of the monofilament fiber 2 can be coated with an adhesive, so that both ends of the monofilament fiber 2 can be fixedly connected to the fixing plate, and the first fixing plate 31 and the second fixing plate 32 can be connected by a bolt, further enhancing the connection strength between the monofilament fiber 2 and the fixing plate, avoiding the monofilament fiber 2 from falling off or shaking during the detection of the shear strength between the fiber and the thermoplastic resin, causing errors.

[0045] Example six

[0046] The second aspect of the present application provides a sample preparation method, which includes the following steps: S1, the monofilament fiber 2 is inserted through the forming mold 12 for forming thermoplastic resin droplets, and the two ends of the monofilament fiber 2 are fixed by the monofilament fixing assembly 3; S2, the passage between the heating mechanism 11 and the forming mold 12 is cut off, the thermoplastic resin to be tested is added into the heating mechanism 11, and the thermoplastic resin is heated by the heating mechanism 11 to melt; S3, the passage between the heating mechanism 11 and the forming mold 12 is opened, and the molten thermoplastic resin flows into the forming mold 12, and after all the molten thermoplastic resin flows in, the passage between the heating mechanism 11 and the forming mold 12 is disconnected.

[0047] Specifically, in the S1 step, the monofilament fiber 2 is extended through the forming mold 12 so that the thermoplastic resin droplets formed in the forming mold 12 can be in contact with the monofilament fiber 2 for detecting the shearing strength between the fiber and the thermoplastic resin, and the two ends of the monofilament fiber 2 are fixed by the monofilament fixing assembly 3 to avoid the movement of the monofilament fiber 2 during the test of the shearing strength, which can cause errors. The suitable monofilament fiber 2 can be selected under the irradiation of the energy-saving lamp.

[0048] Specifically, in the S2 step, after the monofilament fiber 2 is extended through the forming mold 12 and fixed by the monofilament fixing assembly 3, the passage between the heating mechanism 11 and the forming mold 12 can be cut off first, and then the thermoplastic resin to be tested is added into the heating mechanism 11, and the thermoplastic resin is heated by the heating function of the heating mechanism 11.

[0049] Specifically, in the S3 step, after the thermoplastic resin in the heating mechanism 11 is heated to a suitable melting temperature, the passage between the heating mechanism 11 and the forming mold 12 can be opened so that the molten thermoplastic resin can flow into the forming mold 12, and after all the molten thermoplastic resin flows into the forming mold 12, the passage between the heating mechanism 11 and the forming mold 12 is disconnected. The forming mold 12 can also have a heating function, so that the molten thermoplastic resin flowing into the forming mold 12 can be kept warm to form the thermoplastic resin droplets.

[0050] Example Seven

[0051] This embodiment includes all the contents of the embodiment six. In this embodiment, the forming mold 12 is formed by splicing two semicircles, and in the step S1, the inner surface of the forming mold 12 is wiped by a soft cloth before the monofilament fiber 2 is extended through the forming mold 12, and the forming mold 12 is fastened by bolts; the two ends of the monofilament fiber 2 are fixedly connected with the monofilament fixing assembly 3 by an adhesive.

[0052] Specifically, the forming mold 12 can be formed by splicing two semicircles, and before the monofilament fiber 2 is extended through the forming mold 12, the forming mold 12 can be opened to wipe off the dust on the inner surface of the forming mold 12 by a soft cloth to avoid errors; after the monofilament fiber 2 is extended through the forming mold 12, the forming mold 12 formed by splicing two semicircles can be fastened and connected by a fastening device to form a sealed structure to prevent cracks between the forming molds 12, which can cause the molten thermoplastic resin to leak out. Meanwhile, the monofilament fixing assembly 3 can have two upper and lower fixing plates, which can clamp and fix the monofilament fiber 2, and the monofilament fiber 2 can be fixed on the fixing plates by an adhesive, and the fixing plates can be fastened by bolts to avoid the monofilament fiber 2 from falling off. Of course, in other embodiments, the monofilament fixing assembly 3 can also have other forms as long as it can fix the two ends of the monofilament fiber 2.

[0053] Embodiment Eight

[0054] This embodiment contains all the contents of Embodiment Six. And in this embodiment, in step S2, the passage between the heating mechanism 11 and the molding die 12 is cut off by inserting the metal sheet 13 at the communication between the heating mechanism 11 and the molding die 12.

[0055] Specifically, the communication between the heating mechanism 11 and the molding die 12 can be installed with a retractable metal sheet 13, by controlling the extension and retraction of the metal sheet 13, the metal sheet 13 can be inserted into the communication between the heating mechanism 11 and the molding die 12 to cut off the passage between the heating mechanism 11 and the molding die 12, and the metal sheet 13 can also be pulled out to open the passage between the heating mechanism 11 and the molding die 12, so that the molten thermoplastic resin in the heating mechanism 11 can flow into the molding die 12.

[0056] Embodiment Nine

[0057] This embodiment contains all the contents of Embodiment Six. And in this embodiment, a sealing plug 14 is installed in the heating mechanism 11, the sealing plug 14 is connected to a hydraulic device, and in step S3, the hydraulic device is controlled to pressurize the sealing plug 14 to extrude the molten thermoplastic resin to flow smoothly into the molding die 12.

[0058] Specifically, a sealing plug 14 connected to a hydraulic device can be installed in the heating mechanism 11, and the hydraulic device can be used to control the sealing plug 14 to extrude the molten thermoplastic resin in the heating mechanism 11 to flow smoothly into the molding die 12. And under the pressure of the sealing plug 14, bubbles can be avoided between the molten thermoplastic resin, causing errors.

[0059] The preferred embodiments of the present application are described in detail above in combination with the drawings, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application. Each specific technical feature can be combined in any suitable manner. In order to avoid unnecessary repetition, the present application does not further describe various possible combinations. However, these simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A sample preparation device for testing the interfacial shear strength of a fiber and a thermoplastic resin, characterized by, The application relates to a sample preparation device and a sample preparation method. The sealing plug (14) is connected to a hydraulic device to control the sealing plug (14) to extrude the hot plastic resin melted in the heating mechanism (11) to flow towards the forming die (12). The outlet end of the heating mechanism (11) is provided with a metal sheet (13) for controlling the on-off relationship between the heating mechanism (11) and the forming die (12). The forming die (12) comprises two semicircular dies which are spliced together, the center part of the splicing surface of the semicircular dies is provided with a through hole which is adapted to the diameter of the monofilament fiber (2) and extends along the extending direction of the monofilament fiber (2).

2. The sample preparation device for testing the interfacial shear strength of a fiber with a thermoplastic resin according to claim 1, characterized by, The outer side of the semicircular die is provided with a hoop which comprises an upper clamping plate and a lower clamping plate which are arc-shaped and adapted to the forming die (12), the upper clamping plate and the lower clamping plate are hinged at one end and connected by bolts at the other end.

3. The sample preparation device for testing the interfacial shear strength of a fiber with a thermoplastic resin according to claim 1, characterized by, The monofilament fixing assembly (3) comprises fixing plates connected to the two ends of the monofilament fiber (2) and a supporting rod (33) supported on the bottom of the fixing plate, the fixing plate comprises a first fixing plate (31) and a second fixing plate (32) which are screwed to each other, and the monofilament fiber (2) is connected to the connecting part between the first fixing plate (31) and the second fixing plate (32) by an adhesive.

4. A method of sample preparation, characterized by, The sample preparation method uses the sample preparation device according to any one of claims 1-3 and comprises the following steps: S1, the monofilament fiber (2) is penetrated through the forming die (12) for forming the hot plastic resin droplets, and the two ends of the monofilament fiber (2) are fixed by the monofilament fixing assembly (3); S2, the passage between the heating mechanism (11) and the forming die (12) is cut off, the hot plastic resin to be tested is added into the heating mechanism (11), the hot plastic resin is heated by the heating mechanism (11) to be melted; S3, the passage between the heating mechanism (11) and the forming die (12) is opened, the melted hot plastic resin flows into the forming die (12), and after all the hot plastic resin flows in, the passage between the heating mechanism (11) and the forming die (12) is disconnected.

5. The sample preparation method of claim 4, wherein The forming die (12) is spliced by two semicircles, before the monofilament fiber (2) penetrates the forming die (12), the inner surface of the forming die (12) is wiped by a soft cloth, and the forming die (12) is fastened by bolts; the two ends of the monofilament fiber (2) are fixedly connected with the monofilament fixing assembly (3) through an adhesive.

6. The method of claim 4, wherein, In step S2, the passage between the heating mechanism (11) and the forming die (12) is cut off by inserting the metal sheet (13) at the communication between the heating mechanism (11) and the forming die (12).

7. The method of claim 4, wherein, In step S3, the hydraulic device is controlled to pressurize the sealing plug (14) to extrude the molten thermoplastic resin to smoothly flow into the forming die (12).

Images