Method and device for quantifying interface slippage of incompatible polymer

Abstract

The invention relates to the field of high polymer material detection, and discloses a method and device for quantifying incompatible polymer interface slippage, and the method comprises the following steps: preparing a test sample which comprises a plurality of polymers which are stacked together and are mixed with tracer particles, setting test conditions, enabling the polymers in the test sample to generate relative flow, the method comprises the following steps: respectively acquiring coordinate positions of a plurality of preset-depth tracer particles in each polymer at a plurality of moments through a detection device, calculating to obtain the movement speed of the preset-depth tracer particles based on the corresponding coordinate positions and the corresponding movement time, and calculating the movement speed of the preset-depth tracer particles based on the corresponding depths and the corresponding movement speeds of the different-depth tracer particles. And making a depth-motion velocity diagram, and obtaining the interface slip velocity of the adjacent polymers based on the depth-motion velocity diagram. According to the method, the curve of the movement speed of the tracer particles with different depths is made, and then the slippage speed of the adjacent polymers at the interface can be obtained through an extrapolation method.

Description

Technical Field

[0001] This invention relates to the field of polymer material testing, and specifically to a method and apparatus for quantifying the interfacial slip of incompatible polymers. Background Technology

[0002] Polymer blends are physical mixtures formed by two or more homopolymers, copolymers, or mixtures thereof with different molecular structures. Their components are not linked by covalent bonds and belong to heterogeneous systems within the polymer field. This method can improve or impart special properties through component mixing. The preparation process is simple, and the range of component selection is wide, enabling the rapid development of materials with special properties.

[0003] Because there are no covalent bonds between the components of blended polymers, the reduced molecular chain entanglement in the interfacial regions leads to interfacial slip during melt mixing. This is especially true during processing, where the blend is in a flowing state, and the presence of interfacial slip significantly alters the kinetic properties of the incompatible phase interface. Numerous experimental and computational studies have shown that, regardless of shear or tensile flow, interfacial slip promotes the aggregation of the dispersed phase, hinders deformation, and alters the fragmentation mode of the dispersed phase. Interfacial slip causes adverse effects such as low interfacial stress transfer efficiency, weak interfacial adhesion, low blending efficiency, poor stability, and poor mechanical properties of the blend. From a macroscopic perspective, flow-induced interfacial slip leads to an abnormal decrease in the apparent viscosity and stress of the blend under stable shear flow, which is detrimental to the stability of the material's microstructure and results in reduced material properties. Therefore, studying the degree of interfacial slip is helpful in improving the processing efficiency and product stability of blends. Existing research has limited methods for quantitatively studying interfacial slip in incompatible polymer blends; most studies use rheological and simulation methods to indirectly characterize interfacial slip. These methods are complex to operate and cannot directly reflect the interfacial slip rate. Summary of the Invention

[0004] The present invention aims to overcome the shortcomings of the prior art and provide a method and apparatus for quantifying the interfacial slip of incompatible polymers, which can intuitively represent the compatibility between two polymers and provide theoretical support for improving the processing efficiency and phase morphology instability of incompatible polymers.

[0005] To achieve the above objectives, a first aspect of the present invention provides a method for quantifying interfacial slip of incompatible polymers, wherein the method comprises:

[0006] Prepare a test sample, which includes multiple incompatible polymers stacked sequentially from bottom to top, with tracer particles uniformly mixed on the surface and inside of each polymer;

[0007] Set test conditions to cause relative flow among the polymers in the test sample;

[0008] The coordinate positions of tracer particles at multiple preset depths in each polymer are obtained at multiple times using a detection device. Based on the corresponding coordinate positions and corresponding motion times, the motion velocity of the tracer particles at the preset depths is calculated.

[0009] Based on the depth and corresponding motion velocity of tracer particles at multiple preset depths in each polymer, a depth-motion velocity map is generated for each polymer, and the interface slip velocity of adjacent incompatible polymers is obtained based on the depth-motion velocity map of each polymer.

[0010] This invention involves adding tracer particles to a polymer and testing the movement velocity of these particles at different depths. Based on the velocity curves of the tracer particles at different depths, the slip velocity at the interface between adjacent polymers can be obtained through extrapolation. There are no special requirements for the polymers applicable to this invention, as long as the adjacent polymers are incompatible and do not react with each other.

[0011] This invention does not impose any requirements on the selection of tracer particles and detection devices; any commonly used devices in the field are acceptable. The tracer particles selected are generally micron-sized and do not affect the viscosity of the polymer bulk. For example, they can be silica micron-sized particles, and the detection device can be a CCD camera.

[0012] Preferably, the step of setting test conditions to induce relative flow among the polymers in the test sample includes:

[0013] The test sample is placed in a sample cell, wherein the sample cell includes a stationary plate and a moving plate arranged opposite each other, and one of the polymers at the bottom and top of the test sample is placed on the stationary plate and the other is placed on the moving plate.

[0014] The sample cell is heated so that all the polymers are in a molten state;

[0015] A preset shear force is applied to the motion plate to make it rotate at a preset rate.

[0016] The sample cell is heated to a temperature that makes all polymers molten; different heating temperatures can be selected for different polymers.

[0017] Preferably, after heating to a molten state for all the polymers, the distance between the stationary plate and the moving plate is adjusted so that the thickness of the test sample does not exceed 90% of its initial thickness. By adjusting the distance between the stationary plate and the moving plate to be less than the initial thickness of the test sample, the test sample can be pressed together to ensure that the polymers are tightly adhered to each other, facilitating the observation of their interface slippage.

[0018] Preferably, the preset rotation speed is γ, where 0 < γ ≤ 5 / s. The rotation speed of the moving plate is measured in radians, and the maximum speed γ does not exceed 5 radians per second.

[0019] Preferably, the difference between two adjacent preset depths among the plurality of preset depths within the same polymer does not exceed 0.02 mm.

[0020] Preferably, based on the total amount of the polymer, the amount of tracer particles added does not exceed 0.5 wt.%, and the diameter of the tracer particles is between 1 and 5 μm.

[0021] Preferably, the thickness of a single polymer layer does not exceed 0.8 mm, and the total thickness after stacking does not exceed 3 mm.

[0022] Preferably, the step of obtaining the interface slip velocity of adjacent polymers based on the depth-velocity map corresponding to the polymer includes: calculating the difference in motion velocity at the interface of adjacent polymers based on the depth-velocity map corresponding to the polymer, wherein the difference in motion velocity at the interface is the interface slip velocity.

[0023] A second aspect of the present invention provides an apparatus for quantifying the slippage of incompatible polymer interfaces, wherein the apparatus includes a microscope with a detection device mounted on the eyepiece, a shear heating stage mounted on the stage of the microscope, a sample cell mounted inside the shear heating stage, a test sample mounted inside the sample cell, and an observation hole provided on the shear heating stage, the observation hole being configured to allow the detection device to acquire the coordinate positions of tracer particles within the test sample.

[0024] Using the aforementioned device, the detection device can directly observe the positional changes of tracer particles within the test sample.

[0025] Preferably, the shearing heating stage includes an upper cover and a lower cover that are disposed opposite to each other and can be heated. The upper cover covers the lower cover and the distance between the two is adjustable. Both the upper cover and the lower cover have grooves. The grooves in the upper cover and the lower cover are joined together to form a sample slot. The sample pool is installed in the sample slot. The observation hole is provided on the upper cover.

[0026] like Figure 4 and 5 As shown, the principle of the method provided by this invention is as follows: Taking two polymers as examples, the motion velocity of tracer particles at different depths within polymers A and B is obtained through testing (rotation is applied, so the slippage of the tracer particles occurs around the center of rotation, and its velocity is the linear velocity). Depth-motion velocity curves of tracer particles at multiple depths within polymers A and B are then generated, as shown... Figure 5As shown, there is a velocity difference between the depth-velocity curves of tracer particles in polymers A and B at the interface. This velocity difference is the slip velocity at the interface between polymers A and B. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the device.

[0028] Figure 2 This is a schematic diagram of the shear heating stage (with test samples inside).

[0029] Figure 3 for Figure 2 Top view;

[0030] Figure 4 This is a schematic diagram of the installation of the test sample;

[0031] Figure 5 A schematic diagram of the method provided by the present invention;

[0032] Figure 6 This is a depth-velocity diagram of Example 1;

[0033] Figure 7 This is the depth-velocity diagram for Example 2. Detailed Implementation

[0034] The specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this application.

[0035] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0036] Furthermore, the term "and / or" in the specification and claims is used to describe the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0037] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0038] Unless otherwise specified, "multiple" in this invention refers to two or more.

[0039] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto. Unless otherwise specified, the test methods and testing equipment used in the following embodiments are conventional test methods and testing equipment in the art.

[0040] The embodiments of the present invention are all based on the following apparatus:

[0041] like Figure 1 , 2 As shown in Figure 3, the device includes a microscope with a detection device 1 mounted on its eyepiece. A shear heating stage 3 is mounted on the microscope's stage, and a sample cell containing a test sample is installed within the shear heating stage 3. An observation hole 11 is provided on the shear heating stage 3, which is configured to allow the detection device 1 to acquire the coordinate positions of tracer particles 10 within the test sample. Through magnification by the objective lens 2, the detection device 1 can more clearly obtain the coordinate positions of the tracer particles 10.

[0042] In this example, the detection device 1 is specifically a CCD camera. The shearing heating stage 3 includes an upper cover 4 and a lower cover 5 that are arranged opposite each other and can be heated. The upper cover 4 covers the lower cover 5 and the distance between the two is adjustable. Both the upper cover 4 and the lower cover 5 have grooves. The grooves in the upper cover 4 and the lower cover 5 are joined together to form a sample slot. The sample slot is used to install the sample pool. An observation hole 11 is opened on the upper cover 4, and the observation hole 11 is directly opposite the sample pool.

[0043] The sample cell includes a stationary plate 7 and a moving plate 9 arranged opposite each other. Both the stationary plate 7 and the moving plate 9 are transparent plates, such as quartz plates. Since both the stationary plate 7 and the moving plate 9 are transparent, the detection device 1 can see the sample cell through the observation hole 11 on the shear heating stage 3, and further see the tracer particles 10 inside the polymer in the sample cell through the stationary plate 7. When using the device provided by the present invention, the sample is installed as follows: Figure 4 As shown, multiple polymer samples mixed with tracer particles 10 are prepared into shapes identical to the sample well. Since the sample well is typically circular, the polymers are generally prepared into disc-like shapes, or more specifically, disc-like shapes with smooth surfaces. The polymers are then tightly stacked from bottom to top. The stationary plate 7 and the moving plate 9 clamp the test sample from above and below, respectively, forming a sandwich-like structure. This sandwich is then installed into the sample well. The upper cover 4 and lower cover 5 are fastened. The shear heating stage 3 is then mounted on the microscope stage. The upper cover 4 and lower cover 5 are connected to a heating device and heated to a preset temperature (heated until all polymers are molten, adjacent polymers are completely adhered, and there are no air bubbles). The distance between the upper cover 4 and lower cover 5 is then adjusted to ensure the distance between the moving plate 9 and the stationary plate 7 meets the requirements. The shear heating stage 3 can be purchased commercially; the shear heating stage used in the following examples is a Linkam CSS450.

[0044] Example 1

[0045] Taking PE (polyethylene) and PS (polystyrene) as examples, a small amount of silica micron particles with a particle size (D90) of approximately 5 μm were mixed into them as tracer particles (the addition amount was less than 0.5 wt.%). The PE and PS containing the tracer particles were vacuum hot-pressed above their melting temperature into discs 1 and 2, respectively, with a thickness of 0.8 mm and a diameter of 25 mm. The two discs were stacked together to form a test sample (PS at the bottom, PE at the top), and then the test sample was clamped from both the top and bottom using a stationary plate and a moving plate (at this time, as...). Figure 2 As shown, the stationary plate 7 is in contact with the polymer 6 (PE) above and the moving plate 9 is in contact with the polymer 8 (PS) below. After these two plates are placed in the sample cell and heated to 180°C (at which point both PE and PS are in a molten state), the distance between the moving plate 7 and the stationary plate 9 is adjusted to 1 mm.

[0046] The moving plate 9 is rotated at a shearing speed of 1 / s, and the CCD takes pictures at 1-second intervals. The specific steps are as follows:

[0047] Focus on a tracer particle at a certain depth within the PS (PhotoScaping) and capture its position at different times. Represent its position using coordinates, then calculate the coordinate difference between different times (generally 2-3 times are sufficient). Based on this difference and time, calculate the tracer particle's sliding velocity V. d =s / t, since shear force is applied by rotation, the tracer particle moves in a circle around the rotation center at a certain linear velocity. Therefore, the difference in its coordinates at different times is actually the distance of the arc segment of its movement along the circumference. Thus, the final slip velocity is the linear velocity.

[0048] Then, using the same method as before, focus on tracer particles at different depths within the PS to obtain their coordinate changes at different times, and calculate the motion velocity corresponding to the tracer particles at different depths based on the coordinate changes.

[0049] Then, using the same method as before, focus on tracer particles at different depths within the PE to obtain the coordinate changes of tracer particles at different depths at different times, and calculate the motion velocity of tracer particles at different depths based on the coordinate changes.

[0050] In this example, PS is at the bottom and PE is at the top. The tracer particles selected in PS at different depths include (based on the distance to the lower surface of the entire test sample calculated from the thickness of the entire test sample): 0 mm (i.e., the lower surface of the entire test sample), 0.8 mm, 0.16 mm, 0.24 mm, 0.32 mm, and 0.40 mm, a total of six depths. The tracer particles selected in PE at different depths include 0.58 mm, 0.66 mm, 0.75 mm, 0.84 mm, 0.84 mm, 0.92 mm, and 1 mm (i.e., the upper surface of the entire test sample). The linear velocities of the tracer particles at each depth are finally calculated as shown in Table 1.

[0051] Table 1

[0052]

[0053] Depth-velocity curves for the tracer particles within the PS and PE were generated based on the depth and velocity of all tracer particles focused within the PS and PE, respectively. The results are as follows: Figure 6 As shown in the figure, in the polymer stack sample, the velocity of the tracer particles decreases with increasing depth (i.e., the closer to the moving plate, the greater the uniform velocity, and the farther away from the moving plate, the smaller the velocity). However, the degree of decrease is different in PS and PE. The velocity of the tracer particles in PS decreases significantly more than that in PE. The overall change is not linear. A velocity jump occurs at the interface, i.e., interface slip occurs.

[0054] At the interface between PS and PE, i.e. at a depth of 0.5 mm in the test sample, there is a velocity difference in the slip curves of the tracer particles in the two polymers. In this example, the velocity difference is 0.321 mm / s, which is the slip velocity at the interface between PS and PE.

[0055] Example 2

[0056] Taking PP (polypropylene), PS, and HDPE (high-density polyethylene) as examples, a small amount of silica micron particles with a particle size (D90) of about 5μm are mixed into them as tracer particles (the amount added is less than 0.5wt.%). The PP, PS, and HDPE mixed with tracer particles are vacuum hot-pressed at high temperature into discs 1, 2, and 3 with a thickness of 0.6mm and a diameter of 25mm, respectively. They are then stacked together from top to bottom to form a test sample (HDPE at the bottom and PP at the top). The test sample is then clamped from the bottom and top by a moving plate 6 and a stationary plate 9 and placed into the sample tank (HDPE is in contact with the moving plate, and PP is in contact with the stationary plate). After heating to 180℃ (at which point PP, PS, and HDPE are all in a molten state), the distance between the moving plate and the stationary plate is adjusted to 1.5mm.

[0057] A shearing velocity of 1 / s is applied to rotate the moving plate, and the CCD takes pictures at 1-second intervals. The specific steps are as follows:

[0058] Focusing on a tracer particle at a specific depth within HDPE, its position is captured at different times and represented by coordinates. The coordinate differences at different times (generally 2-3 times are sufficient) are then calculated. Based on these differences and time, the slip velocity V of the tracer particle is calculated. d =s / t, since shear force is applied by rotation, the tracer particle moves in a circle around the rotation center at a certain linear velocity. Therefore, the difference in its coordinates at different times is actually the distance of the arc segment of its movement along the circumference. Thus, the final velocity is the linear velocity.

[0059] Then, using the same method as before, focus on tracer particles at different depths within the PS to obtain their coordinate changes at different times, and calculate the motion velocity of the tracer particles at different depths within the PS based on the coordinate changes.

[0060] Then, using the same method as before, focus on tracer particles at different depths within PP to obtain their coordinate changes at different times, and calculate the motion velocity corresponding to the tracer particles at different depths based on the coordinate changes.

[0061] In this example, the tracer particles selected at different depths in HDPE include (based on the distance to the lower surface of the entire test sample calculated from the thickness of the entire test sample): 0 mm (i.e., the lower surface of the entire test sample), 0.1 mm, 0.2 mm, and 0.3 mm, for a total of four depths. The tracer particles selected at different depths in PS include 0.6 mm, 0.7 mm, 0.8 mm, and 0.9 mm, for a total of four depths in PP: 1.2 mm, 1.3 mm, 1.4 mm, and 1.5 mm (i.e., the upper surface of the entire test sample). The final calculated linear velocities of the tracer particles at each depth are shown in Table 2.

[0062] Table 2

[0063]

[0064] Depth-velocity curves for the tracer particles within HDPE, PS, and PP were generated based on the depth and velocity of all tracer particles focused within HDPE, PS, and PP, respectively. The results are as follows: Figure 7 As shown in the figure, at the interface between HDPE and PS, i.e., at a test sample depth of 0.5 mm, there is a velocity difference in the motion curves of the tracer particles in the two polymers. In this example, this velocity difference is 0.091 m / s, which is the sliding velocity at the interface between HDPE and PS. At the interface between PP and PS, i.e., at a test sample depth of 1.0 mm, the velocity difference in the motion curves of the tracer particles in the two polymers is 0.113 mm / s, i.e., the sliding velocity at the interface between PP and PS is 0.113 mm / s.

[0065] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for quantifying interfacial slip of incompatible polymers, characterized in that, The method includes: Prepare a test sample, which includes multiple incompatible polymers stacked sequentially from bottom to top, with tracer particles uniformly mixed on the surface and inside of each polymer; Test conditions are set to cause relative flow among the polymers in the test sample; The coordinate positions of tracer particles at multiple preset depths in each polymer are obtained at multiple times using a detection device. Based on the corresponding coordinate positions and corresponding motion times, the motion velocity of the tracer particles at the preset depths is calculated. Based on the depth and corresponding motion velocity of tracer particles at multiple preset depths in each polymer, a depth-motion velocity map is generated for each polymer, and the interface slip velocity of adjacent incompatible polymers is obtained based on the depth-motion velocity map of each polymer.

2. The method according to claim 1, wherein, The step of setting test conditions to induce relative flow among the polymers in the test sample includes: The test sample is placed in a sample cell, wherein the sample cell includes a stationary plate and a moving plate arranged opposite each other, and one of the polymers at the bottom and top of the test sample is placed on the stationary plate and the other is placed on the moving plate. The sample cell is heated so that all the polymers are in a molten state; A preset shear force is applied to the motion plate, causing it to rotate at a preset rate.

3. The method according to claim 1 or 2, wherein, The step of obtaining the interface slip velocity of adjacent polymers based on the depth-velocity map corresponding to the polymer includes: calculating the difference in motion velocity at the interface of adjacent polymers based on the depth-velocity map corresponding to the polymer, wherein the difference in motion velocity at the interface is the interface slip velocity.

4. The method according to claim 2, wherein, After heating until all the polymers are in a molten state, the distance between the stationary plate and the moving plate is adjusted so that the thickness of the test sample does not exceed 90% of its initial thickness.

5. The method according to claim 2 or 4, wherein, The preset rotation speed is γ, where 0 < γ ≤ 5 / s.

6. The method according to claim 5, wherein, Based on the total amount of the polymer, the amount of tracer particles added does not exceed 0.5 wt.%, and the diameter of the tracer particles is between 1 and 5 μm.

7. The method according to claim 5, wherein, The thickness of a single layer of the polymer does not exceed 0.8 mm, and the total thickness after stacking does not exceed 3 mm.

8. The method according to claim 3, wherein, The difference between any two adjacent preset depths within the same polymer shall not exceed 0.02 mm.

9. An apparatus for quantifying the slippage of incompatible polymer interfaces as described in any one of claims 1-8, characterized in that, The device includes a microscope with a detection device mounted on its eyepiece, a shear heating stage mounted on the microscope's stage, a sample cell mounted inside the shear heating stage, the test sample mounted inside the sample cell, and an observation hole provided on the shear heating stage, which is configured to allow the detection device to obtain the coordinate positions of tracer particles within the test sample.

10. The apparatus according to claim 9, wherein, The shearing heating stage includes an upper cover and a lower cover that are arranged opposite each other and can be heated. The upper cover covers the lower cover and the distance between the two is adjustable. Both the upper cover and the lower cover have grooves. The grooves in the upper cover and the lower cover are joined together to form a sample slot. The sample pool is installed in the sample slot. The observation hole is opened on the upper cover.

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