Thermotropic shape memory polymer performance testing device

Abstract

The invention discloses a thermotropic shape memory polymer performance testing device, which comprises a testing container suitable for controlling the internal temperature through a heating and refrigerating device; the clamping assembly is arranged in the test container and comprises a first clamp and a second clamp which are oppositely arranged along a first direction; the first clamp and the second clamp are used for clamping the thermotropic shape memory polymer; the adjusting assembly is arranged in the testing container and comprises a screw rod which is in transmission connection with the clamping assembly; the screw is suitable for rotating around a first axis in a first direction relative to the test container so as to drive the first clamp and the second clamp to get close to each other or get away from each other in the first direction; and the distance measuring assembly comprises an angle encoder coaxially connected with the screw rod, and the angle encoder is used for measuring the rotation angle of the screw rod so as to calculate the relative displacement of the first clamp and the second clamp in the clamping assembly based on the rotation angle and the screw pitch of the screw rod. By adopting the testing device, the problems that the performance testing operation of the thermotropic shape memory polymer is tedious and the displacement precision control is relatively poor can be solved.

Description

Technical Field

[0001] The invention relates to the field of thermotropic shape memory polymer performance testing, and in particular to a thermotropic shape memory polymer performance testing device. Background Art

[0002] Thermotropic shape memory polymer is a smart material that can recover its shape under external temperature stimulation. Due to its unique shape memory effect, it has shown important application value in cutting-edge fields such as biomedicine, aerospace, and flexible electronics. Shape fixation rate and shape recovery rate are the core indicators for evaluating its performance. Therefore, accurate and reliable measurement of these properties is crucial for the research and development, quality control and application of materials. At present, the performance test of this type of polymer generally relies on manual operation or universal material testing machines. Manual stretching makes it difficult to achieve precise control of the displacement, and although the universal material testing machine is powerful, its design is not optimized for the specific testing process of shape memory polymers. The operation process is complicated, and its mechanical loading mode is not designed for the precise quantification of the shape memory effect. In summary, the performance test of thermotropic shape memory polymers in the existing technology still has the problems of cumbersome operation and poor displacement accuracy control. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above-mentioned defects or problems existing in the background technology and to provide a thermotropic shape memory polymer performance testing device, which can improve the problems of cumbersome performance testing operation and poor displacement accuracy control of thermotropic shape memory polymers, or provide a material basis for improving the problem.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] Technical Solution 1: A thermotropic shape memory polymer performance testing device, comprising: a test container, which is suitable for controlling the internal temperature through a heating and cooling device; a clamping assembly, which is installed in the test container and includes a first clamp and a second clamp arranged opposite to each other along a first direction; the first clamp and the second clamp are used to clamp the thermotropic shape memory polymer; an adjustment assembly, which is installed in the test container and includes a screw that is transmission-connected to the clamping assembly; the screw is suitable for rotating around a first axis in a first direction relative to the test container to drive the first clamp and the second clamp to move closer to or away from each other along the first direction; and a distance measuring assembly, which includes an angle encoder coaxially connected to the screw, and the angle encoder is used to measure the rotation angle of the screw, so as to calculate the relative displacement of the first clamp and the second clamp in the clamping assembly based on the rotation angle and the pitch of the screw.

[0006] Technical Solution 2 based on Technical Solution 1: In the clamping assembly, the position of the second clamp is fixed relative to the test container; the screw is transmission-connected to the first clamp and is suitable for driving the first clamp to move along the first direction.

[0007] Technical solution three based on technical solution two: the adjustment assembly also includes a sliding rod extending along the first direction and fixed relative to the test container; the first clamp is slidingly connected to the sliding rod along the first direction, and is locked in rotation with the sliding rod relative to the first axis.

[0008] Technical solution 4 based on technical solution 3: There are two sliding rods, which are arranged on both sides of the first clamp along a second direction perpendicular to the first direction.

[0009] Technical solution five based on technical solution three or four: the sliding rod is provided with a scale along the first direction.

[0010] Technical solution six based on technical solution five: the first clamp includes a slider and a first clamping head fixed to each other; the slider is threadedly connected to the screw along a first direction; the first clamping head is used to clamp the thermotropic shape memory polymer.

[0011] Technical solution seven based on technical solution six: the second clamp includes a base and a second clamping head fixed to each other; the base is fixed to the test container; the clamping surfaces of the first clamping head and the second clamping head for clamping the thermotropic shape memory polymer are made of rubber and are provided with anti-slip textures.

[0012] Technical Solution 8 based on Technical Solution 7: The adjustment assembly also includes a support; the support is fixed to the test container and is located at the other end relative to the base along the first direction; both ends of the screw are rotatably mounted on the support and the base; both ends of the sliding rod are mounted on the support and the base; the angle encoder is mounted on the support or the base.

[0013] Technical solution nine based on technical solution one: the adjustment assembly also includes a crank located outside the test container and coaxially connected to the screw, and the crank is used to drive the screw to rotate.

[0014] Technical solution 10 based on technical solution 1: the test container is provided with a temperature sensor and a temperature control unit; the temperature sensor is suitable for detecting the internal temperature of the test container; the temperature control unit is suitable for controlling the temperature inside the test container through the heating and cooling device according to the signal transmitted by the temperature sensor.

[0015] From the above description of the present invention, it can be seen that compared with the prior art, the present invention has the following beneficial effects:

[0016] Technical Solution 1 provides a device for testing the performance of thermotropic shape memory polymers, comprising a test container, a clamping assembly, an adjustment assembly, and a distance measuring assembly. Through the interplay of these components, high-precision and high-reliability testing of the performance of thermotropic shape memory polymers is achieved. The test container precisely controls the internal temperature via a heating and cooling device, providing a stable and adaptable environment for polymer performance testing. Both the clamping assembly and the adjustment assembly are housed within the test container. This integrated design allows the entire process of sample stretching, deformation, and shape recovery to be completed within a stable and precise temperature field, avoiding the temperature fluctuations and operational errors introduced by the transfer of the sample between the heating and measuring equipment in the prior art. The clamping assembly conveniently secures the polymer and is connected to a screw in the clamping assembly. The screw converts rotational movement into displacement of the clamping assembly. An angle encoder is incorporated into the clamping assembly, and by combining the encoder's electrical signal with the screw's pitch, the real-time displacement of the fixture can be accurately calculated. This improves the prior art's problem of poor manual displacement control accuracy. Moreover, when conducting performance testing, it is only necessary to clamp the polymer on the clamping component and then operate the adjustment component to easily obtain the performance data of the polymer, which is more convenient to operate.

[0017] In Technical Solution 2, by fixing the second fixture's position relative to the test container and dedicating the screw to the movement of the first fixture, a clear and stable reference base is established for the entire displacement measurement process. With this structure, all displacements calculated by the angle encoder can be definitively attributed to the movement of the first fixture relative to this fixed reference base—the actual change in sample length. This design eliminates systematic errors that can be introduced by simultaneous movement of two fixtures or an unclear reference base, further improving the accuracy of displacement measurements.

[0018] In Technical Solution 3, a slide rod, slidably connected to the first fixture, is added to the adjustment assembly to provide guidance and anti-rotation functions for the moving fixture. While the screw transmits the axial driving force, the slide rod ensures that the first fixture, when subjected to force, follows a strictly predetermined linear path, suppressing any torsional motion that might otherwise occur under the screw's drive. This separation and coordination of the driving and guiding functions ensures that the deformation applied to the sample is purely axial tension, preventing non-axial motion or torsional components from interfering with the test results.

[0019] In Technical Solution 4, by increasing the number of slide bars to two and placing them on either side of the first clamp, the slide bars provide more stable and reliable guidance for the clamping assembly. Compared to a single-slide bar structure, the dual-slide bar structure prevents the first clamp from tilting or swaying due to uneven force, making the entire movement of the first clamp more stable and smooth.

[0020] In technical solution five, a scale is added to the slide bar to enable intuitive observation of the dimensional changes of the polymer.

[0021] In Technical Solution 6, the first fixture consists of a slider and a first clamping head, which are fixedly connected. The slider and the screw directly engage in threaded engagement, forming a transmission pair that converts rotational motion into linear motion. Designing the slider (responsible for transmission) and the clamping head (responsible for clamping the sample) as two independent, fixedly connected components structurally separates the transmission and clamping functions, resulting in a more reliable overall structure and lower manufacturing costs.

[0022] Technical Solution 7 further improves the second fixture's fixing method and the sample-holding surfaces of both fixtures. A base secures the second fixture to the test container, preventing it from shaking. The clamping surface, made of elastic rubber and featuring anti-slip ridges, provides sufficient clamping force by increasing the contact area and friction coefficient without damaging the fragile sample surface. This effectively prevents the sample from slipping in the fixture due to excessive tension during testing, thus avoiding measurement errors caused by relative slip.

[0023] In Technical Solution 8, additional supports are provided to provide a stable mounting base for both ends of the screw and the sliding rod together with the base.

[0024] In technical solution nine, by setting a crank connected to the screw on the outside of the test container, the operator can perform real-time and continuous manual control of the sample's stretching process without opening the test container and destroying the internal stable temperature environment.

[0025] In Technical Solution 10, by adding a temperature sensor and a temperature control unit to the test container, the device's temperature control method is upgraded from simple open-loop heating to precise closed-loop automatic control. The temperature sensor monitors the actual temperature inside the test container in real time and transmits this signal as a feedback signal to the temperature control unit. The control unit compares this feedback value with the preset target temperature and, based on the deviation between the two, automatically adjusts the output power of the heating and cooling device using an internal algorithm. This closed-loop control system accurately maintains the internal temperature at the set value and actively compensates for disturbances caused by ambient temperature changes or heat loss from the device itself. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 A side view of the structure of a thermotropic shape memory polymer performance testing device according to an embodiment of the present invention;

[0028] Figure 2 This is a top view of the structure of a thermotropic shape memory polymer performance testing device according to an embodiment of the present invention.

[0029] Description of main reference numerals:

[0030] Test container 10;

[0031] Clamping assembly 20; first clamp 21; second clamp 22; slider 23; first clamping head 24; base 25; second clamping head 26;

[0032] Adjustment assembly 30; screw 31; slide rod 32; support 33; crank 34;

[0033] Distance measuring component 40; Angle encoder 41. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are preferred embodiments of the present invention and should not be regarded as excluding other embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0035] In the claims, description and drawings of the present invention, unless otherwise clearly defined, the use of terms such as "first", "second" or "third" is for the purpose of distinguishing different objects rather than for describing a specific order.

[0036] In the claims, specification and the above-mentioned drawings of the present invention, unless otherwise expressly defined, directional words such as the terms "center", "transverse", "longitudinal", "horizontal", "vertical", "top", "bottom", "inside", "outside", "up", "down", "front", "back", "left", "right", "clockwise", "counterclockwise" and the like indicating directions or positional relationships are based on the directions and positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the specific scope of protection of the present invention.

[0037] In the claims, description and above-mentioned drawings of the present invention, unless otherwise expressly defined, the terms "fixed connection" or "fixed connection" should be understood in a broad sense, that is, any connection method without displacement relationship and relative rotation relationship between the two parties, that is, including non-detachable fixed connection, detachable fixed connection, integral connection and fixed connection through other devices or elements.

[0038] In the claims, description and drawings of the present invention, if the terms "include", "have" and their variations are used, they are intended to mean "including but not limited to".

[0039] Example

[0040] The embodiment of the present invention relates to a thermotropic shape memory polymer performance testing device, referring to Figure 1 and Figure 2 The testing device includes a testing container, a clamping assembly, an adjustment assembly and a distance measuring assembly.

[0041] Among them, the test container is suitable for controlling the internal temperature by a heating and cooling device. Specifically, the test container 10 is a box body, and its box wall is made of a heat-insulating material with low thermal conductivity, such as polyurethane foam or aerogel board, to minimize heat exchange with the external environment and maintain the stability of the internal temperature. A transparent observation window is provided on the box body or door of the test container 10. The observation window can adopt a double-layer hollow tempered glass structure, which can ensure that the operator can clearly observe the sample state without interfering with the internal temperature field, and can also play a good heat insulation effect. The test container 10 is connected to an external heating and cooling device, which can be a semiconductor refrigeration chip (TEC) system based on the Peltier effect, or an external constant temperature liquid circulating bath, which actively and quickly heats or cools the interior of the test container 10 through a circulating medium (such as air or thermal oil).

[0042] Preferably, the test container is equipped with a temperature sensor and a temperature control unit; the temperature sensor is adapted to detect the internal temperature of the test container; and the temperature control unit is adapted to control the temperature within the test container via the heating and cooling device based on the signal transmitted by the temperature sensor. Specifically, the temperature sensor can be a high-precision platinum resistance thermometer (e.g., PT100) or a K-type thermocouple, with its temperature measuring end positioned near the center of the polymer sample to accurately and sensitively reflect the sample's real-time ambient temperature. The temperature control unit is a standalone controller or a module integrated into the main control system, and its core may utilize a PID (proportional-integral-differential) control algorithm. This unit receives the real-time temperature signal from the temperature sensor and compares it with a user-preset target temperature (e.g., the polymer's glass transition temperature, Tg + 20°C). Based on the deviation between the two, the PID algorithm accurately calculates the required output power of the heating and cooling device, thereby achieving precise control of the internal temperature, stabilizing it at the set value with a fluctuation range of ±0.5°C.

[0043] A clamping assembly is installed in the test container and includes a first clamp and a second clamp arranged opposite to each other along a first direction; the first clamp and the second clamp are used to clamp the thermotropic shape memory polymer. Specifically, the structural design of the first clamp 21 and the second clamp 22 is intended to firmly clamp the sample without damaging its surface. The clamping surface in the clamp that is in direct contact with the sample is made of a material with a high friction coefficient and appropriate elasticity, such as silicone rubber or polyurethane. The clamping surface is also processed with fine anti-slip patterns, which can be parallel grooves, cross-grinding patterns or diamond spray coatings, such as patterns with a depth of 1.5 mm, to increase friction and effectively prevent the sample from slipping when subjected to tensile force. In addition, the clamp itself can be designed as a quickly replaceable structure, for example, connected to the slider or base by a dovetail groove, a locating pin or a magnetic attraction, so that different types of clamps can be easily replaced according to the shape (such as film, fiber, dumbbell-shaped specimen) and size of the sample to be tested.

[0044] Among them, in the clamping assembly, the position of the second clamp is fixed relative to the test container; the screw is transmission-connected to the first clamp and is suitable for driving the first clamp to move along the first direction. In this embodiment, the second clamp includes a base and a second clamping head fixed to each other; the base is fixed to the test container. Specifically, the second clamping head 26 is mounted on the base 25, and the base 25 is firmly mounted on the inner bottom plate or internal frame of the test container 10 by fasteners such as bolts. This rigid fixing method ensures that the position of the second clamp 22 remains absolutely unchanged throughout the test process, thereby providing a stable reference benchmark for displacement measurement. The base 25 itself is a solid metal block. In addition to fixing the second clamping head 26, it also serves as a support and fixing point for one end of the screw 31 and the slide rod 32.

[0045] An adjustment assembly is mounted within the test container and includes a screw in transmission connection with the clamping assembly. The screw is adapted to rotate relative to the test container about a first axis in a first direction to drive the first and second clamps toward or away from each other in the first direction. Specifically, the screw 31 is a precision drive screw, such as a trapezoidal screw or a ball screw, with a precise and known pitch, for example, with a pitch error controlled within ±0.05 mm. The screw 31 is mounted horizontally along the first direction, and its rotational motion is precisely converted into linear displacement of the first clamp 21 by mating with the threads of the slider 23 on the first clamp 21.

[0046] The adjustment assembly further includes a slide rod extending in a first direction and fixed relative to the test container; the first fixture is slidably connected to the slide rod in the first direction and is locked in rotation with the slide rod relative to the first axis. In this embodiment, there are two slide rods, arranged on either side of the first fixture along a second direction perpendicular to the first direction. Specifically, to ensure that the first fixture 21 does not rotate with the screw 31 during movement, thereby ensuring that pure axial tension is applied to the sample, two parallel slide rods 32 are provided in the device. These two slide rods are cylindrical steel rods with a finely ground and hard chrome-plated surface, and their ends are respectively fixed to the support 33 and the base 25. The slider 23 of the first fixture 21 has a precision through-hole that mates with the slide rod 32, and a linear bearing can be installed in the hole. The slider 23 slides on the two slide rods 32. This structure limits the slider's rotational freedom, limiting its smooth linear motion to the axial direction of the slider (i.e., the first direction). To ensure smooth movement and accurate guidance, the surface roughness of the two sliding rods 32 is not higher than Ra1.6μm, and the parallelism error after installation is controlled within ±0.2mm.

[0047] Preferably, the slide bars are provided with a scale along the first direction. Specifically, millimeter-level length scales are produced on the surface of one or both slide bars 32 through laser etching or other processes. Simultaneously, a pointer or cursor is mounted at a corresponding position on the side of the slider 23, thus forming a direct-reading measurement system. This scale can be used to quickly read the initial length of the sample before testing, perform rough positioning, and visually verify electronic measurement results during the experiment.

[0048] In addition, the adjustment assembly also includes a crank located outside the test container and coaxially connected to the screw, and the crank is used to drive the screw to rotate. Specifically, one end of the screw 31 passes through the box wall of the test container 10 through a bearing with a sealing ring and is coaxially connected to the crank 34 installed on the outside. This design allows the operator to drive the screw 31 to rotate by manually turning the crank 34 without opening the test container and destroying the internal constant temperature environment, thereby performing real-time and continuous control of the sample's stretching process. The crank 34 can be a simple crank or a star wheel with multiple handles to facilitate fine adjustment. As an option, a torque adjustment device, such as an adjustable friction clutch, can also be integrated on the crank 34 to allow the operator to set a rough stretching force to improve the consistency of the operation.

[0049] Among them, the first clamp includes a slider and a first clamping head fixed to each other; the slider is threadedly connected to the screw along a first direction; the first clamping head is used to clamp the thermotropic shape memory polymer. Specifically, the first clamp 21 adopts a modular design and consists of two independent components: a slider 23 and a first clamping head 24. The slider 23 is a core component that realizes the motion transmission and guiding functions. Its main body is a metal block with a threaded hole engaged with the screw 31. It also has two smooth through holes (or equipped with linear bearings) that slide with the two slide rods 32. The first clamping head 24 is the part that directly clamps the sample. It is detachably fixed to the end face of the slider 23 by screws or the like. This separate design simplifies manufacturing and maintenance. When different types of clamping heads need to be replaced, there is no need to disassemble the entire transmission and guiding system.

[0050] In this embodiment, the clamping surfaces of the first clamping head and the second clamping head for clamping the thermotropic shape memory polymer are made of rubber and are provided with anti-slip grooves. Specifically, the clamping surfaces of the two clamping heads are covered with a pad made of silicone rubber material. Silicone rubber is selected because it can provide a very high coefficient of friction to prevent the sample from slipping, and has sufficient flexibility and will not crush or cut the polymer sample under the action of the clamping force. The surface of the pad is molded with a specific anti-slip texture, such as a diamond or strip groove with a depth of 1.5 mm. This texture can be embedded in the sample surface to further enhance the reliability of the clamping and ensure that the measured displacement is entirely the deformation of the sample itself, rather than the relative sliding between the sample and the clamp.

[0051] The distance measurement assembly includes an angle encoder coaxially connected to the screw. The angle encoder is used to measure the rotation angle of the screw and calculate the relative displacement of the first and second clamps in the clamping assembly based on the rotation angle and the screw pitch. Specifically, a high-resolution rotary angle encoder 41 has its shaft directly and coaxially rigidly connected to the end of the screw 31. This encoder can be incremental or absolute, with an accuracy of, for example, better than 0.1 degrees. When the crank 34 rotates the screw 31, the angle encoder 41 rotates synchronously and outputs an electrical signal proportional to the rotation angle (for example, an incremental encoder outputs a quadrature pulse signal). This signal is fed into a data processing unit (such as a single-chip microcomputer or a data acquisition card connected to a computer). The data processing unit calculates the linear displacement ΔL of the first clamp 21 by counting pulses or directly reading the absolute angle value according to the following formula: ΔL = (θ / 360) × P. Here, θ is the measured rotation angle (in degrees) and P is the precise pitch of the screw 31 (in millimeters / revolution). The calculated displacement can be displayed on the screen in real time or recorded for subsequent performance analysis calculations.

[0052] The assembly process of the thermotropic shape memory polymer performance testing device involved in this embodiment is as follows:

[0053] First, install the core components. Securely fasten the support 33 and base 25 to designated locations within the test container 10 using bolts and other fasteners, ensuring they are securely mounted and aligned. Next, install the two slide rods 32 parallel to each other between the support 33 and base 25. Use a calibration tool to ensure the parallelism error between the two slide rods 32 is within a specified range (e.g., ±0.2 mm).

[0054] Next, assemble the transmission and guide system. Slide the slider 23 onto the two slide rods 32, with the internal threaded holes engaging the threads of the screw 31. Mount the ends of the screw 31 on the support 33 and the bearing seat of the base 25, respectively. Connect the rotating shaft of the angle encoder 41 coaxially to one end of the screw 31 and secure it. Install the crank 34 on the other end of the screw 31, which extends beyond the test container 10.

[0055] Then, the clamping assembly is installed. According to the type of sample to be tested, a suitable clamping head is selected, and the first clamping head 24 is installed on the slider 23 to form the first clamp 21; the second clamping head 26 is installed on the base 25 to form the second clamp 22.

[0056] Finally, proceed with system connection and debugging. Connect the temperature control unit, temperature sensor, and heating and cooling device, set the target temperature, and check whether the temperature control system is functioning properly and stabilizing the temperature at the set value. Connect the angle encoder 41 to the data processing unit, turn the crank 34, and check whether the displacement measurement system can accurately calculate and display the displacement.

[0057] The test process of the thermotropic shape memory polymer performance test device involved in this embodiment is as follows:

[0058] The first step is sample preparation and installation. Select and install the first and second clamping heads 24, 26 that match the shape and size of the polymer sample to be tested (e.g., film or fiber). Turn the crank 34 to adjust the position of the first clamp 21 so that the distance between the two clamps is appropriate for sample installation. Secure one end of the sample to be tested to the second clamp 22 and the other end to the first clamp 21, ensuring that the sample is securely clamped and in a naturally straight position. Record the initial distance between the two clamps at this point, denoted as L0, using the distance measuring assembly 40 or the scale on the slide bar 32.

[0059] The second step is shape programming. Close the door of the test container 10, set and start the temperature control system, raise the temperature inside the test container 10 to the programming temperature of the material (for example, 10°C to 30°C higher than its glass transition temperature Tg), and keep it warm for a period of time to make the sample temperature uniform. Then, the operator turns the crank 34 at a constant speed to drive the first clamp 21 to move away from the second clamp 22 to stretch the sample. During the stretching process, the data processing unit calculates and displays the stretched length of the sample in real time based on the signal of the angle encoder 41. When the preset programming length L is reached, the sample is stretched. load , stop rotating.

[0060] The third step is to calculate the shape fixation and fixation rate. Keep the sample length L load While the sample is still, start refrigeration and quickly lower the temperature in the test container 10 to a fixed temperature far below its glass transition temperature. After the sample temperature is completely cooled, release the clamp and remove the load. Measure the length of the sample at this time and record it as the shape fixed length L. f According to the formula R f =(L load -L0) / (L f -L0), and calculate the shape fixation rate of the sample.

[0061] Step 4: Calculation of shape recovery and recovery rate. Place the shape-fixed sample back between the clamps (without applying pre-tightening force) and close the door. Start the temperature control system again, raise the temperature inside the test container 10 to the recovery temperature of the material (for example, 5°C to 20°C higher than its glass transition temperature Tg), and keep it warm. Under the action of heat, the sample will spontaneously recover to its original shape. After the sample length no longer changes, that is, the shape recovery is completed, measure its final length and record it as the shape recovery length L r According to the formula R r =(L f -L r ) / (L f -L0), and calculate the shape recovery rate of the sample.

[0062] Through the above steps, accurate and reliable quantitative testing of the shape fixation and recovery performance of thermotropic shape memory polymers can be completed.

[0063] This embodiment relates to a device for testing the performance of thermotropic shape memory polymers (TSMRPs). The device comprises a test container, a clamping assembly, an adjustment assembly, and a distance measuring assembly. Through the interaction of these components, high-precision and high-reliability testing of TSMRPs is achieved. The test container precisely controls the internal temperature via a heating and cooling device, providing a stable and adaptable environment for polymer performance testing. Furthermore, the clamping assembly and adjustment assembly are both housed within the test container. This integrated design allows the entire process of sample stretching, deformation, and shape recovery to be completed within a stable and precise temperature field, avoiding the temperature fluctuations and operational errors introduced by the transfer of the sample between the heating and measuring equipment in the prior art. The clamping assembly conveniently secures the polymer. The clamping assembly is connected to the adjustment assembly through a screw drive, which converts rotational movement into displacement of the clamping assembly. An angle encoder is provided, and by collecting the encoder's electrical signal and combining it with the screw pitch, the real-time displacement of the fixture can be accurately calculated, thus improving the poor precision of manual displacement control in the prior art. Moreover, when conducting performance testing, it is only necessary to clamp the polymer on the clamping component and then operate the adjustment component to easily obtain the performance data of the polymer, which is more convenient to operate.

[0064] The above description and embodiments are intended to explain the scope of protection of the present invention, but do not constitute a limitation thereto. Modifications, equivalent substitutions, or other improvements to the embodiments of the present invention or portions thereof that can be obtained by a person of ordinary skill in the art through logical analysis, reasoning, or limited experimentation based on the teachings of the present invention or the above embodiments, combined with common knowledge, ordinary technical knowledge in the field, and / or prior art, should all be included within the scope of protection of the present invention.

Claims

1. A thermotropic shape memory polymer performance testing device, characterized in that: include: A test container (10) adapted to control the internal temperature by a heating and cooling device; A clamping assembly (20) is installed in the test container (10) and comprises a first clamp (21) and a second clamp (22) arranged opposite to each other along a first direction; the first clamp (21) and the second clamp (22) are used to clamp the thermotropic shape memory polymer; an adjusting assembly (30) installed in the test container (10) and comprising a screw (31) drivingly connected to the clamping assembly (20); the screw (31) being adapted to rotate relative to the test container (10) about a first axis in a first direction to drive the first clamp (21) and the second clamp (22) to move closer to or farther from each other along the first direction; and A distance measuring assembly (40) includes an angle encoder (41) coaxially connected to the screw (31), wherein the angle encoder (41) is used to measure the rotation angle of the screw (31) so as to calculate the relative displacement of the first clamp (21) and the second clamp (22) in the clamping assembly (20) based on the rotation angle and the pitch of the screw (31).

2. A thermotropic shape memory polymer performance testing device as claimed in claim 1, characterized in that: In the clamping assembly (20), the second clamp (22) is fixed relative to the test container (10); the screw (31) is transmission-connected to the first clamp (21) and is suitable for driving the first clamp (21) to move along a first direction.

3. A thermotropic shape memory polymer performance testing device as claimed in claim 2, characterized in that: The adjustment assembly (30) further includes a slide bar (32) extending along a first direction and fixed relative to the test container (10); the first clamp (21) is slidably connected to the slide bar (32) along the first direction and is engaged with the slide bar (32) in a rotationally fixed manner relative to the first axis.

4. A thermotropic shape memory polymer performance testing device as claimed in claim 3, characterized in that: There are two sliding rods (32), which are arranged on both sides of the first clamp (21) along a second direction perpendicular to the first direction.

5. A thermotropic shape memory polymer performance testing device as claimed in claim 3 or 4, characterized in that: The sliding rod (32) is provided with a scale along the first direction.

6. The thermotropic shape memory polymer performance testing device according to claim 4, characterized in that: The first clamp (21) comprises a slider (23) and a first clamping head (24) fixed to each other; the slider (23) is threadedly connected to the screw (31) along a first direction; and the first clamping head (24) is used to clamp the thermotropic shape memory polymer.

7. A thermotropic shape memory polymer performance testing device as claimed in claim 6, characterized in that: The second clamp (22) comprises a base (25) and a second clamping head (26) fixed to each other; the base (25) is fixed to the test container (10); the clamping surfaces of the first clamping head (24) and the second clamping head (26) for clamping the thermotropic shape memory polymer are made of rubber and are provided with anti-slip grooves.

8. The thermotropic shape memory polymer performance testing device according to claim 7, characterized in that: The adjustment assembly (30) further includes a support (33); the support (33) is fixed to the test container (10) and is located at the other end relative to the base (25) along a first direction; both ends of the screw rod (31) are rotatably mounted on the support (33) and the base (25); both ends of the slide rod (32) are mounted on the support (33) and the base (25); and the angle encoder (41) is mounted on the support (33) or the base (25).

9. The thermotropic shape memory polymer performance testing device according to claim 1, characterized in that: The adjustment assembly (30) further comprises a crank (34) located outside the test container (10) and coaxially connected to the screw (31), wherein the crank (34) is used to drive the screw (31) to rotate.

10. The thermotropic shape memory polymer performance testing device according to claim 1, wherein: The test container (10) is provided with a temperature sensor and a temperature control unit; the temperature sensor is suitable for detecting the internal temperature of the test container (10); the temperature control unit is suitable for controlling the temperature inside the test container (10) through the heating and cooling device according to the signal transmitted by the temperature sensor.

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