Piezoelectric nylon 11 microsphere and preparation method thereof
By mixing the molten undecanoic acid in the molten state with a non-polar polymer, a polyamide polymer is generated and washed with a non-polar solvent, the problems of unsmooth surface, uneven particle size and high impurity content are solved, and the preparation of high-quality piezoelectric nylon microspheres is achieved.
Patent Information
- Application Number
- CN202510434333.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-08
- Publication Date
- 2025-07-29
AI Technical Summary
The existing nylon microsphere preparation methods have problems such as unsmooth surface, uneven particle size, high impurity content and the need for additional treatment to obtain piezoelectric properties, resulting in increased costs and process complexity.
By mixing the molten undecanoic acid in the molten state with the non-polar polymer, a homogeneous premix is formed, and a polyamide polymer is formed under polymerization conditions, and then washed with a non-polar solvent to obtain piezoelectric nylon 11 microspheres.
The preparation of nylon microspheres with different piezoelectric properties and particle sizes is realized, which improves product purity and quality, simplifies the process flow and reduces costs.
Smart Images
Figure CN120383746A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the technical field of polymer materials, and particularly to a piezoelectric nylon 11 microsphere and a preparation method thereof. Background Art
[0002] Currently, there are many methods for preparing nylon microspheres, including pulverization and grinding method, solution precipitation method, emulsion method, air flow pulverization method, polymerization method, etc. Among them, the low-temperature pulverization and grinding method is the most widely used. However, the nylon powder prepared by this method has problems such as non-smooth surface and uneven particle size.
[0003] In related technologies, a free radical initiator is often required in the preparation process of nylon microspheres, resulting in a relatively high impurity content in the microspheres; at the same time, the prepared nylon microspheres themselves do not have piezoelectricity and often need to be treated by post-surface metal evaporation, etc., increasing the preparation cost and process complexity. Summary of the Invention
[0004] In view of the above problems, the present disclosure is proposed. The present disclosure provides a piezoelectric nylon 11 microsphere and a preparation method thereof.
[0005] According to a first aspect of the present disclosure, there is provided a method for preparing a piezoelectric nylon 11 microsphere, including:
[0006] Mixing undecylaminoundecanoic acid in a molten state with a non-polar polymer to obtain a premix;
[0007] Placing the premix under polymerization reaction conditions such that the undecylaminoundecanoic acid in the premix undergoes a polymerization reaction to form a polyamide polymer and phase separation occurs, and the polyamide polymer is dispersed in the polymerization reaction system in a spherical form;
[0008] Washing away the non-polar polymer in the polymerization reaction system with a non-polar solvent to obtain piezoelectric nylon 11 microspheres.
[0009] According to a second aspect of the present disclosure, there is provided a piezoelectric nylon 11 microsphere prepared by using the method for preparing a piezoelectric nylon 11 microsphere described in the first aspect.
[0010] In one or more of the technical solutions provided in the embodiments of the present disclosure, first, molten undecylamino undecanoic acid is mixed with a non-polar polymer. The molecular mobility of the molten undecylamino undecanoic acid is enhanced, and there is an intermolecular force (such as van der Waals force) between the molecular structure of undecylamino undecanoic acid and the non-polar polymer molecules, enabling the non-polar polymer molecules to be dispersed in undecylamino undecanoic acid, thereby forming a homogeneous premix. Then, the homogeneous premix is placed under polymerization reaction conditions. Under these conditions, the undecylamino undecanoic acid in the premix starts to undergo a polymerization reaction to generate a polyamide polymer with polar groups. However, the intermolecular force between the polar polymer and the non-polar polymer is weak, and it is difficult to stably maintain the mixed state. Therefore, as the molecular weight of the polyamide polymer continuously increases, its compatibility with the non-polar polymer gradually decreases, eventually leading to a phase separation phenomenon. During the phase separation process, affected by the surface energy of the system, the polyamide polymer tends to form a spherical morphology with the smallest surface area. This is because the spherical structure can minimize the interfacial area between the polymer and the non-polar polymer, thereby reducing the total energy of the system and making the system reach a relatively stable state. Also for this reason, finally, the polyamide polymer is dispersed in the polymerization reaction system in a spherical morphology, forming spherical nylon microspheres. Finally, the non-polar polymer in the polymerization reaction system is washed with a non-polar solvent to obtain the piezoelectric nylon 11 microspheres of the embodiments of the present disclosure.
[0011] On this basis, by using the piezoelectric nylon 11 microspheres and the preparation method of the embodiments of the present disclosure, nylon microspheres with different piezoelectric properties and different particle sizes can be prepared.
[0012] It should be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide further explanation of the claimed technology. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] By describing the embodiments of the present disclosure in more detail in conjunction with the accompanying drawings, the above and other objects, features, and advantages of the present disclosure will become more apparent. The accompanying drawings are used to provide a further understanding of the embodiments of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the present disclosure and do not constitute a limitation to the present disclosure. In the drawings, the same reference numerals generally represent the same components or steps.
[0014] Figure 1 It is a flowchart for preparing the piezoelectric nylon 11 microspheres of the embodiments of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0015] In order to make the purpose, technical solutions and advantages of the present disclosure more apparent, the following will describe in detail exemplary embodiments of the present disclosure with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments of the present disclosure, and it should be understood that the present disclosure is not limited to the exemplary embodiments described herein.
[0016] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this disclosure, "multiple" means two or more, unless otherwise clearly and specifically defined. "Several" means one or more, unless otherwise clearly and specifically defined.
[0017] In the description of the present disclosure, it should be understood that the terms "up", "down", "front", "back", "left", "right", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present disclosure.
[0018] It should be noted that, in the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this disclosure as "exemplary" or "for example" should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.
[0019] In the present invention, "at least one" refers to one or more, and "more" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b or c can represent: a, b, c, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b and c, where a, b, c can be single or multiple.
[0020] In the field of materials science, the preparation technology of nylon microspheres continues to advance, giving rise to a variety of preparation methods, including pulverization and grinding, solution precipitation, emulsion, airflow milling, and polymerization. Among these, cryogenic pulverization and grinding is widely used due to its relative ease of operation. However, the nylon powder produced by cryogenic pulverization and grinding exhibits a rough, less than smooth surface and poor particle size uniformity, which greatly limits its application in fields with stringent quality requirements for nylon microspheres.
[0021] In related preparation technologies, the preparation process of nylon microspheres often relies on free radical initiators to promote the reaction. However, the use of free radical initiators will inevitably introduce a large amount of impurities, resulting in a high impurity content in the final prepared nylon microspheres, which seriously affects the purity and performance of the product. Moreover, the nylon microspheres obtained by conventional preparation methods do not have piezoelectric properties themselves. If the piezoelectric properties of the microspheres are to be obtained, subsequent treatments such as metal evaporation are usually required on the surface of the microspheres. These additional processing steps not only significantly increase the preparation cost, but also make the entire preparation process more cumbersome and complicated, which has brought obstacles to the large-scale industrial production of nylon microspheres and their wider application and promotion.
[0022] To address the above problems, the present disclosure provides a piezoelectric nylon 11 microsphere and a preparation method thereof, which can prepare nylon microspheres with different piezoelectric properties and different particle sizes.
[0023] The method for preparing the piezoelectric nylon 11 microspheres provided in the embodiments of the present disclosure can be used to prepare the piezoelectric nylon 11 microspheres of the embodiments of the present invention. Figure 1 The preparation process of piezoelectric nylon 11 microspheres according to the embodiment of the present disclosure is shown in FIG. Figure 1 As shown, the preparation method of the piezoelectric nylon 11 microspheres of the embodiment of the present disclosure includes:
[0024] Step 101: Mixing molten undecanoic acid with a non-polar polymer to obtain a premix.
[0025] In the disclosed embodiment, molten undecanoic acid is mixed with a non-polar polymer. The molecular mobility of the molten undecanoic acid is enhanced, and intermolecular forces (such as van der Waals forces) exist between the molecular structure of the undecanoic acid and the non-polar polymer molecules, allowing the non-polar polymer molecules to be dispersed in the undecanoic acid, thereby forming a uniform premix. This ensures the uniformity and stability of the mixing, which is beneficial to the subsequent process and the improvement of product quality.
[0026] For example, molten undecanoic acid can be added to a reactor, an inert atmosphere is maintained in the reactor, and a non-polar polymer is added and mixed to obtain a premix.
[0027] In specific implementation, the weighed undecylamino undecanoic acid can be first heated and melted to make the undecylamino undecanoic acid in a molten state. Then, the molten undecylamino undecanoic acid is added to a reaction kettle. After three replacements of positive pressure and negative pressure, the reaction kettle contains 0.04 MPa of inert gas, and a non-polar polymer is added and mixed to obtain a premix. It should be understood that the inert gas can include at least one of nitrogen, argon, and helium. Maintaining an inert atmosphere in the reaction kettle can effectively exclude interfering gases such as air in the reaction kettle, create a relatively pure and stable reaction environment, and avoid adverse situations such as oxidation of undecylamino undecanoic acid or non-polar polymer during the mixing process, ensuring the smooth progress of the mixing reaction and the quality of the product.
[0028] For the above non-polar polymer, it can include at least one of polystyrene, acrylonitrile-butadiene-styrene copolymer, styrene-acrylonitrile copolymer, and polyoxymethylene.
[0029] In an achievable manner, the mass ratio of undecylamino undecanoic acid to non-polar polymer in the embodiments of the present disclosure is (95-99):(1-5). The undecylamino undecanoic acid accounts for a relatively large proportion in the polymerization reaction system, ensuring that the finally formed polyamide polymer dominates in the whole system and can fully exert the excellent properties of polyamide itself, such as high strength, high wear resistance, good heat resistance, and chemical corrosion resistance. At the same time, as the molecular weight of the polyamide polymer increases, the two can undergo phase separation at an appropriate time. And due to the small amount of non-polar polymer present, it will not interfere with the formation of a stable spherical structure of the polyamide polymer, which is beneficial to obtaining piezoelectric nylon 11 microspheres with uniform size and regular morphology. Therefore, within this mass ratio range, it not only ensures that the piezoelectric nylon 11 microspheres have good piezoelectric properties and mechanical properties, but also reduces the surface energy of the material to a certain extent by adding a small amount of non-polar polymer, making the product have better performance.
[0030] Step 102: Place the premix under polymerization reaction conditions so that the undecylamino undecanoic acid in the premix undergoes a polymerization reaction to form a polyamide polymer and phase separation occurs, and the polyamide polymer is dispersed in the polymerization reaction system in a spherical form.
[0031] Exemplarily, the above-mentioned premix is placed under polymerization reaction conditions, such that undecylaminoundecanoic acid in the premix undergoes a polymerization reaction to form a polyamide polymer. Specifically, first, the premix is heated to 225°C to 235°C, pressurized to 1.9 MPa to 2.1 MPa, maintained for 40 min to 50 min, and then reduced to atmospheric pressure. Then, the premix is continuously heated to 245°C to 255°C, evacuated to -0.07 MPa to -0.05 MPa, and the vacuum state of the reaction system is maintained, such that undecylaminoundecanoic acid in the premix undergoes a polymerization reaction to form a polyamide polymer. It should be understood that heating the premix to 225°C to 235°C, pressurizing to 1.9 MPa to 2.1 MPa and maintaining for 40 min to 50 min and then reducing to atmospheric pressure helps the components in the premix to be fully mixed and interact with each other, creating good preliminary conditions for the subsequent polymerization reaction of undecylaminoundecanoic acid and promoting the uniform progress of the reaction. Subsequently, continuously heating to 245°C to 255°C, evacuating to -0.07 MPa to -0.05 MPa and maintaining the vacuum state is beneficial to removing small molecule by-products generated during the reaction, promoting the polymerization reaction of undecylaminoundecanoic acid to proceed in the positive direction, increasing the degree of polymerization and relative molecular mass of the polyamide polymer, and thus improving the performance of the polyamide polymer.
[0032] In specific implementation, the above-mentioned homogeneous premix is placed under polymerization reaction conditions. Under these conditions, undecylaminoundecanoic acid in the premix begins to undergo a polymerization reaction to generate a polyamide polymer with polar groups. However, due to the weak intermolecular force between polar polymers and non-polar polymers, it is difficult to stably maintain the mixed state. Therefore, as the molecular weight of the polyamide polymer continuously increases, its compatibility with the non-polar polymer gradually decreases, and finally phase separation occurs. During the phase separation process, affected by the surface energy of the system, the polyamide polymer tends to form a spherical morphology with the smallest surface area. The spherical structure can minimize the interfacial area between the polymer and the non-polar polymer, thereby reducing the total energy of the system and making the system reach a relatively stable state. Also for this reason, finally the polyamide polymer is dispersed in the polymerization reaction system in a spherical morphology.
[0033] Step 103: Wash away the non-polar polymer in the polymerization reaction system with a non-polar solvent to obtain piezoelectric nylon 11 microspheres.
[0034] The above-mentioned use of a non-polar solvent to wash away the non-polar polymer in the polymerization reaction system can effectively remove the non-polar polymer originally mixed with the polyamide polymer, thereby obtaining piezoelectric nylon 11 microspheres with higher purity and avoiding the interference of the residue of the non-polar polymer on the performance of the piezoelectric nylon 11 microspheres.
[0035] The non-polar solvent may include at least one of toluene, xylene or tetrahydrofuran.
[0036] For example, the particle size of the piezoelectric nylon 11 microspheres of the embodiment of the present disclosure is 20 μm to 70 μm. It should be understood that the particle size of the piezoelectric nylon 11 microspheres of the embodiment of the present disclosure is related to the mass ratio of undecanoundecanoic acid and the non-polar polymer. As the content of the non-polar polymer increases, the particle size of the piezoelectric nylon 11 microspheres also increases. Therefore, the particle size of the piezoelectric nylon 11 microspheres can be adjusted by adjusting the mass ratio of undecanoundecanoic acid and the non-polar polymer according to the particle size requirements.
[0037] In practical applications, as the content of non-polar polymer increases, the interaction between the non-polar polymer and the polyamide polymer changes in the polymerization reaction system. Since the intermolecular force between the polar polymer (polyamide polymer) and the non-polar polymer is weak, more non-polar polymer will cause the polyamide polymer to be more affected during the phase separation process. The non-polar polymer is equivalent to providing more space and opportunities for the aggregation of polyamide polymers, making it easier for polyamide polymers to approach and aggregate with each other when forming a spherical form, thereby resulting in an increase in the particle size of the final piezoelectric nylon 11 microspheres. Moreover, microspheres with smaller particle sizes, due to their large specific surface area, can respond more quickly to external stimuli in certain applications (such as high-sensitivity piezoelectric sensors) and exhibit good piezoelectric properties.
[0038] In one example, the piezoelectric constant of the piezoelectric nylon 11 microspheres of the disclosed embodiment is 2 pC / N to 20 pC / N. The piezoelectric constant of the piezoelectric nylon 11 microspheres of the disclosed embodiment is related to the mass ratio of undecanoylundecanoic acid to the non-polar polymer. As the content of the non-polar polymer increases, the piezoelectric constant of the piezoelectric nylon 11 microspheres decreases. Therefore, the piezoelectric constant of the piezoelectric nylon 11 microspheres can be adjusted by adjusting the mass ratio of undecanoylundecanoic acid to the non-polar polymer according to the piezoelectric constant requirement.
[0039] In summary, the piezoelectric nylon 11 microspheres and preparation method of the embodiments of the present disclosure are as follows: first, molten undecanoic acid with enhanced molecular activity is mixed with a non-polar polymer to form a uniform premix by relying on intermolecular forces (such as van der Waals forces); then, the premix is placed under polymerization reaction conditions, and undecanoic acid is polymerized to form a polymer with polar groups. Since the molecular forces between the polar and non-polar polymers are weak, phase separation occurs as the molecular weight of the polyamide polymer increases. Under the action of the surface energy of the system, the polyamide polymer forms spheres and is dispersed in the system to obtain spherical nylon microspheres; finally, the non-polar polymer in the system is washed away with a non-polar solvent to obtain piezoelectric nylon 11 microspheres.
[0040] To verify the effect of the piezoelectric nylon 11 microspheres provided in the embodiments of the present invention, the embodiments of the present invention are proved by comparing with the comparative examples.
[0041] Example 1
[0042] Embodiment 1 of the present disclosure provides a preparation method of piezoelectric nylon 11 microspheres, which specifically includes the following steps:
[0043] In the first step, undecylaminoundecanoic acid and polystyrene are weighed, and the mass ratio of undecylaminoundecanoic acid to polystyrene is 99:1.
[0044] In the second step, undecylaminoundecanoic acid is melted and then added to a high-temperature and high-pressure reaction kettle. After three positive and negative pressure replacements, the reaction kettle contains 0.04 MPa of nitrogen, and the weighed polystyrene is added. The composition is heated to a temperature of 230 °C and a pressure of 2.0 MPa; after 40 minutes, it is reduced to atmospheric pressure, and at the same time, the temperature is raised to 250 °C, and then evacuated. The temperature is maintained at 250 °C, and the vacuum is pumped to -0.06 MPa to form a composition of polyamide polymer (nylon 11) and polystyrene), and nylon 11 is dispersed in the polymerization reaction system in a spherical form.
[0045] In the third step, polystyrene is washed off with toluene solvent, and the remaining piezoelectric nylon 11 microspheres are obtained.
[0046] Example 2
[0047] Embodiment 2 of the present disclosure provides a preparation method of piezoelectric nylon 11 microspheres, which specifically includes the following steps:
[0048] In the first step, undecylaminoundecanoic acid and polystyrene are weighed, and the mass ratio of undecylaminoundecanoic acid to polystyrene is 98:2.
[0049] In the second step, undecylaminoundecanoic acid is melted and then added to a high-temperature and high-pressure reaction kettle. After three positive and negative pressure replacements, the reaction kettle contains 0.04 MPa of nitrogen, and the weighed polystyrene is added. The composition is heated to a temperature of 230 °C and a pressure of 2.0 MPa; after 40 minutes, it is reduced to atmospheric pressure, and at the same time, the temperature is raised to 250 °C, and then evacuated. The temperature is maintained at 250 °C, and the vacuum is pumped to -0.06 MPa to form a composition of polyamide polymer (nylon 11) and polystyrene), and nylon 11 is dispersed in the polymerization reaction system in a spherical form.
[0050] In the third step, polystyrene is washed off with toluene solvent, and the remaining piezoelectric nylon 11 microspheres are obtained.
[0051] Example 3
[0052] Embodiment 3 of the present disclosure provides a preparation method of piezoelectric nylon 11 microspheres, which specifically includes the following steps:
[0053] In the first step, undecanoyl undecanoic acid and polystyrene are weighed, and the mass ratio of undecanoyl undecanoic acid to polystyrene is 97:3.
[0054] In the second step, undecanoic acid is melted and added to a high-temperature, high-pressure reactor. After three positive and negative pressure changes, the reactor is filled with 0.04 MPa of nitrogen. The weighed polystyrene is then added. The mixture is heated to 230°C and 2.0 MPa. Over 40 minutes, the pressure is lowered to atmospheric pressure, while the temperature is simultaneously raised to 250°C and vacuumed. Maintaining the temperature at 250°C, the pressure is then reduced to -0.06 MPa, forming a polyamide polymer (nylon 11) and polystyrene composite. The nylon 11 is dispersed in the polymerization reaction system in a spherical form.
[0055] In the third step, the polystyrene is washed away with toluene solvent, leaving the remaining piezoelectric nylon 11 microspheres.
[0056] Example 4
[0057] The fourth embodiment of the present disclosure provides a method for preparing piezoelectric nylon 11 microspheres, which specifically includes the following steps:
[0058] In the first step, undecanoyl undecanoic acid and polystyrene are weighed, and the mass ratio of undecanoyl undecanoic acid to polystyrene is 96:4.
[0059] In the second step, undecanoic acid is melted and added to a high-temperature, high-pressure reactor. After three positive and negative pressure changes, the reactor is filled with 0.04 MPa of nitrogen. The weighed polystyrene is then added. The mixture is heated to 230°C and 2.0 MPa. Over 40 minutes, the pressure is lowered to atmospheric pressure, while the temperature is simultaneously raised to 250°C and vacuumed. Maintaining the temperature at 250°C, the pressure is then reduced to -0.06 MPa, forming a polyamide polymer (nylon 11) and polystyrene composite. The nylon 11 is dispersed in the polymerization reaction system in a spherical form.
[0060] In the third step, the polystyrene is washed away with toluene solvent, leaving the remaining piezoelectric nylon 11 microspheres.
[0061] Example 5
[0062] The fifth embodiment of the present disclosure provides a method for preparing piezoelectric nylon 11 microspheres, which specifically includes the following steps:
[0063] In the first step, undecanoyl undecanoic acid and polystyrene are weighed, and the mass ratio of undecanoyl undecanoic acid to polystyrene is 95:5.
[0064] In the second step, undecanoic acid is melted and added to a high-temperature, high-pressure reactor. After three positive and negative pressure changes, the reactor is filled with 0.04 MPa of nitrogen. The weighed polystyrene is then added. The mixture is heated to 230°C and 2.0 MPa. Over 40 minutes, the pressure is lowered to atmospheric pressure, while the temperature is simultaneously raised to 250°C and vacuumed. Maintaining the temperature at 250°C, the pressure is then reduced to -0.06 MPa, forming a polyamide polymer (nylon 11) and polystyrene composite. The nylon 11 is dispersed in the polymerization reaction system in a spherical form.
[0065] In the third step, the polystyrene is washed away with toluene solvent, leaving the remaining piezoelectric nylon 11 microspheres.
[0066] Comparative Example 1
[0067] Comparative Example 1 of the present disclosure provides a method for preparing nylon, which specifically comprises the following steps:
[0068] In the first step, undecanoic acid is weighed.
[0069] In the second step, undecanoic acid is melted and added to a high-temperature, high-pressure reactor. After three positive and negative pressure changes, the reactor is filled with 0.04 MPa of nitrogen. The reactor is heated to 230°C and 2.0 MPa. Over 40 minutes, the pressure is lowered to atmospheric pressure, while the temperature is simultaneously raised to 250°C and vacuumed. Maintaining the temperature at 250°C, the pressure is evacuated to -0.06 MPa, forming a polyamide polymer (nylon 11).
[0070] Comparative Example 2
[0071] Comparative Example 2 of the present disclosure provides a method for preparing piezoelectric nylon 11 microspheres, which specifically includes the following steps:
[0072] In the first step, undecanoyl undecanoic acid and polystyrene are weighed, and the mass ratio of undecanoyl undecanoic acid to polystyrene is 90:10.
[0073] In the second step, undecanoic acid is melted and added to a high-temperature, high-pressure reactor. After three positive and negative pressure changes, the reactor is filled with 0.04 MPa of nitrogen. The weighed polystyrene is then added. The mixture is heated to 230°C and 2.0 MPa. Over 40 minutes, the pressure is lowered to atmospheric pressure, while the temperature is simultaneously raised to 250°C and vacuumed. Maintaining the temperature at 250°C, the pressure is then reduced to -0.06 MPa, forming a polyamide polymer (nylon 11) and polystyrene composite. The nylon 11 is dispersed in the polymerization reaction system in a spherical form.
[0074] In the third step, the polystyrene is washed away with toluene solvent, leaving the remaining piezoelectric nylon 11 microspheres.
[0075] Comparative Example 3
[0076] Comparative Example 3 of the present disclosure provides a method for preparing piezoelectric nylon 11 microspheres, which specifically includes the following steps:
[0077] First step, weigh undecylaminoundecanoic acid and polystyrene, and the mass ratio of undecylaminoundecanoic acid to polystyrene is 10:90.
[0078] Second step, melt undecylaminoundecanoic acid and add it to a high-temperature and high-pressure reaction kettle. After three positive and negative pressure replacements, the reaction kettle contains 0.04 MPa of nitrogen, and the weighed polystyrene is added. Heat the composition to a temperature of 230 °C and a pressure of 2.0 MPa; after 40 minutes, reduce the pressure to atmospheric pressure, and at the same time raise the temperature to 250 °C, evacuate the air, keep the temperature at 250 °C, and evacuate the air to -0.06 MPa to form a composition of polyamide polymer (nylon 11) and polystyrene. Nylon 11 cannot be dispersed in the polymerization reaction system in a spherical form.
[0079] Third step, wash off polystyrene with toluene solvent to obtain nylon 11.
[0080] Measurement of piezoelectric constant (d 33 ): It is measured by using the BOLYBO PEAI1000 high-precision piezoelectric analyzer.
[0081] Table 1 shows the relevant data of Examples 1 to 5 and Comparative Examples 1 to 3 of the present disclosure, as follows:
[0082] Table 1
[0083]
[0084]
[0085] As can be seen from the above Examples 1 to 5 and Comparative Examples 1 to 3, as the proportion of polystyrene in the composition gradually increases (the mass ratio changes from 99:1 to 95:5), the particle size of the microspheres shows a gradually increasing trend, increasing from 20 to 70; at the same time, the piezoelectric constant shows an obvious downward trend, decreasing from 20 to 2. This indicates that within a certain range, the increase in the content of polystyrene will promote the increase in the particle size of the microspheres, but will lead to a decrease in the piezoelectric constant. The pure nylon 11 prepared in Comparative Example 1 without adding polystyrene did not show the microsphere morphology and had no piezoelectric properties. Therefore, the addition of polystyrene in the embodiments of the present disclosure is very important for the formation of piezoelectric nylon 11 microspheres. The mass ratio of Comparative Example 2 is 90:10, and the prepared microsphere particle size is significantly increased to 200, and the piezoelectric constant is greatly decreased to 1, further indicating that a higher proportion of polystyrene will cause the microsphere particle size to increase sharply and the piezoelectric performance to decrease significantly. The mass ratio of Comparative Example 3 is 10:90, and microspheres cannot be formed. Therefore, by reasonably controlling the mass ratio of undecylamino undecanoic acid to the non-polar polymer, the particle size and piezoelectric performance of the piezoelectric nylon 11 microspheres can be effectively regulated to meet different application requirements.
[0086] The basic principles of the present disclosure have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, advantages, effects, etc. mentioned in the present disclosure are only examples and not limitations, and it cannot be considered that these advantages, advantages, effects, etc. are essential for each embodiment of the present disclosure. In addition, the above-disclosed specific details are only for the purposes of illustration and easy understanding, rather than limitations. The above details do not limit the present disclosure to necessarily adopt the above specific details to implement.
[0087] The block diagrams of the devices, apparatuses, equipment, and systems involved in the present disclosure are only illustrative examples and do not intend to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open-ended words, meaning "including but not limited to", and can be used interchangeably with each other. The words "or" and "and" used herein refer to the word "and / or" and can be used interchangeably with each other, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to" and can be used interchangeably with each other.
[0088] In addition, as used herein, the "or" used in the enumeration of items starting with "at least one" indicates a separate enumeration, so that for example, the enumeration of "at least one of A, B, or C" means A or B or C, or AB or AC or BC, or ABC (that is, A and B and C). In addition, the term "exemplary" does not mean that the described examples are preferred or better than other examples.
[0089] It should also be noted that in the systems and methods of the present disclosure, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent solutions of the present disclosure.
[0090] Various changes, substitutions, and alterations to the technologies described herein can be made without departing from the teachings defined by the appended claims. In addition, the scope of the claims of the present disclosure is not limited to the specific aspects of the processes, machines, manufactures, compositions of events, means, methods, and acts described above. Current or later-developed processes, machines, manufactures, compositions of events, means, methods, or acts that perform substantially the same function or achieve substantially the same result as the corresponding aspects described herein can be utilized. Accordingly, the appended claims include such processes, machines, manufactures, compositions of events, means, methods, or acts within their scope.
[0091] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the present disclosure. Therefore, the present disclosure is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.
[0092] The above description has been presented for purposes of illustration and description. In addition, this description is not intended to limit the embodiments of the present disclosure to the forms disclosed herein. Although several example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and subcombinations thereof.
Claims
1. A preparation method of piezoelectric nylon 11 microspheres, characterized in that, Comprising: Mixing undecylaminoundecanoic acid in a molten state with a non-polar polymer to obtain a premix; Placing the premix under polymerization reaction conditions such that the undecylaminoundecanoic acid in the premix undergoes a polymerization reaction to form a polyamide polymer and phase separation occurs, and the polyamide polymer is dispersed in the polymerization reaction system in a spherical form; Washing away the non-polar polymer in the polymerization reaction system with a non-polar solvent to obtain piezoelectric nylon 11 microspheres.
2. The preparation method of the piezoelectric nylon 11 microspheres according to claim 1, characterized in that, The mixing of undecylaminoundecanoic acid in a molten state with a non-polar polymer to obtain a premix comprises: Adding undecylaminoundecanoic acid in a molten state to a reaction kettle, maintaining an inert atmosphere in the reaction kettle, and adding a non-polar polymer for mixing to obtain a premix.
3. The preparation method of the piezoelectric nylon 11 microspheres according to claim 1, wherein Placing the premix under polymerization reaction conditions such that the undecylaminoundecanoic acid in the premix undergoes a polymerization reaction to form a polyamide polymer comprises: Heating the premix to 225°C to 235°C, pressurizing to 1.9 MPa to 2.1 MPa, maintaining for 40 min to 50 min and then reducing to atmospheric pressure; Continuing to heat the premix to 245°C to 255°C, evacuating to -0.07 MPa to -0.05 MPa, maintaining the vacuum state of the reaction system such that the undecylaminoundecanoic acid in the premix undergoes a polymerization reaction to form a polyamide polymer.
4. The preparation method of the piezoelectric nylon 11 microspheres according to claim 1, wherein, The mass ratio of the undecylaminoundecanoic acid to the non-polar polymer is (95 - 99):(1 - 5).
5. The preparation method of the piezoelectric nylon 11 microspheres according to claim 1, characterized in that, The non-polar polymer is selected from at least one of polystyrene, acrylonitrile-butadiene-styrene copolymer, styrene-acrylonitrile copolymer, and polyoxymethylene.
6. The preparation method of the piezoelectric nylon 11 microspheres according to claim 1, characterized in that, The non-polar solvent is selected from at least one of toluene, xylene, or tetrahydrofuran.
7. The preparation method of the piezoelectric nylon 11 microspheres according to any one of claims 1 to 6, characterized in that, The particle size of the piezoelectric nylon 11 microspheres is 20 μm to 70 μm.
8. The preparation method of the piezoelectric nylon 11 microspheres according to any one of claims 1 to 6, characterized in that, The piezoelectric constant of the piezoelectric nylon 11 microspheres is 2 pC / N to 20 pC / N.
9. A piezoelectric nylon 11 microsphere, characterized in that, Prepared by the preparation method of the piezoelectric nylon 11 microspheres according to any one of claims 1 to 8.