Acoustic matching material and preparation method thereof, ultrasonic transducer, ultrasonic probe and ultrasonic imaging device

Abstract

The invention relates to the technical field of acoustic materials, in particular to an acoustic matching material and a preparation method thereof, an ultrasonic transducer, an ultrasonic probe and an ultrasonic imaging device. The acoustic matching material comprises a polystyrene telechelic polymer with a chemical structure shown as a formula I: # imgabs0 #, wherein n1 and n2 are positive integers; x comprises at least one of halogen atoms, hydroxyl, carboxyl, amino, propargyl, methoxyl, azido, pyrimidyl and malonate. The sound matching material provided by the invention not only has a good low sound attenuation characteristic, but also has a good adhesive property, can improve the stability and reliability of sound transmission, and has a good application prospect in medical ultrasonic probes.

Description

Technical Field

[0001] The present application belongs to the technical field of acoustic materials, and in particular relates to an acoustic matching material and a preparation method thereof, an ultrasonic transducer, an ultrasonic probe and an ultrasonic imaging device. Background Art

[0002] Medical ultrasound technology is a diagnostic technology that uses the characteristics of high-frequency sound waves propagating and reflecting in the internal tissues of the human body to obtain images. With its non-invasive and real-time characteristics, it has become an important branch of modern medical imaging diagnosis. Its working principle is based on the Doppler effect and echolocation. It transmits ultrasound waves of a specific frequency into the body, uses the difference in the reflection of sound waves by different tissues, receives them through the ultrasound probe and converts them into electrical signals, and finally forms an image that can be diagnosed. As the core of the ultrasound equipment, the medical ultrasound probe is responsible for the transmission and reception of ultrasound waves. The piezoelectric crystal built into the ultrasound probe can vibrate under the action of the electric field to generate ultrasound waves, and generate electrical signals when receiving echoes. The application of ultrasound probes runs through the entire medical diagnosis process, from routine physical examinations to navigation of complex surgeries. Its high-precision imaging capabilities provide doctors with intuitive and real-time anatomical information.

[0003] In order to achieve the best imaging effect of the ultrasound probe, the ultrasonic waves generated by the vibration of the piezoelectric unit need to achieve acoustic matching with the human body, so a matching layer is required between the piezoelectric unit and the human body to adjust the acoustic matching degree. The acoustic matching layer of a medical ultrasound probe is a key medium. The acoustic matching layer is usually composed of a material with a specific acoustic impedance, which is between the acoustic impedance of the piezoelectric crystal and the human tissue. The acoustic matching layer not only enhances the quality of ultrasound images, but also improves the sensitivity and resolution of the probe. It helps reduce artifacts and improve the accuracy of imaging, thereby providing doctors with clearer diagnostic information.

[0004] Common acoustic matching layer materials include ceramic materials and polymers such as epoxy resins. These materials are widely used to manufacture the acoustic matching layer of medical ultrasound probes due to their good acoustic properties and easy processing properties. The acoustic impedance of a material is proportional to the density of the material and the speed of ultrasound propagating in the material, so adding fillers of different specific gravity can obtain acoustic materials with different impedances. Epoxy resin can be ring-opening polymerized with a multifunctional curing agent under corresponding reaction conditions, and can also be mixed with different fillers in proportion to obtain epoxy resin composite materials, so it is often used as an acoustic matching layer matrix material. Polystyrene (PS) is a thermoplastic polymer made from styrene monomers by polymerization.

[0005] The epoxy resin currently used in the acoustic matching layer has a high acoustic attenuation coefficient. However, polystyrene, which has low acoustic attenuation characteristics, has poor adhesion and low reliability as a matching layer material. Summary of the invention

[0006] The purpose of this application is to provide an acoustic matching material and a preparation method thereof, an ultrasonic transducer, an ultrasonic probe and an ultrasonic imaging device, aiming to solve the technical problem of how to provide an acoustic matching material having both low acoustic attenuation characteristics and good adhesion.

[0007] In order to achieve the above application purpose, the technical solution adopted in this application is as follows:

[0008] In a first aspect, the present application provides an acoustic matching material, wherein the acoustic matching material comprises a polystyrene telechelic polymer having a chemical structure as shown in Formula I:

[0009]

[0010] Wherein, n1 and n2 are positive integers; X includes at least one of a halogen atom, a hydroxyl group, a carboxyl group, an amino group, a propargyl group, a methoxy group, an azido group, a pyrimidinyl group, and a malonate group.

[0011] In some embodiments, n1 and n2 are the same, or n1=n2=100-400;

[0012] And / or, X is a carboxyl group or an amino group.

[0013] In some embodiments, the acoustic impedance of the acoustic matching material is in the range of 2.5 to 2.9 MRayl, and the acoustic attenuation at 20 MHz is 11 to 13 dB / cm; and / or the adhesive force of the acoustic matching material is 0.36 to 0.66 KN / m.

[0014] In a second aspect, the present application provides a method for preparing an acoustic matching material, comprising:

[0015] The styrene monomer is polymerized in an initiation system containing p-dicumyl chloride, and then 1,3-butadiene is added for end-capping to generate a polystyrene telechelic polymer having a chemical structure as shown in Formula Ia, thereby obtaining an acoustic matching material;

[0016]

[0017] Wherein, n1 and n2 are positive integers.

[0018] In some embodiments, the chlorine atoms in the polystyrene telechelic polymer represented by Formula Ia are substituted so that the chlorine atoms in the chemical structure of Formula Ia are replaced by X; wherein X includes at least one of a non-chlorine halogen atom, a hydroxyl group, a carboxyl group, an amino group, a propargyl group, a methoxy group, an azido group, a pyrimidine group, and a malonate group.

[0019] In some embodiments, X is a bromine atom, and the chlorine atom is substituted by: reacting the polystyrene telechelic polymer represented by Formula Ia with lithium bromide at 70 to 90° C.;

[0020] Alternatively, X is a hydroxyl group, and the chlorine atom substitution treatment comprises: reacting the polystyrene telechelic polymer represented by formula Ia with lithium bromide at 70 to 90° C., and then reacting with a quaternary ammonium base at 20 to 30° C.;

[0021] Alternatively, X is an amino group, and the chlorine atom substitution treatment comprises: reacting the polystyrene telechelic polymer represented by formula Ia with lithium bromide at 70 to 90° C., and then reacting with potassium phthalimide and hydrazine hydrate in sequence at 60 to 80° C.;

[0022] Alternatively, X is a malonate group, and the chlorine atom substitution treatment comprises: reacting the polystyrene telechelic polymer represented by formula Ia with lithium bromide at 70 to 90° C., and then reacting with malonate at 50 to 70° C.;

[0023] Alternatively, X is a carboxyl group, and the chlorine atom substitution treatment comprises: reacting the polystyrene telechelic polymer represented by formula Ia with lithium bromide at 70-90° C., and then reacting with malonate and alkali metal hydroxide in sequence at 50-70° C.

[0024] In some embodiments, the initiation system in the polymerization reaction further comprises a co-initiator, and the co-initiator comprises at least one of TiCl4, BCl3, and AlCl3;

[0025] And / or, the polymerization reaction conditions include: temperature of -80 to -60°C, time of 10 to 20 min;

[0026] and / or, the molar ratio of the 1,3-butadiene to the styrene monomer in the end-capping treatment is 1:(100-400);

[0027] And / or, the end-capping treatment conditions include: temperature of -80 to -60°C and time of 2 to 8 minutes.

[0028] In a third aspect, the present application provides an ultrasonic transducer, comprising the acoustic matching material provided in the first aspect of the present application and / or the acoustic matching material prepared by the preparation method provided in the second aspect of the present application.

[0029] In a fourth aspect, the present application provides an ultrasonic probe, comprising the ultrasonic transducer provided in the third aspect of the present application; or comprising a piezoelectric crystal and an acoustic matching layer, wherein the acoustic matching layer comprises the acoustic matching material provided in the first aspect of the present application and / or the acoustic matching material prepared by the preparation method provided in the second aspect of the present application.

[0030] In a fifth aspect, the present application provides an ultrasonic imaging device, comprising the ultrasonic transducer provided in the third aspect of the present application or the ultrasonic probe provided in the fourth aspect of the present application.

[0031] The acoustic matching material provided in the first aspect of the present application includes a polystyrene telechelic polymer having a chemical structure as shown in Formula I. The polystyrene telechelic polymer has a polystyrene main structure and is functionalized with an allyl group containing X at the end. Such a polystyrene telechelic polymer not only has excellent low acoustic attenuation characteristics, but also has excellent bonding properties. As an acoustic matching material, it can greatly improve the stability and reliability of the sound transmission of the material and has good application prospects in medical devices such as medical ultrasound probes.

[0032] The second aspect of the present application provides a preparation method, which involves polymerizing styrene monomer in an initiator system containing p-dicumyl chloride, and then adding 1,3-butadiene for end-capping, thereby obtaining an acoustic matching material having both low acoustic attenuation characteristics and high bonding properties; the preparation method is simple in process and easy to synthesize, and the obtained acoustic matching material has good application.

[0033] The ultrasonic transducer provided in the third aspect of the present application includes the acoustic matching material provided in the first aspect of the present application and / or the acoustic matching material prepared by the preparation method provided in the second aspect of the present application. Based on the characteristics of the acoustic matching material used, which has both low acoustic attenuation and high bonding performance, the ultrasonic transducer has excellent stability and reliability in terms of acoustic-to-electric conversion and electroacoustic conversion performance.

[0034] The ultrasonic probe provided in the fourth aspect of the present application uses the acoustic matching material provided in the first aspect of the present application and / or the acoustic matching material prepared by the preparation method provided in the second aspect of the present application. Since the acoustic matching material used has the characteristics of low acoustic attenuation and high bonding performance, such an ultrasonic probe has good reliability for ultrasonic signal detection.

[0035] The ultrasonic imaging device provided in the fifth aspect of the present application includes the ultrasonic transducer provided in the third aspect of the present application or the ultrasonic probe provided in the fourth aspect of the present application, and therefore has good reliability in medical imaging diagnosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 It is a schematic diagram of some preparation methods of the acoustic matching material provided in the embodiments of the present application. DETAILED DESCRIPTION

[0038] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0039] In this application, the term "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0040] In the present application, "at least one" means one or more, "more than one" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items.

[0041] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0042] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0043] The weight of the relevant components mentioned in the embodiment description of the present application can not only refer to the specific content of each component, but also represent the proportional relationship between the weights of the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the embodiment description of the present application, it is within the scope disclosed in the embodiment description of the present application. Specifically, the mass described in the embodiment description of the present application can be a mass unit known in the chemical industry such as μg, mg, g, kg, etc.

[0044] The terms "first" and "second" are used only for descriptive purposes to distinguish objects such as substances from each other, and should not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. For example, without departing from the scope of the embodiments of the present application, the first XX may also be referred to as the second XX, and similarly, the second XX may also be referred to as the first XX. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0045] An ultrasonic transducer is an "electric-to-acoustic" signal converter that converts electrical signals into ultrasonic waves, and can convert the ultrasonic reverse signal received from the object being tested into an electrical signal. It is widely used in the field of medical ultrasonic diagnosis.

[0046] Ultrasonic probe, also known as ultrasonic probe, is a device that transmits and receives ultrasonic waves during ultrasonic testing. The probe used in ultrasonic testing is a transducer that uses the piezoelectric effect of the material to achieve the conversion of electrical energy and acoustic energy. The key component in the probe is the chip, which is a single crystal or polycrystalline thin film with piezoelectric effect. Its function is to convert electrical energy and acoustic energy into each other. Medical ultrasonic probes have built-in piezoelectric crystals that can vibrate under the action of an electric field to generate ultrasonic waves, and generate electrical signals when receiving echoes.

[0047] Acoustic matching materials refer to dielectric materials with a certain acoustic impedance that can adjust the acoustic matching degree. They can be used in the acoustic matching layer of ultrasonic transducers or ultrasonic probes. Whether it is an ultrasonic transducer or an ultrasonic probe, it requires acoustic matching materials to adjust the acoustic matching degree.

[0048] The advantages of epoxy resin are that it can be cast and is a high-quality adhesive. It can be prepared into composite materials with many fillers and has a wide range of applications in the field of ultrasound probes. The density of epoxy resin is usually 1.1 to 1.25 g / cm 3 In the range, the acoustic impedance is about 3.0-3.6 MRayl, and the acoustic attenuation at 20 MHz is 120 dB / cm. Therefore, the acoustic attenuation coefficient is relatively large. Generally, it is necessary to modify the epoxy resin to obtain an epoxy resin composite material with good acoustic performance.

[0049] Polystyrene can be obtained through free radical polymerization, cationic polymerization, anionic polymerization and other methods of styrene monomer. It has good mechanical properties and is easy to process. It is mostly used in packaging materials, shell materials and disposable medical supplies. The density of polystyrene is 1.05g / cm 3 , with low acoustic attenuation characteristics, acoustic impedance is 2.43MRayl, and the acoustic attenuation at 20MHz is only 12dB / cm, which is much smaller than the 120dB / cm acoustic attenuation of epoxy resin. However, due to the difficult bonding characteristics of polystyrene, its application in the field of matching layer materials is limited.

[0050] Based on this, the embodiment of the present application modifies polystyrene to form a polystyrene telechelic polymer with styrene as the basic unit, copolymerized with other structural units and having functionalized groups at the end, and uses it as an acoustic matching material. It not only has excellent low acoustic attenuation characteristics, but also has the characteristics of high adhesion, and can effectively replace epoxy resin as an acoustic matching material. The specific technical solution is as follows.

[0051] In a first aspect, an embodiment of the present application provides an acoustic matching material. Specifically, the acoustic matching material of the embodiment of the present application includes a polystyrene telechelic polymer having a chemical structure as shown in Formula I:

[0052]

[0053] Wherein, n1 and n2 are positive integers; X includes at least one of a halogen atom, a hydroxyl group, a carboxyl group, an amino group, a propargyl group, a methoxy group, an azido group, a pyrimidinyl group, and a malonic ester.

[0054] In the embodiment of the present application, the polystyrene telechelic polymer shown in Formula I has a polystyrene main structure, and at the same time has an X-containing allyl functionalized group at the end, that is, a telechelic polystyrene with various functionalizations at both ends. Such a polystyrene telechelic polymer not only has good low sound attenuation characteristics, but also has good bonding properties. Therefore, the polystyrene telechelic polymer of the embodiment of the present application is used as an acoustic matching material, which can greatly improve the stability and reliability of the sound transmission of the material, and has a good application prospect in medical devices such as medical ultrasound probes, and can replace epoxy resin for the preparation of acoustic matching layer sound transmission materials.

[0055] In some embodiments, n1 and n2 may be the same or different. Specifically, n1 and n2 are the same.

[0056] In some embodiments, n1=n2=100-400. For example, n1=n2=100-400 may be 100, 120, 150, 200, 220, 250, 280, 300, 350, 400, etc.

[0057] In some embodiments, X is on the terminal allyl group of polystyrene, and X may include at least one of a halogen atom, a hydroxyl group, a carboxyl group, an amino group, a propargyl group, a methoxy group, an azido group, a pyrimidinyl group, and a malonate group. Among them, the halogen atom may be fluorine, chlorine, bromine, etc.; the malonate group may be di-2-malonic acid C 1-3 The alkyl ester group, i.e., the carbonyl carbon of malonic acid in the malonic ester group, is connected to the allyl group at the end of the polystyrene telechelic polymer, specifically, it can be dimethyl 2-malonate, diethyl 2-malonate, or dipropyl 2-malonate. The above X group at the end can make the polystyrene telechelic polymer have good adhesion.

[0058] Furthermore, X is a carboxyl group or an amino group. The polystyrene telechelic polymer corresponding to the two groups has better adhesion when used as an acoustic matching material.

[0059] Further, the acoustic matching material provided in the embodiment of the present application is a polystyrene telechelic polymer with a high molecular weight and a narrow molecular weight distribution obtained by cationic polymerization. For the polystyrene telechelic polymer shown in Formula I, the number average molecular weight can be 20000 to 80000. Specifically, it can be 20000, 25000, 30000, 35000, 40000, 45000, 50000, 60000, 70000, 80000, etc., and the polystyrene telechelic polymer with the above number average molecular weight range can be formed according to the type of X group, the value range of n1 and n2.

[0060] The acoustic matching material provided in the embodiment of the present application has a polystyrene telechelic polymer whose acoustic impedance range can be 2.5 to 2.9 MRayl, and the acoustic attenuation at 20 MHz is only 11 to 13 dB / cm; at the same time, the anti-peel bonding strength can be increased from 0.03 KN / m of polystyrene to 0.36 to 0.66 KN / m, with good adhesion, and the acoustic attenuation coefficient is significantly lower than that of epoxy resin.

[0061] The bonding strength test of the acoustic matching material is to use the acoustic matching material and the aluminum plate as the substrate, use epoxy adhesive to bond and cure, and then perform a 90° peel test to test the bonding strength.

[0062] In a second aspect, an embodiment of the present application provides a method for preparing an acoustic matching material. The method for preparing an acoustic matching material in an embodiment of the present application comprises the following steps:

[0063] The styrene monomer is polymerized in an initiation system containing p-dicumyl chloride, and then 1,3-butadiene is added for end-capping to generate a polystyrene telechelic polymer having a chemical structure as shown in Formula Ia, thereby obtaining an acoustic matching material;

[0064]

[0065] Wherein, n1 and n2 are positive integers.

[0066] In the embodiment of the present application, styrene monomer is polymerized in an initiation system containing p-dicumyl chloride, and then 1,3-butadiene is added for end-capping treatment, so that an acoustic matching material with low acoustic attenuation characteristics and high bonding performance can be obtained; the preparation method is simple in process and easy to synthesize, and the obtained acoustic matching material has good application.

[0067] Among them, the initiation system containing para-dicumyl chloride (DCC) is a cationic double-end initiation system, and styrene monomer polymerization can be carried out at both ends. In the later stage of the polymerization reaction, 1,3-butadiene is added and copolymerized at the end of the polystyrene. After the reaction is completed, the polystyrene telechelic polymer shown in Formula Ia is a double-end allyl chloride functionalized polystyrene telechelic polymer (DPSCl). After that, a series of functionalization reactions can be performed on DPSCl to obtain polystyrene telechelic polymers including but not limited to X as a non-chlorine halogen atom (such as bromine), hydroxyl, carboxyl, amino, propargyl, methoxy, azido, pyrimidine, malonate, etc. as telechelics, and obtain the various acoustic matching layer materials provided in the first aspect of the corresponding embodiments of the present application. Comparing the epoxy resin-based and polystyrene matching layer materials, the polystyrene telechelic polymer prepared in the embodiments of the present application has good molding processability, good adhesion, good mechanical properties and low acoustic attenuation characteristics as an acoustic matching material, and can be processed into a matching layer film, which can effectively replace epoxy resin in the matching layer material of medical ultrasound probes.

[0068] In some embodiments, the initiator system containing p-dicumyl chloride includes, in addition to p-dicumyl chloride, a co-initiator, wherein the co-initiator includes at least one of TiCl4, BCl3, and AlCl3; this can better promote the cationic double-end initiated polymerization of styrene monomers. In the embodiments of the present application, the initiator system uses a combination of p-dicumyl chloride and TiCl4.

[0069] In some embodiments, the polymerization reaction conditions of styrene monomer under the above initiation system conditions include: temperature of -80 to -60°C and time of 10 to 20 minutes; under these conditions, styrene monomer can be fully polymerized.

[0070] In some embodiments, after the styrene monomer is polymerized under the above initiation system conditions, 1,3-butadiene is added for end-capping treatment, and the end-capping treatment is end-capping polymerization with 1,3-butadiene. In the end-capping treatment, the amount of 1,3-butadiene added is added at a molar ratio of 1,3-butadiene to styrene monomer of 1: (100-400), so that both ends can be allyl chloride functionalized.

[0071] In some embodiments, the conditions for adding 1,3-butadiene for end-capping treatment include: temperature of -80 to -60°C and time of 2 to 8 minutes. Under these conditions, both ends can be fully functionalized into allyl chloride.

[0072] Furthermore, after the end-capping treatment, ethanol can be added to terminate the polymerization.

[0073] In some embodiments, after the synthesis of the allyl chloride-functionalized polystyrene telechelic polymer (DPSCl) is completed, the chlorine atoms in the polystyrene telechelic polymer represented by Formula Ia can be further substituted so that the chlorine atoms in the chemical structure of Formula Ia are replaced by X; wherein X includes at least one of a non-chlorine halogen atom, a hydroxyl group, a carboxyl group, an amino group, a propargyl group, a methoxy group, an azido group, a pyrimidine group, and a malonate group.

[0074] like Figure 1 As shown, styrene monomer is polymerized under the conditions of p-dicumyl chloride / TiCl4 initiation system, and then 1,3-butadiene is added for end-capping to generate double-terminal allyl bromide functionalized telechelic polystyrene (DPSBr) having a chemical structure as shown in formula Ia, and then various reactions are carried out in sequence to obtain various functionalized polystyrene telechelic polymers.

[0075] For example, taking the synthesis of a double-terminal allyl bromide-functionalized telechelic polystyrene (DPSBr) as an example, a double-terminal allyl chloride-functionalized polystyrene telechelic polymer represented by formula Ia and lithium bromide are reacted at 70 to 90° C., so that the chlorine in the double-terminal allyl chloride-functionalized polystyrene telechelic polymer is replaced by bromine to obtain a double-terminal allyl bromide-functionalized telechelic polystyrene. Exemplarily, the reaction process can be carried out in a mixed solvent system of toluene and acetone.

[0076] For example, taking the synthesis of double-terminal allyl hydroxyl functionalized telechelic polystyrene (DPSOH) as an example, the double-terminal allyl chlorine functionalized polystyrene telechelic polymer shown in formula Ia and lithium bromide are reacted at 70-90° C., so that the chlorine in the double-terminal allyl chlorine functionalized polystyrene telechelic polymer is replaced by bromine to obtain double-terminal allyl bromine functionalized telechelic polystyrene (exemplarily, the reaction process can be carried out in a mixed solvent system of toluene and acetone); then react with a quaternary ammonium base at 20-30° C. to obtain double-terminal allyl hydroxyl functionalized telechelic polystyrene (exemplarily, the reaction process can be carried out in a tetrahydrofuran solvent system). The quaternary ammonium base can be tetrabutylammonium hydroxide, tetrapropylammonium hydroxide, etc.

[0077] For example, taking the synthesis of double-terminal allylamino-functionalized telechelic polystyrene (DPSNH2) as an example, the double-terminal allylchlorine-functionalized polystyrene telechelic polymer shown in Formula Ia and lithium bromide are reacted at 70-90°C, so that the chlorine in the double-terminal allylchlorine-functionalized polystyrene telechelic polymer is replaced by bromine to obtain double-terminal allylbromide-functionalized telechelic polystyrene (exemplarily, the reaction process can be carried out in a mixed solvent system of toluene and acetone); then, it is first reacted with potassium phthalimide at 60-80°C (exemplarily, the reaction process can be carried out in a mixed solvent system of tetrahydrofuran and N-methylpyrrolidone), and then reacted with hydrazine hydrate (exemplarily, the reaction process can be carried out in a mixed solvent system of tetrahydrofuran and ethanol) to obtain double-terminal allylamino-functionalized telechelic polystyrene.

[0078] For example, taking the synthesis of dimethyl malonate-functionalized telechelic polystyrene (DPSME) as an example, the dimethyl malonate-functionalized telechelic polystyrene telechelic polymer of formula Ia is reacted with lithium bromide at 70 to 90°C, so that the chlorine in the dimethyl malonate-functionalized polystyrene telechelic polymer is replaced by bromine to obtain dimethyl malonate-functionalized telechelic polystyrene (illustratively, the reaction process can be carried out in a mixed solvent system of toluene and acetone); then, the dimethyl malonate is reacted with dimethyl malonate at 50 to 70°C to obtain dimethyl malonate-functionalized telechelic polystyrene. Among them, dimethyl malonate can be mixed with K2CO3 and added to the reaction system, and further, the reaction can be carried out in an acetonitrile solvent system.

[0079] For example, taking the synthesis of dual-terminal allyl carboxylic acid functionalized telechelic polystyrene (DPSCOOH) as an example, the dual-terminal allyl chloride functionalized polystyrene telechelic polymer shown in formula Ia is reacted with lithium bromide at 70-90° C., so that the chlorine in the dual-terminal allyl chloride functionalized polystyrene telechelic polymer is replaced by bromine to obtain dual-terminal allyl bromide functionalized telechelic polystyrene (illustratively, the reaction process can be carried out in a mixed solvent system of toluene and acetone); then, it is reacted with dimethyl malonate at 50-70° C. to obtain dual-terminal allyl dimethyl malonate functionalized telechelic polystyrene, wherein dimethyl malonate can be mixed with K2CO3 and added to the reaction system, and further, the reaction can be carried out in an acetonitrile solvent system; finally, the obtained dual-terminal allyl dimethyl malonate functionalized telechelic polystyrene is reacted with an alkali metal hydroxide to obtain dual-terminal allyl carboxylic acid functionalized telechelic polystyrene. Wherein, the alkali metal hydroxide can be potassium hydroxide, and the reaction can be carried out in a tetrahydrofuran solvent system.

[0080] In some embodiments, in the above preparation method, after synthesizing various polystyrene telechelic polymers, further impurity removal treatment is included. For example, the polystyrene telechelic polymer is fully dissolved in a mixed solvent of hexane and dichloromethane, ethanol is added to the solution to precipitate the product, and impurities and oligomers are washed off. The product is dried to constant weight, and then pressed into shape using a mold in a flat vulcanizer to obtain a sound-transmitting material with an acoustic impedance range of 2.5 to 2.9 MRayl.

[0081] In a third aspect, an embodiment of the present application provides an ultrasonic transducer. Specifically, the ultrasonic transducer of the embodiment of the present application includes the acoustic matching material provided in the first aspect of the embodiment of the present application and / or the acoustic matching material prepared by the preparation method provided in the second aspect of the embodiment of the present application. The acoustic matching material used in the ultrasonic transducer of the embodiment of the present application has the characteristics of low acoustic attenuation and high bonding performance, so that the ultrasonic transducer has good stability and reliability in terms of acoustic-to-electric conversion and electroacoustic conversion performance.

[0082] In a fourth aspect, an embodiment of the present application provides an ultrasonic probe. Specifically, the ultrasonic probe of the embodiment of the present application is a medical ultrasonic probe. Specifically, it includes the ultrasonic transducer provided in the third aspect of the embodiment of the present application; or includes a piezoelectric crystal and an acoustic matching layer, and the acoustic matching layer includes the acoustic matching material provided in the first aspect of the embodiment of the present application and / or the acoustic matching material prepared by the preparation method provided in the second aspect of the embodiment of the present application. The acoustic matching material used in the ultrasonic probe of the embodiment of the present application has the characteristics of low acoustic attenuation and high bonding performance, so such an ultrasonic probe has good reliability for ultrasonic signal detection.

[0083] In a fifth aspect, an embodiment of the present application provides an ultrasonic imaging device. Specifically, the ultrasonic imaging device of the embodiment of the present application includes the ultrasonic transducer provided in the third aspect of the embodiment of the present application or the ultrasonic probe provided in the fourth aspect of the embodiment of the present application. The ultrasonic imaging device of the embodiment of the present application has good reliability in medical imaging diagnosis.

[0084] The following describes the invention in conjunction with specific embodiments.

[0085] Example 1

[0086] An acoustic matching material, namely, double-terminal allyl chloride-functionalized telechelic polystyrene (DPSCl).

[0087] The preparation method comprises: using a p-dicumyl chloride / TiCL4 cationic double-end initiation system to initiate cationic polymerization of 10g styrene, performing a polymerization reaction at -80°C for 15min, then adding 1,3-butadiene, and performing a capping reaction at -80°C for 5min, wherein the molar ratio of 1,3-butadiene to styrene monomer is 1:300. After the capping reaction is completed, 3mL of anhydrous ethanol is added to the system to terminate the polymerization. After the polymerization is terminated, ethanol is added to the reaction system to precipitate the polymerization product, the polymerization product is fully dissolved again in a mixed solvent (hexane and dichloromethane are mixed), ethanol is added to the solution to precipitate the product, and impurities and oligomers are repeatedly eluted to finally obtain a double-end allyl chloride functionalized telechelic polystyrene (DPSCl) with a number average molecular weight of about 60,000.

[0088] The obtained DPSC1 was pressed into shape by a mold in a flat vulcanizer, and the density was tested to be 1.07 g / cm 3 , acoustic impedance is 2.59MRayl, 20MHz acoustic attenuation is 12.64dB / cm. After bonding with the aluminum plate, a 90° peeling test was performed, and the anti-peeling bonding strength was 0.36KN / m.

[0089] Example 2

[0090] An acoustic matching material, namely, telechelic polystyrene functionalized with double terminal allyl bromide (DPSBr).

[0091] The preparation method comprises: dissolving the DPSCl prepared in Example 1 in a mixed solvent of toluene and acetone, adding anhydrous lithium bromide for reaction, placing the reaction system under high-purity nitrogen for protection, and reacting at 80° C. for 14 hours. After the reaction is completed, the impurities in the product are washed with deionized water, and after rotary evaporation and drying, a double-terminal allyl bromide functionalized telechelic polystyrene (DPSBr) is obtained, which is subsequently purified by reprecipitation with a hexane-dichloromethane mixed solvent and ethanol.

[0092] The obtained DPSBr was pressed into shape by a mold in a flat vulcanizer, and the density was tested to be 1.08 g / cm 3 , acoustic impedance is 2.71MRayl, 20MHz acoustic attenuation is 12.07dB / cm. After bonding with the aluminum plate, a 90° peeling test was performed, and the anti-peeling bonding strength was 0.40KN / m.

[0093] Example 3

[0094] An acoustic matching material, namely, telechelic polystyrene functionalized with double terminal allyl hydroxyl groups (DPSOH).

[0095] The preparation method comprises: dissolving the DPSBr prepared in Example 2 in tetrahydrofuran, adding an aqueous solution of tetrabutylammonium hydroxide to react, placing the reaction system under high-purity nitrogen for protection, and reacting at 25° C. for 2 hours. After the reaction is completed, the impurities in the product are washed with deionized water, and after rotary evaporation and drying, a double-terminal allyl hydroxyl functionalized telechelic polystyrene (DPSOH) is obtained, which is subsequently purified by reprecipitation with a hexane-dichloromethane mixed solvent and ethanol.

[0096] The obtained DPSOH was pressed into shape by a mold in a flat vulcanizer, and the density was tested to be 1.06 g / cm 3 , acoustic impedance is 2.60MRayl, 20MHz acoustic attenuation is 11.67dB / cm. After bonding with the aluminum plate, a 90° peeling test was performed, and the anti-peeling bonding strength was 0.52KN / m.

[0097] Example 4

[0098] An acoustic matching material, namely, telechelic polystyrene functionalized with dimethylmalonate at the double end, DPSME.

[0099] The preparation method comprises: dissolving the DPSBr prepared in Example 2 in tetrahydrofuran, sequentially adding a mixture of dry acetonitrile, dimethyl malonate and K2CO3, placing the reaction system under high-purity nitrogen for protection, and reacting at 60°C for 20 hours. After the reaction is completed, the reaction is cooled to room temperature, and after rotary evaporation and drying, a double-terminal allyl malonate functionalized telechelic polystyrene (DPSME) is obtained, which is subsequently purified by reprecipitation using a hexane-dichloromethane mixed solvent and ethanol.

[0100] The obtained DPSME was pressed into shape by a mold in a flat vulcanizer, and the density was tested to be 1.06 g / cm 3 , acoustic impedance is 2.52MRayl, 20MHz acoustic attenuation is 13.04dB / cm. After bonding with the aluminum plate, a 90° peeling test was performed, and the anti-peeling bonding strength was 0.38KN / m.

[0101] Example 5

[0102] An acoustic matching material, namely, telechelic polystyrene functionalized with double terminal allyl carboxylic acid (DPSCOOH).

[0103] The preparation method comprises: dissolving the DPSME prepared in Example 4 in tetrahydrofuran, adding deionized water and potassium hydroxide in sequence to react, placing the reaction system under high-purity nitrogen for protection, and reacting at 60°C for 24 hours; acidifying the mixture to pH=3 with concentrated hydrochloric acid, evaporating excess tetrahydrofuran under reduced pressure, washing the product with ethanol, then dissolving it in pyridine, adding water to reflux and stirring for 40 hours, terminating the reaction, and adding the mixture to a hydrochloric acid aqueous solution. The residue is separated and dissolved in a mixed solvent of hexane-dichloromethane, and after rotary evaporation and drying, a telechelic polystyrene (DPSCOOH) functionalized with double-terminal allyl carboxylic acid is obtained, which is subsequently purified by reprecipitation with a mixed solvent of hexane-dichloromethane and ethanol.

[0104] The obtained DPSCOOH was pressed into shape using a mold in a flat vulcanizer, and the density was tested to be 1.06 g / cm 3 , acoustic impedance is 2.64MRayl, 20MHz acoustic attenuation is 12.66dB / cm. After bonding with the aluminum plate, a 90° peeling test was performed, and the anti-peeling bonding strength was 0.64KN / m.

[0105] Example 6

[0106] An acoustic matching material, namely, telechelic polystyrene functionalized with double terminal allylamino groups (DPSNH2).

[0107] The preparation method comprises: dissolving the DPSBr prepared in Example 2 in a mixed solvent of tetrahydrofuran and N-methylpyrrolidone, adding potassium phthalimide to react, placing the reaction system under high-purity nitrogen for protection, reacting at 70°C for 16 hours, obtaining an intermediate product of double-terminal phthalimide functionalized polystyrene, and washing the intermediate product stock solution three times with deionized water to remove impurities. After rotary evaporation and drying, the intermediate product is dissolved in a mixed solvent of tetrahydrofuran and ethanol, adding hydrazine hydrate to react, placing the reaction system under high-purity nitrogen for protection, reacting at 70°C for 36 hours, and obtaining double-terminal allylamino functionalized telechelic polystyrene (DPSNH2) after rotary evaporation and drying, and then reprecipitating and purifying with a mixed solvent of hexane-dichloromethane and ethanol.

[0108] The obtained DPSNH2 was pressed into shape by a mold in a flat vulcanizer, and the density was tested to be 1.06 g / cm 3 , acoustic impedance is 2.64MRayl, 20MHz acoustic attenuation is 12.81dB / cm. After bonding with the aluminum plate, a 90° peeling test was performed, and the anti-peeling bonding strength was 0.66KN / m.

[0109] Comparative Example 1

[0110] A sound matching material: epoxy resin cured material.

[0111] Preparation method: Add 50g epoxy resin into a 250ml flask, add 14g curing agent, stir at 25℃ for 3min, fully mix and vacuum degas in a degassing machine for 3.5min, pour into a mold for casting, and cure at 60℃ for 16h to obtain epoxy resin cured product (EP).

[0112] The tested density is 1.16g / cm 3 , acoustic impedance is 3.14MRayl, 20MHz acoustic attenuation is 122.5dB / cm. After bonding with the aluminum plate, a 90° peeling test was performed, and the anti-peeling bonding strength was 0.67KN / m.

[0113] Comparative Example 2

[0114] An acoustically matching material: polystyrene.

[0115] Preparation method: The polystyrene (PS) product is obtained by living cationic polymerization using a C6H5CH(CH3)Br / SnCl4 initiation system under the action of a common ion salt n-Bu4NBr.

[0116] The obtained polystyrene product was pressed into shape using a mold in a flat vulcanizer, and the density was tested to be 1.05 g / cm 3 The acoustic impedance is 2.43MRayl, and the 20MHz acoustic attenuation is 11.64dB / cm. After being bonded to the aluminum plate, a 90° peeling test is performed, and the anti-peeling bonding strength is 0.03KN / m.

[0117] The test structure is shown in Table 1.

[0118] Table 1

[0119] The density is measured by a solid density tester. The specific steps include: firstly placing the sample on the measuring table of the tester to measure the mass of the sample in the air, pressing the memory key, then placing the sample on the water measuring table of the tester, pressing the corresponding memory key, and the instrument will directly display the density result.

[0120] The acoustic performance test is carried out by water immersion insertion method. The specific steps include: a transmitting probe and a receiving probe are inserted into the water tank, both of which use a 20MHz single-element transducer, and a pulse signal generator excites the transmitting probe to generate an ultrasonic signal, which is transmitted to the receiving probe in the water and displayed on the oscilloscope. First, the waveform and amplitude of the pulse signal of pure water before the sample is placed are measured and recorded, and then the waveform and amplitude of the pulse signal after the sample is placed are measured and recorded. These two data are imported into the test software to automatically calculate the sound velocity, acoustic impedance, and acoustic attenuation data of the material.

[0121] The above-mentioned anti-peel adhesive strength refers to the anti-peel adhesive strength after the sample is bonded to the standard aluminum plate with reference to GBT 7760-2003. The specific steps include: using epoxy glue to bond the sample to the standard aluminum plate, the thickness of the adhesive layer is 3μm and the size of the sample strip is 125×25×6mm. Use a universal testing machine with a special 90° peeling fixture for testing. The fixture is designed so that the upper fixture can swing left and right to ensure that the direction of the peeling force always maintains 90° with the bonding surface. Fix the sample on the testing machine, apply external force to peel the sample strip from the standard aluminum plate in the 90° direction, record the maximum peeling force, minimum peeling force and average peeling force, and calculate the anti-peel adhesive strength based on the test results.

[0122] It can be seen from the data in Table 1 above that, relative to the epoxy resin cured product of Comparative Example 1, Examples 1-6 of the present application have a lower sound attenuation coefficient, and relative to the polystyrene of Comparative Example 2, Examples 1-6 of the present application have better bonding properties, and the bonding force of Examples 5 and 6 of the present application is stronger.

[0123] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. An acoustic matching material, characterized in that: The acoustic matching material includes a polystyrene telechelic polymer having a chemical structure as shown in Formula I: Wherein, n1 and n2 are positive integers; X includes at least one of a halogen atom, a hydroxyl group, a carboxyl group, an amino group, a propargyl group, a methoxy group, an azido group, a pyrimidinyl group, and a malonate group.

2. The acoustic matching material according to claim 1, characterized in that n1 and n2 are the same, or n1=n2=100~400; And / or, X is a carboxyl group or an amino group.

3. The acoustic matching material according to claim 1 or 2, characterized in that: The acoustic impedance range of the acoustic matching material is 2.5-2.9 MRayl, and the acoustic attenuation at 20 MHz is 11-13 dB / cm; and / or the adhesive force of the acoustic matching material is 0.36-0.66 KN / m.

4. A method for preparing an acoustic matching material, characterized in that: include: The styrene monomer is polymerized in an initiation system containing p-dicumyl chloride, and then 1,3-butadiene is added for end-capping to generate a polystyrene telechelic polymer having a chemical structure as shown in Formula Ia, thereby obtaining an acoustic matching material; Wherein, n1 and n2 are positive integers.

5. The preparation method according to claim 4, characterized in that: Also includes: The chlorine atoms in the polystyrene telechelic polymer represented by Formula Ia are substituted so that the chlorine atoms in the chemical structure of Formula Ia are replaced by X; wherein X includes at least one of a non-chlorine halogen atom, a hydroxyl group, a carboxyl group, an amino group, a propargyl group, a methoxy group, an azido group, a pyrimidine group, and a malonate group.

6. The preparation method according to claim 5, characterized in that: The X is a bromine atom, and the chlorine atom is substituted by: reacting the polystyrene telechelic polymer represented by Formula Ia with lithium bromide at 70 to 90° C.; Alternatively, X is a hydroxyl group, and the chlorine atom substitution treatment comprises: reacting the polystyrene telechelic polymer represented by formula Ia with lithium bromide at 70 to 90° C., and then reacting with a quaternary ammonium base at 20 to 30° C.; Alternatively, X is an amino group, and the chlorine atom substitution treatment comprises: reacting the polystyrene telechelic polymer represented by formula Ia with lithium bromide at 70 to 90° C., and then reacting with potassium phthalimide and hydrazine hydrate in sequence at 60 to 80° C.; Alternatively, X is a malonate group, and the chlorine atom substitution treatment comprises: reacting the polystyrene telechelic polymer represented by formula Ia with lithium bromide at 70 to 90° C., and then reacting with malonate at 50 to 70° C.; Alternatively, X is a carboxyl group, and the chlorine atom substitution treatment comprises: reacting the polystyrene telechelic polymer represented by formula Ia with lithium bromide at 70-90° C., and then reacting with malonate and alkali metal hydroxide in sequence at 50-70° C.

7. The preparation method according to any one of claims 4 to 6, characterized in that: The initiation system in the polymerization reaction further includes a co-initiator, and the co-initiator includes at least one of TiCl4, BCl3, and AlCl3; And / or, the polymerization reaction conditions include: temperature of -80 to -60°C, time of 10 to 20 min; and / or, the molar ratio of the 1,3-butadiene to the styrene monomer in the end-capping treatment is 1:(100-400); And / or, the end-capping treatment conditions include: temperature of -80 to -60°C and time of 2 to 8 minutes.

8. An ultrasonic transducer, characterized in that: The invention comprises the acoustic matching material according to any one of claims 1 to 3 and / or the acoustic matching material prepared by the preparation method according to any one of claims 4 to 7.

9. An ultrasonic probe, characterized in that: It comprises the ultrasonic transducer according to claim 8; or, it comprises a piezoelectric crystal and an acoustic matching layer, wherein the acoustic matching layer comprises the acoustic matching material according to any one of claims 1 to 3 and / or the acoustic matching material prepared by the preparation method according to any one of claims 4 to 7.

10. An ultrasonic imaging device, characterized in that: It comprises the ultrasonic transducer according to claim 8 or the ultrasonic probe according to claim 9.

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