A method for preparing a curved piezoelectric composite material by using a shape memory polymer material

Abstract

The present application relates to the technical field of underwater acoustic transducer, in particular to a method for preparing curved piezoelectric composite material by using shape memory high polymer material, comprising the following steps: step 1: according to the required shape and size, corresponding shape memory high polymer material pouring tooling is prepared; step 2: shape memory high polymer material is poured and solidified; step 3: the solidified shape memory high polymer material is taken out, heated to above its glass transition temperature to soften, then clamped flat with two metal plates, and then cooled into flat plate type shape memory high polymer material; step 4: piezoelectric ceramic plate is firmly pasted on the flat plate type shape memory high polymer material; step 5: a series of cutting is carried out on the piezoelectric ceramic along the X direction, and a series of cutting is carried out on the piezoelectric ceramic along the Y direction, the curved piezoelectric composite material is prepared by the method, the curved surface is uniform and controllable, the preparation process is simple and easy to operate, and the method is suitable for large-scale production of various curved piezoelectric composite materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of underwater acoustic transducer, in particular to a method for preparing curved piezoelectric composite material by using shape memory high polymer material. BACKGROUND

[0002] Piezoelectric composite material is composed of piezoelectric ceramic and polymer, which has good flexibility and mechanical processing performance. The introduction of polymer matrix effectively reduces the coupling between d33 and d31, and reduces the density and acoustic impedance of piezoelectric composite material, so that it is more easily acoustically matched with water, air or polymer elastomer. The curved piezoelectric composite material is formed into a curved surface, and an arc array transducer is prepared by using the curved surface as an acoustic element, which can reduce the array process, realize large opening angle of directivity, and increase the detection range of the transducer. It has been widely used in underwater acoustic, oil exploration, ocean development and ultrasonic.

[0003] At present, there are four kinds of methods for preparing curved piezoelectric composite material, i.e. mechanical processing method, 3D printing method, injection molding method and plane bending method. The error of curved composite material prepared by using mechanical processing method and 3D printing method is large; the injection molding method is suitable for large area curved composite material forming, and the internal stress is not uniform during the cooling and pre-plasticizing process of the material; the plane bending method keeps the composite material in curved shape under certain temperature and pressure, and the stress and temperature of the piezoelectric ceramic sheet must be considered. When the operating temperature exceeds the Curie point of the piezoelectric ceramic, the piezoelectric effect of the ceramic sheet is lost. SUMMARY

[0004] In view of the shortcomings of the prior art, the present application provides a method for preparing curved piezoelectric composite material by using shape memory high polymer material. The method for preparing curved piezoelectric composite material is uniform and controllable, the preparation process is simple and easy to operate, and it is suitable for large-scale production of various curved piezoelectric composite materials.

[0005] The present application is realized by the following technical solutions:

[0006] A method for preparing curved piezoelectric composite material by using shape memory high polymer material, comprising the following steps:

[0007] Step 1: According to the required shape and size, the corresponding shape memory high polymer material pouring tool is made;

[0008] Step 2: Pouring shape memory high polymer material and curing;

[0009] Step 3: Take out the cured shape memory high polymer material, heat it to above its glass transition temperature to soften it, then clamp it flat with two metal plates, and then cool it into a flat type shape memory high polymer material;

[0010] Step 4: firmly paste the piezoelectric ceramic flat plate on the flat plate type shape memory high polymer material;

[0011] Step 5: cut the piezoelectric ceramic along the X direction in a series of cuts, and then cut the piezoelectric ceramic along the Y direction in a series of cuts;

[0012] Step 6: put into the oven, set a certain temperature and time, and then obtain the required curved surface shape;

[0013] Step 7: put the curved surface shape into the pouring tool, pour resin in the cutting gap, and solidify;

[0014] Step 8: take out the solidified piezoelectric composite material, polish and polish the electrodes on both sides, and then obtain the curved piezoelectric composite material with the required shape and size.

[0015] Preferably, the glass transition temperature in step 3 is 50-170℃.

[0016] Preferably, the oven heating temperature in step 6 is 2-70℃ higher than the glass transition temperature, and the heating time is 0.5-12h.

[0017] Preferably, the resin in step 7 is epoxy resin or polyurethane resin.

[0018] Preferably, the inner curved surface in step 7 is the same size as the inner mold of the poured shape memory high polymer material plus the recovery rate, and the outer curved surface is the same as the outer curved surface of the final required curved piezoelectric composite material.

[0019] The beneficial effects of the present application are:

[0020] The shape memory characteristics of shape memory high polymer material are used for the first time to prepare curved piezoelectric composite material, and different shapes and sizes of shape memory high polymer material can be prepared by pouring with tooling, so that curved piezoelectric composite materials with different shapes (spherical cap, single curved surface, double curved surface, etc.) and various sizes can be prepared, and the curved surface is uniform and controllable. The preparation method of the present application is simple in process and easy to control in forming conditions, and is suitable for large-scale production of curved piezoelectric composite materials with various radii of curvature. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0022] Figure 1 The structure diagram of the curved surface shape memory high polymer material in step 2 of the present application;

[0023] Figure 2 Process flow chart for step 3 in the present application;

[0024] Figure 3 Structure chart after step 4 processing in the present application;

[0025] Figure 4 Structure chart after step 5 processing in the present application;

[0026] Figure 5 Structure chart after step 6 processing in the present application;

[0027] Figure 6 Structure chart after step 7 processing in the present application;

[0028] Figure 7 Structure chart after step 8 processing in the present application.

[0029] In the figure: 1 - curved shape memory polymer material, 2 - flat plate, 3 - flat plate type shape memory polymer material, 4 - piezoelectric ceramic, 5 - glue layer, 6 - resin, 7 - electrode. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0031] Embodiment 1:

[0032] Please refer to Figures 1-7The method for preparing a curved piezoelectric composite material by using a shape memory polymer material comprises the following steps: Step 1: a corresponding shape memory polymer material pouring tool is prepared according to the required shape and size; Step 2: the shape memory polymer material is poured and solidified; Step 3: the solidified shape memory polymer material is taken out, heated to above the glass transition temperature (i.e. 2-70℃ above the glass transition temperature) to soften it, then clamped flat with two metal plates, and then cooled to a flat plate type shape memory polymer material; Step 4: a piezoelectric ceramic plate is firmly pasted on the flat plate type shape memory polymer material; Step 5: the piezoelectric ceramic is cut in a series of cuts along the X direction, and then cut in a series of cuts along the Y direction; Step 6: the piezoelectric ceramic is placed in an oven, and after setting a certain temperature and time, the required curved shape is obtained; Step 7: the curved shape is placed in the pouring tool, and resin is poured into the cutting gap and solidified; Step 8: the solidified piezoelectric composite material is taken out, polished and polished, and electrodes are applied to both sides, so that the curved piezoelectric composite material of the required shape and size is obtained.

[0033] In the present embodiment, the glass transition temperature in step 3 is 50-170℃, and specifically 50℃, 80℃, 100℃, 120℃, 150℃, 165℃ or 170℃ can be used. The oven heating temperature in step 6 is 2-70℃ above the glass transition temperature, and the heating time is 0.5-12h, and specifically 5-10h is used. The resin in step 7 is epoxy resin or polyurethane resin. The inner curved surface in step 7 is the same size as the inner mold of the poured shape memory polymer material plus the recovery rate, and the outer curved surface is the same as the outer curved surface of the final required curved piezoelectric composite material.

[0034] The present method uses shape memory polymer material as a substrate for cutting piezoelectric ceramic material, and uses its characteristics of being able to be shaped below the glass transition temperature and being able to recover the original shape above the glass transition temperature to prepare a curved piezoelectric composite material. The curved surface is uniform and controllable, the preparation process is simple and easy to implement, and it is suitable for large-scale production of curved piezoelectric composite materials with large curvature radius.

[0035] The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a curved piezoelectric composite material using a shape memory polymer material, characterized by, The method comprises the following steps: Step 1: making a corresponding shape memory polymer material pouring tool according to the required shape and size; Step 2: pouring the shape memory polymer material and curing; Step 3: taking out the cured shape memory polymer material, heating it to above its glass transition temperature to soften it, then clamping it flat with two metal plates, and cooling it into a flat plate type shape memory polymer material; Step 4: firmly pasting a piezoelectric ceramic flat plate on the flat plate type shape memory polymer material; Step 5: cutting the piezoelectric ceramic in a series of cuts along the X direction, and then cutting it in a series of cuts along the Y direction; Step 6: placing it in an oven, setting a certain temperature and time, and then obtaining the required curved surface shape; Step 7: placing the curved surface shape into the pouring tool, pouring resin into the cutting gap, and curing; Step 8: taking out the cured piezoelectric composite material, polishing and polishing both sides to obtain the required shape and size of the curved surface piezoelectric composite material.

2. The method for preparing a curved piezoelectric composite material using a shape memory polymer material according to claim 1, characterized in that: The glass transition temperature in step 3 is 50-170℃.

3. The method for preparing a curved piezoelectric composite material using a shape memory polymer material according to claim 2, characterized in that: The oven heating temperature in step 6 is 2-70℃ above the glass transition temperature, and the heating time is 0.5-12h.

4. The method for preparing a curved piezoelectric composite material using a shape memory polymer material according to claim 1, characterized in that: The resin in step 7 is epoxy resin or polyurethane resin.

5. The method for preparing a curved piezoelectric composite material using a shape memory polymer material according to claim 1, characterized in that: The inner curved surface in step 7 is the same size as the inner mold of the poured shape memory polymer material plus the recovery rate, and the outer curved surface is the same as the outer curved surface of the final required curved surface piezoelectric composite material.

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