A 3D-printable / thermoformable piezoelectric composite material and its preparation method

Abstract

The present invention discloses a 3D printable / thermocompression-moldable piezoelectric composite material and a preparation method thereof. The piezoelectric composite material comprises the following components: surface-modified barium titanate and a polymer. The surface-modified barium titanate provided by the present invention has excellent biocompatibility, and the 3D printable / thermocompression-moldable piezoelectric composite material composed of the surface-modified barium titanate and the polymer has moderate piezoelectric properties and mechanical properties; in the present invention, the surface-modified barium titanate and the polymer are mixed, and then processed and formed and polarized to obtain the piezoelectric composite material. The preparation process of the piezoelectric composite material is simple, the conditions are mild, the cost is low, and it is suitable for industrial mass production; the piezoelectric composite material can be widely applied to the field of biomedical materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of materials, and particularly relates to a piezoelectric composite material capable of 3D printing / thermocompression molding and a preparation method thereof. Background Art

[0002] Large-scale bone injuries caused by injuries, diseases or traumas often lack the ability of self-repair. The repair of bone defects has always been a rather difficult problem in clinical practice. Although autologous transplantation and allogeneic transplantation have been clinically approved and shown satisfactory therapeutic effects, morbidity, immunity and inflammatory reactions at the donor site often occur clinically. Reconstructing the defective bone tissue by means of tissue engineering is currently an ideal solution. And research has confirmed that human bones are a special "piezoelectric material", with bioelectric phenomena and piezoelectric properties. The piezoelectric coefficient of human bones is about 0.7 pC / N. The piezoelectric properties of bones mainly come from bone collagen, and microelectrical stimulation can promote fracture healing. If the piezoelectric effect is introduced into bone implant materials, it can endow the bone implant materials with bioelectric activity similar to that of natural bones, which has important value for obtaining bone implant materials that are more bionic in terms of composition, structure, function and performance.

[0003] Barium titanate (BT) has good biocompatibility and biosafety, and is also a bio-piezoelectric material, with the ability to convert the received mechanical force stimulation into electrical signals. After being acted upon by force, barium titanate will generate charges, stimulating the migration, proliferation and differentiation of osteoblast-related cells. However, for traditional piezoelectric biomaterials such as barium titanate, the human body does not have the ability to degrade them. Therefore, the piezoelectric materials will exist in the human body for a long time after implantation, not only hindering the growth of new tissues, but also causing chronic inflammation, namely "foreign body reaction", bringing many unnecessary troubles. In addition, the piezoelectric ceramic forming requires steps such as high-temperature sintering and debinding, and the forming process is cumbersome. For example, Chinese patent application CN112773939A discloses a bionic bone implant material, a bone repair 3D printing material with a low barium titanate content, its preparation method and application. The blank needs to be calcined at a temperature of 900-1300°C, and the piezoelectricity is too different from that of human bones. In order to solve the problems existing in the existing piezoelectric ceramic materials, such as difficult processing, difficult degradation, difficult forming when the ceramic filler content is too high and complex process, and inability to provide corresponding piezoelectric activity when the ceramic filler content is too low, it is necessary to develop a new piezoelectric composite material capable of 3D printing / thermocompression molding. Summary of the Invention

[0004] In order to overcome the problems existing in the above-mentioned prior art, one of the purposes of the present invention is to provide a piezoelectric composite material capable of 3D printing / thermocompression molding; the second purpose of the present invention is to provide a preparation method of this piezoelectric composite material; the third purpose of the present invention is to provide the application of this piezoelectric composite material.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] In the first aspect of the present invention, a piezoelectric composite material that can be 3D printed / thermally pressed is provided, and the piezoelectric composite material includes the following components:

[0007] Surface-modified barium titanate and a polymer.

[0008] Preferably, the surface-modified barium titanate is 0-87% by mass fraction of the piezoelectric composite material, but not 0; further preferably, the surface-modified barium titanate is 30%-80% by mass fraction of the piezoelectric composite material; still further preferably, the surface-modified barium titanate is 60%-77% by mass fraction of the piezoelectric composite material.

[0009] Preferably, the surface-modified barium titanate is prepared from a surface modifier and barium titanate.

[0010] Preferably, the surface modifier includes at least one of a silane coupling agent and dopamine hydrochloride; further preferably, the surface modifier includes at least one of γ-aminopropyltriethoxysilane (KH-550) and dopamine hydrochloride.

[0011] Preferably, in the surface-modified barium titanate, the mass ratio of barium titanate to the surface modifier is (20-2000):1; further preferably, in the surface-modified barium titanate, the mass ratio of barium titanate to the surface modifier is (30-200):1; still further preferably, in the surface-modified barium titanate, the mass ratio of barium titanate to the surface modifier is (40-100):1.

[0012] Preferably, the polymer is a biodegradable polymer; further preferably, the polymer includes at least one of PLGA (poly(lactic acid-co-glycolic acid)), PHB (poly(3-hydroxybutyrate)), PHBV (copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate), PLA (polylactic acid), PGA (polyglycolic acid), PCL (polycaprolactone), PA (polyamide); still further preferably, the polymer includes at least one of PHBV, PLA, and PCL.

[0013] Preferably, the particle diameter of the barium titanate is 0.5 μm-5 μm.

[0014] Preferably, the flexural strength of the piezoelectric composite material is 35 MPa-95 MPa; further preferably, the flexural strength of the piezoelectric composite material is 43 MPa-78 MPa.

[0015] Preferably, the piezoelectric constant of the piezoelectric composite material is 1.0 pC / N to 7.0 pC / N; more preferably, the piezoelectric constant of the piezoelectric composite material is 1.2 pC / N to 5.0 pC / N.

[0016] The second aspect of the present invention provides a method for preparing the 3D-printable / thermally formable piezoelectric composite material according to the first aspect of the present invention, comprising the following steps:

[0017] 1) Mix the surface-modified barium titanate with the polymer to obtain a composite material;

[0018] 2) Process the obtained composite material into a shape and then perform poling to obtain the piezoelectric composite material.

[0019] Preferably, the surface-modified barium titanate is obtained by mixing a surface modifier with barium titanate.

[0020] Preferably, the mixing of barium titanate and the surface modifier is carried out in a solvent; more preferably, the solvent includes at least one of water, ethanol, DMF, and toluene; still more preferably, the solvent includes at least one of water and ethanol.

[0021] Preferably, the mixing time of barium titanate and the surface modifier is 12 h - 24 h; more preferably, the mixing time of barium titanate and the surface modifier is 12 h - 18 h.

[0022] Preferably, the mixing temperature of barium titanate and the surface modifier is 20°C - 60°C; more preferably, the mixing temperature of barium titanate and the surface modifier is 30°C - 50°C.

[0023] Preferably, in step 1) of the preparation method, the mixing of barium titanate and the polymer is carried out in an organic solvent; more preferably, the organic solvent includes at least one of DMF, dichloromethane, and chloroform; still more preferably, the organic solvent is dichloromethane.

[0024] Preferably, in step 1) of the preparation method, after mixing barium titanate and the polymer, a precipitation step is further included.

[0025] Preferably, the precipitating agent is an alcohol reagent; more preferably, the precipitating agent includes at least one of ethanol, propanol, and isopropanol.

[0026] Preferably, in step 2) of the preparation method, the processing and forming method includes 3D printing, thermoforming, or solution film forming.

[0027] Preferably, the thermoforming satisfies at least one of the following conditions:

[0028] The heating temperature is 60°C - 190°C;

[0029] The preloading pressure is 4 MPa - 9 MPa;

[0030] The preloading time is 1 min - 10 min;

[0031] The boosting pressure is 10 MPa - 20 MPa;

[0032] The boosting time is 1 min - 60 min.

[0033] Preferably, the 3D printing satisfies at least one of the following conditions:

[0034] The heating temperature is 60 °C - 200 °C;

[0035] The pressure is 100 kPa - 700 kPa;

[0036] The printing speed is 20 mm / min - 300 mm / min.

[0037] Preferably, the polarization satisfies at least one of the following conditions:

[0038] The polarization voltage is 1 kV / mm - 10 kV / mm;

[0039] The thermal polarization temperature is 30 °C - 120 °C;

[0040] The thermal polarization time is 15 min - 120 min;

[0041] The cold polarization temperature is 10 °C - 30 °C;

[0042] The cold polarization time is 30 min - 180 min.

[0043] The third aspect of the present invention provides an application of the 3D printable / thermocompression - moldable piezoelectric composite material according to the first aspect of the present invention in the field of biomedical materials.

[0044] Preferably, the biomedical material is a bone repair material.

[0045] The beneficial effects of the present invention are as follows:

[0046] The surface - modified barium titanate provided by the present invention has excellent biocompatibility. The 3D printable / thermocompression - moldable piezoelectric composite material composed of it and a polymer has moderate piezoelectric properties and mechanical properties. The present invention mixes surface - modified barium titanate with a polymer, and then processes, forms, and polarizes to obtain a piezoelectric composite material. The preparation process of this piezoelectric composite material is simple, the conditions are mild, the cost is low, and it is suitable for industrial mass production. This piezoelectric composite material can be widely applied in the field of biomedical materials.

[0047] Specifically, the present invention has the following advantages:

[0048] 1. Through a chemical modification method, the surface-modified barium titanate obtained in the present invention can reduce agglomeration and make it easy to disperse in organic solutions and polymer matrices, solving the problem of poor dispersion of barium titanate in polymer matrices. Barium titanate is compounded with polymers by physical blending to obtain a bioelectrically active piezoelectric bone repair material. The piezoelectric composite material prepared in the present invention has good biocompatibility, is easy to process, has moderate piezoelectricity and is similar to human bone, and can promote bone growth.

[0049] 2. The preparation process of the piezoelectric composite material provided by the present invention is simple, the conditions are mild, it is easy to control, has strong operability, the reagents are safe and non-toxic, and the cost is low, and it is suitable for industrial mass production.

[0050] 3. The piezoelectric composite material prepared by the invention can be widely applied in the field of biomedical materials, especially in the field of bone repair. The piezoelectric composite material can print various bone defect sites through 3D printing, and at the same time, the piezoelectric composite material can be applied to various processing methods such as 3D printing, hot pressing molding, solution film forming, and electrospinning. Description of the Drawings

[0051] Figure 1 It is a bar graph of osteoblast proliferation of the piezoelectric composite material in Example 3.

[0052] Figure 2 It is the staining effect diagram of alkaline phosphatase at 14D of the piezoelectric composite material in Example 3.

[0053] Figure 3 It is a scanning electron microscope image of the cross-section surface of the piezoelectric composite material in Example 1.

[0054] Figure 4 It is a scanning electron microscope image of the cross-section surface of the piezoelectric composite material in Comparative Example 1.

[0055] Figure 5 It is a graph of the d33 test results of the piezoelectric composite materials in Examples 1-3 and Comparative Example 1.

[0056] Figure 6 It is a preparation sample diagram of 3D printing of the piezoelectric composite material in Example 3.

[0057] Figure 7 It is a preparation sample diagram of solution film forming of the piezoelectric composite material in Example 3.

[0058] Figure 8 It is a bending diagram of the preparation sample of hot pressing molding of the piezoelectric composite material in Example 3.

[0059] Figure 9 It is a preparation sample diagram of hot pressing molding of the piezoelectric composite material in Example 3. Detailed Embodiments

[0060] The following further describes the specific implementation of the present invention in conjunction with the attached drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that for the processes not specifically described in detail below, those skilled in the art can implement or understand them with reference to the prior art. For the reagents or instruments whose manufacturers are not specified, they are regarded as conventional products that can be obtained through commercial purchase.

[0061] The barium titanate used in the specific implementation is selected from barium titanate with a particle diameter of 0.5 μm - 5 μm.

[0062] Example 1

[0063] The preparation method of the piezoelectric composite material in this example is as follows:

[0064] Add 200 parts by mass of barium titanate, 900 parts by mass of ethanol, and 100 parts by mass of water into the reaction flask. Ultrasonically disperse for 0.5 h and magnetically stir for 0.5 h. After repeating this 3 times, add 4 parts by mass of KH550 and heat to 45 °C, then mechanically stir for 12 h. Centrifuge, wash, and repeat three times to obtain the dried modified barium titanate (BT).

[0065] Add 24.3 parts by mass of modified BT, 200 parts by mass of dichloromethane, and 7.5 parts by mass of the copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate (PHBV) into a beaker. Ultrasonically disperse for 0.5 h and magnetically stir for 0.5 h. After repeating 3 times, magnetically stir for 4 h, and then add an ethanol precipitant to precipitate, filter, and dry the composite material.

[0066] After hot-pressing the composite material (heating temperature is 175 °C, pre-pressing pressure is 8 MPa, pre-pressing time is 4 min, boosting pressure is 14 MPa, boosting time is 5 min), polarize it in silicone oil. The specific parameters are: heat to 70 °C, polarization voltage is 10 kv / mm, polarize for 1 h, stop heating, and then continue to polarize for 1 h to obtain the piezoelectric composite material in this example, denoted as PHBV-40.

[0067] Example 2

[0068] The preparation method of the piezoelectric composite material in this example is as follows:

[0069] Add 200 parts by mass of barium titanate, 1000 parts by mass of water, and Trish-HCl solution into the reaction flask to make the pH = 7.4. Ultrasonically disperse for 0.5 h and magnetically stir for 0.5 h. After repeating this 3 times, add 4 parts by mass of dopamine hydrochloride and heat to 45 °C, then mechanically stir for 12 h. The dopamine hydrochloride undergoes a self-polymerization reaction to embed the barium titanate particles. Centrifuge, wash, and repeat three times to obtain the dried modified barium titanate.

[0070] Add 18.2 parts by mass of modified BT, 200 parts by mass of dichloromethane, and 7.1 parts by mass of polycaprolactone (PCL) to a beaker. Ultrasonically disperse for 0.5 h, magnetically stir for 0.5 h, repeat 3 times, then magnetically stir for 4 h, and add ethanol precipitant to precipitate, filter, and dry the composite material.

[0071] After hot-pressing the composite material (heating temperature is 70 °C, pre-pressing pressure is 5 MPa, pre-pressing time is 2 min, boosting pressure is 10 MPa, boosting time is 4 min), polarize it in silicone oil. The specific parameters are: heat to 50 °C, polarization voltage is 6 kv / mm, polarize for 0.5 h, stop heating, and continue to polarize for 1.5 h to obtain the piezoelectric composite material of this example, denoted as PCL-30.

[0072] Example 3

[0073] The preparation method of the piezoelectric composite material of this example is as follows:

[0074] Add 200 parts by mass of barium titanate, 900 parts by mass of ethanol, and 100 parts by mass of water to a reaction flask. Ultrasonically disperse for 0.5 h, magnetically stir for 0.5 h, repeat 3 times, then add 4 parts by mass of γ-aminopropyltriethoxysilane coupling agent, heat to 45 °C, and mechanically stir for 12 h, centrifuge, wash, repeat three times to obtain the dried modified barium titanate.

[0075] Add 15.2 parts by mass of modified BT, 200 parts by mass of dichloromethane, and 9.4 parts by mass of polylactic acid (PLA) to a beaker. Ultrasonically disperse for 0.5 h, magnetically stir for 0.5 h, repeat 3 times, then magnetically stir for 6 h, and add ethanol precipitant to precipitate, filter, and dry the composite material.

[0076] After thermoforming the composite material (heating temperature is 195 °C, pre-pressing pressure is 8 MPa, pre-pressing time is 2 min, boosting pressure is 14 MPa, boosting time is 2 min), polarize it in silicone oil. The specific parameters are: heat to 110 °C, polarization voltage is 10 kv / mm, polarize for 0.5 h, stop heating, and continue to polarize for 1 h to obtain the piezoelectric composite material of this example, denoted as PLA-25.

[0077] Comparative Example 1

[0078] The preparation method of the piezoelectric composite material of this example is as follows:

[0079] Add 24.3 parts by mass of unmodified BT, 200 parts by mass of dichloromethane, and 7.5 parts by mass of PHBV to a beaker. Ultrasonically disperse for 0.5 h, magnetically stir for 0.5 h, repeat 3 times, then magnetically stir for 4 h, and add ethanol precipitant to precipitate, filter, and dry the composite material.

[0080] After hot pressing the composite material (heating temperature: 175 °C, pre-pressing pressure: 8 MPa, pre-pressing time: 4 min, boosting pressure: 14 MPa, boosting time: 5 min), it was polarized in silicone oil. The specific parameters were: heating to 70 °C, polarization voltage: 10 kV / mm, polarization for 1 h, stopping heating, and then continuing polarization for 1 h to obtain the piezoelectric composite material of this example, denoted as PHBV-40-D.

[0081] Comparative Example 2

[0082] The preparation method of the piezoelectric composite material of this example is as follows:

[0083] Add 15.2 parts by mass of unmodified BT, 200 parts by mass of dichloromethane, and 9.4 parts by mass of PLA into a beaker. Ultrasonic disperse for 0.5 h, magnetic stir for 0.5 h, repeat 3 times and then magnetic stir for 6 h. Add ethanol precipitant to precipitate, filter, and dry the composite material.

[0084] After hot forming the composite material (heating temperature: 195 °C, pre-pressing pressure: 8 MPa, pre-pressing time: 2 min, boosting pressure: 14 MPa, boosting time: 2 min), it was polarized in silicone oil. The specific parameters were: heating to 110 °C, polarization voltage: 10 kV / mm, polarization for 0.5 h, stopping heating, and then continuing polarization for 1 h to obtain the piezoelectric composite material PLA-25-D.

[0085] Performance Test

[0086] 1. Test on cell proliferation and differentiation of piezoelectric composite materials

[0087] The unpolarized PLA-25, polarized PLA-25, and pure PLA prepared in Example 3 were respectively tested for the proliferation and differentiation of BMSC cells on their surfaces under the synergistic action of LIPUS. Take 3×10 5 BMSC cells of mice and seed them in a 24-well plate. Each day, use LIPUS to ultrasonically stimulate for 10 min (to promote the release of electrical signals by barium titanate), and the test results are as Figure 1 、 Figure 2 shown. Figure 1 It is the column chart of osteocyte proliferation of the piezoelectric composite material in Example 3. Figure 1 The OD value (optical density value, i.e., absorbance) of the cell proliferation effect of the PLA / barium titanate composite (PLA-25) in Example 3 is significantly higher than that of pure PLA, proving that the modified barium titanate can promote cell proliferation; Figure 1 The cell proliferation effects of the unpolarized PLA-25, polarized PLA-25, and blank control in Example 3 are comparable, proving that the polarization process has no obvious effect on the cell proliferation process of the piezoelectric composite material. Figure 2Alkaline phosphatase (ALP) 14D staining effect diagram of the piezoelectric composite material in Example 3, where Figure 2 (a) is the alkaline phosphatase 14D staining effect diagram of pure PLA, Figure 2 (b) is the alkaline phosphatase 14D staining effect diagram of non-polarized PLA-25, Figure 2 (c) is the alkaline phosphatase 14D staining effect diagram of polarized PLA-25. The darker the staining, the higher the ALP activity and the higher the degree of osteogenic differentiation. From Figure 2 the ALP (14D) staining effect, it can be seen that Figure 2 (b) the staining of non-polarized PLA-25 is deeper than that of Figure 2 (a) pure PLA, indicating that the PLA / barium titanate composite material promotes osteogenic differentiation; Figure 2 (c) the staining of polarized PLA-25 is deeper than that of Figure 2 (b) non-polarized PLA-25, indicating that piezoelectric polarization has the effect of promoting osteocyte differentiation.

[0088] 2. Surface electron microscopy scanning test of piezoelectric composite materials

[0089] The cross-section of the piezoelectric composite materials prepared in Example 1 and Comparative Example 1 was subjected to a surface electron microscopy scanning test (SEM), and the results are as shown in Figure 3 and Figure 4 . Figure 3 is the surface electron microscopy scanning diagram of the cross-section of the piezoelectric composite material in Example 1, Figure 4 is the surface electron microscopy scanning diagram of the cross-section of the piezoelectric composite material in Comparative Example 1. From the comparison between Figure 3 and Figure 4 , it can be seen that the modified barium titanate has better dispersion and less agglomeration in the matrix material than the unmodified barium titanate. It shows that the surface modification process is beneficial to the dispersion of barium titanate in the matrix material and reduces agglomeration.

[0090] 3. Quasi-static d 33 test of piezoelectric composite materials

[0091] The piezoelectric constant d 33 of Examples 1-3 and Comparative Example 1 after polarization was tested using a quasi-static d 33 tester. Figure 5 is the d 33 test result diagram of the piezoelectric composite materials in Examples 1-3 and Comparative Example 1, where Figure 5 (a) is the d 33 test result diagram of PHBV-40 prepared in Example 1, Figure 5 (b) is the d 33 test result diagram of PCL-30 prepared in Example 2, Figure 5 (c) is the d 33 test result diagram of PLA-25 prepared in Example 3, Figure 5(d) is the d33 test result graph of PHBV-40-D prepared in Comparative Example 1. The piezoelectric constant of PHBV-40 prepared in Example 1 is 4.0 pC / N, the piezoelectric constant of PCL-30 prepared in Example 2 is 3.7 pC / N, the piezoelectric constant of PLA-25 prepared in Example 3 is 1.2 pC / N, and the piezoelectric constant of PHBV-40-D prepared in Comparative Example 1 is -2.1 pC / N. The above test results show that after modification, barium titanate can be better dispersed in the matrix, making the voltage distribution of the piezoelectric composite more uniform during polarization, and the polarization effect is better than that of the unmodified composite under the same polarization conditions.

[0092] 4. Flexural property test of piezoelectric composites

[0093] The piezoelectric composites were 3D printed under the following conditions: heating temperature 200 °C, extrusion pressure 550 kPa, printing speed 100 mm / min. Figure 6 It is the preparation sample graph of the 3D printing of the piezoelectric composite material in Example 3, indicating that the composite material meets the conditions of the 3D printing process. Figure 7 It is the preparation sample graph of the solution casting film of the piezoelectric composite material in Example 3, indicating that the piezoelectric composite material can be processed into the required thin film material by solution casting. Figure 8 It is the bending graph of the hot pressing molded preparation sample of the piezoelectric composite material in Example 3; Figure 9 It is the preparation sample graph of the hot pressing molded piezoelectric composite material in Example 3, indicating that the composite material can be widely used in the hot pressing molding process to prepare the required materials and components. Figures 6 - 9 It can be seen that the piezoelectric composites can all be well molded. Through the hybrid modification of barium titanate and polymer, they can also be shaped while maintaining appropriate piezoelectricity, expanding their application scope.

[0094] Table 1 shows the flexural property test results of the polarized PLA-25, pure PLA, and the piezoelectric composite material PLA-25-D in Comparative Example 2 prepared in Example 3. The test standard is ASTM D790-2017.

[0095] Table 1 Flexural property test

[0096] Sample Flexural Strength / MPa PLA 80 Example 3 53 Comparative Example 2 32

[0097] From the comparison between Example 3 and pure PLA in Table 1, it can be seen that in order to maintain a certain piezoelectricity, a certain amount of barium titanate needs to be added. Although the mechanical properties decrease to some extent, there are still good mechanical properties while maintaining appropriate piezoelectricity. From the comparison between Example 3 and Comparative Example 2 in Table 1, it can be seen that the modified composite material helps to improve the mechanical properties of the composite material, especially the flexural strength of the piezoelectric composite material.

[0098] The above test results indicate that the piezoelectric composite material prepared in this application has excellent biocompatibility, internal material dispersibility, piezoelectric properties, easy processing properties, and bending properties, indicating that the piezoelectric composite material can be widely used in bone repair piezoelectric composite materials for 3D printing or hot pressing molding.

[0099] The above examples are the preferred embodiments of the present invention, but the embodiments of the invention are not limited by the above examples. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A 3D printable / thermocompression-moldable piezoelectric composite material, characterized in that: The piezoelectric composite material comprises the following components: surface-modified barium titanate and a polymer; The surface-modified barium titanate accounts for 30%-80% of the mass fraction of the piezoelectric composite material; The surface modifier is selected from γ-aminopropyltriethoxysilane, dopamine hydrochloride or a combination thereof; In the surface-modified barium titanate, the mass ratio of barium titanate to the surface modifier is (20-2000):1; The polymer is selected from a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate, polylactic acid, polycaprolactone or a combination thereof; The 3D-printable / thermocompression-moldable piezoelectric composite material is prepared by a method comprising the following steps: 1) Mix the surface-modified barium titanate and the polymer to obtain a composite material; 2) Process and mold the composite material, and then perform polarization to obtain the piezoelectric composite material; Among them, the polarization satisfies the following conditions: the polarization voltage is 1 kV / mm - 10 kV / mm; The thermal polarization temperature is 30°C - 120°C; The thermal polarization time is 15 min - 120 min; The cold polarization temperature is 10°C - 30°C; The cold polarization time is 30 min - 180 min; In the step 2), the processing and molding method includes 3D printing, thermocompression molding or solution film formation.

2. The 3D printable / thermoformable piezoelectric composite material according to claim 1, characterized in that: The particle diameter of the barium titanate is 0.5 μm - 5 μm.

3. Application of the 3D-printable / thermocompression-moldable piezoelectric composite material according to claim 1 or 2 in the field of biomedical materials.

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