Shape memory composite material and preparation method and application thereof
By preparing a shape memory composite material with a metal core and a magnetically responsive polymer sheath, and combining force programming and magnetic programming, the problems of local programming flexibility and precise control in a fully enclosed space are solved, and multi-morphological adjustment and precise morphological control are achieved, which is suitable for medical devices in the biomedical field.
Patent Information
- Application Number
- CN202510652748.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-21
- Publication Date
- 2025-09-09
AI Technical Summary
The local programming flexibility and precise control of existing shape memory polymers in a fully enclosed space are difficult to achieve, especially in applications requiring high precision in biomedicine, intelligent robotics, and flexible electronic devices.
A shape memory composite material with a metal core and a magnetically responsive polymer sheath is used. Combining force programming and magnetic programming, the core-sheath structure is prepared through coaxial 3D printing technology to achieve force programming of the material at room temperature and magnetic programming at high temperature, and shape recovery is performed using a magnetic field.
It achieves precise morphological control of materials in different environments, supports multiple initial forms and temporary shape adjustments, and is suitable for interventional and implantable medical devices in the biomedical field, such as vascular stents and intestinal stents.
Smart Images
Figure CN120608344A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of smart materials, and in particular relates to a shape memory composite material and a preparation method and application thereof. Background Art
[0002] Shape memory polymers (SMPs) are a class of smart materials that exhibit a shape memory effect, which enables them to change and fix their shape in response to external stimuli. This process typically involves two steps: shape programming and shape recovery. During the programming phase, SMPs deform and fix into a temporary shape in response to external stimuli. During the recovery phase, the material returns to its original form upon application of external stimuli (such as heating). This property enables SMPs to play an important role in medical devices, microrobotics, implants, and other fields.
[0003] The shape programming processes reported in existing studies mainly include four methods: light, heat, force, and magnetism. Light programming can provide high-precision local control, but operations in fully enclosed spaces still need to be further optimized. Thermal programming is suitable for manipulation in enclosed spaces and can complete the shape memory process without an external light source or electric field. It is usually difficult to meet the flexibility of local programming, especially in applications that require precise control of a single part. Force programming is used in smart structures and dynamic brackets for its flexibility and safety. Magnetic programming combines the advantages of local and global manipulation and is suitable for complex and dynamic environments. In the future, SMPs that combine multiple programming methods are expected to further expand their applications in biomedicine, intelligent robots, and flexible electronic devices.
[0004] The shape recovery process mainly relies on a variety of external stimuli, including heat, light, electricity, solvents and magnetism. Among them, unlike other recovery methods, magnetic recovery has several unique advantages. First, the magnetic field can be effectively manipulated in a closed space, allowing the material to complete shape recovery without direct contact, greatly expanding its scope of application. Secondly, magnetic recovery also has the ability to manipulate locally. Through the action of a local magnetic field, it can precisely control the recovery of a certain part of the material without affecting other areas. This combination of local and global manipulation gives magnetic recovery an incomparable advantage in high-precision operations and dynamic environments, which provides broad application prospects for future biomedicine, flexible electronics, intelligent robots and other fields.
[0005] Therefore, it is of great significance to develop materials with multiple programming methods and more precise and controllable morphology. Summary of the Invention
[0006] The purpose of the present invention is to overcome the problems existing in the above-mentioned prior art and to provide a shape memory composite material and a preparation method and application thereof.
[0007] The present invention is achieved through the following technical solutions:
[0008] In a first aspect, the present invention provides a shape memory composite material, comprising a core material and a sheath material wrapping the core material, wherein the core material comprises a metal material having a melting point of 25°C-80°C; the sheath material comprises a magnetically responsive polymer material, and the magnetically responsive polymer comprises a neodymium iron boron material and a polymer material.
[0009] The shape memory composite material of the present invention has a core-sheath structure, wherein the sheath material is a magnetically responsive polymer composed of NdFeB and a polymer material. The polymer material has a certain elasticity, and the NdFeB particles give the composite material magnetic responsiveness after magnetization. The core material is a metal material with a melting point of 25°C-80°C. It is solid at room temperature and has good ductility, enabling force programming. It can be converted to a liquid state after heating. When a magnetic field is applied at high temperature, the composite material deforms into a pre-magnetized shape, thereby achieving magnetic programming. Due to the integration of the special properties of the core and sheath materials, the composite material of the present invention forms a shape memory composite material with both rigid-flexible switching and magnetic responsiveness.
[0010] Preferably, the melting point of the metal material is 25°C-80°C.
[0011] Preferably, the metal material is Field's alloy or other liquid metal alloys having good mechanical properties in solid state.
[0012] More preferably, the metal material is Field's alloy.
[0013] Specifically, the Fields alloy includes bismuth (Bi): 32.5%, indium (In): 51%, and tin (Sn): 16.5%, and has a melting point of about 62°C.
[0014] Field metal has good ductility at room temperature and can realize force programming at room temperature. When it is heated to about 62°C, it turns into a liquid metal material, thus having a flexible state under high-temperature magnetic response, making the morphological changes diverse.
[0015] Preferably, the average particle size of the NdFeB material is 3 μm-8 μm.
[0016] Preferably, the polymer material includes at least one of polydimethylsiloxane (PDMS), silicone rubber, thermoplastic polyurethane (TPU), and styrene elastomer (SEBS / SBS). Specifically, the polymer material includes at least one of PDMS, silicone rubber, TPU, SEBS, and SBS.
[0017] More preferably, the polymer material is polydimethylsiloxane.
[0018] Polydimethylsiloxane has certain elasticity and good biocompatibility. When used with neodymium iron boron permanent magnet material as sheath material, it can diversify the shape of shape memory composite materials and expand their application scenarios.
[0019] The present invention does not impose any particular restrictions on the mixing ratio of the NdFeB material and the polymer material, as long as the two have a certain fluidity after mixing. Optionally, the weight ratio of the NdFeB material and the polymer material is (5-8): (2-5).
[0020] In a second aspect, the present invention provides a method for preparing the shape memory composite material, comprising the following steps: uniformly mixing NdFeB material and polymer material to obtain a sheath material, then coaxially printing the obtained sheath material and core material to form a core-sheath structure, and curing to obtain the shape memory composite material.
[0021] The present invention obtains a shape memory composite material with a core-sheath structure through coaxial 3D printing technology. It can customize the printing of fibers of any thickness, any inner diameter ratio, and any shape, as well as two-dimensional and three-dimensional planes composed of fibers, according to needs. The preparation method is simple, the material shape is adjustable, and it has a wide range of application scenarios.
[0022] Specifically, the magnetization process of the shape memory composite material is as follows: the prepared unmagnetized shape memory composite material is deformed into a preset shape through a mold and magnetized by a pulsed magnetic field Bmag (about 3T). Under the action of the pulsed magnetic field Bmag, the shape memory composite material reaches saturation magnetization intensity, and the magnetization direction is the same as the pulsed magnetic field Bmag. When the pulsed magnetic field Bmag disappears, the shape memory material forms a stable residual magnetization intensity.
[0023] Preferably, the curing temperature is 60° C.-80° C., and the curing time is 0.5 h-3 h.
[0024] Preferably, in the shape memory composite material, the thickness ratio of the core layer formed by the core material to the sheath layer formed by the sheath material is greater than 0.1; in this case, the shape memory composite material fiber has good mechanical properties.
[0025] In a third aspect, the present invention provides applications of the shape memory composite material in the biomedical field.
[0026] The shape memory composite material of the present invention has two programming modes: force programming and magnetic programming. It can be programmed by force at room temperature and has multi-morphological adjustment, diversified initial shapes, diversified temporary shapes programmed by force, diversified temporary shapes programmed by magnetic programming, and diversified magnetothermal recovery modes. It is expected to be applied in the biomedical field.
[0027] Preferably, the application is in the preparation of interventional and implantable medical device materials; specifically, the application is in the preparation of vascular stents and intestinal stents.
[0028] Compared with the prior art, the present invention has the following beneficial effects:
[0029] 1. Multiple programming methods: The shape memory composite material of the present invention has two programming methods: force programming and magnetic programming, which enable the material to flexibly select programming methods in different environments and achieve precise morphological control.
[0030] 2. Multi-morphological adjustment: The shape memory composite material of the present invention supports multiple initial forms and temporary shape adjustment under force programming and magnetic programming, and has diversified magnetothermal recovery modes, providing a wider range of application possibilities.
[0031] 3. Rigidity and Flexibility: The shape memory composite material of this invention is rigid at room temperature and flexible after electromagnetic induction heating. This significant difference in elastic modulus makes it suitable for a wide range of applications. Furthermore, the coaxial manufacturing process enables the personalized manufacture of shape memory materials. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Figure 1 A photograph of the coaxial manufacturing apparatus used in Example 1;
[0033] Figure 2 This is a cross-sectional representation of the shape memory composite material prepared in Example 1;
[0034] Figure 3 This is a magnetron pipe bracket made of the shape memory composite material prepared in Example 1 by coaxial printing and an infrared thermal imaging image of the bracket during its deformation process;
[0035] Figure 4 This is a graph showing changes in the storage modulus of the shape memory composite material prepared in Example 1 during heating and cooling;
[0036] Figure 5 This is an infrared thermal image of the magnetically controlled fiber prepared by coaxial printing of the shape memory composite material obtained in Example 1 and its deformation process. DETAILED DESCRIPTION
[0037] To better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.
[0038] Unless otherwise specified, the experimental methods used in the examples are conventional methods; the materials, reagents, etc. used are all available from commercial sources unless otherwise specified.
[0039] Example 1
[0040] A method for preparing a shape memory composite material comprises the following steps:
[0041] 1. Weigh NdFeB particles (average diameter: 5 μm) and PDMS (SE 1700) in a weight ratio of 7:3. Mix thoroughly with a mechanical mixer at 2000 rpm for 3 minutes, and then degas in a vacuum chamber for 10 minutes to obtain the sheath material. Field metal (bismuth (Bi): 32.5%, indium (In): 51%, tin (Sn): 16.5%) is used as the core material.
[0042] 2. Adoption Figure 1 The coaxial manufacturing device shown performs coaxial printing: a shape is constructed using SolidWorks and converted into G code using repetier-host, the core material and the sheath material are respectively injected into two different syringes, and then the core material and the sheath material in the two syringes are extruded through a coaxial nozzle (inner tube diameter di: 0.8 cm; nozzle diameter do: 1.8 μm), and the nozzle is extruded and moved synchronously according to the design code to prepare a fiber with a core-sheath structure, and then the fiber with a core-sheath structure obtained by coaxial printing is cured in an oven at 70°C for 1 hour to obtain the shape memory composite material.
[0043] Figure 2 The cross-sectional characterization of the shape memory composite material prepared in Example 1 is shown in FIG. Figure 2 It can be seen from the figure that the shape memory composite material of the present invention has a core-sheath structure, and the elements are evenly distributed, which facilitates the regulation of performance.
[0044] Figure 3 This is a magnetron pipe bracket prepared by coaxial printing using the shape memory composite material prepared in Example 1, and its infrared thermal imaging during the deformation process. Figure 3 It is shown in the figure that the magnetically controlled conduit stent has three spatial forms: a one-dimensional strip structure, a two-dimensional mesh structure, and a three-dimensional tubular structure. The switching strategy between the three states is as follows: 1. Initially, it is a two-dimensional mesh structure, which is manually programmed into a compact one-dimensional strip, and is accurately and safely delivered to the target area using magnetic navigation technology; 2. After induction heating, the liquid metal changes from a solid state to a liquid state, and the stent unfolds into the initial two-dimensional mesh under the elastic action of the soft sheath; 3. Under the action of a further magnetic field, the stent can be driven from a two-dimensional mesh to a three-dimensional tubular shape, adaptively adapting to the position of complex pipelines, accurately fitting the pipeline wall, and maintaining a three-dimensional tubular shape after cooling to provide stable support for the diseased area, thereby ensuring long-term fluid flow. In addition, the stent can be adjusted to a one-dimensional strip structure again, and the stent can be removed under magnetic navigation. The magnetically controlled conduit stent obtained by the shape memory composite material of the present invention can be customized to any size and is expected to be used in biomedical fields such as vascular stents and intestinal stents.
[0045] Figure 4The graph of the change of storage modulus of the shape memory composite material prepared in Example 1 during heating and cooling is shown in FIG. Figure 4 It can be seen that below the melting point it is solid and above the melting point it is liquid, and the difference between the solid and liquid moduli is 6.7 GPa, which shows that the elastic modulus difference of the material is large; the test uses a dynamic thermomechanical analyzer, the test mode is three-point bending, and the measurement temperature range is 20℃-80℃.
[0046] Figure 5 This is an infrared thermal image of the magnetically controlled fiber prepared by coaxial printing of the shape memory composite material obtained in Example 1 and its deformation process. Figure 5 The magnetically controlled fiber initially forms a single fiber. Manually wrapped around a weight twice in the solid state, the fiber can maintain this shape and lift a 100g weight. After induction heating, the liquid metal transitions from solid to liquid, and the elastic sheath returns the fiber to its initial state, causing the weight to fall. Further magnetic field action drives the fiber to deform into a curved hook, which remains in this shape after cooling, allowing it to lift a 100g weight. These programmable, restorable, and magnetically controllable variable stiffness properties hold promise for applications in soft robotics and other fields.
[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.
Claims
1. A shape memory composite material, characterized in that: It includes a core material and a sheath material wrapping the core material, the core material includes a metal material, the melting point of the metal material is 25°C-80°C; the sheath material includes a magnetically responsive polymer material, and the magnetically responsive polymer includes a neodymium iron boron material and a polymer material.
2. The shape memory composite material according to claim 1, characterized in that: The melting point of the metal material is 50°C-70°C.
3. The shape memory composite material according to claim 1, characterized in that: The metal material includes Fieldsmetal.
4. The shape memory composite material according to claim 1, characterized in that: The average particle size of the NdFeB material is 3 μm-8 μm.
5. The shape memory composite material according to claim 1, characterized in that: The polymer material includes at least one of polydimethylsiloxane, silicone rubber, thermoplastic polyurethane, and styrene elastomer.
6. The shape memory composite material according to claim 1, characterized in that: The weight ratio of the NdFeB material to the polymer material is (5-8): (2-5).
7. A method for preparing the shape memory composite material according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: uniformly mixing NdFeB material and polymer material to obtain sheath material, then coaxially printing the obtained sheath material and core material to form a core-sheath structure, and solidifying the mixture to obtain the shape memory composite material.
8. The method for preparing the shape memory composite material according to claim 7, characterized in that: The curing temperature is 60° C.-80° C., and the curing time is 0.5 h-3 h.
9. Use of the shape memory composite material according to any one of claims 1 to 7 in the biomedical field.
10. Application of the shape memory composite material according to claim 9 in the biomedical field, characterized in that: The application is in the preparation of interventional and implantable medical device materials.