阅读说明：本技术 一种可选择性响应的形状记忆聚合物结构及其制备方法 (Shape memory polymer structure capable of selectively responding and preparation method thereof ) 是由 黄舒 单铭远 张航 盛杰 魏洁安 周建忠 周双流 徐玮 于 2020-11-23 设计创作，主要内容包括：本发明提供了一种可选择性响应的形状记忆聚合物结构及其制备方法,包括如下步骤：用形状记忆聚合物制作具有若干空腔的本体结构；在本体结构的空腔内填充纳米粒子溶液,所述纳米粒子溶液在外部激励作用下可生热；将填充纳米粒子溶液的本体结构加热,通过外力使本体结构变形；将变形后的本体结构冷却定形,定形后的本体结构在外部激励作用下可恢复到外力变形前的本体结构。本发明通过向空腔内部选择性地注入各种类别和不同浓度的粒子液,赋予了结构多种激励方式,顺序可控响应能力和可选择性响应多种外部刺激的能力。(The invention provides a shape memory polymer structure capable of selectively responding and a preparation method thereof, which comprises the following steps: manufacturing a body structure with a plurality of cavities by using a shape memory polymer; filling a nanoparticle solution in a cavity of the body structure, wherein the nanoparticle solution can generate heat under the action of external excitation; heating the body structure filled with the nano particle solution, and deforming the body structure through external force; and cooling and shaping the deformed body structure, wherein the shaped body structure can be restored to the body structure before the deformation of the external force under the external excitation action. The invention selectively injects particle liquid of various types and different concentrations into the cavity, thereby endowing the structure with various excitation modes, sequential controllable response capability and capability of selectively responding to various external stimuli.)

1. A method of making a selectively responsive shape memory polymer structure, comprising the steps of:

manufacturing a body structure with a plurality of cavities by using a shape memory polymer;

filling a nanoparticle solution in a cavity of the body structure, wherein the nanoparticle solution can generate heat under the action of external excitation;

heating the body structure filled with the nano particle solution, and deforming the body structure through external force; and cooling and shaping the deformed body structure, wherein the shaped body structure can be restored to the body structure before the deformation of the external force under the external excitation action.

2. The method of claim 1, wherein the body structure having a plurality of cavities is fabricated by photo-curing 3D printing.

3. The method of claim 1, wherein the solubility of the nanoparticle solution filled in any one of the cavities is different, such that the recovery rate of the shaped bulk structure can be controlled by the external excitation according to the difference of the solubility.

4. The method of claim 1, wherein the nanoparticle solution filled in the cavities is carbon nanotube solution, and the carbon nanotube solution is heated by the radio frequency electric field.

5. The method according to claim 1, wherein the nanoparticle solution filled in the cavities is entirely magnetic fluid, and the alternating magnetic field is used to generate heat.

6. The method according to claim 1, wherein the nanoparticle solution filled in one part of the cavity is magnetic fluid, and the nanoparticle solution filled in the other part of the cavity is carbon nanotube solution, so that the shaped body structure can be selectively restored in a radio frequency electric field or an alternating magnetic field.

7. The method of claim 1, wherein the ratio of the thickness of the cavity to the thickness of the body structure is 1:2 to 1: 4.

8. The selectively-responsive shape memory polymer structure prepared by the method for preparing the selectively-responsive shape memory polymer structure according to claim 1, which comprises a body structure and a nanoparticle solution, wherein a plurality of cavities are arranged in the body structure, and the nanoparticle solution is filled in the cavities.

Technical Field

The invention relates to the field of shape memory material preparation, in particular to a shape memory polymer structure capable of selectively responding and a preparation method thereof.

Background

Shape Memory Polymers (SMPs), which are excellent stimuli-responsive materials, have the ability to return from a temporary shape to a permanent shape upon application of an external stimulus, and their shape memory effect can be triggered by direct heat, magnetic field, electricity, light, water, and like stimuli. Shape memory polymers are currently used in a variety of fields, such as spatially expandable structures, joint muscles, intelligent actuators, minimally invasive surgical sutures, tissue engineering scaffolds, mobile assembly/disassembly and textiles, among others.

Most of the existing shape memory polymers can only respond to a single external excitation mode, and can not use multiple excitation modes for selectively and controllably recovering the shape. For example, pure shape memory polylactic acid has a single thermally responsive shape memory capability. Some shape memory polymers have two excitation modes, for example, magnetic response capability can be endowed to materials by adding magnetic nanoparticles into a matrix, and magnetic response and thermal response can be simultaneously realized, but because the excitation is realized by thermal response essentially, and particles are uniformly distributed in the whole matrix, selective recovery of different parts of a sample cannot be respectively carried out by using an alternating magnetic field and direct heating, and sequential recovery of different parts of the sample cannot be realized.

To achieve a selective response of shape memory polymers to a variety of external stimuli, existing studies have mainly imparted additional modes of excitation to shape memory polymers and nanoparticle solutions by direct blending thereof. The subject group of the Cold-stiff pine of Harbin industry university is prepared by respectively blending nano Fe into a shape memory polymer matrix₃O₄And carbon nano-tube, SMP and nano Fe are polymerized by step-by-step thermal polymerization₃O₄Preparation of three different regions of a sample from the SMP blend and the carbon nanotube-SMP blend, the sample being passed through an alternating magnetic field (Fe)₃O₄SMP domain response), radio frequency field (CNT-SMP domain response) and direct heating (SMP domain response), wherein each domain is only responsive to a specific one of the excitation modes. The above documents only allow simple production of rectangular structures, which is difficult to form complicated structures, and have high requirements on the adhesion of materials, which greatly limits the choice of materials.

Chinese patent literature discloses a preparation method of a micropattern film with selective stimulus recovery function, which is prepared by mixing Fe₃O₄Carbon nano tube and spiropyran are respectively mixed with SMP, and respectively dropped on 4 connected silicon wafers with surface micropatterns to make them implement heat curing, and the formed square piece can be used for magnetic field (Fe)₃O₄SMP domain response), radio frequency field (carbon nanotube-SMP domain response), ultraviolet light (spiropyran-SMP domain response) and heat (SMP domain response) to perform selective shape recovery. The preparation method of the above patent is very cumbersome, requires a special mold, and requires a lot of time for block polymerization.

The above patents and documents all give additional excitation means by direct blending of shape memory polymer and nanoparticle solution, however, the blending method has more disadvantages: firstly, the requirement on the precision of the process is high, the dispersion degree, the particle content and the contact between the particle surface and the matrix of the nanoparticle solution in the SMP can greatly influence the printability, the shape memory capability and the mechanical property of the blended composite material, and the dispersion degree, the content, the surface modification mode, the particle size and the particle type of the nanoparticle solution need to be accurately controlled so as to reduce the agglomeration of the nanoparticle solution in the resin. Direct blending of nanoparticle solutions also limits the processing means of the materials, for example, particles inside the resin can refract ultraviolet laser, and long-time printing can cause deposition of particles inside the resin, so that the directly blended materials cannot be suitable for the photocuring 3D printing process.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a shape memory polymer structure with selective response and a preparation method thereof, and solves the problems of complicated working procedures, limited processing mode and the like caused by the adoption of a blending means to prepare a shape memory composite structure in the prior art.

The present invention achieves the above-described object by the following technical means.

A method of making a selectively responsive shape memory polymer structure comprising the steps of:

manufacturing a body structure with a plurality of cavities by using a shape memory polymer;

filling a nanoparticle solution in a cavity of the body structure, wherein the nanoparticle solution can generate heat under the action of external excitation;

heating the body structure filled with the nano particle solution, and deforming the body structure through external force; and cooling and shaping the deformed body structure, wherein the shaped body structure can be restored to the body structure before the deformation of the external force under the external excitation action.

Further, a body structure with a plurality of cavities is manufactured through photocuring 3D printing.

Furthermore, the solubility of the nanoparticle solution filled in any cavity is different, so that the recovery speed of the shaped body structure can be controlled according to different solubility under the action of external excitation.

Furthermore, all the nano particle solutions filled in the cavities are carbon nano tubes, and heat is generated under the action of a radio frequency electric field.

Furthermore, all the nano particle solutions filled in the cavities are magnetic fluids, and heat is generated under the action of the alternating magnetic field.

Furthermore, a part of the nano particle solution filled in the cavity is magnetic fluid, and the other part of the nano particle solution filled in the cavity is carbon nano tubes, so that the selective recovery of the shaped body structure under a radio frequency electric field or an alternating magnetic field is realized.

Further, the ratio of the thickness of the cavity to the thickness of the body structure is 1: 2-1: 4.

The shape memory polymer structure capable of selectively responding prepared by the preparation method of the shape memory polymer structure capable of selectively responding comprises a body structure and a nano particle solution, wherein a plurality of cavities are formed in the body structure, and the nano particle solution is filled in the cavities.

The invention has the beneficial effects that:

1. the preparation method of the shape memory polymer structure capable of selectively responding, disclosed by the invention, can endow the structure with multiple excitation modes, sequential controllable response capability and capability of selectively responding to multiple external stimuli by selectively injecting particle liquids of various types and different concentrations into the cavity.

2. The preparation method of the shape memory polymer structure capable of selectively responding does not adopt the traditional blending means, and does not need to consider the dispersion degree of the particles in the matrix and the contact condition of the particle surface and the matrix.

3. The invention widens the manufacturing means of the shape memory composite material, and can adopt all 3D printing modes including photocuring printing to manufacture the shape memory composite structure.

4. The structure proposed by the invention allows to easily change the excitation mode by replacing the liquid in the holes after the manufacture is completed.

5. The invention only needs to adopt any one conventional desktop-level 3D printing equipment for one-step molding, can prepare samples with various complex structures, greatly improves the application flexibility and the manufacturing efficiency of the composite structure, greatly shortens the manufacturing period of the complex structure and reduces the manufacturing cost of the complex structure.

6. The invention can realize the controllable deformation of the shape memory polymer under the action of different external stimuli by controlling the shape of a printing piece, the wall thickness and the number of the grooves/holes, the category and the concentration of the injected dispersion liquid and the like.

Drawings

Fig. 1 is a schematic diagram of a modification of embodiment 2 of the present invention.

Fig. 2 is a schematic diagram of a modification of embodiment 3 of the present invention.

Fig. 3 is a schematic diagram of a modification of embodiment 4 of the present invention.

Detailed Description

The invention will be further described with reference to the following figures and specific examples, but the scope of the invention is not limited thereto.

The preparation method of the shape memory polymer structure capable of selectively responding comprises the following steps:

printing a body structure with a plurality of cavities by using a shape memory polymer through a 3D printing device;

weighing a certain mass of nano particles, adding the nano particles into solvents such as silicone oil, water and the like, and stirring to prepare a particle solution with a certain concentration; and filling a nano particle solution in the cavity of the body structure, and sealing by using AB glue after injection. The nanoparticle solution can generate heat under the action of external excitation;

heating the body structure filled with the nano particle solution, and deforming the body structure through external force; and cooling and shaping the deformed body structure, wherein the shaped body structure can be restored to the body structure before the deformation of the external force under the external excitation action.

The nano particle solution added in the invention is magnetic fluid, carbon nano tube solution or other particles which can generate heat under the action of special external excitation such as a magnetic field or a radio frequency field. Injecting particle liquids with different particle types into different cavities can endow the body structure with multiple excitation modes and selective recovery capability under different excitation modes.

The heating rate is faster as the concentration of the nanoparticle solution is higher, and the heating rate of different parts can be controlled by injecting liquid with different concentrations into different cavities, so that the sample has the capability of sequential controllable recovery.

The concentration, the particle size and the content of the injected particle liquid and the size, the shape and the position of the cavity can be flexibly designed and adjusted according to the processing requirement and the matrix performance, and the particle liquid is prepared and obtained through 3D printing.

After the cavity is sealed, the sealing AB glue can be removed subsequently, and the particle liquid in the cavity is replaced to obtain different excitation modes and effects. The thinner the thickness of the cavity, the better the shape memory of the sample, but the slower the heat transfer rate, the slower the deformation rate. The ratio of the thickness of the cavity to the total thickness of the sample is 1: 2-1: 4.

Example 1

80% epoxidized soybean oil acrylate and 20% methacrylic acid were blended to prepare a shape memory polymer, and an LCD photocuring printer was used to print a rectangular groove having an outer cross-sectional dimension of 10X 2.5mm²The cross-sectional dimension of the groove is 8 multiplied by 2mm²The length of the body is 50 mm. Cleaning uncured resin inside and outside the sample by using absolute ethyl alcohol, and sealing one end of the groove by using AB glue after cleaning;

mixing 30% of nano Fe by mass₃O₄Adding dimethyl silicone oil, performing ultrasonic dispersion for 20 minutes, injecting the mixed particle liquid into the sample from the unsealed end of the through groove, and sealing by using AB glue after injection. Nano Fe₃O₄The relaxation phenomenon can occur under the action of the alternating magnetic field, so that heat is generated, and the sample can be endowed with additional magnetic response capability.

Heating the body with hot water, bending by applying external force, shaping in cold water for 5 min, and placing the shaped body in alternating magnetic field to obtain nanometer Fe₃O₄The relaxation phenomenon generates heat rapidly, so that the shape of the sample recovers after the temperature of the sample rapidly exceeds the glass transition temperature of the sample, and the recovery time is about 30 seconds.

Example 2, as shown in figure 1:

80% epoxidized soybean oil acrylate and 20% methacrylic acid were blended to prepare a shape memory polymer, and an LCD photocuring printer was used to print a rectangular slot having dimensions of 10X 2.5X 50mm³The rectangular piece is provided with 2 through grooves along the length direction, and the section size of each through groove is 20 multiplied by 2mm². Cleaning uncured resin inside and outside the sample by using absolute ethyl alcohol, and sealing one end of the groove by using AB glue after cleaning;

respectively preparing Fe with the mass fraction of 30 percent and 40 percent₃O₄And dimethyl silicone oil dispersion liquid, which is respectively injected into the two through grooves, and AB glue is used for sealing after the injection is finished. Nano Fe₃O₄The speed and magnitude of the heat generated by the alternating magnetic field is related to the particle content, with more particles generating heat more quickly and at higher temperatures.

The sample is heated by hot water, an external force is applied to bend the body into an S shape along the two through grooves, the S shape is placed in cold water for shaping for 5 minutes, the shaped sample is placed in an alternating magnetic field, the temperature rising speed is high at the place with high particle concentration, the recovery speed is high, the temperature rising speed is low at the place with low particle concentration, the recovery speed is low, and therefore sequential recovery is achieved. Meanwhile, the accurate control of the sample recovery degree can be realized by adjusting the components and the concentration of the dispersion liquid.

Example 3, as shown in fig. 2:

80% epoxidized soybean oil acrylate and 20% methacrylic acid were blended to prepare a shape memory polymer, and an LCD photocuring printer was used to print a rectangular slot having dimensions of 10X 2.5X 50mm³The rectangular groove is provided with 2 through grooves along the length direction, and the section dimension is 20 multiplied by 2mm². Cleaning uncured resin inside and outside the sample by using absolute ethyl alcohol, and sealing one end of the groove by using AB glue after cleaning;

respectively preparing Fe with the mass fraction of 40%₃O₄And respectively injecting the dispersion liquid and the carbon nano tube dispersion liquid into the two through holes, and sealing by using AB glue after injection. Using Fe₃O₄And carbon nanotubesThe material has the characteristic of generating heat under an alternating magnetic field and a radio frequency electric field of certain frequency, and additional magnetic response and radio frequency electric field response capabilities are given to the material.

The sample is heated by hot water, and after an external force is applied to bend the body into an S shape along the two through holes, the body is placed in cold water for setting for 5 minutes. Firstly, putting the shaped body into an alternating magnetic field, wherein the alternating magnetic field is Fe₃O₄Generates heat after relaxation phenomenon in a magnetic field, resulting in filling with Fe₃O₄The portion of the dispersion is quickly recovered and the carbon nanotubes do not generate heat in the alternating magnetic field, so that the shape of the portion filled with the carbon nanotubes remains unchanged. And subsequently, the sample is placed in a radio frequency field, and the carbon nano tubes generate heat under the action of the radio frequency field, so that the part filled with the carbon nano tube dispersion liquid is subjected to rapid shape recovery. Thereby achieving selective recovery under different excitation modes.

Example 4, as shown in fig. 3:

blending 80% of epoxidized soybean oil acrylate and 20% of methacrylic acid to prepare a shape memory polymer, and printing a flower-shaped sample by using an LCD photocuring printer, wherein six petals are in a hollow structure; the uncured resin inside and outside the sample was cleaned with absolute ethanol.

Adding magnetic fluid into 3 petals, adding carbon nanotube dispersion liquid into the other 3 petals, and sealing with AB glue. The sample was put into hot water to apply an external force to deform it into a bud shape, and then put into cold water to cool and set for 5 minutes. Putting the shaped sample into an alternating magnetic field, and filling the sample with Fe₃O₄The petals of the dispersion spread rapidly, while the shape of the petals filled with carbon nanotubes remains unchanged. The sample was subsequently placed in a radio frequency field and the petals filled with carbon nanotubes rapidly spread. And different particle liquids can be filled in the adjacent petals.

The present invention is not limited to the above-described embodiments, and any obvious improvements, substitutions or modifications can be made by those skilled in the art without departing from the spirit of the present invention.