Foldable and deployable support rod based on coupling of shape memory effect and pneumatic effect and preparation method thereof

Abstract

The application discloses a foldable and unfolded supporting rod based on coupling of shape memory effect and pneumatic effect and a preparation method thereof, and belongs to the field of shape memory material preparation.The supporting rod comprises a shell, an inner container, end head covers and a gas valve.The inner container is a sealed cylindrical polyimide film inflatable inner container, both sides of which are provided with the end head covers for sealing, and the lower end cover side is provided with an inflation port for inflation and unfolding of the supporting rod and stable pressure maintaining.The shell is an epoxy resin-acrylate / strengthening fiber composite material, which is used for realizing softening, flexible deformation and rigid support of the intelligent strengthening structure.The shape memory inflatable supporting rod has the advantages of light weight, simple and easy control and strong stability.Based on the unfolding and automatic retraction capacity of the shape memory inflatable supporting rod, the supporting rod can realize directional support or driving directional movement of various objects, and can give different temporary shapes according to the complexity of the use position, so that the supporting rod can be unfolded / retracted as required and has universal application capacity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of shape memory material preparation, and particularly relates to a foldable and deployable support rod based on coupling of shape memory effect and pneumatic effect and a preparation method thereof. BACKGROUND

[0002] Intelligent material is a new type of intelligent multifunctional material capable of sensing external environment changes and autonomously judging, processing and responding moderately, and is the fourth generation of material after natural material, synthetic polymer material and artificially designed material. The rise of intelligent material has triggered a new revolution in material science. At present, shape memory intelligent structural material can be roughly divided into two categories, one is shape memory alloy made of titanium nickel and other alloys, and the other is shape memory polymer compounded by resin curing agent. Both of the two types of shape memory materials have unique characteristics and play a huge role in the fields of aerospace, national defense and microelectronic sensors.

[0003] Shape memory polymer has many advantages such as light weight, easy manufacturing, high shape deformation rate and adjustable shape transition temperature, and has been proved to be used as an active deformation structure in the field of aviation and aerospace. However, the poor mechanical properties of shape memory polymer material limit its application range. Researchers have introduced nanoparticles, carbon fibers, glass fibers and other fillers into shape memory polymer to improve the performance of the polymer and have obtained a large number of experimental results. There are also some studies on improving the overall shape memory performance by combining shape memory alloy wires, but there are few reports on the application of composite structures combining fibers and shape memory materials in deformable support structures.

[0004] So far, the research on intelligent structural material has attracted widespread attention. However, the current research is often based on the performance of a single material to exhibit the function of the structure, and how to effectively integrate multiple different intelligent features to design and prepare a structure with high intelligent degree and strong controllable performance is still rarely reported. SUMMARY

[0005] The purpose of the present application is to effectively integrate multiple different intelligent features, and to provide a foldable and deployable support rod based on coupling of shape memory effect and pneumatic effect and a preparation method thereof. According to the actual needs of lightweight deployable structures, the present application proposes to effectively integrate different intelligent features of materials (such as soft / rigid convertible features and shape memory deformation features), and designs a new type of intelligent reinforced structural material, which not only provides a technical solution for deployable nozzles, but also is expected to provide potential technical support in other devices.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] A foldable and deployable support rod based on coupling of shape memory effect and pneumatic effect, the support rod comprising a shell, an inner container, end caps and a gas valve;

[0008] The inner container is a sealed cylindrical polyimide film inflatable container, both sides of which are provided with end caps for sealing, and an inflation port is designed on the side of the lower end cap for inflation and deployment of the support rod and stable pressure retention.

[0009] The shell is an epoxy-acrylate / strengthening fiber composite material, which is used to realize intelligent strengthening structure heating softening, flexible deformation and rigid support.

[0010] Further, the reinforcing fiber is carbon fiber or aramid fiber.

[0011] A preparation method of the above-mentioned foldable and deployable support rod based on coupling of shape memory effect and pneumatic effect, the method comprising:

[0012] Step one: preparation of the support rod inner container: first cut the polyimide film to the designed size, glue the wide side with two end caps, and seal the long side by gluing;

[0013] Step two: preparation of the shape memory composite material shell: take 2-5g of acrylate A, 0.2-0.6g of acrylate B, 0.04g of photoinitiator 2-2-dimethoxy-2-phenylphenylacetophenone and 4-8g of epoxy resin, mix them evenly by heating, cool to room temperature, add 1-4g of curing agent, heat in an oven to make the mixture thin, pour the resin mixture on the surface of the reinforcing fiber cloth according to the proportion of 60-80 mass%, make the resin coat evenly on the surface of the fiber, and remove the surface bubbles; ultraviolet irradiation, turn over the composite fiber, and ultraviolet irradiate the back surface to make the resin react in the first stage, obtaining a flexible composite material shell;

[0014] Step three: preparation of the shape memory support rod: wrap the flexible composite material shell obtained in step two outside the support rod inner container, shape the support rod, and put it into an oven at 80℃ for 2h to make the resin in the composite material react in the second stage, the composite material changes from flexible to rigid, obtaining a shape memory support rod.

[0015] Step four: support rod deployment process, first heat the support rod in an oven at 80℃ for 10min, then take it out, bend it and clamp the middle part with a butterfly clamp, fix it in a "convex" shape and cool it down, giving the support rod a temporary shape, as shown in the accompanying Figure 4 Subsequently, high-temperature gas at 80℃ is introduced into the support rod, under the combined action of shape memory effect and gas pressure, the support rod returns to the vertical permanent state, as shown in the accompanying Figure 5 .

[0016] Further, in step one, end cap A bonding area, end cap B bonding area, side positive bonding area, side reverse bonding area are set around the polyimide film, for bonding when the liner is formed; the side reverse bonding area is coated with quick finish glue; after waiting for the side reverse bonding area to complete the glue coating, the area is covered with a polyvinyl chloride sheet to prevent accidental bonding during operation; then the end cap A bonding area, end cap B bonding area and side positive bonding area are coated with quick finish glue, twice, with a 20 min interval; after completing the glue coating of the liner film, the side of the end cap is coated with quick finish glue, twice, with a 20 min interval; after the end cap glue coating is complete, end caps A and B are bonded to the corresponding positions of the film, and the front and back bonding positions of the side of the film are bonded, to finally obtain the finished inflatable liner. The entire support rod was subjected to airtightness testing, and after 1440 min, the internal pressure of the support rod remained stable and did not decrease significantly, as shown in Figure 9 .

[0017] Further, in step two, 2-5 g of acrylate A, 0.2-0.6 g of acrylate B, 0.04 g of photoinitiator 2-2-dimethoxy-2-phenylphenylacetophenone, and 4-8 g of epoxy resin are placed in a disposable plastic cup, heated in an oven at 80°C for 5-20 min to mix the reagents uniformly, removed and stirred with a glass rod and cooled to room temperature, 1-4 g of curing agent is added, placed in an oven at 80°C for 3-10 min to make the mixture thin for subsequent vacuum degassing, the resin mixture is poured onto the surface of a reinforcing fiber cloth with a length of 150 mm and a width of 52 mm according to the proportion of 60-80 mass% of glue content, the resin is evenly coated on the surface of the fiber to remove surface bubbles; then placed under a 365 nm ultraviolet lamp, irradiated at an intensity of 50 mW / cm 2 for 5-15 min; the composite fiber is turned over, the back is irradiated for 5-15 min, the resin undergoes the first stage of reaction, and a flexible composite material shell is obtained.

[0018] Further, in step two, the acrylate A is one of CN966, CN996, CN9021, CN9001, and CN9006; the acrylate B is one of SR399, CN8000, SR351, and SR350; the epoxy resin is one of E51, E44, and TDE85; and the curing agent is one of polyetheramine D-230, polyetheramine D400, and isophorone diamine.

[0019] Further, in step three, the flexible composite shell is stacked together and stitched on one side using aramid thread; the prepared inflatable inner bag is placed in the composite sandwich, and the other side of the composite is stitched to wrap the inflatable inner bag in the composite; after stitching, the excess fibers on both sides of the composite are trimmed with scissors, and the stitching area is bonded with polyimide tape to prevent damage to the stitching area.

[0020] Further, in step two, after removing the surface bubbles, the polyimide self-made heating film with conductive wires is cut to the corresponding size, adhered to one side of the carbon fiber cloth with resin, and the two conductive wire heads are inserted from the other side of the polyimide film. After the support rod contains the conductive wire, the specific control process is as follows: adjust the power supply controller to 1A current, pass the current through the conductive wire to the support rod for 5 minutes, then gradually increase the temperature of the composite shell to above 80℃, then take out the support rod and bend it and clamp the middle part with a butterfly clamp, fold it and cool it to fix it, giving the support rod a temporary shape. Then pass the current to the support rod for 5 minutes, and then introduce gas into the support rod. Under the combined action of shape memory effect and gas pressure, the support rod returns to the vertical permanent state, as shown in FIG. 8. Figure 7

[0021] The beneficial effects of the present application relative to the prior art are:

[0022] 1. The shape memory inflatable support rod prepared by the present application is a tubular composite material composed of polyimide film, shape memory resin and fiber, which has the advantages of light weight, simple operation, and strong stability.

[0023] 2. The shape memory inflatable support rod can realize directional support or drive directional movement of various objects based on its unfolding and automatic retraction ability, such as application in an unfoldable nozzle, which can realize rapid and controllable unfolding of the nozzle, and can give it different temporary shapes according to the complexity of the use position, achieving unfolding / retraction on demand, and having good universal application ability. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a schematic diagram of the support rod unfolding and shrinking;

[0025] Figure 2 is a schematic diagram of the intelligent deformable support rod structure;

[0026] Figure 3 is a schematic diagram of the support rod inner bag size design;

[0027] Figure 4 is a photo of the support rod folding and fixing;

[0028] Figure 5 ​Photos of shape memory support rod inflation deployment process;

[0029] Figure 6 Intelligent variable shape support rod structure with heating wire;

[0030] Figure 7 Photos of shape memory support rod heating inflation deployment process;

[0031] Figure 8 Photos of shape memory support rod heating inflation deployment and heating retraction process;

[0032] Figure 9 Shape memory support rod pressure maintaining performance test diagram. DETAILED DESCRIPTION

[0033] The technical solutions of the present application are further described below in combination with the drawings and examples, but are not limited thereto. Any modification or equivalent replacement of the technical solutions of the present application without departing from the spirit of the technical solutions shall be covered in the protection scope of the present application.

[0034] The shape memory effect of the shape memory support rod is derived from the shape memory resin used. In the present application, the resin polymer used has a crosslinked network structure, and the resin form after high temperature curing is the permanent form of the material. At this time, the polymer network conformation is in a thermodynamic stable state, and the material has a high stiffness at room temperature. When the resin material is heated, the resin material changes from a glassy state to a rubbery state when the temperature is higher than its glass transition temperature, and the modulus of the entire material sharply decreases, and the material becomes soft. At this time, the shape of the material can be deformed arbitrarily under the action of an external force. With the change of the shape of the material, the polymer network conformation also changes accordingly. At this time, the polymer network conformation is in a thermodynamic metastable state, and with the decrease of temperature, the mobility of the molecular chain decreases. When cooled to room temperature, the entire molecular chain will be locked again, so that the result reflected in the macroscopic shape is that the material remembers to keep its temporary form. When the resin is heated again, the mobility of the polymer molecular chain is enhanced again when the temperature is higher than its glass transition temperature. At this time, due to the principle of entropy increase, the polymer network will spontaneously change from its metastable state to the thermodynamic stable state, and at the same time, the spontaneous change of its shape from the temporary form to the permanent form is exhibited in the macroscopic form.

[0035] The controllable deployment of the support rod depends on the shape memory characteristics of the resin material. As shown in the accompanying drawings, Figure 1As shown, the prepared support rod is in a folded shape and is in a rigid state at room temperature, so it can maintain a stable folded shape. When the intelligent reinforced structure needs to be deployed, the support rod is heated to soften it, and then quickly inflated. Under the action of air pressure, the softened and easily deformed composite material tube will change to a vertical deployed form. In the inflated state, the temperature is lowered to room temperature, and the support rod reverts to a rigid state, regaining its support ability. After heating again, the contraction is completed, realizing the reversible stretching and contraction control of the intelligent reinforced structure.

[0036] Example 1:

[0037] The shape memory support rod designed in this embodiment is composed of a shell, an inner container, an end cap and a gas valve. The inner layer is a sealed resin film inflatable container, and end caps are installed on both sides for sealing. An inflation port is designed on the lower end cap side for the inflation and stable pressure retention of the support rod. The outer layer is an epoxy resin-acrylate / aramid fiber composite material, which is used to realize the softening, flexible deformation and rigid support of the intelligent reinforced structure after heating.

[0038] 1. Preparation of support rod inner container. The design of the film of the inner container is shown in the attached Figure 3 As shown, the length is 150 mm, the width is 62.8 mm, and end cap A bonding areas, end cap B bonding areas, side positive bonding areas and side reverse bonding areas are arranged on the four sides for bonding during the molding of the inner container. First, the polyimide film is cut to the designed size, then the side reverse bonding area is coated with fast adhesive. After the side reverse bonding area is coated with glue, the area is covered with a polyvinyl chloride sheet to prevent accidental bonding during operation. Then, the end cap A bonding area, the end cap B bonding area and the side positive bonding area are coated with fast adhesive, twice, with an interval of 20 min. After the inner container film is coated with glue, the side of the end cap is coated with fast adhesive, twice, with an interval of 20 min. After the end cap is coated with glue, the end cap A and B are bonded to the corresponding positions of the film, and the positive and negative bonding positions of the side of the film are bonded, finally obtaining the inflatable inner container product.

[0039] 2. Preparation of the shape memory composite shell, after the inner bag is completed, the composite material of the support rod is further prepared, first cut two pieces of aramid fiber with the length and width of 150mm and 52mm respectively, and use masking tape to bond around to prevent the fiber from falling off. Take 3.6g of acrylate CN966, 0.4g of acrylate SR399, 0.04g of light initiator 2-2-dimethoxy-2-phenylphenylacetone and 6g of epoxy resin E51 and place them in a disposable plastic cup, heat them in an oven at 80℃ for 10min to mix them evenly, take them out and stir them with a glass rod and cool them to room temperature, add 2g of curing agent polyetheramine D230, heat them in an oven at 80℃ for 5min to make the mixture thin for subsequent vacuuming to remove bubbles, pour a certain amount of resin mixture on the surface of the fiber cloth, evenly coat the resin on the surface of the fiber, and remove the surface bubbles. Then place it under a 365nm ultraviolet lamp and irradiate it for 10min under the intensity of 50mW / cm 2 . Turn over the composite fiber and irradiate the back for 10min to make the resin react in the first stage to obtain a flexible composite shell.

[0040] 3. Preparation of the shape memory support rod, superimpose the two flexible composite shells obtained above on each other, then sew one side using aramid thread. Put the prepared inflatable inner bag into the composite sandwich, sew the other side of the composite, and wrap the inflatable inner bag in the composite. After sewing, trim the excess fiber on both sides of the composite using scissors, then use polyimide tape to bond the sewing area to prevent damage to the sewing area. Finally, heat it in an oven at 80℃ for 2h to make the resin in the composite react in the second stage, and the composite changes from flexible to rigid. After the reaction is completed, remove the tape and trim the composite at the inflation port to finally obtain a rigid shape memory support rod.

[0041] 4. Support rod deployment process, first heat the support rod in an oven at 80℃ for 10min, then bend the support rod and clamp the middle part with a butterfly clamp, fix it in a "convex" shape and cool it down to give the support rod a temporary shape, as shown in FIG. 4. Then, pass 80℃ hot gas into the support rod, under the combined action of shape memory effect and air pressure, the support rod returns to the vertical permanent state, as shown in FIG. 5. Figure 4 Figure 5

[0042] Example 2:

[0043] The difference between this example and example 1 is that the composite shell of the support rod is different, the shell material is selected as carbon fiber and is compounded with heating wire, as shown in FIG. 6, so the deployment process is also different. Figure 6

[0044] ​​​1. Preparation of shape memory composite shell, after the inner bag is made, cut out a polyimide film with a size of 18 cm long and 12.5 cm wide and a carbon fiber cloth, and spread the polyimide film evenly under the cut fiber cloth. The adhesive tape is adhered to the two sides of the fiber cloth to prevent the carbon fiber cloth from scattering and to maintain the regularity of the carbon fiber cloth. Take 3.6 g of acrylate CN966, 0.4 g of acrylate SR399, 0.04 g of light initiator 2-2-dimethoxy-2-phenylphenylacetone and 6 g of epoxy resin E51 into a disposable plastic cup, and put it into an oven at 80°C for 10 min to mix the reagents evenly. Take out and stir with a glass rod and cool to room temperature. Add 2 g of curing agent polyetheramine D230, and put it into an oven at 80°C for 5 min to make the mixture thin and facilitate the subsequent vacuum degassing. Pour a certain amount of resin mixture onto the surface of the fiber cloth, coat the resin evenly on the fiber surface, and remove the surface bubbles. Then, cut the self-made polyimide film with conductive wire to the corresponding size, adhere it to one side of the carbon fiber cloth with resin, and insert two conductive wire heads from the other side of the polyimide film (pointing to the heating wire in the polyimide film, avoiding contact with the carbon fiber to cause short circuit). Then place it under a 365 nm ultraviolet lamp at an intensity of 50 mW / cm 2 for 10 min to obtain a flexible composite shell.

[0045] 2. Preparation of shape memory support rod: wrap the prepared composite shell around the prepared inflatable tube liner, then use needle thread to sew the side gap, cut off the excess part with scissors after sewing, and fix the bottom with a fixing ring. Place it in an oven at 80°C for 2h to completely cure, and you can get a rigid support rod with shape memory performance.

[0046] 3. Adjust the power controller to 1A current, and pass the current through the conductive wire to the support rod for 5 min, then the temperature of the composite shell gradually rises above 80°C, then take out and bend the support rod and clamp the middle part with a butterfly clamp, in a folded state and cooled to fix it, giving the support rod a temporary shape. Pass the current to the support rod for 5 min, then pass the gas into the support rod, under the combined action of shape memory effect and gas pressure, the support rod returns to the vertical permanent state, as shown in FIG. 2. Figure 7

[0047] Example 3:

[0048] The difference between this example and example 2 is the permanent shape of the support rod, so the support rod will automatically retract after unfolding under the action of shape memory.

[0049] ​1. The prepared composite material shell is wrapped on the prepared inflatable tube liner, then the needle thread is used to suture the closure of one side, after the suture is completed, the excess part is cut off with scissors, the supporting rod is bent and the middle part is clamped with a butterfly clamp, which is fixed in a folded state, and is put into an oven at 80℃ for heating for 2h, and a shape memory supporting rod in a permanent shape in a contracted state is obtained.

[0050] 2. The power supply controller is adjusted to 1A current, the conducting wire is electrified for 5min, then gas is introduced into the supporting rod, under the combined action of shape memory effect and gas pressure, the supporting rod is elongated to an unfolded state, the current is kept unchanged and the inflation pump is removed, the supporting rod slowly shrinks to a folded state under the action of shape memory effect, as shown in the accompanying drawings. Figure 8 ​

Claims

1. A method for preparing a foldable and deployable support rod based on the coupling of shape memory effect and pneumatic action, characterized in that: The support rod comprises an outer shell, an inner shell, an end cap and an air valve; The inner liner is a sealed cylindrical polyimide film inflatable liner with end caps installed on both sides for sealing. An inflation port is designed on the side of the lower end cap for inflation and stable pressure maintenance of the support rod; The shell is an epoxy resin-acrylate / reinforced fiber composite material, which is used to realize heating softening, flexible deformation and rigid support of the intelligent reinforced structure; the reinforcing fiber is carbon fiber or aramid fiber; The method is: Step 1: Preparation of the support rod liner: First, cut the polyimide film to the designed size, glue the wide side to the two end caps, and seal the long side by gluing. In step 1, set the end cap A bonding area, end cap B bonding area, side positive bonding area, and side negative bonding area around the polyimide film for bonding during the liner molding process. Apply Quick-drying glue to the reverse bonding area on the side; After the glue coating of the side reverse bonding area is completed, cover the area with a polyvinyl chloride sheet to prevent accidental bonding during operation; then apply quick-drying glue to the bonding area of ​​end cap A, the bonding area of ​​end cap B, and the positive bonding area of ​​the side, twice with an interval of 20 minutes; after the glue coating of the liner film is completed, apply quick-drying glue to the side of the end cap, twice with an interval of 20 minutes; after the glue coating of the end cap is completed, bond the end caps A and B to the corresponding positions of the film respectively, and then bond the positive and negative bonding positions of the side of the film to finally obtain the finished inflatable liner; Step 2: Preparation of shape memory composite shell: 2-5 g of acrylate A, 0.2-0.6 g of acrylate B, 0.04 g of photoinitiator 2-2-dimethoxy-2-phenylacetophenone, and 4-8 g of epoxy resin are placed in a container and heated to mix the reagents evenly. After cooling to room temperature, 1-4 g of curing agent is added and the mixture is heated in an oven to dilute it. The resin mixture is poured onto the surface of the reinforced fiber cloth at a ratio of 60-80 mass% of glue content to evenly coat the fiber surface with the resin and remove surface bubbles. After UV irradiation, the composite fiber is turned over and the back side is UV irradiated to cause the resin to undergo the first stage reaction, thereby obtaining a flexible composite shell. Step 3: Preparation of shape memory support rod: Wrap the flexible composite material shell obtained in step 2 around the outside of the support rod inner shell, shape the support rod, and place it in an oven and heat it at 80°C for 2 hours to allow the resin in the composite material to undergo the second stage reaction. The composite material changes from flexible to rigid, and a shape memory support rod is obtained.

2. The method for preparing a foldable and deployable support rod based on the coupling of shape memory effect and pneumatic effect according to claim 1, characterized in that: In step 2, 2-5 g of acrylate A, 0.2-0.6 g of acrylate B, 0.04 g of photoinitiator 2-2-dimethoxy-2-phenylacetophenone and 4-8 g of epoxy resin were placed in a disposable plastic cup, placed in an oven and heated at 80 ° C for 5-20 min to mix the reagents evenly, taken out and stirred with a glass rod and cooled to room temperature, 1-4 g of curing agent was added, placed in an oven and heated at 80 ° C for 3-10 min to make the mixture thinner for subsequent vacuum removal of bubbles, and the resin mixture was poured on the surface of the reinforced fiber cloth with a length and width of 150 mm and 52 mm respectively according to the glue content of 60-80 mass%, and the resin was evenly coated on the fiber surface to remove surface bubbles; then placed under a 365 nm ultraviolet lamp at 50 mW / cm 2 The composite fiber is turned over and the back side is irradiated for 5 to 15 minutes to make the resin undergo the first stage reaction and obtain a flexible composite material shell.

3. The method for preparing a foldable and deployable support rod based on the coupling of shape memory effect and pneumatic effect according to claim 1, characterized in that: In step 2, the acrylate A is one of CN966, CN996, CN9021, CN9001, and CN9006; the acrylate B is one of SR399, CN8000, SR351, and SR350; the epoxy resin is one of E51, E44, and TDE85; and the curing agent is one of polyetheramine D-230, polyetheramine D400, and isophorone diamine.

4. The method for preparing a foldable and deployable support rod based on the coupling of shape memory effect and pneumatic effect according to claim 1, characterized in that: In step three, the flexible composite shell is stacked up and down, and then sewed on one side with aramid thread; the prepared inflatable inner capsule is placed in the interlayer of the composite material, and then the other side of the composite material is sewed to wrap the inflatable inner capsule in the composite material; after the suturing is completed, the excess fibers on both sides of the composite material are cut with scissors, and then the sutured area is bonded with polyimide tape to prevent the sutured area from being damaged.

5. The method for preparing a foldable and deployable support rod based on the coupling of shape memory effect and pneumatic effect according to any one of claims 1 to 4, characterized in that: In step 2, after removing the surface bubbles, the following steps are also included: cutting the homemade polyimide heating film bonded with conductive wire to the corresponding size, adhering it to one side of the carbon fiber cloth with resin, and inserting two conductive wire heads through the polyimide film on the other side.

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