Terpolymer adhesive material as well as preparation method and application thereof

Abstract

The invention relates to a terpolymer adhesive material as well as a preparation method and application thereof. The terpolymer adhesive material is prepared from octadecyl acrylate, tetradecyl acrylate, N-vinyl pyrrolidone, a cross-linking agent and an initiator. The preparation method comprises the following steps: mixing octadecyl acrylate, tetradecyl acrylate, N-vinyl pyrrolidone, a cross-linking agent and an initiator to obtain a prepolymer solution; and transferring the prepolymer solution into a mold, carrying out free radical random copolymerization reaction at 50-70 DEG C, and then carrying out post-treatment at 90-120 DEG C to obtain the terpolymer adhesive material. Compared with the prior art, the terpolymer adhesive material has the function of on-demand adhesion / deadhesion triggered by skin temperature, and also has the shape memory characteristic and excellent mechanical property.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesive materials, and particularly to a terpolymer adhesive material, a preparation method thereof, and an application thereof. Background Art

[0002] Traditional adhesive materials generally achieve firm and lasting skin adhesion based on chemical adhesion. For example, strong interactions based on covalent bonds have been widely used in electronic skin. Since chemical bonds are broken during separation, most of these adhesive materials can only be used once, so it is difficult to achieve on-demand adhesion-detachment. And residues and damages may be left during separation from the epidermis, which will greatly limit their practical applications. Therefore, adhesive materials also need to have excellent mechanical properties.

[0003] The copolymer formed by monomers A and B can achieve the transition from an amorphous state to a crystalline state. It loses adhesiveness without residue at a lower temperature, and has a wide temperature range, and can achieve the on-demand adhesion / detachment function triggered by skin temperature. For example, the binary copolymer PST of octadecyl acrylate (SA) and tetradecyl acrylate (TA) can achieve the on-demand adhesion / detachment function triggered by skin temperature, but its strength is low.

[0004] Existing methods for improving the strength of the binary copolymer PST include, one method is to increase the crosslinking density and the amount of crosslinking agent. The increase in crosslinking density means an increase in the number of crosslinking points between polymer chains. The crosslinking points fix the polymer chains together, reducing the free movement of polymer chains, thereby improving the tensile strength and rigidity of the material, but at the same time the flexibility of the polymer becomes worse and it is more likely to break; another method is to add nano-fillers or inorganic fillers, such as carbon nanotubes, silica, and barium sulfate. These fillers can improve the rigidity, impact resistance of the polymer, and can also increase the density and hardness of the polymer. However, when adding fillers, the dispersion and compatibility in the matrix need to be considered. The fillers often have the problem of agglomeration. The agglomerated filler particles often become the weakness inside the material, resulting in a decrease in strength and rigidity; and there is no report on the work of copolymerizing with other monomers to greatly improve the mechanical properties.

[0005] Patent Publication No. CN115089753A discloses a preparation method and application of an anti-adhesion double-layer wound patch. The double-layer wound patch is composed of a bottom tissue adhesive and an upper ion-conductive elastomer. The bottom tissue adhesive includes the following components: octadecyl acrylate, tetradecyl acrylate, polyurethane diacrylate, and 2,2-dimethoxy-2-phenylacetophenone. The bottom tissue adhesive provides unique temperature-triggered rapid adhesion / removal and the property of no solid clot complex generation on the wound, thereby preventing wound tearing during the peeling of the patch. However, there is no performance test on the bottom tissue adhesive such as tensile strength. If the mechanical strength is low, it is easy to cause the separation of the bonding part, and even cause the adhesive fragments to enter the surrounding tissues, triggering an inflammatory reaction and causing damage to the surrounding healthy tissues, and its temperature-triggered range is small. Summary of the Invention

[0006] The purpose of the present invention is to overcome the defects of the above-mentioned existing technologies and provide a terpolymer adhesion material, its preparation method and application, so that the obtained terpolymer adhesion material has the function of skin temperature-triggered on-demand adhesion / detachment while having excellent mechanical properties.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] One of the technical solutions of the present invention is to provide a terpolymer adhesion material, which includes octadecyl acrylate, tetradecyl acrylate, N-vinylpyrrolidone (NVP), a cross-linking agent, and an initiator.

[0009] Furthermore, the terpolymer adhesion material has a homogeneous cross-linked network structure. Each monomer unit is randomly distributed on the polymer molecular chain, without obvious phase separation regions. Each macromolecular chain is intertwined with each other to form a continuous overall structure; the cross-linking agent is a monomer with double bonds at both ends, and copolymerizes randomly with the mixed monomers to form a cross-linked structure. The cross-linking points are evenly distributed in the whole system and will not concentrate in certain specific regions. This structure is beneficial to providing good tensile strength, compressive strength, and elastic recovery force; due to the crystallization of the side chain groups melting and unfolding on the surface of the adhered object and adhering through the mechanism of intermolecular force and mechanical interlocking, it can show good adhesion to a variety of substrates, and the firmness after adhesion is relatively high.

[0010] Furthermore, the molar ratio of N-vinylpyrrolidone, octadecyl acrylate, and tetradecyl acrylate is 5-20:2:5-10.

[0011] Furthermore, the mass of the cross-linking agent is 0.05%-0.5% of the sum of the masses of octadecyl acrylate, tetradecyl acrylate, and N-vinylpyrrolidone.

[0012] Furthermore, the mass of the initiator is 0.01% - 0.5% of the sum of the masses of octadecyl acrylate, tetradecyl acrylate, and N-vinylpyrrolidone.

[0013] Furthermore, the crosslinking agent includes 1,6-hexanediol diacrylate and N,N'-methylenebisacrylamide.

[0014] Furthermore, the initiator includes azobisisobutyronitrile, azobisisoheptonitrile, and benzoyl peroxide.

[0015] Furthermore, the triggering temperature for the transformation of the ternary copolymer adhesive material from a semi-crystalline state to an amorphous state is 10 - 20°C. Compared with the binary copolymer material of octadecyl acrylate and tetradecyl acrylate, its triggering temperature range is wider, and the dosage of each component can be adjusted as needed, without the situation where the tensile strength is very low after the temperature is appropriate in the binary copolymer material. The triggering temperature is the melting temperature T m , and it has adhesiveness when it reaches the triggering temperature, and the human body temperature is within the triggering temperature range.

[0016] The second technical solution of the present invention is to provide a preparation method of a ternary copolymer adhesive material, which is characterized in that octadecyl acrylate, tetradecyl acrylate, N-vinylpyrrolidone, a crosslinking agent, and an initiator are mixed to obtain a prepolymer solution; the prepolymer solution is transferred to a mold, and first subjected to a free radical random copolymerization reaction at 50 - 70°C, and then post-treated at 90 - 120°C to make the free radical random copolymerization reaction more complete, obtaining a ternary copolymer adhesive material.

[0017] Furthermore, the time for the free radical random copolymerization reaction is 2 - 10 h, and the time for the post-treatment is 0.5 - 2 h.

[0018] The third technical solution of the present invention is to provide an application of a ternary copolymer adhesive material, and the ternary copolymer adhesive material is applied to the fields of temperature sensors, drug patches, protective films, and shape memory mechanical grasping.

[0019] Furthermore, according to the characteristics of the ternary copolymer adhesive material changing from opaque, semi-transparent to transparent during the crystallization and melting process, the ternary copolymer adhesive material is used as a temperature sensor.

[0020] Furthermore, according to the characteristics of the ternary copolymer adhesive material generating adhesiveness and debonding due to melting and crystallization, it can be used as a matrix material for drug patches, replacing gauze, non-woven fabric, hydrogel, etc. Drugs such as antibiotics, growth factors, and painkillers are added to one side of the adhesive material, and the melting point T of the adhesive material mIt is regulated to trigger viscosity at skin temperature, firmly adhere to the skin surface, and will not break due to movement, stretching, compression, etc. When the drug effect is lost or replacement is needed, simply apply an ice pack for 10 s to lower the temperature to the crystallization temperature T c Below, the adhesive material loses its viscosity and can be removed or replaced.

[0021] Furthermore, according to the characteristics of the triblock copolymer adhesive material that generates viscosity and debonding due to melting and crystallization, the triblock copolymer adhesive material is used as a protective film for important objects such as calligraphy and paintings for film coating protection. Different-sized molds can be selected according to the actual size requirements of the object to prepare protective films with different thicknesses. When transporting and storing precious objects (such as calligraphy and paintings), when the temperature reaches the melting temperature T m Above, the alkyl side chains are in an amorphous state and no longer maintain local ordered arrangement, which will help the copolymer chains to expand on the substrate surface, enhance the van der Waals force between the molecular chains and the contact surface, and generate mechanical interlocking with the rough surface, etc., thereby enhancing the adhesion. When peeling is required, lower the temperature to the crystallization temperature T c Below, the alkyl side chains are rearranged regularly and return to the crystalline state, losing adhesion and can be removed effortlessly.

[0022] Furthermore, according to the shape memory characteristics of the triblock copolymer adhesive material, it can be used for mechanical grasping in special occasions. The triblock copolymer adhesive material can change its shape and size above T m Above and maintain a temporary state after the temperature is lowered. Once the temperature is raised to T m Above, the triblock copolymer adhesive material will return to its initial shape and size after polymerization. It can be made into a ring-shaped intelligent gripper of a certain size. First, raise the temperature to expand the inner diameter of the ring, lower the temperature and maintain it. Under special conditions, raise the temperature to T m Above to complete the process of grasping the object.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] (1) Since SA and TA have crystallizable long alkyl side chains, the trigger temperature for the transformation of the diblock copolymer PST from semi-crystalline to amorphous state can be adjusted within a range of about 10 - 20 °C (including human skin temperature) by controlling the molar ratio of SA and TA monomers. Under the condition of specifying the ratio of SA and TA, the trigger temperature range of the triblock copolymer adhesive material is wider.

[0025] (2) Due to the long alkyl side chain structure of SA and TA, when these ordered alkyl side chains are at T mWhen the nearby region transforms from the crystalline state to the disordered amorphous state, the alkyl side chains of the copolymer lose the ability to store energy, and the tensile strength and storage modulus decrease sharply. In the present invention, NVP is copolymerized with SA and TA in a ternary system, which can enhance the intermolecular force, improve the compatibility, and enhance the mechanical properties of the copolymer. NVP has an appropriate glass transition temperature (T g ), and its polymer has a relatively high storage modulus. When copolymerized with other monomers, it can effectively improve the tensile strength and elongation at break of the polymer; hydrogen bonds and dipole-dipole interactions are formed between the polar amide groups of NVP and the ester groups of SA and TA, which can enhance the intermolecular binding force and thus improve the mechanical properties of the material; the copolymer of NVP, SA and TA has good compatibility at the molecular level, reduces phase separation, makes the material structure more uniform, and further improves the mechanical properties.

[0026] (3) The ternary copolymer adhesive material of the present invention has excellent mechanical properties, and its strength reaches more than 1.5 Mpa. When applied, it does not require a high-strength material as a liner support, while the strength of the binary copolymer PST of SA and TA is only a few hundred kPa.

[0027] (4) The ternary copolymer adhesive material of the present invention has differences in opacity, semi-transparency and transparency within a certain temperature range and can be used as a temperature sensor. Temperature has a more sensitive effect on the transparency change of the ternary copolymer. When the dosages of SA and TA remain unchanged, after adding NVP, due to the amorphous structure of PVP, it will have a certain hindering effect on the crystallization of the alkyl side chains. Compared with the binary copolymer PST, the crystallization melting process of the ternary copolymer PNST will have a certain lag, so the transparency and the corresponding temperature can correspond to each other more accurately.

[0028] (5) The ternary copolymer adhesive material of the present invention has the characteristics of viscosity and debonding due to melting and crystallization, and can be used as a matrix material for drug patches to replace gauze, non-woven fabric, hydrogel, etc. Drugs such as antibiotics, growth factors, and painkillers are added to one side of the adhesive material. The melting point T m of the adhesive material is regulated so that it can promote viscosity at skin temperature and firmly adhere to the skin surface without breaking due to movement, stretching, compression, etc.; when the drug effect is lost or replacement is needed, only apply an ice pack for 10 s to lower the temperature to below the crystallization temperature T c of the material, and the adhesive material will lose its viscosity and can be removed or replaced. Compared with the binary copolymer PST, since the mechanical properties of the ternary copolymer PNST are significantly improved, its tensile ability, flexibility and strength are balanced, and it can prevent being damaged during use.

[0029] (6) The ternary copolymer adhesion material of the present invention can be used as a protective film for protecting specific materials (such as calligraphy and paintings) during storage, transportation, etc. When the temperature reaches the melting temperature T of the ternary copolymer m or above, the alkyl side chains are in an amorphous state, and the local ordered arrangement is interrupted, which will help the polymer chains to diffuse on the substrate surface, and the van der Waals force between the molecular chains and the contact surface is enhanced, thereby enhancing the adhesion. When peeling is required, it can be easily removed by lowering the temperature. The reason is that when the temperature reaches the crystallization temperature T c , the alkyl side chains are rearranged regularly and return to the crystalline state, losing adhesion. It can be used as a protective film for precious objects such as calligraphy and paintings. Compared with the binary copolymer PST, since the mechanical properties of the ternary copolymer PNST are significantly improved, its tensile ability, flexibility, and strength are balanced, and it can prevent damage during use.

[0030] (7) The mechanism of the shape memory effect is related to the internal stress of the structure. The release of the internal stress prompts the material to recover from the temporary shape to the original shape. The crystallizable alkyl side chains and chemical cross-linking in the ternary copolymer PNST are the main factors leading to the shape memory characteristics. The switching between the crystallization and melting of the alkyl side chains triggers the temperature-responsive behavior of the shape change. When the temperature is higher than the melting point (T m ), the alkyl side chains are in an amorphous state, the material becomes soft, and can be programmed into various shapes under the action of external forces. As the temperature drops to T m or below, the long alkyl side chains begin to crystallize, thus fixing the temporary shape. At this time, the elastic energy stored in the cross-linked network provides the driving force for shape recovery, enabling the material to return to the original shape when heated. It has the advantages of reversibility, repeatability, efficient energy storage and release, programmability, etc. 1. Reversibility and repeatability: The ternary copolymer PNST of the present invention can repeatedly switch between different shapes under the action of temperature or other external stimuli. This reversibility enables them to maintain good performance after multiple uses and is suitable for occasions that require repeated deformation and recovery. 2. Efficient energy storage and release: The ternary copolymer PNST of the present invention can effectively store and release energy. For example, the internal stress and elastic energy stored during the cooling process can be released when heated, driving the material to return to the original shape. This energy conversion characteristic makes them have important applications in self-driving systems or sensors. 3. Programmability: The ternary copolymer PNST of the present invention can be "programmed" into different shapes according to external environmental conditions. This programmability provides a broad application space for intelligent materials and adaptive systems. Brief Description of the Drawings

[0031] Figure 1Schematic diagram of using the terpolymer adhesion material as a temperature sensor. (a) Transparency reflects the corresponding different temperatures. As the temperature rises, the crystalline state transforms into the amorphous state, gradually changing from opaque through translucent to transparent. (b) Schematic diagram of its application on an intelligent temperature control outerwear.

[0032] Figure 2 Schematic diagram of using the terpolymer adhesion material as the matrix material of a drug patch. (a) Front and back schematic diagrams of the drug patch. (b) Applying the patch on the back of the hand. (c) Removing it easily.

[0033] Figure 3 Schematic diagram of using the terpolymer adhesion material as a protective film for a painting. (a) The painting. (b) The protective film adhered to the painting. (c) The protective film detached from the painting.

[0034] Figure 4 Schematic diagram of applying the terpolymer adhesion material in the field of shape - memory grasping. (a) At 0°C, fixing the temporary shape with the inner diameter of the ring enlarged. (b) Restoring the original inner diameter of the ring in hot water to grasp the weight. (c) The weight being lifted without falling off.

[0035] Figure 5 DSC curves of the terpolymer adhesion materials of Comparative Example 1 and Examples 1, 2, and 3. (a) Heating melting heat - flow curve and the corresponding peak temperature. (b) Cooling crystallization heat - flow curve and the corresponding peak temperature.

[0036] Figure 6 (a) Peel strength between the terpolymer adhesion materials of Examples 1, 2, and 3 and different materials. (b) Schematic diagram of on - demand adhesion / debonding of the terpolymer adhesion material of Example 3.

[0037] Figure 7 Stress - strain curves of the terpolymer adhesion material. (a) Comparative Example 1, 5 - 7 and Examples 1 - 3. (b) Comparative Example 2 - 4 and Examples 1 - 3. Detailed implementation mode

[0038] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. These embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments. Based on the given embodiments, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

[0039] Unless otherwise specified, the reagents, methods, instruments, and equipment used in the present invention are conventional reagents, methods, instruments, and equipment in the art.

[0040] In the following examples, the CAS number of NVP is 88-12-0, purchased from Shanghai Merck Chemical Technology Co., Ltd.; the CAS number of SA is 4813-57-4, the CAS number of TA is 21643-42-5, the CAS number of AIBN is 78-67-1, and the CAS number of HDDA is 13048-33-4, all purchased from Shanghai Adamas Reagent Co., Ltd. The polyimide film is the kapton film of DuPont Company in the United States, with a size of 0.05 mm thick * 15 mm wide * 25 m long.

[0041] Example 1

[0042] A ternary copolymer adhesion material, the ternary copolymer adhesion material includes SA, TA, NVP, crosslinking agent 1,6-hexanediol diacrylate (HDDA), and initiator 2,2'-azobisisobutyronitrile (AIBN).

[0043] In this example, the ternary copolymer adhesion material is a homogeneous crosslinked network structure.

[0044] In this example, the molar ratio of NVP, SA, and TA is 20:2:8.

[0045] In this example, the mass of HDDA is 0.05% of the sum of the masses of NVP, SA, and TA.

[0046] In this example, the mass of AIBN is 0.1% of the sum of the masses of NVP, SA, and TA.

[0047] A preparation method of a ternary copolymer adhesion material, including the following steps:

[0048] (1) Preparation of the prepolymer solution: Weigh the corresponding masses (2.2145 g: 0.6465 g: 2.139 g) of the monomers NVP, SA, and TA according to the molar ratio of 20:2:8 and put them into a beaker to stir and dissolve. Add 0.0025 g of crosslinking agent HDDA (0.05 wt% of the total monomers) and 0.005 g of initiator AIBN (0.1 wt% of the total monomers), and continue to stir and dissolve to obtain the prepolymer solution.

[0049] (2) Preparation of the ternary copolymer adhesion material: Transfer the prepolymer solution in step (1) to a polytetrafluoroethylene mold, carry out a free radical random copolymerization reaction at 65 °C for 6 h, and then carry out a post-treatment at 100 °C for 0.5 h to make the free radical random copolymerization reaction more complete, obtaining the ternary copolymer adhesion material, named PNST2028.

[0050] Example 2

[0051] A ternary copolymer adhesion material, the ternary copolymer adhesion material comprising SA, TA, NVP, HDDA, AIBN.

[0052] In this embodiment, the ternary copolymer adhesion material is a homogeneous cross-linked network structure.

[0053] In this embodiment, the molar ratio of NVP, SA and TA is 10:2:8.

[0054] In this embodiment, the mass of HDDA is 0.05% of the sum of the masses of NVP, SA and TA.

[0055] In this embodiment, the mass of AIBN is 0.1% of the sum of the masses of NVP, SA and TA.

[0056] A preparation method of a ternary copolymer adhesion material, comprising the following steps:

[0057] (1) Preparation of a prepolymer solution: Weigh the corresponding masses (1.422 g: 0.8305 g: 2.7475 g) of the monomers NVP, SA and TA according to the molar ratio of 10:2:8 and put them into a beaker and stir to dissolve. Add 0.0025 g of the cross-linking agent HDDA (0.05 wt% of the total monomers) and 0.005 g of the initiator AIBN (0.1 wt% of the total monomers), and continue to stir to dissolve to obtain a prepolymer solution.

[0058] (2) Preparation of the ternary copolymer adhesion material: Transfer the prepolymer solution in step (1) to a polytetrafluoroethylene mold, carry out a free radical random copolymerization reaction at 65 °C for 6 h, and then carry out a post-treatment at 100 °C for 0.5 h to make the free radical random copolymerization reaction more complete, to obtain a ternary copolymer adhesion material, named PNST1028.

[0059] Example 3

[0060] A ternary copolymer adhesion material, the ternary copolymer adhesion material comprising SA, TA, NVP, HDDA, AIBN.

[0061] In this embodiment, the ternary copolymer adhesion material is a homogeneous cross-linked network structure.

[0062] In this embodiment, the molar ratio of NVP, SA and TA is 5:2:8.

[0063] In this embodiment, the mass of HDDA is 0.05% of the sum of the masses of NVP, SA and TA.

[0064] In this embodiment, the mass of AIBN is 0.1% of the sum of the masses of NVP, SA and TA.

[0065] A preparation method of a terpolymer adhesion material, comprising the following steps:

[0066] (1) Preparation of the prepolymer solution: Weigh the corresponding masses (0.829 g: 0.968 g: 3.203 g) of the monomers NVP, SA, and TA in a molar ratio of 5:2:8 and place them in a beaker and stir to dissolve. Add 0.0025 g of the crosslinking agent HDDA (0.05 wt% of the total monomers) and 0.005 g of the initiator AIBN (0.1 wt% of the total monomers), and continue to stir to dissolve to obtain the prepolymer solution.

[0067] (2) Preparation of the terpolymer adhesion material: Transfer the prepolymer solution in step (1) to a polytetrafluoroethylene mold, carry out a free radical random copolymerization reaction at 65 °C for 6 h, and then perform a post-treatment at 100 °C for 0.5 h to make the free radical random copolymerization reaction more complete, obtaining the terpolymer adhesion material, named PNST528.

[0068] Example 4

[0069] An application of the terpolymer adhesion material, wherein the terpolymer adhesion material is used as a temperature sensor.

[0070] Weigh the corresponding masses (2.2145 g: 0.6465 g: 2.139 g) of the monomers NVP, SA, and TA in a molar ratio of 20:2:8 and place them in a beaker and stir to dissolve. Add 0.0025 g of the crosslinking agent HDDA (0.05 wt% of the total monomers) and 0.005 g of the initiator AIBN (0.1 wt% of the total monomers), and continue to stir to dissolve to obtain the prepolymer solution.

[0071] Inject the prepolymer solution in step (1) into a film-shaped mold, conduct a free radical random copolymerization reaction at 65 °C for 6 h, then perform a post-treatment at 100 °C for 0.5 h to make the free radical random copolymerization reaction more complete. After polymerization and shaping, lower the temperature to room temperature to demold and obtain a terpolymer adhesion material. Embed the terpolymer adhesion material in a specific area of the outer garment (such as the chest or armpit) as a temperature-responsive sensing film. The terpolymer adhesion material is connected to a controller, and the controller is connected to a temperature regulation system. Users can intuitively understand the current temperature state through the change in transparency. When the temperature is too high or too low, the transparency of the material changes significantly, which is used to determine whether to activate the temperature regulation system. When the temperature is below 10 °C, the terpolymer adhesion material becomes opaque, and it transmits a signal to the controller to control the temperature regulation system to heat up and increase the temperature; when the temperature is above 30 °C, the terpolymer adhesion material becomes transparent, and it transmits a signal to the controller to control the temperature regulation system to stop working; when the temperature is between 10 and 30 °C, the terpolymer adhesion material is in a semi-transparent state, and it transmits a signal to the controller to control the temperature regulation system to maintain the original state unchanged. According to the ratio of different monomers selected, the crystallinity of the alkyl side chain is regulated to make the material undergo a transition from opaque to semi-transparent to transparent within a predetermined temperature range. The prepared temperature-responsive film can be applied to a temperature sensing system. For example, it can be used in an intelligent temperature control outer garment, and the schematic diagram is as shown in Figure 1 shown.

[0072] Example 5

[0073] An application of a terpolymer adhesion material, where the terpolymer adhesion material is used as a matrix material for a drug patch.

[0074] Weigh the corresponding masses (2.2145 g: 0.6465 g: 2.139 g) of monomers NVP, SA, and TA according to a molar ratio of 20:2:8 and put them into a beaker and stir to dissolve. Add 0.0025 g of cross-linking agent HDDA (accounting for 0.05 wt% of the total monomers) and 0.005 g of initiator AIBN (accounting for 0.1 wt% of the total monomers), and continue to stir to dissolve to obtain a prepolymer solution.

[0075] Inject the prepolymer solution in step (1) into a strip-shaped mold, conduct a free radical random copolymerization reaction at 65 °C for 6 h, then perform a post-treatment at 100 °C for 0.5 h to make the free radical random copolymerization reaction more complete. After polymerization and shaping, lower the temperature to room temperature to demold and obtain a terpolymer adhesion material. Stick a layer of polyimide film on the front side of this adhesion material to make the front side non-adhesive, and stick the required drug dressing on the back side (the side in contact with the skin) of this adhesion material. The schematic diagram is as shown in Figure 2 shown.

[0076] It can trigger the viscosity of the adhesive material at skin temperature, making it firmly adhere to the skin surface without breaking or cracking due to movement, stretching, compression, etc. When the drug efficacy is lost or replacement is needed, just apply an ice pack for 10 s to lower the temperature to the crystallization temperature T of the material c Hereinafter, when the adhesive material loses its viscosity, it can be removed or replaced.

[0077] Example 6

[0078] Application of a terpolymer adhesive material, wherein the terpolymer adhesive material is used as a protective film.

[0079] Weigh the corresponding masses (2.2145 g: 0.6465 g: 2.139 g) of the monomers NVP, SA and TA according to the molar ratio of 20:2:8, put them into a beaker and stir to dissolve. Then add 0.0025 g of crosslinking agent HDDA (0.05 wt% of the total monomers) and 0.005 g of initiator AIBN (0.1 wt% of the total monomers), and continue to stir to dissolve to obtain a prepolymer solution.

[0080] Inject the prepolymer solution in step (1) into a film-shaped mold, carry out a random free radical copolymerization reaction at 65 °C for 6 h, and then carry out a post-treatment at 100 °C for 0.5 h to make the random free radical copolymerization reaction more complete. After polymerization and shaping, lower the temperature to room temperature to demold it, and obtain a protective film with an appropriate thickness. Stick it on the surface of the painting (schematic diagram as Figure 3 shown).

[0081] When the temperature reaches above 10 °C, the protective film adheres to the painting. When the temperature drops below 10 °C, the protective film loses its adhesiveness and detaches from the painting. When the temperature reaches above the melting temperature T of the terpolymer m above, the alkyl side chains are in an amorphous state, which will help the copolymer chains to diffuse on the substrate surface, and the van der Waals force between the molecular chains and the contact surface is enhanced, thereby enhancing the adhesion. When peeling is needed, it can be easily removed by lowering the temperature. Once the temperature drops to the crystallization temperature T c when, the alkyl side chains are rearranged regularly and return to the crystalline state, losing adhesiveness.

[0082] Example 7

[0083] Application of a terpolymer adhesive material, wherein the terpolymer adhesive material is used for shape memory mechanical grasping.

[0084] Weigh the corresponding masses (2.2145 g: 0.6465 g: 2.139 g) of the monomers NVP, SA, and TA according to a molar ratio of 20:2:8, put them into a beaker and stir to dissolve. Then add 0.0025 g of the crosslinking agent HDDA (0.05 wt% of the total monomers) and 0.005 g of the initiator AIBN (0.1 wt% of the total monomers), and continue to stir to dissolve to obtain a prepolymer solution.

[0085] Inject the prepolymer solution in step (1) into a circular mold, carry out a free radical random copolymerization reaction at 65 °C for 6 h, and then perform a post-treatment at 100 °C for 0.5 h to make the free radical random copolymerization reaction more complete. After polymerization and shaping, lower the temperature to room temperature to demold and obtain a circular ternary copolymer adhesion material. Hang it on a robotic gripper, and the schematic diagram is as Figure 4 shown. The robotic gripper can be installed on a fixed bracket or a workbench for fixed-point operation, grasping experimental equipment such as test tubes, petri dishes, and weights, or for sample transfer. It can also be installed on an underwater robot for underwater operations such as underwater sample collection.

[0086] Its working process is as follows: Hang the circular ternary copolymer adhesion material on a robotic gripper with a bending function. When it attempts to pick up a weight from hot water (30 °C), first expand the circular ternary copolymer to 2 - 3 times its original inner diameter and fix its temporary size in ice water (0 °C), then put it into hot water (30 °C), grasp a certain mass of the weight, and the circular ternary copolymer quickly returns to its original inner diameter, thereby controlling the robotic gripper to rise and take out the weight. When the temperature rises, the inner diameter of the circular ternary copolymer can expand again to make the weight fall off.

[0087] Comparative Example 1

[0088] A binary copolymer adhesion material, which includes SA, TA, HDDA, and AIBN. Compared with Example 1, NVP is not added.

[0089] In this embodiment, the binary copolymer adhesion material has a homogeneous structure and is composed of single-chain molecules, and there is no chemical cross-linking connection between the molecular chains.

[0090] In this embodiment, the molar ratio of SA to TA is 2:8.

[0091] In this embodiment, the mass of HDDA is 0.05% of the sum of the masses of SA and TA.

[0092] In this embodiment, the mass of AIBN is 0.1% of the sum of the masses of SA and TA.

[0093] A preparation method of a binary copolymer adhesion material, comprising the following steps:

[0094] (1) Preparation of the prepolymer solution: Weigh the corresponding masses of monomers SA and TA in a molar ratio of 2:8 (1.1605 g: 3.8395 g) and place them in a beaker to stir and dissolve. Add 0.0025 g of crosslinking agent HDDA (0.05 wt% of the total monomers) and 0.005 g of initiator AIBN (0.1 wt% of the total monomers), and continue to stir and dissolve to obtain the prepolymer solution.

[0095] (2) Preparation of the binary copolymer adhesion material: Transfer the prepolymer solution in step (1) to a polytetrafluoroethylene mold, carry out a free radical random copolymerization reaction at 65 °C for 6 h, and then carry out a post-treatment at 100 °C for 0.5 h to make the free radical random copolymerization reaction more complete, obtaining the binary copolymer adhesion material, named PNST28.

[0096] Comparative Example 2

[0097] A ternary copolymer adhesion material, the ternary copolymer adhesion material comprising SA, TA, NVP, AIBN. Compared with Example 1, HDDA is not added.

[0098] In this embodiment, the binary copolymer adhesion material is a homogeneous crosslinked network structure.

[0099] In this embodiment, the molar ratio of NVP, SA and TA is 20:2:8.

[0100] In this embodiment, the mass of AIBN is 0.1% of the sum of the masses of NVP, SA and TA.

[0101] A preparation method of a ternary copolymer adhesion material, comprising the following steps:

[0102] (1) Preparation of the prepolymer solution: Weigh the corresponding masses of monomers NVP, SA and TA in a molar ratio of 20:2:8 (2.2145 g: 0.6465 g: 2.139 g) and place them in a beaker to stir and dissolve. Add 0.005 g of initiator AIBN (0.1 wt% of the total monomers), and continue to stir and dissolve to obtain the prepolymer solution.

[0103] (2) Preparation of the ternary copolymer adhesion material: Transfer the prepolymer solution in step (1) to a polytetrafluoroethylene mold, carry out a free radical random copolymerization reaction at 65 °C for 6 h, and then carry out a post-treatment at 100 °C for 0.5 h to make the free radical random copolymerization reaction more complete, obtaining the ternary copolymer adhesion material, named PNST2028-0.

[0104] Comparative Example 3

[0105] A terpolymer adhesion material, the terpolymer adhesion material comprising SA, TA, NVP, AIBN. Compared with Example 2, HDDA is not added.

[0106] In this embodiment, the binary copolymer adhesion material is a homogeneous cross-linked network structure.

[0107] In this embodiment, the molar ratio of NVP, SA and TA is 10:2:8.

[0108] In this embodiment, the mass of AIBN is 0.1% of the sum of the masses of NVP, SA and TA.

[0109] A preparation method of a terpolymer adhesion material, comprising the following steps:

[0110] (1) Preparation of a prepolymer solution: Weigh the corresponding masses (1.422 g: 0.8305 g: 2.7475 g) of the monomers NVP, SA and TA according to a molar ratio of 10:2:8 and put them into a beaker and stir to dissolve. Add 0.005 g of the initiator AIBN (0.1 wt% of the total monomers), and continue to stir to dissolve to obtain a prepolymer solution.

[0111] (2) Preparation of the terpolymer adhesion material: Transfer the prepolymer solution in step (1) to a polytetrafluoroethylene mold, carry out a free radical random copolymerization reaction at 65 °C for 6 h, and then carry out a post-treatment at 100 °C for 0.5 h to make the free radical random copolymerization reaction more complete, to obtain a terpolymer adhesion material, named PNST1028-0.

[0112] Comparative Example 4

[0113] A terpolymer adhesion material, the terpolymer adhesion material comprising SA, TA, NVP, AIBN. Compared with Example 3, HDDA is not added.

[0114] In this embodiment, the binary copolymer adhesion material is a homogeneous cross-linked network structure.

[0115] In this embodiment, the molar ratio of NVP, SA and TA is 5:2:8.

[0116] In this embodiment, the mass of AIBN is 0.1% of the sum of the masses of NVP, SA and TA.

[0117] A preparation method of a terpolymer adhesion material, comprising the following steps:

[0118] (1) Preparation of the prepolymer solution: Weigh the corresponding masses (0.829 g: 0.968 g: 3.203 g) of the monomers NVP, SA, and TA according to a molar ratio of 5:2:8 and place them in a beaker to stir and dissolve. Add 0.005 g of the initiator AIBN (0.1 wt% of the total monomers), and continue to stir and dissolve to obtain the prepolymer solution.

[0119] (2) Preparation of the terpolymer adhesion material: Transfer the prepolymer solution in step (1) to a polytetrafluoroethylene mold, and carry out a random radical copolymerization reaction at 65 °C for 6 h. Then, perform a post-treatment at 100 °C for 0.5 h to make the random radical copolymerization reaction more complete, and obtain the terpolymer adhesion material, named PNST528-0.

[0120] Comparative Example 5

[0121] Compared with Example 1, most of them are the same, except that NVP is adjusted to carbon nanotubes (CNTs), and the mass of CNTs is 10 wt% of the sum of the masses of SA and TA.

[0122] A binary copolymer adhesion material, which includes SA, TA, CNTs, HDDA, and AIBN.

[0123] In this example, the binary copolymer adhesion material has a homogeneous cross-linked network structure.

[0124] In this example, the molar ratio of SA to TA is 2:8.

[0125] In this example, the mass of CNTs is 10% of the sum of the masses of SA and TA.

[0126] In this example, the mass of HDDA is 0.05% of the sum of the masses of NVP, SA, and TA.

[0127] In this example, the mass of AIBN is 0.1% of the sum of the masses of NVP, SA, and TA.

[0128] A preparation method of a binary copolymer adhesion material, comprising the following steps:

[0129] (1) Preparation of prepolymer solution: Weigh the corresponding masses (1.1605 g: 3.8395 g) of monomers SA and TA according to a molar ratio of 2:8 and place them in a beaker for stirring and dissolution. Add 1 mg / mL CNTs dispersion (CNTs account for 10 wt% of the monomers), ultrasonically disperse at 40 °C to remove the solvent, add 0.0025 g of crosslinking agent HDDA (accounting for 0.05 wt% of the total monomers) and 0.005 g of initiator AIBN (accounting for 0.1 wt% of the total monomers), and continue stirring and dissolving to obtain the prepolymer solution.

[0130] (2) Preparation of binary copolymer adhesive material: Transfer the prepolymer solution in step (1) to a polytetrafluoroethylene mold, conduct a free radical random copolymerization reaction at 65 °C for 6 h, and then perform a post-treatment at 100 °C for 0.5 h to make the free radical random copolymerization reaction more complete, obtaining a ternary copolymer adhesive material named PST28 - 10 wt%.

[0131] Comparative Example 6

[0132] Compared with Example 1, most of them are the same, except that the molar ratio of NVP, SA, and TA is adjusted to 30:2:8 (masses are 2.72 g: 0.53 g: 1.75 g) respectively.

[0133] Comparative Example 7

[0134] Compared with Example 1, most of them are the same, except that the molar ratio of NVP, SA, and TA is 1:2:8 (masses are 0.190 g: 1.115 g: 3.695 g) respectively.

[0135] Comparative Example 8

[0136] Compared with Example 1, most of them are the same, except for the preparation of the ternary copolymer adhesive material: Transfer the prepolymer solution in step (1) to a polytetrafluoroethylene mold, conduct a free radical random copolymerization reaction at 65 °C for 6.5 h to obtain a ternary copolymer adhesive material named PNST2028 - 65.

[0137] Comparative Example 9

[0138] Compared with Example 1, most of them are the same, except for the preparation of the ternary copolymer adhesive material: Transfer the prepolymer solution in step (1) to a polytetrafluoroethylene mold, conduct a free radical random copolymerization reaction at 100 °C for 6.5 h to obtain a ternary copolymer adhesive material named PNST2028 - 100.

[0139] Figure 5DSC curves of the terpolymer adhesion materials of Comparative Example 1 and Examples 1, 2, and 3, (a) melting peak curve and corresponding peak temperature, (b) cooling crystallization curve and corresponding peak temperature. It can be seen that the NVP content in the terpolymers PNST2028, PNST1028, and PNST528 in Examples 1, 2, and 3 gradually decreases, and their corresponding melting temperatures (T m ) and crystallization temperatures (T c ) gradually increase. The binary copolymer PST in Comparative Example 1 contains the same proportion of SA and TA, and its corresponding melting temperature (T m ) and crystallization temperature (T c ) have the highest values. This is because the amorphous structure of the NVP unit hinders the crystallization behavior of the acrylate unit with a long alkyl side chain. Specifically, the addition of NVP reduces the proportion of the crystalline chains in the copolymer, hinders the ordered arrangement of some side chains, and thus reduces the T m and T c of the terpolymer. Generally speaking, based on the ratio of SA:TA = 1:4, both Comparative Example 1 and Examples 1, 2, and 3 can achieve the skin temperature-triggered on-demand adhesion / detachment function. Reducing T m and T c can more easily achieve human skin temperature-triggered adhesion / detachment. The advantage of the present invention is that the mechanical properties of the terpolymer adhesion material are significantly improved, and its tensile ability, flexibility, and strength are balanced, which can prevent damage during use. And because the main bonding agents are SA and TA, the addition of NVP can affect the bonding strength, making its regulation and selectivity stronger, and can reduce the adjustment of the ratio of SA and TA, so as to obtain a more accurate triggering temperature on the premise of not reducing the bonding strength.

[0140] Figure 6 (a) Peel strength between the terpolymer adhesion materials of Examples 1, 2, and 3 and different materials. There are obvious differences in the peel strength of the copolymers of different examples and different substrates. The peel strength between the adhesion material and different materials such as iron, glass, and wood was measured. When the temperature exceeds its T m , the copolymer adhesion material becomes soft and the adhesion force increases. This is because the ordered arrangement of the long alkyl side chains is interrupted, which helps the polymer chains to diffuse on the substrate surface, thereby enhancing the adhesion force. When adhering to different materials, the bonding strength order is wooden sheet > glass sheet > iron sheet; for the copolymers of the examples, the obtained bonding strength order is Example 3 > Example 2 > Example 1. However, in Comparative Examples 1 to 4, due to poor mechanical properties, the samples were damaged during the measurement of the peel strength and accurate data could not be obtained. In addition, Figure 6(b) shows the on-demand adhesion / de-adhesion schematic diagram of the terpolymer adhesion material of Example 3. The PNST528 in the crystalline state has little adhesion and can be easily separated from the human skin. After about 10 s, the adhesion material is in a molten state and can firmly adhere to the human skin. In this state, it is difficult to separate from the skin surface. After being cooled with an ice pack for a few seconds, it returns to the crystalline state and loses adhesion.

[0141] Figure 7 is the stress-strain curve of the terpolymer adhesion material. (a) Comparative Examples 1, 5-7 and Examples 1-3; (b) Examples 1-3 and Comparative Examples 2, 3, 4. The results show that the fracture strength (0.11 MPa) and elongation at break (191%) of Comparative Example 1 are significantly lower, far lower than those of Examples 1-3. With the introduction and increase of the NVP monomer, the fracture strength increases from 0.14 MPa in Example 3 to 1.67 MPa in Example 1, and the elongation at break decreases from 666% in Example 3 to 483% in Example 1. Generally speaking, NVP significantly improves the mechanical properties of the pure acrylate copolymer by enhancing intermolecular forces, improving compatibility, increasing crosslinking density, optimizing molecular chain arrangement and increasing T g ,.

[0142] Compared with Examples 1-3, in Comparative Examples 2-4, without adding a crosslinking agent under the same other conditions, the fracture strength decreases and the elongation at break increases. When there is no crosslinking agent, the molecular chains of the copolymer are linear and are mainly connected by weak interactions such as van der Waals forces or hydrogen bonds between molecules. The molecular chains can slide relatively freely, showing high flexibility and ductility. After adding the crosslinking agent, the linear molecular chains are connected into a three-dimensional network structure. This crosslinked structure restricts the free movement of the molecular chains and enhances the rigidity and strength of the material. Therefore, the presence of the crosslinking agent is very necessary.

[0143] Comparing Comparative Example 5 with Examples 1-3, CNTs have high strength and stiffness and can bear and transfer stress. Therefore, compared with Comparative Example 1, the tensile strength and elastic modulus of the material are significantly improved (0.18 MPa, 55.23%). However, compared with the pure polymers (Examples 1-3) whose mechanical properties are improved by adding NVP, there will inevitably be problems of filler agglomeration and uneven dispersion. The agglomeration of CNTs leads to stress concentration and forms weak points. Therefore, the tensile strength, elongation at break and toughness of Comparative Example 5 are all inferior to those of Examples 1-3.

[0144] Comparing Comparative Examples 6 and 7 with Examples 1 to 3, the content of NVP in Comparative Example 6 is the highest compared to Examples 1 to 3, and its mechanical properties are also the best (2.01 MPa, 436%). However, considering the adhesion of the terpolymer adhesive material, excessive NVP content will result in insufficient adhesion (undetectable due to too small adhesion), affecting its practical application. Therefore, an appropriate amount of NVP needs to be added during the actual process. The content of NVP in Comparative Example 7 is the lowest compared to Examples 1 to 3. By comparison, it can be seen that the maximum fracture stress it can withstand is only 0.13 MPa, and at the same time, the elongation at break is only 337%, both of which are much smaller than those of the examples. This is because when the NVP content is too small, the interaction with SA and TA is relatively weak, and the mechanical properties of the material cannot be significantly improved.

[0145] In Comparative Examples 8 and 9, only radical random copolymerization reaction is carried out during the material preparation process, without post-treatment. The temperature of Comparative Example 8 is 65 °C, and the temperature of Comparative Example 9 is 100 °C. During the preparation process, the sample of Comparative Example 8 does not react completely, and the sample of Comparative Example 9 will undergo explosive polymerization in a short time.

[0146] Although the present invention has been described in detail above with general descriptions, specific embodiments and experiments, based on the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. A terpolymer adhesive material, characterized in that: The terpolymer adhesive material comprises octadecyl acrylate, tetradecyl acrylate, N-vinyl pyrrolidone, a crosslinking agent and an initiator.

2. A terpolymer adhesive material according to claim 1, characterized in that: The terpolymer adhesive material is a homogeneous cross-linked network structure.

3. A terpolymer adhesive material according to claim 1, characterized in that: The molar ratio of N-vinyl pyrrolidone, octadecyl acrylate and tetradecyl acrylate is 5-20:2:5-10.

4. A terpolymer adhesive material according to claim 1, characterized in that: The mass of the cross-linking agent is 0.05% to 0.5% of the sum of the mass of octadecyl acrylate, tetradecyl acrylate and N-vinyl pyrrolidone.

5. The terpolymer adhesive material according to claim 1, characterized in that: The mass of the initiator is 0.01% to 0.5% of the sum of the mass of octadecyl acrylate, tetradecyl acrylate and N-vinyl pyrrolidone.

6. The terpolymer adhesive material according to claim 1, characterized in that: The crosslinking agent includes 1,6-hexanediol diacrylate and N,N'-methylenebisacrylamide.

7. The terpolymer adhesive material according to claim 1, characterized in that: The initiator includes azobisisobutyronitrile, azobisisoheptanenitrile and dibenzoyl peroxide.

8. The method for preparing a terpolymer adhesive material according to any one of claims 1 to 7, characterized in that: Octadecyl acrylate, tetradecyl acrylate, N-vinyl pyrrolidone, a crosslinking agent and an initiator are mixed to obtain a prepolymer solution; the prepolymer solution is transferred to a mold, firstly subjected to a free radical random copolymerization reaction at 50-70° C., and then subjected to a post-treatment at 90-120° C. to obtain a terpolymer adhesive material.

9. The method for preparing a terpolymer adhesive material according to claim 7, characterized in that: The time of the free radical random copolymerization reaction is 2 to 10 hours, and the time of the post-treatment is 0.5 to 2 hours.

10. Use of a terpolymer adhesive material as claimed in any one of claims 1 to 7, characterized in that: The terpolymer adhesive material is used in the fields of temperature sensors, drug dressings, protective films, and shape memory mechanical grasping.

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