Composition for producing polycaprolactone shape memory material, polycaprolactone shape memory material, and method for producing the same and use

Abstract

The present invention relates to the field of polycaprolactone shape memory materials, and discloses a composition for producing a polycaprolactone shape memory material, a polycaprolactone shape memory material, and a method for producing and using the same. The material includes a plurality of modified polyrotaxane polymer chains and a plurality of composite polymer chains connecting different modified polyrotaxane polymer chains, each of the composite polymer chains including at least two polycaprolactone polymer chain segments, a reversible linking group between the different polycaprolactone polymer chains, and a linking modification group connecting the polycaprolactone polymer chain and a cyclodextrin-derived ring structure contained in the modified polyrotaxane polymer chain, and the reversible linking group is a photoreversible linking group or a thermoreversible linking group. The present invention improves the toughness of a shape memory material by adjusting defects in the network topology of the polymer, and realizes the designability of complex shapes of the shape memory material and the reshapeability in the solid state.

Description

Cross-reference of related applications

[0001] This application claims the benefits of Chinese Patent Application No. 202111266177.2, filed on 28 October 2021, the contents of which are incorporated herein by reference. [Technical Field]

[0002] The present invention relates to the field of polycaprolactone shape memory materials, and more specifically to compositions for producing polycaprolactone shape memory materials, polycaprolactone shape memory materials, and methods for producing and using the same. [Background technology]

[0003] Shape memory materials are materials that maintain a fixed shape (initial state) under certain conditions, but can change shape and maintain this temporary shape when external conditions change, such as when stimulated by heat, light, electricity, or chemical treatment. When the external environment changes again in a specific way and pattern, they can reversibly recover to their original state. Shape memory polymer materials (SMPs) are a type of shape memory material that has advantages over other shape memory materials (alloys, ceramics), such as good shape change (up to 1000% deformation recovery), low density, low cost, structural design flexibility, and controllability of deformation recovery behavior. They are widely applied in fields such as biomedicine, aerospace, and the automotive and robotics industries.

[0004] Generally, to prevent a decrease in memory performance caused by the displacement of polymer molecular chains during the shape memory cycle, it is necessary to crosslink the polymer to permanently fix its shape. However, the mixing of polymer network precursors, end linking, and chain growth reactions continue until the polymer network is formed, and this is a statistical process that introduces defects into most polymer networks, limiting the material's properties. For example, if the distribution of network nodes is non-uniform, the stress distribution within the material becomes non-uniform during the stress-strain cycle, causing the shape recovery performance and toughness to fail to meet the predetermined requirements. Furthermore, since the crosslinked networks of conventional polymers are generally irreversible covalent bonds, shape memory materials cannot change their permanent shape once molded and cannot be reprocessed or molded, thus limiting their application range in various fields. Polycaprolactone shape memory materials are often used as biomedical materials due to their excellent biodegradability and biocompatibility. However, due to their non-uniform crosslinked networks and lack of reprocessability, this material has a slow shape recovery rate and a low failure tolerance rate when used in disposable medical products.

[0005] Therefore, improved methods are needed for manufacturing polycaprolactone shape memory materials. [Overview of the project] [Problems that the invention aims to solve]

[0006] The object of the present invention is to provide a composition for producing a polycaprolactone shape memory material, a polycaprolactone shape memory material, and a method for producing and using the same, in order to solve the problems that exist with conventional polycaprolactone shape memory materials regarding toughness, designability of complex shapes, and remoldingability in a solid state. [Means for solving the problem]

[0007] To achieve the above objectives, a first aspect of the present invention is: A polycaprolactone shape memory material is provided, which includes a plurality of modified polyrotaxane polymer chains and a plurality of composite polymer chains that connect the different modified polyrotaxane polymer chains. Each of the composite polymer chains includes segments of at least two polycaprolactone polymer chains, a reversible linking group between the different polycaprolactone polymer chains, and a linking modifier group that links the polycaprolactone polymer chain and a cyclic structure derived from cyclodextrin contained in the modified polyrotaxane polymer chain. The reversible linking group is a photo-reversible linking group or a thermo-reversible linking group.

[0008] A second aspect of the present invention is A composition for producing the polycaprolactone shape memory material of the present invention, which includes a polyrotaxane-based initiator, a terminal group modifier, ε-caprolactone, a catalyst, and a crosslinking agent. The terminal group modifier is selected from nitro cinnamic acid compounds and / or 4-((4-methyl-2-oxo-2H-chromen-7-yl)oxy)butyric acid. A composition is provided

[0009] A third aspect of the present invention is Step (1) of hydroxypropylating the polyrotaxane to obtain a hydroxypropylated polyrotaxane Step (2) of ring-opening polymerization of the hydroxypropylated polyrotaxane and ε-caprolactone in the presence of a catalyst to obtain a polycaprolactone graft polyrotaxane copolymer Step (III) of subjecting the polycaprolactone graft polyrotaxane copolymer and a photo-reversible group of a terminal group modifier to a modification reaction to obtain a polymer network precursor with a terminal group partially modified with a photo-reversible group Step (4) of crosslinking the polymer network precursor by reacting the photo-reversible group under the action of heat and ultraviolet light in the presence of a crosslinking agent to obtain a polycaprolactone shape memory material. A method for producing a polycaprolactone shape memory material is provided [[ID=二十]]

[0010] [[ID=二十一]] [[ID=二十二]]A fourth aspect of the present invention provides a polycaprolactone shape memory material produced by the method of the present invention. [[ID=二十三]]

[0011] The fifth aspect of the present invention provides the use of the polycaprolactone shape memory material of the present invention in medical fixatives. recovery

Advantages of the Invention

[0012] According to the above technical solution, in the present invention, a polyrotaxane modifier is used as an initiator, and a slidable polycaprolactone polymer chain (PCL) is produced by ring-opening polymerization. Then, a part of the terminal groups of the PCL is modified with a photo-reversible group and then cross-linked to form a cross-linked structure, thereby obtaining the polycaprolactone shape memory material of the present application. By designing the cross-linked network of the polycaprolactone shape memory material as a slidable structure, the defects of the polymer network topology are adjusted to improve the toughness of the shape memory material. By changing the cross-linking method to a connection by a reversible bond, the dynamic covalent bond introduced realizes the design possibility of a complex shape and the re-molding property in the solid state of the shape memory material.

Brief Description of the Drawings

[0013] [Figure 1] It is a nuclear magnetic comparison chart of polyethylene glycol diamine, α-cyclodextrin, and the produced polyrotaxane in Example 1. Fig. 1(a) is a structural schematic diagram and 1H-NMR spectrum of α-cyclodextrin, Fig. 1(b) is a structural schematic diagram and 1H-NMR spectrum of polyethylene glycol diamine, and Fig. 1(c) is a structural schematic diagram and 1H-NMR spectrum of the polyrotaxane produced in Example 1. [Figure 2] It is a GPC comparison chart of polyethylene glycol diamine, α-cyclodextrin, and the produced polyrotaxane in Example 1. [Figure 3] It is a 1H-NMR chart of hydroxypropylated polyrotaxane produced in Example 1. [Figure 4] ​This is an infrared comparison chart of the polyrotaxane, hydroxypropylated polyrotaxane, and polycaprolactone-grafted polyrotaxane copolymer produced in Example 1. [Figure 5] This is the 1H-NMR chart of the polycaprolactone-grafted polyrotaxane copolymer produced in Example 1. [Figure 6] This is a schematic diagram of the cross-linked structural network of a polycaprolactone shape memory material. [Figure 7] This is a demonstration diagram of the shape reformation process of the polycaprolactone shape memory material according to the present invention. [Modes for carrying out the invention]

[0014] The endpoints and any values ​​of the ranges disclosed herein are not limited to exact ranges or values, and these ranges or values ​​should be understood to include values ​​close to them. In the case of numerical ranges, the intervals between the endpoint values ​​of individual ranges, the intervals between the endpoint values ​​of individual ranges and individual point values, and the intervals between individual point values ​​can be combined to obtain one or more new numerical ranges, and these numerical ranges should be considered as specifically disclosed herein.

[0015] A first aspect of the present invention is: The present invention provides a polycaprolactone shape memory material comprising a plurality of modified polyrotaxane polymer chains and a plurality of composite polymer chains linking different modified polyrotaxane polymer chains, wherein each composite polymer chain comprises at least two segments of polycaprolactone polymer chains, reversible linking groups between different polycaprolactone polymer chains, and linking modification groups that link the polycaprolactone polymer chains to cyclic structures derived from cyclodextrin contained in the modified polyrotaxane polymer chains, and the reversible linking groups are photoreversible linking groups or thermally reversible linking groups.

[0016] The structure of the polycaprolactone shape memory material according to the present invention is shown in Figure 6.

[0017] In some embodiments of the present invention, the photoreversible linking group is preferably derived from a compound having a photoreversible group, and preferably the compound is selected from nitrocinnamic acid compounds and / or 4-((4-methyl-2-oxo-2H-chromen-7-yl)oxy)butyric acid. The nitrocinnamic acid compound may be a compound represented by the following formula.

[0018] [ka]

[0019] (Here, R′ represents a substituent that is substituted at at least one position on the benzene ring that is numbered 1 to 5, and R′ is the structure shown in the following formula,

[0020] [ka]

[0021] Here, R′′′′ and R′′′ are independently selected from H or a linear or branched alkyl group of C1-C6, * represents a linkage point with the benzene ring, R′′ is a substituent that substitutes at at least one position other than the R′ substitution position among the positions numbered 1-5 on the benzene ring, and R′′ is H or a linear or branched alkyl group of C1-C6.

[0022] Preferably, the nitrocinnamic acid compound is a compound represented by the following formula.

[0023] [ka]

[0024] (Here, R 1# , R 2# and R 3# Each is independently selected from H or a linear or branched alkyl group of C1-C6, and R 1#The substitution position is at least one of the positions labeled with numbers 1' to 4' on the benzene ring, and most preferably, it is 4-nitrocinnamic acid (R 1# , R 2# and R 3# are H.).

[0025] Taking 4-nitrocinnamic acid as an example, the formed photo-reversible linking group may have the following schematic structure.

[0026]

Chemical formula

[0027] The photo-reversible process may be as follows.<00,00181>

[0028]

Chemical formula

[0029] (Here, R 1 and R 2 represent each polycaprolactone polymer chain linked to different modified polyrotaxanes.) In some embodiments of the present invention, preferably, the thermo-reversible linking group is derived from diisocyanate, and preferably, the diisocyanate is at least one selected from hexamethylene diisocyanate, toluene diisocyanate, isophorone diisocyanate, and lysine diisocyanate. The formed reversible linking group may have the following schematic structure,

[0030]

Chemical formula

[0031] [[ID=5i]] Taking hexamethylene diisocyanate as an example, the thermo-reversible process may be as follows.

[0032]

Chemical formula

[0033] (Here, R1, R2, R3, and R4 represent the respective polycaprolactone polymer chains linked to different modified polyrotaxanes, and R represents the main group of the diisocyanate (the structure other than the two isocyanate groups).) In some embodiments of the present invention, the linking modifying group is preferably derived from a compound for hydroxypropylation. For example, it may be a polycaprolactone polymer chain structure formed by ring-opening polymerization caused by a modifying group formed by the hydroxypropylation reaction between a cyclodextrin-derived cyclic structure contained in the polyrotaxane polymer chain and propylene oxide. Preferably, it is a group represented by the structural formula -CH2-CH(CH3)-O-.

[0034] In some embodiments of the present invention, the total amount of the polycaprolactone polymer chain is preferably 80 to 100 wt%, preferably 95 to 99.9 wt%, based on the total amount of the modified polyrotaxane polymer chain.

[0035] In some embodiments of the present invention, the weight-average molecular weight of the polycaprolactone polymer chain is preferably 5,000 to 100,000 kDa, and more preferably 10,000 to 80,000 kDa.

[0036] In some embodiments of the present invention, the weight-average molecular weight of the modified polyrotaxane polymer chain is preferably 10 kDa to 100 kDa, preferably 30 kDa to 90 kDa.

[0037] In some embodiments of the present invention, the polycaprolactone shape memory material has improved toughness, exhibits large tensile deformation, good recovery performance, and is reshapeable. Preferably, the polycaprolactone shape memory material has a fracture elongation of over 900%, a gel content of 37-78 wt%, and a recovery time of 5 seconds or less to the initial shape under 100% strain.

[0038] In the present invention, the above structure of the polycaprolactone shape memory material is determined by Raman spectroscopy, gel content measurement, GPC, Fourier transform infrared spectroscopy, and 1 The properties can be analyzed by means of combining 1H NMR, or determined in combination with the reactions and supply of the manufacturing process for synthesizing the material, and the reversible change process of the reversible linking groups can also be determined. The above physical and chemical properties of the polycaprolactone shape memory material can be measured by mechanical property tests to measure the elongation at break, Soxhlet extraction to measure the gel content, and plate heating tensile testing to measure the shape recovery rate and shape recovery percentage.

[0039] A second aspect of the present invention provides a composition for producing the polycaprolactone shape memory material of the present invention, the composition comprising a polyrotaxane initiator, a terminal group modifier, ε-caprolactone, a catalyst, and a crosslinking agent, wherein the terminal group modifier is selected from nitrocinnamic acid compounds and / or 4-((4-methyl-2-oxo-2H-chromen-7-yl)oxy)butyric acid.

[0040] The above-mentioned composition according to the present invention contains a polyrotaxane as an initiator to initiate ring-opening polymerization of ε-caprolactone into a slidable polycaprolactone molecular chain. The terminal group modifier modifies some of the terminal groups of polycaprolactone into photoreversible groups, changing the crosslinking method to linkage by reversible bonding, thereby solving the problems related to toughness, designability, and remolding properties present in conventional polycaprolactone shape memory materials.

[0041] In some embodiments of the present invention, the weight-average molecular weight of the polyrotaxane initiator is preferably 10 kDa to 100 kDa, preferably 30 kDa to 90 kDa. The polyrotaxane initiator may be obtained commercially or prepared in-house. It is acceptable as long as it satisfies the above requirements.

[0042] In some embodiments of the present invention, the catalyst is preferably at least one selected from stannous octanoate, lithium diisopropylamide, scandium(III) trifluoromethanesulfonate, and phosphazene base (BEMP).

[0043] In some embodiments of the present invention, the crosslinking agent is preferably selected from diisocyanates, and preferably at least one selected from hexamethylene diisocyanate, toluene diisocyanate, isophorone diisocyanate, and lysine diisocyanate. Different polycaprolactone polymer chains formed by ring-opening polymerization of ε-caprolactone can be linked.

[0044] In the present invention, the photoreversible group may be a cinnamic acid group or a coumarinyl group. For example, a nitrocinnamic acid compound may be a compound having the structure described above, and although not described in detail here, it can provide a cinnamic acid group, and 4-((4-methyl-2-oxo-2H-chromen-7-yl)oxy)butyric acid can provide a coumarinyl group. The structural formula of 4-((4-methyl-2-oxo-2H-chromen-7-yl)oxy)butyric acid is shown below.

[0045] [ka]

[0046] The photoreversible group modifies one end of the polycaprolactone polymer chain formed by the ring-opening polymerization of ε-caprolactone. Then, bonding occurs between the photoreversible groups on different polycaprolactone polymer chains, and the resulting structure can be broken or bonded by irradiation with ultraviolet light of various wavelengths. The resulting polycaprolactone shape memory material is thus given designability and remolding properties in a solid state.

[0047] In some embodiments of the present invention, preferably, based on the total amount of the composition, the composition contains 0.01 to 0.1 wt% of the polyrotaxane initiator, 99.99 to 99 wt% of ε-caprolactone, 0.5 to 2 wt% of the catalyst, 0.02 to 0.05 wt% of the terminal group modifier, and 0.1 to 1 wt% of the crosslinking agent.

[0048] A third aspect of the present invention is: Step (1) involves hydroxypropylating polyrotaxane to obtain hydroxypropylated polyrotaxane, Step (2) involves ring-opening polymerization of the hydroxypropylated polyrotaxane and ε-caprolactone in the presence of a catalyst to obtain a polycaprolactone grafted polyrotaxane copolymer, Step (3) involves a modification reaction between the polycaprolactone grafted polyrotaxane copolymer and the photoreversible groups of the terminal group modifier to obtain a polymer network precursor in which some of the terminal groups have been modified into photoreversible groups. The present invention provides a method for producing a polycaprolactone shape memory material, comprising the step (4) of reacting the photoreversible groups with the action of heating and ultraviolet light in the presence of a crosslinking agent to crosslink the polymer network precursor and obtain a polycaprolactone shape memory material.

[0049] In some embodiments of the present invention, preferably, in step (1), the hydroxypropylation process includes dissolving the polyrotaxane in an alkaline solution and washing the product obtained by reacting it with a hydroxide reagent. The hydroxide reagent may be propylene oxide.

[0050] In some embodiments of the present invention, preferably in step (2), the catalyst is at least one selected from stannous octanoate, lithium diisopropylamide, scandium(III) trifluoromethanesulfonate, and a phosphazene base.

[0051] In some embodiments of the present invention, the amount of catalyst used is preferably 0.5 to 2 wt%, preferably 0.8 to 1.2 wt%, of the total mass of the hydroxypropylated polyrotaxane and ε-caprolactone.

[0052] In some embodiments of the present invention, preferably, the molar ratio of the hydroxypropylated polyrotaxane to ε-caprolactone is 1:50 to 600, preferably 1:50 to 1:200, when calculated based on the number of active hydroxyl groups present in the hydroxypropylated polyrotaxane. The number of active hydroxyl groups is determined from the ratio of the integral area of ​​the cyclodextrin to the integral area of ​​the hydrogen nuclear magnetic spectrum at a chemical shift of 1.1 ppm.

[0053] In some embodiments of the present invention, the ring-opening polymerization temperature is preferably 100 to 140°C, preferably 110 to 130°C, and the ring-opening polymerization time is 40 to 50 hours, preferably 45 to 50 hours.

[0054] In some embodiments of the present invention, the ring-opening polymerization process preferably includes polymerizing a mixture of the hydroxypropylated polyrotaxane, ε-caprolactone, and the catalyst under nitrogen protection, dissolving the resulting primary product in tetrahydrofuran, then performing precipitation multiple times in n-hexane, drying the resulting solid-phase precipitate to obtain the polycaprolactone-grafted polyrotaxane copolymer.

[0055] In some embodiments of the present invention, preferably in step (3), the molar ratio of the terminal group modifier to the polycaprolactone grafted polyrotaxane copolymer is 100 to 400:1.

[0056] In some embodiments of the present invention, the terminal group modifier is preferably a compound having a photoreversible group, and is preferably selected from nitrocinnamic acid compounds and / or 4-((4-methyl-2-oxo-2H-chromen-7-yl)oxy)butyric acid. Specific compounds are as described above.

[0057] In some embodiments of the present invention, the temperature of the terminal group modification reaction is preferably 40 to 60°C, and the duration of the terminal group modification reaction is preferably 15 to 25 hours.

[0058] In some embodiments of the present invention, the process of the end group modification reaction preferably includes mixing solutions prepared in a first organic solvent using the end group modifier and the polycaprolactone grafted polyrotaxane copolymer, adding the water absorbent-I and the esterification catalyst to the resulting mixed solution to carry out the end group modification reaction, and precipitating the resulting primary product multiple times, drying the resulting solid precipitate to obtain the polymer network precursor.

[0059] In some embodiments of the present invention, preferably, the first organic solvent is at least one selected from tetrahydrofuran, N,N-dimethylformamide, dichloromethane, and dioxane; the water absorbent-I is at least one selected from N,N-diisopropylcarbodiimide, dicyclohexylcarbodiimide, and concentrated sulfuric acid; and the esterification catalyst is at least one selected from 4-dimethylaminopyridine, p-toluenesulfonic acid, and thionyl chloride.

[0060] In some embodiments of the present invention, the amount of the first organic solvent used is preferably such that the concentration of the mixed solution is 1 to 10 g / mL, preferably 2 to 8 g / mL. That is, it is the total amount of the above-mentioned terminal group modifier and the polycaprolactone graft polyrotaxane copolymer contained in the mixed solution.

[0061] In some embodiments of the present invention, the amount of the water absorbent-I used is preferably 1 to 5 wt%, preferably 1.5 to 4.5 wt%, of the total amount of the terminal group modifier and the polycaprolactone graft polyrotaxane copolymer.

[0062] In some embodiments of the present invention, the molar ratio of the esterification catalyst to the polycaprolactone-grafted polyrotaxane copolymer is preferably 1:1.5 to 3.5, and more preferably 1:2 to 3.

[0063] In some embodiments of the present invention, the photoreversible group is derived from a terminal group modifier and may be a cinnamic acid group or a coumarinyl group. Preferably, the polymer network precursor has a plurality of slidable polycaprolactone molecular chains, and some of the ends of the polycaprolactone molecular chains contain a photoreversible group derived from the terminal group modifier. For example, some of the ends of the polycaprolactone molecular chains contain a hydroxyl group and a cinnamic acid group.

[0064] In some embodiments of the present invention, preferably in step (4), the crosslinking agent is at least one selected from diisocyanates, preferably hexamethylene diisocyanate, toluene diisocyanate, isophorone diisocyanate, and lysine diisocyanate. Since the modification reaction may not be completely carried out in step (3), not all end groups of the polycaprolactone polymer chains in the polycaprolactone graft polyrotaxane copolymer are modified into photoreversible groups. That is, the polymer network precursor may contain unmodified hydroxyl end groups of the polycaprolactone polymer chains, making it possible to thermally reversibly link different polycaprolactone polymer chains through the diisocyanate provided by the crosslinking agent. Furthermore, re-linking can also be enabled through transesterification, which corresponds to the exchange and linking of different polycaprolactone polymer chains to the same polycaprolactone polymer chain.

[0065] In some embodiments of the present invention, the amount of crosslinking agent used is preferably 0.1 to 1 wt% of the polymer network precursor.

[0066] In some embodiments of the present invention, the heating temperature is preferably 70 to 90°C, and the heating time is 45 to 60 hours.

[0067] In some embodiments of the present invention, the wavelength of the ultraviolet light is preferably 250 to 380 nm.

[0068] In some embodiments of the present invention, the crosslinking process preferably includes dissolving the polymer network precursor in a second organic solvent, then adding a butyl acetate solution of the crosslinking agent and crosslinking catalyst to obtain a liquid mixture, and heating and drying the liquid mixture, irradiating it with ultraviolet light, and obtaining the polycaprolactone shape memory material.

[0069] In some embodiments of the present invention, the second organic solvent is preferably at least one selected from tetrahydrofuran, N,N-dimethylformamide, dichloromethane, and dioxane, and the crosslinking catalyst is at least one selected from dibutyltin dilaurate, an organobismuth catalyst, and N,N-dimethylcyclohexylamine.

[0070] In some embodiments of the present invention, the amount of the second organic solvent used is preferably such that the concentration of the liquid mixture is 1 to 10 g / mL, preferably 2 to 8 g / mL. That is, it is the total content of the polymer network precursor, the crosslinking agent, and the crosslinking catalyst in the liquid mixture. The amount of the crosslinking catalyst used is 1 to 5 wt%, preferably 2 to 4 wt%, of the polymer network precursor.

[0071] In some embodiments of the present invention, the polyrotaxane may be prepared in-house. Preferably, the polyrotaxane is produced by reacting α-cyclodextrin with polyethylene glycol diamine in the presence of a highly sterically hindered compound.

[0072] In some embodiments of the present invention, the sterically hindered compound is preferably at least one selected from N-benzyloxycarbonyl-L-tyrosine, 1-adamantanacetate, fluorescein isothiocyanate, and L-phenylalanine.

[0073] In some embodiments of the present invention, the weight-average molecular weight of polyethylene glycol diamine is preferably 5 kDa to 40 kDa, preferably 10 kDa to 35 kDa.

[0074] In some embodiments of the present invention, the molar ratio of α-cyclodextrin to polyethylene glycol diamine is preferably 50 to 100:1, and more preferably 80 to 90:1.

[0075] In some embodiments of the present invention, the molar ratio of the highly sterically hindered compound to the polyethylene glycol diamine is preferably 2 to 10:1, and more preferably 5 to 8:1.

[0076] In some embodiments of the present invention, preferably, the reaction process is: (i) Add the polyethylene glycol diamine to a saturated aqueous solution of α-cyclodextrin, stir at 20-35°C for 20-40 hours, dry the resulting white precipitate to obtain the inclusion compound. (ii) Dissolve the sterically hindered compound, the amidation catalyst, and the water absorbent-II in a third organic solvent to prepare a solution, then add the inclusion compound to the solution and amidate the resulting suspension to precipitate, wash and dry the resulting solid-phase precipitate to obtain the polyrotaxane.

[0077] In some embodiments of the present invention, preferably, the amidation catalyst is at least one selected from Carter condensation reagent, zinc chloride, and iron chloride hexahydrate; the water absorbent-II is at least one selected from N,N-diisopropylethylamine, 1-hydroxybenzotriazole, and dicyclohexylcarbodiimide; and the third organic solvent is at least one selected from N,N-dimethylformamide, tetrahydrofuran, and dichloromethane.

[0078] In some embodiments of the present invention, the amount of the amidation catalyst used is preferably 1 to 5 wt%, preferably 2 to 4 wt%, of the total amount of the polyethylene glycol diamine and α-cyclodextrin, the amount of the water absorbent-II used is preferably 1 to 5 wt%, preferably 2 to 4 wt%, of the total amount of the polyethylene glycol diamine and α-cyclodextrin, and the amount of the third organic solvent used is such that the concentration of the solution is 1 to 10 g / mL, preferably 2 to 8 g / mL. That is, the total content of the sterically hindered compound, the amidation catalyst, and the water absorbent-II in the solution.

[0079] In some embodiments of the present invention, the weight-average molecular weight of the polyrotaxane is preferably 10 to 100 kDa, preferably 30 to 90 kDa.

[0080] A fourth aspect of the present invention provides a polycaprolactone shape memory material manufactured by the method of the present invention.

[0081] In some embodiments of the present invention, the polycaprolactone shape memory material preferably has polycaprolactone molecular chains that can slide on polyethylene glycol molecular chains, can recover more than 95% of its original shape within 5 seconds, has a crosslinked structure, and has photoreversible dynamic covalent bonds at the node portion of the crosslinked structure, thereby imparting to the solid material the ability to break the covalent bonds and reform its original shape by irradiation with ultraviolet light at 256 nm. The process of reforming the shape of the polycaprolactone shape memory material is shown in Figure 7. The polycaprolactone shape memory material has an elongation at break of more than 900%, a gel content of 37-78 wt%, and a recovery time of 5 seconds or less to the initial shape under 100% strain.

[0082] A fifth aspect of the present invention is a medical recovery The present invention provides for the use of the polycaprolactone shape memory material in a fixative.

[0083] Preferably, use includes shape-memory medical fixation clips.

[0084] The present invention will be described in detail below with reference to examples. In the following examples, 1 The 1H-NMR spectrum is measured using a Bruker ARX-500 from Bruker, Switzerland, with a resolution <0.2 Hz and sensitivity >100. For the analysis, 1 ¹H-NMR is used, with deuterated chloroform or deuterated dimethyl sulfoxide as the solvent. The test is performed at an operating frequency of 500 MHz, a magnetic field strength of 7.05 T, and at room temperature.

[0085] GPC spectra were measured using triple detection-size exclusion chromatography (TD-SEC) manufactured by Waters, Inc., USA, to characterize the molecular weight and molecular weight distribution (PDI) of the polymer at 35°C. Polystyrene was used as the standard sample, THF as the mobile phase, and the test flow rate was 1.0 mL / min.

[0086] The Fourier transform infrared spectrum was measured using an Avatar 370 from Nicolet, Inc., USA. The test used a KBr pressed sample, transmission mode, and a scanning range of 500–4000 cm². -1 The resolution is 2cm -1 Let's assume that.

[0087] The gel content is measured by the Soxhlet extraction method, which involves extracting the sample with chloroform for 24 hours and then weighing the sample before and after extraction to obtain the gel content.

[0088] The shape recovery speed and shape recovery rate are measured using a Q800 universal testing machine from TA Instruments, USA, according to the plate heating tensile method.

[0089] The manufactured PCL samples are cut into dumbbell-shaped specimens using a standard 4x25 cutter, and mechanical properties are tested using an electronic universal tester at a tensile speed of 20 mm / min and a preload of 0.5 N. The elongation at break and tensile strength of each sample are then calculated using the following formulas. Before testing, a mark is made with a marker 2 cm from the center of the specimen, and the thickness of the marked area is measured three times at equal intervals using a standard caliper. The average value is calculated and recorded as the average thickness of the sample.

[0090]

number

[0091] Here, L1 is the length at sample fracture, L0 is the initial length of the sample, and F max is the maximum tensile force during the tensile process, and A is the initial cross-sectional area of ​​the sample.

[0092] [Example 1] The steps for producing a reformable polycaprolactone shape memory material are as follows:

[0093] Step 1: Polyethylene glycol diamine with a weight-average molecular weight of 10 kDa, 5.3 × 10 -5 The moles were weighed and added to a saturated aqueous solution of α-cyclodextrin (7.25 g / 50 mL, redistilled H2O). The mixture was stirred at room temperature for 24 hours to obtain a white precipitate, and then freeze-dried in a freeze-dryer for 48 hours to obtain the inclusion compound.

[0094] 2.6 × 10 -3Mol of N-benzyloxycarbonyl-L-tyrosine (ZL-Tyr), Carter condensation reagent (BOP), 1-hydroxybenzotriazole (HOBt), and N,N-diisopropylethylamine (DIEA) were sequentially dissolved in a small amount of N,N-dimethylformamide (DMF). Next, the inclusion compounds were added to the solution, and the suspension was amidated at 25°C for 24 hours. After that, the suspension was placed in excess ethyl ether to precipitate the primary product, which was then centrifuged at room temperature at 1800 rpm for 20 minutes. The precipitate was collected, and then washed three times in succession with large amounts of acetone, methanol, and water, and freeze-dried to obtain polyrotaxane (PR).

[0095] An appropriate amount of polyrotaxane was weighed and dissolved in 50 mL of 1 mol / L NaOH solution. Under ice bath conditions, an appropriate amount of propylene oxide was added dropwise, and the mixture was stirred overnight. As the ice in the solution melted, the reaction temperature gradually rose to room temperature. The sample was purified by dialyzing with deionized water for one week and then freeze-dried. The freeze-dried sample was added to 100 mL of dichloromethane and stirred overnight to filter off the free polyethylene glycol produced by decomposition during hydroxypropylation. The mixture was then washed with a large amount of acetone, centrifuged to collect the precipitate, and vacuum-dried at 60°C to obtain hydroxypropylated polyrotaxane (HP-PR).

[0096] Step 2: HP-PR and purified ε-caprolactone (ε-Cl) were added to a silane-treated dry round-bottom flask in a molar ratio (number of active hydroxyl groups on HP-PR: ε-Cl = 1:200). 1 wt% of stannous octanoate (by total mass of HP-PR and ε-caprolactone, same as below) was added, and the mixture was purged with high-purity nitrogen gas. The mixture was reacted at 120°C for 48 hours. The primary product was then dissolved in a small amount of tetrahydrofuran and precipitated three times in excess n-hexane. The precipitate was vacuum-dried at 60°C for 48 hours to obtain polycaprolactone grafted polyrotaxane copolymer (PCL-g-PR).

[0097] Step 3: Weigh 0.5 molar equivalents of 4-nitrocinnamic acid with HP-PR activated hydroxyl groups, dissolve in 25 mL of DMF at 50°C, then add the DMF solution of PCL-g-PR to the DMF solution of 4-nitrocinnamic acid and stir for 30 min. Next, add 1 molar equivalent of N,N-diisopropylcarbodiimide and 0.5 molar equivalents of 4-dimethylaminopyridine, and react the mixture at 50°C for 20 hours. Precipitate the primary product in excess ethyl ether, collect the solid by centrifugation, dissolve the solid product in a small amount of toluene, precipitate three more times in ethyl ether, and vacuum dry overnight at 60°C to obtain a polymer network precursor in which some of the terminal groups have been modified to cinnamic acid groups.

[0098] Step 4: The polymer network precursor was dissolved in N,N-dimethylformamide at 80°C, and then an appropriate amount of butyl acetate solution of hexamethylene diisocyanate and dibutyltin dilaurate was added and stirred for 5 minutes. The liquid mixture was placed between two glass plates separated by a silicone rubber gasket and left in an 80°C oven for 48 hours, then vacuum dried overnight at 80°C, and finally irradiated for 12 hours in a UV box with four 5W 365nm UV lamps to obtain a polycaprolactone shape memory material.

[0099] Figure 1 shows the relationship between the manufactured PR, PEG (polyethylene glycol), and α-CD. 1This is a comparison chart of 1H-NMR spectra. In (a), the peak at chemical shift 3.28 ppm is the proton peak on the carbon of mark 2, the peaks at chemical shifts 3.5 to 3.7 ppm correspond to the proton peaks on the carbons of marks 4, 5, and 6, the peak at chemical shift 3.76 ppm corresponds to the proton peak on the carbon of mark 3, the peak at chemical shift 4.51 ppm is the proton peak of the hydroxyl group on the carbon of mark 6, the peak at chemical shift 4.80 ppm is the proton peak on the carbon of mark 1, the peak at chemical shift 5.45 ppm is the proton peak of the hydroxyl group on the carbon of mark 3, and the peak at chemical shift 5.54 ppm is the proton peak of the hydroxyl group on the carbon of mark 2. In (b), the peak at chemical shift 2.04 ppm (mark j) is a proton peak on the amino groups at both ends of PEG-NH2, and the peak at chemical shift 3.58 ppm (mark i) is a proton peak on the methylene group of PEG-NH2. In (c), the peak at chemical shift 3.51 ppm is a proton peak on the methylene group of PEG, and the peaks at chemical shifts 4.4 to 5.7 ppm are proton peaks on α-CD. As can be seen from the nuclear magnetic spectrum, the nuclear magnetic spectrum of the synthesized PR contains both the characteristic methylene peak at PEG 3.5 ppm and the characteristic carbon peak at mark 1 on α-CD at 4.8 ppm, which proves that the PR molecule contains PEG and α-CD structural units. Integrating the characteristic peaks at 4.8 ppm and 3.5 ppm, we found a ratio of ∫4.8:∫3.5=1:4, indicating that, on average, approximately one α-CD molecule is present on every six PEG structural units.

[0100] Figure 2 is a GPC comparison chart of the synthesized PR with PEG-NH2 and α-CD. As can be seen from the retention times, the molecular weight of PR is larger than that of PEG-NH2, and it is clear that no small molecule components are present. Referring to the nuclear magnetic data in Figure 1, the α-CD found in the nuclear magnetic spectrum is attached to the PEG molecular chain, indicating that the synthesis of PR was successful.

[0101] Figure 3 shows the nuclear magnetic spectrum of HP-PR after hydroxypropyl modification. Compared to the nuclear magnetic spectrum of PR, the positions above 2.0 ppm are almost the same, but HP-PR has one more methyl proton peak at chemical shift 1.0 ppm (mark k), indicating that the hydroxypropyl modification of α-CD on PR was successful. The hydroxypropyl modification rate DS of PR was calculated from the area integral ratio of the peaks at 4.2–6.0 ppm and 1.0 ppm by integrating the peaks at these points, and the hydroxypropyl modification rate DS of PR was found to be 6.

[0102] Figure 4 is an infrared comparison chart of manufactured PR, HP-PR, and PCL-g-PR, where the figure shows values ​​of 3436 cm². -1 Absorption peaks in and at 3400 cm for PR and HP-PR -1 The absorption peak at this point is due to stretching vibrations of -OH on -OH and -NH on -NH, and is at 2946 cm² in PCL-g-PR. -1 Absorption peaks in and at 2923 cm for PR and HP-PR. -1 The absorption peak at -CH2- is due to the asymmetric stretching vibration of -CH, and is at 2866 cm² of PCL-g-PR. -1 The absorption peak at -CH2- is due to the symmetric stretching vibration of -CH, and is at 1725 cm² of PCL-g-PR. -1 The absorption peak at 1640 cm² is due to the stretching vibration (C=O) of the carbonyl group on the side chain of polycaprolactone, and is present in PR and HP-PR. -1 The absorption peak at (C=O) is due to the stretching vibration of the carbonyl group on the amide bond. PR, HP-PR, and PCL-g-PR are at 1300-1500 cm⁻¹. -1 This is due to bending vibration within the CH plane, and occurs at 1000-1300 cm. -1 The absorption peaks in this region are due to CC skeletal vibrations and CC skeletal vibrations, and are in the range of 650-1000 cm. -1The absorption peaks in the CH region are due to out-of-plane bending vibrations. The carbonyl peaks found in PR and HP-PR are due to amide bonds, while the carbonyl peak found in PCL-g-PR has a significantly higher frequency and corresponds to an ester bond. This demonstrates that HP-PR was used as an initiator to initiate ring-opening polymerization of ε-caprolactone, forming a large molecule ester bond. The infrared characteristic peaks of PR and HP-PR are almost identical, however, the intensity of the characteristic peak of HP-PR is higher. This is thought to be because, after the α-cyclodextrin on PR is hydroxypropylated, the hydrogen bonds between the α-cyclodextrins weaken, and the interatomic vibration frequency increases.

[0103] Figure 5 shows the nuclear magnetic spectrum of the fabricated PCL-g-PR. The peak at chemical shift 1.32 ppm (mark d) corresponds to the proton peak on the central methylene group in the caprolactone segment, the peak at chemical shift 1.58 ppm (mark c) corresponds to the proton peak on the methylene group adjacent to the central carbon atom in the caprolactone segment, the peak at chemical shift 2.24 ppm (mark b) corresponds to the proton peak on the carbon in the ortho position of the carbonyl group in the caprolactone segment, and the peak at chemical shift 3.99 ppm (mark a) corresponds to the proton peak on the carbon in the ortho position of the oxygen atom in the caprolactone segment. At chemical shift 3.58 ppm, there is a very weak characteristic peak, which is thought to be PEG methylene, and this is because the growth of the PCL segment in the PCL-g-PR side chain is shielding the peak signal of the methylene proton on the PEG chain.

[0104] Figure 6 illustrates the crosslinked network structure of the polycaprolactone shape memory material obtained in Example 1. In the figure, the polyethylene glycol polymer chain has large sterically hindered groups (derived from N-benzyloxycarbonyl-L-tyrosine) shown as dots, and these groups penetrate the α-cyclodextrin shown as rings on the polycaprolactone polymer chain, forming a crosslinked network structure between the polyethylene glycol polymer chain and the polycaprolactone polymer chain. Furthermore, the cyclic structure provided by the α-cyclodextrin allows the polycaprolactone polymer chain to slide on the polyethylene glycol polymer chain. The polycaprolactone polymer chain also has reversible linking groups represented by squares that provide reversible covalent bonds. These reversible linking groups are formed by photoreversible groups provided by a terminal group modifier or thermoreversible groups provided by a crosslinking agent, introducing dynamic covalent bonds into the polycaprolactone shape memory material, enabling linking by reversible bonding, and realizing the design possibilities for complex shapes and the remolding properties in the solid state of the shape memory material.

[0105] [Example 2] The steps for producing a reformable polycaprolactone shape memory material are as follows:

[0106] Step 1: 6.4 × 10⁶ polyethylene glycol diamine with a weight-average molecular weight of 15 kDa -5 The moles were weighed and added to a saturated aqueous solution of α-cyclodextrin (7.25 g / 50 mL, redistilled H2O). The mixture was stirred at 30°C for 30 hours to obtain a white precipitate, and then freeze-dried in a freeze-dryer for 48 hours to obtain the inclusion compound.

[0107] 3.4 × 10 -3Moles of N-benzyloxycarbonyl-L-tyrosine (ZL-Tyr), Carter condensation reagent (BOP), 1-hydroxybenzotriazole (HOBt), and N,N-diisopropylethylamine (DIEA) were sequentially dissolved in small amounts of N,N-dimethylformamide (DMF). Next, the inclusion compounds were added to the solution, and the suspension was amidated at 25°C for 26 hours. After that, the suspension was added to excess ethyl ether to precipitate the primary product, which was then centrifuged at 1800 rpm at room temperature for 25 minutes, and the precipitate was collected. Subsequently, the precipitate was washed three times in succession with large amounts of acetone, methanol, and water, and lyophilized to obtain polyrotaxane.

[0108] An appropriate amount of polyrotaxane was weighed and dissolved in 50 mL of 1 mol / L NaOH solution. Under ice bath conditions, an appropriate amount of propylene oxide was added dropwise, and the mixture was stirred overnight. As the ice in the solution melted, the reaction temperature gradually rose to room temperature. The sample was purified by dialyzing with deionized water for one week and then freeze-dried. The freeze-dried sample was added to 100 mL of dichloromethane and stirred overnight to filter off the free polyethylene glycol produced by decomposition during hydroxypropylation. The mixture was then washed with a large amount of acetone, centrifuged to collect the precipitate, and vacuum-dried at 55°C to obtain hydroxypropylated polyrotaxane (HP-PR).

[0109] Step 2: HP-PR and purified ε-caprolactone were added to a silane-treated dry round-bottom flask in a molar ratio (number of active hydroxyl groups on HP-PR: ε-CL = 1:400), and 1 wt% of stannous octanoate (total mass of HP-PR and ε-caprolactone) was added. The mixture was then replaced with high-purity nitrogen gas and reacted at 130°C for 50 hours. Subsequently, the primary product was dissolved in a small amount of tetrahydrofuran and precipitated three times in excess n-hexane. The precipitate was vacuum-dried at 60°C for 48 hours to obtain polycaprolactone grafted polyrotaxane copolymer (PCL-g-PR).

[0110] Step 3: Weigh 0.5 molar equivalents of 4-nitrocinnamic acid with HP-PR activated hydroxyl groups, dissolve in 25 mL of DMF at 50°C, then add the DMF solution of PCL-g-PR to the DMF solution of 4-nitrocinnamic acid and stir for 40 min. Next, add 1 molar equivalent of N,N-diisopropylcarbodiimide and 0.5 molar equivalents of 4-dimethylaminopyridine, and react the mixture at 55°C for 22 hours. Precipitate the primary product in excess ethyl ether, collect the solid by centrifugation, dissolve the solid product in a small amount of toluene, precipitate three more times in ethyl ether, and vacuum dry overnight at 60°C to obtain a polymer network precursor in which some of the terminal groups have been modified to cinnamic acid groups.

[0111] Step 4: The polymer network precursor was dissolved in N,N-dimethylformamide at 80°C, and then an appropriate amount of butyl acetate solution of hexamethylene diisocyanate and dibutyltin dilaurate was added and stirred for 5 minutes. The liquid mixture was placed between two glass plates separated by a silicone rubber gasket and left in an 80°C oven for 48 hours, then vacuum dried overnight at 80°C, and finally irradiated for 14 hours in a UV box with four 5W 370nm UV lamps to obtain a polycaprolactone shape memory material.

[0112] [Example 3] The steps for producing a reformable polycaprolactone shape memory material are as follows:

[0113] Step 1: Polyethylene glycol diamine 8.0 × 10⁻¹⁶ with a weight-average molecular weight of 20 kDa -5 The moles were weighed and added to a saturated aqueous solution of α-cyclodextrin (7.25 g / 50 mL, redistilled H2O). The mixture was stirred at room temperature for 24 hours to obtain a white precipitate, and then freeze-dried in a freeze-dryer for 48 hours to obtain the inclusion compound.

[0114] 4.2 × 10 -3Moles of N-benzyloxycarbonyl-L-tyrosine (ZL-Tyr), Carter condensation reagent (BOP), 1-hydroxybenzotriazole (HOBt), and N,N-diisopropylethylamine (DIEA) were sequentially dissolved in small amounts of N,N-dimethylformamide (DMF). Next, the inclusion compounds were added to the solution, and the suspension was amidated at 30°C for 25 hours. After that, the suspension was added to excess ethyl ether to precipitate the primary product, and the precipitate was collected by centrifugation at 2000 rpm at room temperature for 15 minutes. Subsequently, the precipitate was washed three times in succession with large amounts of acetone, methanol, and water, and then freeze-dried to obtain polyrotaxane.

[0115] An appropriate amount of polyrotaxane was weighed and dissolved in 50 mL of 1 mol / L NaOH solution. Under ice bath conditions, an appropriate amount of propylene oxide was added dropwise, and the mixture was stirred overnight. As the ice in the solution melted, the reaction temperature gradually rose to room temperature. The sample was purified by dialyzing with deionized water for one week and then freeze-dried. The freeze-dried sample was added to 100 mL of dichloromethane and stirred overnight to filter off the free polyethylene glycol produced by decomposition during hydroxypropylation. The mixture was then washed with a large amount of acetone, centrifuged to collect the precipitate, and vacuum-dried at 60°C to obtain hydroxypropylated polyrotaxane (HP-PR).

[0116] Step 2: HP-PR and purified ε-caprolactone were added to a silane-treated dry round-bottom flask in a molar ratio (number of active hydroxyl groups on HP-PR: ε-CL = 1:600), and 1 wt% of stannous octanoate (total mass of HP-PR and ε-caprolactone) was added. The mixture was then replaced with high-purity nitrogen gas and reacted at 130°C for 55 hours. Subsequently, the primary product was dissolved in a small amount of tetrahydrofuran and precipitated three times in excess n-hexane. The precipitate was vacuum-dried at 60°C for 48 hours to obtain polycaprolactone grafted polyrotaxane copolymer (PCL-g-PR).

[0117] Step 3: Weigh 0.5 molar equivalents of 4-nitrocinnamic acid with HP-PR activated hydroxyl groups, dissolve in 25 mL of DMF at 50°C, then add the DMF solution of PCL-g-PR to the DMF solution of 4-nitrocinnamic acid and stir for 30 min. Next, add 1 molar equivalent of N,N-diisopropylcarbodiimide and 0.5 molar equivalents of 4-dimethylaminopyridine, and react the mixture at 45°C for 15 hours. Precipitate the primary product in excess ethyl ether, collect the solid by centrifugation, dissolve the solid product in a small amount of toluene, precipitate three more times in ethyl ether, and vacuum dry overnight at 60°C to obtain a polymer network precursor in which some of the terminal groups have been modified to cinnamic acid groups.

[0118] Step 4: The polymer network precursor was dissolved in N,N-dimethylformamide at 80°C, and then an appropriate amount of butyl acetate solution of hexamethylene diisocyanate and dibutyltin dilaurate was added and stirred for 5 minutes. The liquid mixture was placed between two glass plates separated by a silicone rubber gasket and left in an 80°C oven for 48 hours, then vacuum dried overnight at 80°C, and finally irradiated for 10 hours in a UV box with four 5W 380nm UV lamps to obtain the polycaprolactone shape memory material.

[0119] [Example 4] The steps for manufacturing polycaprolactone shape memory material are as follows:

[0120] Step 1: 5.3 × 10³ polyethylene glycol diamine with a weight-average molecular weight of 20 kDa -5 The moles were weighed and added to a saturated aqueous solution of α-cyclodextrin (7.25 g / 50 mL, redistilled H2O). The mixture was stirred at room temperature for 24 hours to obtain a white precipitate, and then freeze-dried in a freeze-dryer for 48 hours to obtain the inclusion compound.

[0121] 2.6 × 10 -3Moles of N-benzyloxycarbonyl-L-tyrosine (ZL-Tyr), Carter condensation reagent (BOP), 1-hydroxybenzotriazole (HOBt), and N,N-diisopropylethylamine (DIEA) were sequentially dissolved in small amounts of N,N-dimethylformamide (DMF). Next, the inclusion compounds were added to the solution, and the suspension was amidated at 25°C for 30 hours. After that, the suspension was added to excess ethyl ether to precipitate the primary product, which was then centrifuged at 2000 rpm at room temperature for 25 minutes, and the precipitate was collected. Subsequently, the precipitate was washed three times in succession with large amounts of acetone, methanol, and water, and lyophilized to obtain polyrotaxane.

[0122] An appropriate amount of polyrotaxane was weighed and dissolved in 50 mL of 1 mol / L NaOH solution. Under ice bath conditions, an appropriate amount of propylene oxide was added dropwise, and the mixture was stirred overnight. As the ice in the solution melted, the reaction temperature gradually rose to room temperature. The sample was purified by dialyzing with deionized water for one week and then freeze-dried. The freeze-dried sample was added to 100 mL of dichloromethane and stirred overnight to filter off the free polyethylene glycol produced by decomposition during hydroxypropylation. The mixture was then washed with a large amount of acetone, centrifuged to collect the precipitate, and vacuum-dried at 60°C to obtain hydroxypropylated polyrotaxane (HP-PR).

[0123] Step 2: HP-PR and purified ε-caprolactone were added to a silane-treated dry round-bottom flask in a molar ratio (number of active hydroxyl groups on HP-PR: ε-CL = 1:200), and 1 wt% of stannous octanoate (total mass of HP-PR and ε-caprolactone) was added. The mixture was then replaced with high-purity nitrogen gas and reacted at 120°C for 48 hours. Subsequently, the primary product was dissolved in a small amount of tetrahydrofuran and precipitated three times in excess n-hexane. The precipitate was vacuum-dried at 60°C for 48 hours to obtain polycaprolactone grafted polyrotaxane copolymer (PCL-g-PR).

[0124] Step 3: Weigh 0.5 molar equivalents of 4-nitrocinnamic acid with HP-PR activated hydroxyl groups, dissolve in 25 mL of DMF at 50°C, then add the DMF solution of PCL-g-PR to the DMF solution of 4-nitrocinnamic acid and stir for 30 min. Next, add 1 molar equivalent of N,N-diisopropylcarbodiimide and 0.5 molar equivalents of 4-dimethylaminopyridine, and react the mixture at 60°C for 15 hours. Precipitate the primary product in excess ethyl ether, collect the solid by centrifugation, dissolve the solid product in a small amount of toluene, precipitate three more times in ethyl ether, and vacuum dry overnight at 60°C to obtain a polymer network precursor in which some of the terminal groups have been modified to cinnamic acid groups.

[0125] Step 4: The polymer network precursor was dissolved in N,N-dimethylformamide at 80°C, then an appropriate amount of butyl acetate solution of hexamethylene diisocyanate and dibutyltin dilaurate was added and stirred for 5 minutes. The liquid mixture was placed between two glass plates separated by a silicone rubber gasket and left in an 80°C oven for 48 hours, then vacuum dried overnight at 80°C, and finally irradiated for 13 hours in a UV box with four 5W 375nm UV lamps to obtain a polycaprolactone shape memory material.

[0126] [Example 5] The steps for manufacturing polycaprolactone shape memory material are as follows:

[0127] Step 1: Polyethylene glycol diamine with a weight-average molecular weight of 20 kDa, 5.7 × 10 -5 The moles were weighed and added to a saturated aqueous solution of α-cyclodextrin (7.25 g / 50 mL, redistilled H2O). The mixture was stirred at 30°C for 24 hours to obtain a white precipitate, which was then freeze-dried for 50 hours in a freeze-dryer to obtain the inclusion compound.

[0128] 2.7 × 10 -3Moles of N-benzyloxycarbonyl-L-tyrosine (ZL-Tyr), Carter condensation reagent (BOP), 1-hydroxybenzotriazole (HOBt), and N,N-diisopropylethylamine (DIEA) were sequentially dissolved in small amounts of N,N-dimethylformamide (DMF). Next, the inclusion compounds were added to the solution, and the suspension was amidated at 25°C for 28 hours. After that, the suspension was added to excess ethyl ether to precipitate the primary product, which was then centrifuged at 1800 rpm at room temperature for 30 minutes, and the precipitate was collected. Subsequently, the precipitate was washed three times in succession with large amounts of acetone, methanol, and water, and lyophilized to obtain polyrotaxane.

[0129] An appropriate amount of polyrotaxane was weighed and dissolved in 50 mL of 1 mol / L NaOH solution. Under ice bath conditions, an appropriate amount of propylene oxide was added dropwise, and the mixture was stirred overnight. As the ice in the solution melted, the reaction temperature gradually rose to room temperature. The sample was purified by dialyzing with deionized water for one week and then freeze-dried. The freeze-dried sample was added to 100 mL of dichloromethane and stirred overnight to filter off the free polyethylene glycol produced by decomposition during hydroxypropylation. The mixture was then washed with a large amount of acetone, centrifuged to collect the precipitate, and vacuum-dried at 60°C to obtain hydroxypropylated polyrotaxane (HP-PR).

[0130] Step 2: HP-PR and purified ε-caprolactone were added to a silane-treated dry round-bottom flask in a molar ratio (number of active hydroxyl groups on HP-PR: ε-CL = 1:400), 1 wt% of the total mass of stannous octanoate was added, and the mixture was replaced with high-purity nitrogen gas. The mixture was reacted at 125°C for 50 hours. Subsequently, the primary product was dissolved in a small amount of tetrahydrofuran and precipitated three times in excess n-hexane. The precipitate was vacuum-dried at 60°C for 48 hours to obtain polycaprolactone grafted polyrotaxane copolymer (PCL-g-PR).

[0131] Step 3: Weigh 0.5 molar equivalents of 4-nitrocinnamic acid with HP-PR activated hydroxyl groups, dissolve in 25 mL of DMF at 50°C, then add the DMF solution of PCL-g-PR to the DMF solution of 4-nitrocinnamic acid and stir for 30 min. Next, add 1 molar equivalent of N,N-diisopropylcarbodiimide and 0.5 molar equivalents of 4-dimethylaminopyridine, and react the mixture at 40°C for 25 hours. Precipitate the primary product in excess ethyl ether, collect the solid by centrifugation, dissolve the solid product in a small amount of toluene, precipitate three more times in ethyl ether, and vacuum dry overnight at 60°C to obtain a polymer network precursor in which some of the terminal groups have been modified to cinnamic acid groups.

[0132] Step 4: The polymer network precursor was dissolved in N,N-dimethylformamide at 80°C, and then an appropriate amount of butyl acetate solution of hexamethylene diisocyanate and dibutyltin dilaurate was added and stirred for 5 minutes. The liquid mixture was placed between two glass plates separated by a silicone rubber gasket and left in an 80°C oven for 48 hours, then vacuum dried overnight at 80°C, and finally irradiated for 15 hours in a UV box with four 5W 365nm UV lamps to obtain the polycaprolactone shape memory material.

[0133] [Example 6] The steps for producing a reformable polycaprolactone shape memory material are as follows:

[0134] Step 1: 7.4 × 10¹³ polyethylene glycol diamine with a weight-average molecular weight of 30 kDa -5 The moles were weighed and added to a saturated aqueous solution of α-cyclodextrin (7.25 g / 50 mL, redistilled H2O). The mixture was stirred at room temperature for 24 hours to obtain a white precipitate, and then freeze-dried in a freeze-dryer for 48 hours to obtain the inclusion compound.

[0135] 3.5 × 10 -3Moles of N-benzyloxycarbonyl-L-tyrosine (ZL-Tyr), Carter condensation reagent (BOP), 1-hydroxybenzotriazole (HOBt), and N,N-diisopropylethylamine (DIEA) were sequentially dissolved in small amounts of N,N-dimethylformamide (DMF). Then, the inclusion compounds were added to the solution, and the suspension was reacted at 25°C for 24 hours. The suspension was placed in excess ethyl ether to precipitate the primary product, and the mixture was centrifuged at room temperature at 1800 rpm for 30 minutes to collect the precipitate. The precipitate was then washed three times in succession with large amounts of acetone, methanol, and water, and freeze-dried to obtain polyrotaxane.

[0136] An appropriate amount of polyrotaxane was weighed and dissolved in 50 mL of 1 mol / L NaOH solution. Under ice bath conditions, an appropriate amount of propylene oxide was added dropwise, and the mixture was stirred overnight. As the ice in the solution melted, the reaction temperature gradually rose to room temperature. The sample was purified by dialyzing with deionized water for one week and then freeze-dried. The freeze-dried sample was added to 100 mL of dichloromethane and stirred overnight to filter off the free polyethylene glycol produced by decomposition during hydroxypropylation. The mixture was then washed with a large amount of acetone, centrifuged to collect the precipitate, and vacuum-dried at 60°C to obtain hydroxypropylated polyrotaxane (HP-PR).

[0137] Step 2: HP-PR and purified ε-caprolactone were added to a silane-treated dry round-bottom flask in a molar ratio (number of active hydroxyl groups on HP-PR: ε-CL = 1:600), 1 wt% of the total mass of stannous octanoate was added, and the mixture was replaced with high-purity nitrogen gas. The mixture was reacted at 110°C for 50 hours. The primary product was then dissolved in a small amount of tetrahydrofuran and precipitated three times in excess n-hexane. The precipitate was vacuum-dried at 60°C for 48 hours to obtain polycaprolactone grafted polyrotaxane copolymer (PCL-g-PR).

[0138] Step 3: Weigh 0.5 molar equivalents of 4-nitrocinnamic acid with HP-PR activated hydroxyl groups, dissolve in 25 mL of DMF at 50°C, then add the DMF solution of PCL-g-PR to the DMF solution of 4-nitrocinnamic acid and stir for 40 min. Next, add 1 molar equivalent of N,N-diisopropylcarbodiimide and 0.5 molar equivalents of 4-dimethylaminopyridine, and react the mixture at 60°C for 20 hours. Precipitate the primary product in excess ethyl ether, collect the solid by centrifugation, dissolve the solid product in a small amount of toluene, precipitate three more times in ethyl ether, and vacuum dry overnight at 60°C to obtain a polymer network precursor in which some of the terminal groups have been modified to cinnamic acid groups.

[0139] Step 4: The polymer network precursor was dissolved in N,N-dimethylformamide at 80°C, then an appropriate amount of butyl acetate solution of hexamethylene diisocyanate and dibutyltin dilaurate was added and stirred for 10 minutes. The liquid mixture was placed between two glass plates separated by a silicone rubber gasket and left in an 80°C oven for 48 hours, then vacuum dried overnight at 80°C, and finally irradiated in a UV box with four 5W 380nm UV lamps for 12 hours to obtain the polycaprolactone shape memory material.

[0140] [Example 7] The steps for manufacturing polycaprolactone shape memory material are as follows:

[0141] Step 1: 5.3 × 10³ polyethylene glycol diamine with a weight-average molecular weight of 35 kDa -5 The moles were weighed and added to a saturated aqueous solution of α-CD (7.25 g / 50 mL, redistilled H2O). The mixture was stirred at 30°C for 26 hours to obtain a white precipitate, and then freeze-dried in a freeze-dryer for 48 hours to obtain the inclusion compound.

[0142] 2.6 × 10 -3Moles of N-benzyloxycarbonyl-L-tyrosine (ZL-Tyr), Carter condensation reagent (BOP), 1-hydroxybenzotriazole (HOBt), and N,N-diisopropylethylamine (DIEA) were sequentially dissolved in small amounts of N,N-dimethylformamide (DMF). Then, the inclusion compounds were added to the solution, and the suspension was amidated at 25°C for 24 hours. The suspension was placed in excess ethyl ether to precipitate the primary product, which was then centrifuged at 2000 rpm at room temperature for 20 minutes, and the precipitate was collected. The precipitate was then washed three times in succession with large amounts of acetone, methanol, and water, and freeze-dried to obtain polyrotaxane.

[0143] An appropriate amount of polyrotaxane was weighed and dissolved in 50 mL of 1 mol / L NaOH solution. Under ice bath conditions, an appropriate amount of propylene oxide was added dropwise, and the mixture was stirred overnight. As the ice in the solution melted, the reaction temperature gradually rose to room temperature. The sample was purified by dialyzing with deionized water for one week and then freeze-dried. The freeze-dried sample was added to 100 mL of dichloromethane and stirred overnight to filter off the free polyethylene glycol produced by decomposition during hydroxypropylation. The mixture was then washed with a large amount of acetone, centrifuged to collect the precipitate, and vacuum-dried at 60°C to obtain hydroxypropylated polyrotaxane (HP-PR).

[0144] Step 2: HP-PR and purified ε-caprolactone were added to a silane-treated dry round-bottom flask in a molar ratio (number of active hydroxyl groups on HP-PR: ε-CL = 1:200), 1 wt% of the total mass of stannous octanoate was added, and the mixture was replaced with high-purity nitrogen gas. The mixture was reacted at 130°C for 45 hours. The primary product was then dissolved in a small amount of tetrahydrofuran and precipitated three times in excess n-hexane. The precipitate was vacuum-dried at 60°C for 48 hours to obtain polycaprolactone grafted polyrotaxane copolymer (PCL-g-PR).

[0145] Step 3: Weigh 0.5 molar equivalents of 4-nitrocinnamic acid with HP-PR activated hydroxyl groups, dissolve in 25 mL of DMF at 50°C, then add the DMF solution of PCL-g-PR to the DMF solution of 4-nitrocinnamic acid and stir for 30 min. Next, add 1 molar equivalent of N,N-diisopropylcarbodiimide and 0.5 molar equivalents of 4-dimethylaminopyridine, and react the mixture at 50°C for 20 hours. Precipitate the primary product in excess ethyl ether, collect the solid by centrifugation, dissolve the solid product in a small amount of toluene, precipitate three more times in ethyl ether, and vacuum dry overnight at 60°C to obtain a polymer network precursor in which some of the terminal groups have been modified to cinnamic acid groups.

[0146] Step 4: The polymer network precursor was dissolved in N,N-dimethylformamide at 80°C, and then an appropriate amount of butyl acetate solution of hexamethylene diisocyanate and dibutyltin dilaurate was added and stirred for 5 minutes. The liquid mixture was placed between two glass plates separated by a silicone rubber gasket and left in an 80°C oven for 48 hours, then vacuum dried overnight at 80°C, and finally irradiated for 15 hours in a UV box with four 5W 370nm UV lamps to obtain a polycaprolactone shape memory material.

[0147] [Example 8] The steps for manufacturing polycaprolactone shape memory material are as follows:

[0148] Step 1: 6.9 × 10⁻¹⁶ polyethylene glycol diamine with a weight-average molecular weight of 35 kDa -5 The moles were weighed and added to a saturated aqueous solution of α-CD (7.25 g / 50 mL, redistilled H2O). The mixture was stirred at room temperature for 24 hours to obtain a white precipitate, and then freeze-dried in a freeze-dryer for 48 hours to obtain the inclusion compound.

[0149] 3.5 × 10 -3Moles of N-benzyloxycarbonyl-L-tyrosine (ZL-Tyr), Carter condensation reagent (BOP), 1-hydroxybenzotriazole (HOBt), and N,N-diisopropylethylamine (DIEA) were sequentially dissolved in small amounts of N,N-dimethylformamide (DMF). Then, the inclusion compounds were added to the solution, and the suspension was amidated at 25°C for 26 hours. The suspension was placed in excess ethyl ether to precipitate the primary product, which was then centrifuged at 1800 rpm at room temperature for 30 minutes, and the precipitate was collected. The precipitate was then washed three times in succession with large amounts of acetone, methanol, and water, and freeze-dried to obtain polyrotaxane.

[0150] An appropriate amount of polyrotaxane was weighed and dissolved in 50 mL of 1 mol / L NaOH solution. Under ice bath conditions, an appropriate amount of propylene oxide was added dropwise, and the mixture was stirred overnight. As the ice in the solution melted, the reaction temperature gradually rose to room temperature. The sample was purified by dialyzing with deionized water for one week and then freeze-dried. The freeze-dried sample was added to 100 mL of dichloromethane and stirred overnight to filter off the free polyethylene glycol produced by decomposition during hydroxypropylation. The mixture was then washed with a large amount of acetone, centrifuged to collect the precipitate, and vacuum-dried at 60°C to obtain hydroxypropylated polyrotaxane (HP-PR).

[0151] Step 2: HP-PR and purified ε-caprolactone were added to a silane-treated dry round-bottom flask in a molar ratio (number of active hydroxyl groups on HP-PR: ε-CL = 1:400), 1 wt% of the total mass of stannous octanoate was added, and the mixture was replaced with high-purity nitrogen gas. The mixture was reacted at 110°C for 50 hours. The primary product was then dissolved in a small amount of tetrahydrofuran and precipitated three times in excess n-hexane. The precipitate was vacuum-dried at 60°C for 48 hours to obtain polycaprolactone grafted polyrotaxane copolymer (PCL-g-PR).

[0152] Step 3: Weigh 0.5 molar equivalents of 4-nitrocinnamic acid with HP-PR activated hydroxyl groups, dissolve in 25 mL of DMF at 50°C, then add the DMF solution of PCL-g-PR to the DMF solution of 4-nitrocinnamic acid and stir for 30 min. Next, add 1 molar equivalent of N,N-diisopropylcarbodiimide and 0.5 molar equivalents of 4-dimethylaminopyridine, and react the mixture at 60°C for 20 hours. Precipitate the primary product in excess ethyl ether, collect the solid by centrifugation, dissolve the solid product in a small amount of toluene, precipitate three more times in ethyl ether, and vacuum dry overnight at 60°C to obtain a polymer network precursor in which some of the terminal groups have been modified to cinnamic acid groups.

[0153] Step 4: The polymer network precursor was dissolved in N,N-dimethylformamide at 80°C, and then an appropriate amount of butyl acetate solution of hexamethylene diisocyanate and dibutyltin dilaurate was added and stirred for 10 minutes. The liquid mixture was placed between two glass plates separated by a silicone rubber gasket and left in an 80°C oven for 48 hours, then vacuum dried overnight at 80°C, and finally irradiated for 15 hours in a UV box with four 5W 365nm UV lamps to obtain a polycaprolactone shape memory material.

[0154] [Example 9] The steps for manufacturing polycaprolactone shape memory material are as follows:

[0155] Step 1: 5.8 × 10⁻¹⁵ polyethylene glycol diamine with a weight-average molecular weight of 35 kDa -5 The moles were weighed and added to a saturated aqueous solution of α-cyclodextrin (7.25 g / 50 mL, redistilled H2O). The mixture was stirred at room temperature for 24 hours to obtain a white precipitate, and then freeze-dried in a freeze-dryer for 48 hours to obtain the inclusion compound.

[0156] 2.7 × 10 -3Moles of N-benzyloxycarbonyl-L-tyrosine (ZL-Tyr), Carter condensation reagent (BOP), 1-hydroxybenzotriazole (HOBt), and N,N-diisopropylethylamine (DIEA) were sequentially dissolved in small amounts of N,N-dimethylformamide (DMF). Then, the inclusion compounds were added to the solution, and the suspension was amidated at 20°C for 30 hours. The suspension was precipitated in excess ethyl ether, and the precipitate was collected by centrifugation at 2000 g for 20 minutes at room temperature. The precipitate was then washed three times in succession with large amounts of acetone, methanol, and water, and lyophilized to obtain polyrotaxane.

[0157] An appropriate amount of polyrotaxane was weighed and dissolved in 50 mL of 1 mol / L NaOH solution. Under ice bath conditions, an appropriate amount of propylene oxide was added dropwise, and the mixture was stirred overnight. As the ice in the solution melted, the reaction temperature gradually rose to room temperature. The sample was purified by dialyzing with deionized water for one week and then freeze-dried. The freeze-dried sample was added to 100 mL of dichloromethane and stirred overnight to filter off the free polyethylene glycol produced by decomposition during hydroxypropylation. The mixture was then washed with a large amount of acetone, centrifuged to collect the precipitate, and vacuum-dried at 60°C to obtain hydroxypropylated polyrotaxane (HP-PR).

[0158] Step 2: HP-PR and purified ε-caprolactone were added to a silane-treated dry round-bottom flask in a molar ratio (number of active hydroxyl groups on HP-PR: ε-CL = 1:600), 1 wt% of the total mass of stannous octanoate was added, and the mixture was replaced with high-purity nitrogen gas. The mixture was reacted at 130°C for 48 hours. The primary product was then dissolved in a small amount of tetrahydrofuran and precipitated three times in excess n-hexane. The precipitate was vacuum-dried at 60°C for 48 hours to obtain polycaprolactone grafted polyrotaxane copolymer (PCL-g-PR).

[0159] Step 3: Weigh 0.5 molar equivalents of 4-nitrocinnamic acid with HP-PR activated hydroxyl groups, dissolve in 25 mL of DMF at 50°C, then add the DMF solution of PCL-g-PR to the DMF solution of 4-nitrocinnamic acid and stir for 30 min. Next, add 1 molar equivalent of N,N-diisopropylcarbodiimide and 0.5 molar equivalents of 4-dimethylaminopyridine, and react the mixture at 40°C for 25 hours. Precipitate the primary product in excess ethyl ether, collect the solid by centrifugation, dissolve the solid product in a small amount of toluene, precipitate three more times in ethyl ether, and vacuum dry overnight at 60°C to obtain a polymer network precursor in which some of the terminal groups have been modified to cinnamic acid groups.

[0160] Step 4: The polymer network precursor was dissolved in N,N-dimethylformamide at 80°C, and then an appropriate amount of butyl acetate solution of hexamethylene diisocyanate and dibutyltin dilaurate was added and stirred for 10 minutes. The liquid mixture was placed between two glass plates separated by a silicone rubber gasket and left in an 80°C oven for 48 hours, then vacuum dried overnight at 80°C, and finally irradiated for 12 hours in a UV box with four 5W 380nm UV lamps to obtain a polycaprolactone shape memory material.

[0161] [Comparative Example 1] The thermally crosslinked polycaprolactone shape memory plate material was manufactured using 90 parts by weight of polycaprolactone, 5 parts by weight of benzoyl peroxide as a crosslinking agent, 80 parts by weight of dichloromethane as a solvent, and 1 part by weight of a mold release agent as components.

[0162] The manufacturing method for the above-described thermally crosslinked polycaprolactone shape memory board material includes the following manufacturing steps.

[0163] Step 1: Polycaprolactone, benzoyl peroxide as a crosslinking agent, and dichloromethane as a solvent were placed in a round-bottom flask and blended. After sonication for 30 minutes, the mixture was transferred to a mechanical mixer and stirred for 1 hour to obtain the mixture.

[0164] Step 2: The solvent was evaporated from the resulting mixture at room temperature for 1-2 hours, and then the mixture was vacuum-dried at 50-70°C for 24 hours to obtain a PCL / BPO solid mixture.

[0165] Step 3: The solid mixture obtained in Step 2 was placed in a customized iron mold, a release agent was sprayed on it, and a thermal crosslinking treatment of polycaprolactone was started using a flat vulcanizer at 140-160°C with peroxide for 5-15 minutes and a maximum pressure of 10 MPa to obtain a thermal crosslinked polycaprolactone shape memory plate.

[0166] For the products obtained in Examples 1-9 and Comparative Example 1, the gel content, shape recovery rate, shape recovery rate, elongation at break, and tensile strength were measured, and the results are shown in Table 1.

[0167] [Table 1]

[0168] The results in Table 1 show that the polycaprolactone shape memory materials of Examples 1 to 9 obtained by the method according to the present invention exhibited a faster shape recovery rate and a higher shape recovery rate than the products produced in the comparative examples, recovering more than 95% of the original shape within 5 seconds. Furthermore, measurements of the elongation at break and tensile strength of the products obtained in the examples showed a clear improvement in elongation at break compared to Comparative Example 1. For example, in Example 9, the elongation at break improved by 1x, demonstrating that the toughness of the shape memory material can be improved.

[0169] Although preferred embodiments of the present invention have been described in detail above, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution means of the present invention, including combining each technical feature in other appropriate ways. These simple modifications and combinations should also be considered as part of the content disclosed in the present invention and all fall within the scope of protection of the present invention.

Claims

1. The material comprises a plurality of modified polyrotaxane polymer chains and a plurality of composite polymer chains linking different modified polyrotaxane polymer chains, each of the composite polymer chains comprising at least two segments of polycaprolactone polymer chains, reversible linking groups between different polycaprolactone polymer chains, and linking modification groups that link the polycaprolactone polymer chains to cyclic structures derived from cyclodextrin contained in the modified polyrotaxane polymer chains, wherein the reversible linking groups are photoreversible linking groups, or photoreversible linking groups and thermally reversible linking groups. The aforementioned photoreversible linking group is derived from a compound having a photoreversible group selected from nitrocinnamic acid compounds and / or 4-((4-methyl-2-oxo-2H-chromen-7-yl)oxy)butyric acid, A polycaprolactone shape memory material characterized in that the aforementioned thermoreversible linking group is derived from diisocyanate.

2. The polycaprolactone shape memory material according to claim 1, wherein the diisocyanate is at least one selected from hexamethylene diisocyanate, toluene diisocyanate, isophorone diisocyanate, and lysine diisocyanate.

3. The polycaprolactone shape memory material according to claim 1, wherein the linking modification group is derived from a compound for hydroxypropylation.

4. The aforementioned linkage modifying group is structural formula -CH ２ -CH(CH ３ The polycaprolactone shape memory material according to claim 3, wherein the group is represented by )-O-.

5. The polycaprolactone shape memory material according to claim 1, wherein the total amount of the polycaprolactone polymer chain is 80 to 100 wt%, based on the total amount of the modified polyrotaxane polymer chain.

6. The polycaprolactone shape memory material according to claim 1, wherein the weight-average molecular weight of the polycaprolactone polymer chain is 5,000 to 100,000 kDa.

7. The polycaprolactone shape memory material according to claim 1, wherein the weight-average molecular weight of the modified polyrotaxane polymer chain is 10 kDa to 100 kDa.

8. The polycaprolactone shape memory material according to claim 1, wherein the polycaprolactone shape memory material has a fracture elongation of more than 900%, the gel content of the polycaprolactone shape memory material is 37 to 78 wt%, and the time it takes for the polycaprolactone shape memory material to recover to its initial shape under 100% strain is 5 s or less.

9. The solution comprises a polyrotaxane initiator, a terminal group modifier, ε-caprolactone, a catalyst, and a crosslinking agent, wherein the terminal group modifier is selected from nitrocinnamic acid compounds and / or 4-((4-methyl-2-oxo-2H-chromen-7-yl)oxy)butyric acid. A composition for producing a polycaprolactone shape memory material according to any one of claims 1 to 8, characterized in that the crosslinking agent is a diisocyanate.

10. The weight-average molecular weight of the polyrotaxane initiator is 10 kDa to 100 kDa. The composition according to claim 9, wherein the catalyst is at least one selected from stannous octanoate, lithium diisopropylamide, scandium(III) trifluoromethanesulfonate, and a phosphazene base.

11. Step (1) involves hydroxypropylating polyrotaxane to obtain hydroxypropylated polyrotaxane, Step (2) involves ring-opening polymerization of the hydroxypropylated polyrotaxane and ε-caprolactone in the presence of a catalyst to obtain a polycaprolactone grafted polyrotaxane copolymer, Step (3) involves a modification reaction between the polycaprolactone-grafted polyrotaxane copolymer and the photoreversible groups of the terminal group modifier to obtain a polymer network precursor in which the terminal group portion is modified into a photoreversible group, The process includes (4) the step of crosslinking the polymer network precursor by reacting the photoreversible groups with heating and ultraviolet light in the presence of a crosslinking agent to obtain a polycaprolactone shape memory material, The terminal group modifier is selected from nitrocinnamic acid compounds and / or 4-((4-methyl-2-oxo-2H-chromen-7-yl)oxy)butyric acid, A method for producing a polycaprolactone shape memory material, characterized in that the crosslinking agent is diisocyanate.

12. In step (2), the catalyst is at least one selected from stannous octanoate, lithium diisopropylamide, scandium(III) trifluoromethanesulfonate, and phosphazene base. The amount of catalyst used is 0.5 to 2 wt% of the total mass of the hydroxypropylated polyrotaxane and ε-caprolactone. When the number of active hydroxyl groups in the hydroxypropylated polyrotaxane is calculated, the molar ratio of the hydroxypropylated polyrotaxane to ε-caprolactone is 1:50 to 600. The ring-opening polymerization temperature is 100-140°C, and the ring-opening polymerization time is 40-50 hours. The method according to claim 11, wherein the ring-opening polymerization step comprises polymerizing a mixture of the hydroxypropylated polyrotaxane, ε-caprolactone, and the catalyst under nitrogen protection, and dissolving the obtained primary product in tetrahydrofuran, then performing precipitation multiple times in n-hexane, drying the obtained solid-phase precipitate to obtain the polycaprolactone-grafted polyrotaxane copolymer.

13. In step (3), the molar ratio of the terminal group modifier to the polycaprolactone graft polyrotaxane copolymer is 100 to 400:

1. The temperature for the terminal group modification reaction is 40 to 60°C, and the duration of the terminal group modification reaction is 15 to 25 hours. The process of the terminal group modification reaction includes mixing solutions prepared in a first organic solvent using the terminal group modifier and the polycaprolactone grafted polyrotaxane copolymer, adding the water absorbent-I and esterification catalyst to the resulting mixed solution to carry out the terminal group modification reaction, and precipitating the resulting primary product multiple times, drying the resulting solid precipitate to obtain the polymer network precursor. The first organic solvent is at least one selected from tetrahydrofuran, N,N-dimethylformamide, dichloromethane, and dioxane; the water absorbent-I is at least one selected from N,N-diisopropylcarbodiimide, dicyclohexylcarbodiimide, and concentrated sulfuric acid; and the esterification catalyst is at least one selected from 4-dimethylaminopyridine, p-toluenesulfonic acid, and thionyl chloride. The amount of the first organic solvent used is such that the concentration of the mixed solution is 1 to 10 g / mL, the amount of the water absorbent-I used is 1 to 5 wt% of the total amount of the terminal group modifier and the polycaprolactone grafted polyrotaxane copolymer, and the molar ratio of the esterification catalyst to the polycaprolactone grafted polyrotaxane copolymer is 1:1.5 to 3.

5. The method according to claim 11, wherein the polymer network precursor has a plurality of slidable polycaprolactone molecular chains, and a photoreversible group derived from the terminal group modifier is contained at the chain ends of some of the polycaprolactone molecular chains, and the photoreversible group is a coumarinyl group or a cinnamic acid group.

14. In step (4), The amount of the crosslinking agent used is 0.1 to 1 wt% of the polymer network precursor. The heating temperature is 70 to 90°C, and the heating time is 45 to 60 hours. The wavelength of the ultraviolet light is 250 to 380 nm. The crosslinking process includes dissolving the polymer network precursor in a second organic solvent, then adding a butyl acetate solution of the crosslinking agent and crosslinking catalyst to obtain a liquid mixture, and heating and drying the liquid mixture, irradiating it with ultraviolet light, and obtaining the polycaprolactone shape memory material. The second organic solvent is at least one selected from tetrahydrofuran, N,N-dimethylformamide, dichloromethane, and dioxane, and the crosslinking catalyst is at least one selected from dibutyltin dilaurate, organobismuth catalyst, and N,N-dimethylcyclohexylamine. The method according to any one of claims 11 to 13, wherein the amount of the second organic solvent used is such that the concentration of the liquid mixture is 1 to 10 g / mL, and the amount of the crosslinking catalyst used is 1 to 5 wt% of the polymer network precursor.

15. The aforementioned polyrotaxane is produced by reacting α-cyclodextrin with polyethylene glycol diamine in the presence of a highly sterically hindered compound. The aforementioned highly sterically hindered compound is at least one selected from N-benzyloxycarbonyl-L-tyrosine, 1-adamantanacetate, fluorescein isothiocyanate, and L-phenylalanine. The weight-average molecular weight of the polyethylene glycol diamine is 5 kDa to 40 kDa. The molar ratio of α-cyclodextrin to the polyethylene glycol diamine is 50 to 100:

1. The molar ratio of the highly sterically hindered compound to the polyethylene glycol diamine is 2 to 10:

1. The process of the above reaction is, (i) Add the polyethylene glycol diamine to a saturated aqueous solution of α-cyclodextrin, stir at 20-35°C for 20-40 hours, dry the resulting white precipitate to obtain an inclusion compound. (ii) Dissolve the sterically hindered compound, the amidation catalyst, and the water absorbent-II in a third organic solvent to prepare a solution, then add the inclusion compound to the solution and amidate the resulting suspension to precipitate, wash and dry the resulting solid-phase precipitate to obtain the polyrotaxane, The amidation catalyst is at least one selected from Carter condensation reagent, zinc chloride, and iron chloride hexahydrate; the water absorbent-II is at least one selected from N,N-diisopropylethylamine, 1-hydroxybenzotriazole, and dicyclohexylcarbodiimide; and the third organic solvent is at least one selected from N,N-dimethylformamide, tetrahydrofuran, and dichloromethane. The amount of the amidation catalyst used is 1 to 5 wt% of the total amount of polyethylene glycol diamine and α-cyclodextrin, the amount of the water absorbent-II used is 1 to 5 wt% of the total amount of polyethylene glycol diamine and α-cyclodextrin, and the amount of the third organic solvent used is such that the concentration of the solution is 1 to 10 g / mL. The method according to any one of claims 11 to 13, wherein the weight-average molecular weight of the polyrotaxane is 10 to 100 kDa.

16. Use of a polycaprolactone shape memory material according to any one of claims 1 to 8 in a medically reversible fixation material.

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