A polyurethane material with shape memory function, biocompatibility and degradability and a preparation method thereof

Abstract

The application discloses a preparation method of a polyurethane material with shape memory function, biocompatibility and degradability, and comprises the following steps: (1) hydroxyl-terminated polyether or polyester polyol is mixed with isosorbide under a nitrogen atmosphere, and then diisocyanate is added for pre-polymerization; (2) hydroxyethyl hexahydro-s-triazine is added into the pre-polymerization solution, stirring, dissolution and reaction are carried out, and then the mixed solution is poured into a mold; (3) the mold is placed under the condition of 80 DEG C to volatilize the solvent and solidify, so that a polyurethane film is obtained. The polyurethane film prepared by the application has superior mechanical properties. Meanwhile, the polyurethane film has good biocompatibility, shape memory function and double degradation. Compared with traditional polyurethane materials, the polyurethane material prepared by the application uses biomass-based compound isosorbide as raw material, integrates excellent comprehensive performance, functionality and degradability, and is a new sustainable material with wide application.

Description

Technical Field

[0001] This invention relates to the field of biodegradable functional polyurethane materials, specifically to a polyurethane material with shape memory function, biocompatibility and biodegradability, and its preparation method. Background Technology

[0002] For sustainable environmental development, the emerging green polyol-based polyurethane production method is an effective means of alleviating the resource crisis. However, relying solely on biomass feedstocks to replace petroleum-based feedstocks in the preparation of polyurethane materials, especially cross-linked polyurethane materials, suffers from low degradation rates and incomplete degradation. This is due to the stability of urethane bonds and the chemical cross-linking network in polyurethane products, making the degradation of cross-linked polyurethane materials relatively difficult. Polyurethane degradation is mainly achieved through the chemical decomposition of urethane bonds in the backbone, including alcoholysis, hydrolysis, acidolysis, pyrolysis, and ammonolysis. These degradation methods typically require harsh conditions, such as high-temperature, high-pressure, and strong acid / alkali environments, making it difficult to control the degradation rate, resulting in incomplete degradation, and potentially the generation of toxic byproducts. Therefore, introducing degradable structures into the polyurethane molecular chain to achieve controlled degradation and efficient recycling is an effective way to fundamentally solve the degradation difficulties of cross-linked polyurethane materials.

[0003] Introducing biodegradable structures into the molecular structure can solve the problem of difficult degradation of polyurethane materials. The patent "A High-Mechanical-Performance Biodegradable Polyurethane Material and Its Synthesis Method" (CN118878782A) discloses the preparation of a high-performance biodegradable polyurethane material from polylactic acid and diisocyanate, but does not mention a specific degradation time. This invention, starting from the perspective of molecular structure design, develops a polyurethane material based on the hexahydrotriazine cyclic acid hydrolysis strategy, possessing a series of characteristics including high mechanical strength, shape memory function, and biodegradability, thus achieving the sustainable development of polyurethane materials.

[0004] The above background information is provided only to aid in understanding the inventive concept and technical solution of this invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0005] The purpose of this invention is to propose a polyurethane material with shape memory function, biocompatibility and degradability and its preparation method, so as to solve the problems of degradability and sustainability, and expand its application by endowing it with multifunctionality.

[0006] To solve the above technical problems, the present invention has the following technical solution:

[0007] A polyurethane material with shape memory function, biocompatibility, and biodegradability is disclosed. Its polyurethane structure includes isosorbide, a bio-based raw material; two biodegradable structures: hydroxyethyl hexahydrotriazine; and a polyester polyol. Its strength and toughness can be controlled by the soft segment structure and molecular weight, as well as the ratio of soft to hard segments. The synthesis reaction process is as follows:

[0008]

[0009] The rigid hexahydrotriazine ring's unique three-arm structure and isosorbide impart high crosslinking density and tensile strength to the material, while the acid-sensitive hexahydrotriazine ring gives the material degradability.

[0010] This invention also provides a method for preparing a polyurethane material with shape memory function, biocompatibility, and biodegradability, characterized by comprising the following steps:

[0011] (1) Take a certain amount of isosorbide and hydroxyl-terminated polyether or polyester polyol, place them in a three-necked flask, heat and melt them evenly under a nitrogen atmosphere, add diisocyanate monomer dissolved in solvent to the mixture, and react to obtain a viscous liquid. Add an appropriate amount of solvent to control the viscosity of the reaction system.

[0012] (2) In the polymerization system of step (1), hydroxyethyl hexahydrotriazine is added, stirred and mixed, and then the reaction mixture is poured into a polytetrafluoroethylene mold to level it;

[0013] (3) Place the mold in an oven to evaporate the solvent and cure it to obtain a polyurethane material with shape memory function, biocompatibility and degradability.

[0014] Further, the hydroxyl-terminated polyether or polyester polyol mentioned in step (1) includes one or more of the following: hydroxyl-terminated poly(1,4-butanediol adipate) (PBA), polyethylene glycol (PEG), polypropylene glycol (PPG), polytetramethylene ether glycol (PTMEG), polybutylene succinate (PBS), and polylactic acid (PLA), with a molecular weight of 1000-3000.

[0015] Further, the diisocyanate mentioned in step (1) includes one or more of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), and isophorone diisocyanate (IPDI).

[0016] Furthermore, in step (1), the ratio of the number of groups NCO:OH is 1.2:1.

[0017] Further, the solvent mentioned in step (1) includes one or more of tetrahydrofuran (THF), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP).

[0018] Furthermore, the reaction conditions for adding diisocyanate monomer in step (1) are a reaction at 120°C for 10 h.

[0019] Furthermore, the mixing time in step (2) is 30 minutes.

[0020] Furthermore, the temperature for solvent evaporation and curing in step (3) is 40-100℃.

[0021] Furthermore, the curing time in step (3) is 12 hours.

[0022] Furthermore, the polyurethane material prepared by this invention contains polar groups such as urethane structures and ester bonds, which easily form intermolecular hydrogen bonds and enhance the interaction between molecular chains.

[0023] Compared with existing technologies, this invention demonstrates significant progress and unique advantages in multiple dimensions, specifically in the following aspects:

[0024] (1) In terms of material composition and performance improvement, this invention ingeniously introduces a rigid hexahydrotriazine ring and isosorbide as synergistic factors. This innovative design enhances the overall mechanical properties of the material. This structural optimization enables the polyurethane material of this invention to exhibit higher strength and toughness when subjected to external forces, and its comprehensive performance surpasses many publicly disclosed similar patented products. It is particularly worth mentioning that this material exhibits excellent rapid degradation characteristics in acidic environments, and can completely decompose in a short time. This is undoubtedly a major technological breakthrough for today's increasingly stringent environmental protection requirements.

[0025] (2) In the exploration of smart material applications, a major highlight of the polyurethane material of this invention lies in its unique shape memory function. This characteristic enables the material to automatically adjust its shape according to environmental changes under specific temperature conditions. Specifically, in a high-temperature environment, the soft segments of the material exhibit an amorphous state, allowing the molecular chains to rearrange freely, thus enabling free shape changes; while when the temperature drops to a certain threshold, the deformation-induced molecular chain orientation effect begins to appear, molecular movement is restricted, and the temporary shape is stably maintained. This intelligent response mechanism opens up broad prospects for the application of materials in fields such as smart wearables and adaptive structures, demonstrating significant progress in the field of materials science and engineering.

[0026] (3) The polyurethane material of this invention also achieves significant innovation in terms of the diversity of degradation mechanisms. The acid-sensitive hexahydrotriazine ring in the material endows it with rapid and complete degradation capability under specific conditions (such as 50°C and 2 mol / L phosphoric acid / ethanol solution), achieving complete degradation in just 2.2 hours. This is of great significance for applications requiring precise control of degradation time. In addition, the polyester segment structure embedded in the material endows it with biodegradable functionality, meaning that the material can also be partially degraded under the action of specific enzymes, greatly reducing the risk of environmental pollution. This composite degradation mechanism design not only enhances the environmental protection properties of the material but also makes it possible for its wide application in fields such as medical implants and environmentally friendly packaging materials, marking a significant leap forward in the field of sustainable development materials.

[0027] In summary, the polyurethane material of this invention, through a series of innovative designs, has not only achieved significant progress in mechanical properties, intelligent response, and degradation mechanisms, but also injected new vitality into the development of materials science, indicating that it will play an immeasurable role in many high-tech fields in the future. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a typical structure of PBA-based polyurethane.

[0029] Figure 2 FTIR spectra of PBA-based polyurethane films with different soft segment molecular weights.

[0030] Figure 3 Stress-strain curves of PBA-based polyurethane films with different soft segment molecular weights are shown.

[0031] Figure 4 The shape memory fixation rate (R) of PBA-based polyurethane series films f ) and recovery rate (R r )picture.

[0032] Figure 5 Fluorescence micrographs of L929 cells after co-culturing with PBA-based polyurethane films for 24 h, 48 h, and 72 h.

[0033] Figure 6 The graph shows the degradation phenomenon of PBA-based polyurethane films with different soft segment molecular weights in a 2 mol / L phosphoric acid / ethanol solution.

[0034] Figure 7 Digital images of PBA-based polyurethane films after 6 weeks of enzymatic hydrolysis and their acid hydrolysis phenomena. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be emphasized that the following description is merely exemplary and not intended to limit the scope or application of the invention. All advantages and variations that can be conceived by those skilled in the art are included in the present invention, which covers all modifications, substitutions, equivalent methods and schemes made within the spirit and scope of the invention as defined in the claims. The preparation processes, reaction conditions, reagents, experimental methods, etc., used in implementing the present invention, except for those specifically addressed below, are all common knowledge and common sense in the art, and the present invention has no specific limitations. To enable the public to better understand the present invention, some specific details are described in detail herein; however, those skilled in the art can fully understand the present invention even without these details.

[0036] Non-limiting and non-exclusive embodiments will be described with reference to the following figures, wherein the same reference numerals denote the same parts unless otherwise specifically stated.

[0037] Example 1

[0038] Two g of hydroxyl-terminated poly(1,4-butanediol adipate) (PBA) with a number average molecular weight of 1000 and 0.30 g of isosorbide (ISO) were added to a three-necked flask equipped with a stirrer. The mixture was heated to 60°C and the water was removed under vacuum for 40 min with stirring. Then, 1.2 g of hexamethylene diisocyanate (HDI) dissolved in N,N-dimethylformamide (DMF) was added to the mixture, and the temperature was raised to 120°C and the reaction was continued for 10 h. At the same time, a certain amount of N,N-dimethylformamide (DMF) was added to adjust the viscosity of the system to form a prepolymer. 0.3 g of hydroxyethyl hexahydrotriazine (HT) was added to the prepolymer solution and the mixture was stirred for 30 min. The reaction solution was then poured into a polytetrafluoroethylene mold and dried under vacuum at 80°C for 12 h to obtain a polyurethane film PU1 with an NCO / OH ratio of 1.2:1.

[0039] The prepared PU1 film had a tensile strength of 10.6 MPa and an elongation at break of 665%. The PU1 film exhibited 100% degradation in a 2 mol / L phosphoric acid / ethanol solution at 50 °C, with a mass loss of 9.88% after six weeks of enzymatic hydrolysis. The biocompatibility of the PU1 film was assessed using the CCK-8 assay. After co-culturing L929 cells directly seeded onto the film surface for 24 h, 48 h, and 72 h, the cell proliferation rate (RGR) was 98.15%, 98.29%, and 98.30%, respectively. The shape fixation rate (Rshape) of the PU1 film at 55 °C was [not specified in the original text]. f ) and shape recovery rate (R r The percentages were 88.7% and 50.3%, respectively.

[0040] Example 2

[0041] 4 g of hydroxyl-terminated poly(1,4-butanediol) adipate (PBA) with a number average molecular weight of 2000 and 0.30 g of isosorbide (ISO) were added to a three-necked flask equipped with a stirrer. The mixture was heated to 60 °C and the water was removed under vacuum for 40 min with stirring. Then, 1.2 g of hexamethylene diisocyanate (HDI) dissolved in N,N-dimethylformamide (DMF) was added to the mixture, and the temperature was raised to 120 °C and the reaction was continued for 10 h. At the same time, a certain amount of N,N-dimethylformamide (DMF) was added to adjust the viscosity of the system to form a prepolymer. 0.3 g of hydroxyethyl hexahydrotriazine (HT) was added to the prepolymer solution and the mixture was stirred for 30 min. The reaction solution was then poured into a polytetrafluoroethylene mold and dried under vacuum at 80 °C for 12 h to obtain a polyurethane film PU2 with an NCO / OH ratio of 1.2:1.

[0042] The prepared PU2 film had a tensile strength of 25.7 MPa and an elongation at break of 860%. The PU2 film exhibited 100% degradation in a 2 mol / L phosphoric acid / ethanol solution at 50 °C, with a mass loss of 12.98% after six weeks of enzymatic hydrolysis. The biocompatibility of the PU2 film was assessed using the CCK-8 assay. After co-culturing L929 cells directly seeded onto the film surface for 24 h, 48 h, and 72 h, the cell proliferation rate (RGR) was 98.27%, 98.38%, and 98.22%, respectively. The PU2 film also showed good shape retention (R²) at 55 °C. f ) and shape recovery rate (R r The figures were 94.8% and 84.8%, respectively.

[0043] Example 3

[0044] 8 g of hydroxyl-terminated poly(1,4-butanediol) adipate (PBA) with a number average molecular weight of 3000 and 0.30 g of isosorbide (ISO) were added to a three-necked flask equipped with a stirrer. The mixture was heated to 60 °C and the water was removed under vacuum for 40 min with stirring. Then, 1.2 g of hexamethylene diisocyanate (HDI) dissolved in N,N-dimethylacetamide (DMAc) was added to the mixture, and the temperature was raised to 120 °C and the reaction was continued for 10 h. At the same time, a certain amount of N,N-dimethylacetamide (DMAc) was added to adjust the viscosity of the system to form a prepolymer. 0.3 g of hydroxyethyl hexahydrotriazine (HT) was added to the prepolymer solution and the mixture was stirred for 30 min. The reaction solution was then poured into a polytetrafluoroethylene mold and dried under vacuum at 80 °C for 12 h to obtain a polyurethane film PU3 with an NCO / OH ratio of 1.2:1.

[0045] The prepared PU3 film had a tensile strength of 18.9 MPa and an elongation at break of 978%. The PU3 film exhibited 100% degradation in a 2 mol / L phosphoric acid / ethanol solution at 50 °C, with a mass loss of 49.95% after six weeks of enzymatic hydrolysis. The biocompatibility of the PU3 film was assessed using the CCK-8 assay. After co-culturing L929 cells directly seeded onto the film surface for 24 h, 48 h, and 72 h, the cell proliferation rate (RGR) was 98.30%, 98.37%, and 98.33%, respectively. The PU3 film also showed good shape retention at 55 °C. f ) and shape recovery rate (R r The percentages were 95.1% and 87.5%, respectively.

[0046] Example 4

[0047] Two g of hydroxyl-terminated poly(1,4-butanediol) adipate (PBA) with a number average molecular weight of 2000 and 1 g of isosorbide (ISO) with a number average molecular weight of 1000, and 0.30 g of isosorbide (ISO) were added to a three-necked flask equipped with a stirrer. The mixture was heated to 60°C and the water was removed under vacuum for 40 min with stirring. Then, 1.2 g of hexamethylene diisocyanate (HDI) dissolved in N-methylpyrrolidone (NMP) was added to the mixture, and the temperature was raised to 120°C and the reaction was continued for 10 h. At the same time, a certain amount of N-methylpyrrolidone (NMP) was added to adjust the viscosity of the system to form a prepolymer. 0.3 g of hydroxyethyl hexahydrotriazine (HT) was added to the prepolymer solution and the mixture was stirred for 30 min. The reaction solution was then poured into a polytetrafluoroethylene mold and dried under vacuum at 100°C for 12 h to obtain a polyurethane film PU12 with an NCO / OH ratio of 1.2:1.

[0048] The prepared PU12 film had a tensile strength of 16.6 MPa and an elongation at break of 718%. The PU12 film exhibited 100% degradation in a 2 mol / L phosphoric acid / ethanol solution at 50 °C, with a mass loss of 10.43% after six weeks of enzymatic hydrolysis. The biocompatibility of the PU12 film was assessed using the CCK-8 assay. After co-culturing L929 cells directly seeded onto the film surface for 24 h, 48 h, and 72 h, the cell proliferation rate (RGR) was 98.21%, 98.30%, and 98.34%, respectively. The PU12 film also showed good shape retention at 55 °C. f ) and shape recovery rate (R r The percentages were 95.4% and 69.7%, respectively.

[0049] Example 5

[0050] Two g of hydroxyl-terminated poly(1,4-butanediol) adipate (PBA) with a number average molecular weight of 2000 and 4 g of isosorbide (ISO) with a number average molecular weight of 3000, and 0.30 g of isosorbide (ISO) were added to a three-necked flask equipped with a stirrer. The mixture was heated to 60°C and the water was removed under vacuum for 40 min with stirring. Then, 1.2 g of hexamethylene diisocyanate (HDI) dissolved in N,N-dimethylformamide (DMF) was added to the mixture, and the temperature was raised to 120°C and the reaction was continued for 10 h. At the same time, a certain amount of N,N-dimethylformamide (DMF) was added to adjust the viscosity of the system to form a prepolymer. 0.3 g of hydroxyethyl hexahydrotriazine (HT) was added to the prepolymer solution and the mixture was stirred for 30 min. The reaction solution was then poured into a polytetrafluoroethylene mold and dried under vacuum at 80°C for 12 h to obtain a polyurethane film PU23 with an NCO / OH ratio of 1.2:1.

[0051] The prepared PU23 film had a tensile strength of 22.9 MPa and an elongation at break of 875%. The PU23 film exhibited 100% degradation in a 2 mol / L phosphoric acid / ethanol solution at 50 °C, with a mass loss of 18.89% after six weeks of enzymatic hydrolysis. The biocompatibility of the PU23 film was assessed using the CCK-8 assay. After co-culturing L929 cells directly seeded onto the film surface for 24 h, 48 h, and 72 h, the cell proliferation rate (RGR) was 98.17%, 98.31%, and 98.30%, respectively. The PU23 film also showed good shape retention at 55 °C. f ) and shape recovery rate (R r The percentages were 95.7% and 85.1%, respectively.

[0052] Example 6

[0053] 1 g of polyethylene glycol (PEG) with a number average molecular weight of 1000, 1 g of polylactic acid (PLA) with a number average molecular weight of 1000, and 0.30 g of isosorbide (ISO) were added to a three-necked flask equipped with a stirrer. The mixture was heated to 60°C and the water was removed under vacuum for 40 min with stirring. Then, 1.3 g of toluene diisocyanate (TDI) dissolved in tetrahydrofuran (THF) was added to the mixture, and the temperature was raised to 120°C and the reaction was continued for 10 h. A certain amount of tetrahydrofuran (THF) was added to adjust the viscosity of the system to form a prepolymer. 0.3 g of hydroxyethyl hexahydrotriazine (HT) was added to the prepolymer solution, and the mixture was stirred for 30 min. The reaction solution was then poured into a polytetrafluoroethylene mold and dried under vacuum at 40°C for 12 h to obtain a polyurethane film PU6 with an NCO / OH ratio of 1.2:1.

[0054] The prepared PU6 film had a tensile strength of 19.4 MPa and an elongation at break of 889%. The PU6 film exhibited 100% degradation in a 2 mol / L phosphoric acid / ethanol solution at 50 °C, with a mass loss of 24.30% after six weeks of enzymatic hydrolysis. The biocompatibility of the PU6 film was assessed using the CCK-8 assay. After co-culturing L929 cells directly seeded onto the film surface for 24 h, 48 h, and 72 h, the cell proliferation rate (RGR) was 98.46%, 98.50%, and 98.39%, respectively. The PU6 film also showed good shape retention at 55 °C. f ) and shape recovery rate (R r The percentages were 96.3% and 81.43%, respectively.

[0055] Example 7

[0056] 1 g of hydroxyl-terminated polybutylene succinate (PBS) with a number average molecular weight of 1000, 1 g of polytetramethylene ether glycol (PTMEG) with a number average molecular weight of 1000, and 0.30 g of isosorbide (ISO) were added to a three-necked flask equipped with a stirrer. The mixture was heated to 60 °C and the water was removed under vacuum for 40 min with stirring. Then, 1.6 g of isophorone diisocyanate (IPDI) dissolved in N,N-dimethylformamide (DMF) was added to the mixture, and the temperature was raised to 120 °C and the reaction was continued for 10 h. At the same time, a certain amount of N,N-dimethylformamide (DMF) was added to adjust the viscosity of the system to form a prepolymer. 0.3 g of hydroxyethyl hexahydrotriazine (HT) was added to the prepolymer solution and the mixture was stirred for 30 min. The reaction solution was then poured into a polytetrafluoroethylene mold and dried under vacuum at 80 °C for 12 h to obtain a polyurethane film PU7 with an NCO / OH ratio of 1.2:1.

[0057] The prepared PU7 film had a tensile strength of 15.8 MPa and an elongation at break of 703%. The PU7 film exhibited 100% degradation in a 2 mol / L phosphoric acid / ethanol solution at 50℃, with a mass loss of 13.34% after six weeks of enzymatic hydrolysis. The biocompatibility of the PU7 film was assessed using the CCK-8 assay. After co-culturing L929 cells directly seeded onto the film surface for 24 h, 48 h, and 72 h, the cell proliferation rate (RGR) was 97.21%, 98.00%, and 97.31%, respectively. The PU7 film also showed good shape retention at 55℃. f ) and shape recovery rate (R r The percentages were 89.47% and 69.36%, respectively.

[0058] Example 8

[0059] 1 g of hydroxyl-terminated poly(1,4-butanediol adipate) (PBA) with a number average molecular weight of 1000, 1 g of polypropylene glycol (PPG) with a number average molecular weight of 1000, and 0.30 g of isosorbide (ISO) were added to a three-necked flask equipped with a stirrer. The mixture was heated to 60 °C and the water was removed under vacuum for 40 min with stirring. Then, 2.6 g of diphenylmethane diisocyanate (MDI) dissolved in N,N-dimethylformamide (DMF) was added to the mixture, and the temperature was raised to 120 °C and the reaction was continued for 10 h. At the same time, a certain amount of N,N-dimethylformamide (DMF) was added to adjust the viscosity of the system to form a prepolymer. 0.3 g of hydroxyethyl hexahydrotriazine (HT) was added to the prepolymer solution and the mixture was stirred for 30 min. The reaction solution was then poured into a polytetrafluoroethylene mold and dried under vacuum at 80 °C for 12 h to obtain a polyurethane film PU8 with an NCO / OH ratio of 1.2:1.

[0060] The prepared PU8 film had a tensile strength of 17.4 MPa and an elongation at break of 914%. The PU8 film exhibited 100% degradation in a 2 mol / L phosphoric acid / ethanol solution at 50 °C, with a mass loss of 19.34% after six weeks of enzymatic hydrolysis. The biocompatibility of the PU8 film was assessed using the CCK-8 assay. After co-culturing L929 cells directly seeded onto the film surface for 24 h, 48 h, and 72 h, the cell proliferation rate (RGR) was 98.33%, 98.40%, and 98.31%, respectively. The PU8 film showed good shape retention (R...) at 55 °C. f ) and shape recovery rate (R r The percentages were 90.47% and 74.36%, respectively.

[0061] Examples 1-8 show that polyurethanes containing hexahydrotriazine structures and polyester and polyether segments all possess good dual degradability, biocompatibility, and shape memory function.

[0062] See Figure 1 The polyurethane films prepared in Examples 1-5 contain hexahydrotriazine rings and biodegradable aliphatic polyester linear chains. Due to the inherent incompatibility between the soft and hard segments of polyurethane, microphase separation structures are easily formed. Poly(1,4-butanediol adipate), as the soft segment in the polyurethane material, imparts excellent mechanical strength, resistance to organic solvents, and heat resistance to the material, while also exhibiting high crystallinity and influencing the interactions between molecular chain segments. The shape memory behavior, strength, and toughness of the elastomer can be adjusted by regulating the ratio of soft to hard segments in the polyurethane structure. Furthermore, the presence of acid-sensitive hexahydrotriazine rings in the structure allows the elastomer to degrade rapidly and completely in acidic environments.

[0063] See Figure 2 The molecular weights of different soft segments in polyurethane films were characterized by ATR-FTIR at 3320 cm⁻¹. -1The signal appearing at 1160 cm⁻¹ corresponds to the NH stretching vibration peak in carbamates. -1 The peaks at 2943 and 2863 cm⁻¹ belong to the stretching vibration peaks of COC. -1 The absorption peak at 1726 cm⁻¹ is caused by the stretching vibration of CH in the methyl or methylene components. -1 The C=O stretching vibration peak of the ester bond in the urethane was observed. Infrared spectra of polyurethane films with soft segments of different molecular weights confirmed the successful synthesis of polyurethane.

[0064] See Figure 3 Taking the polyurethane film prepared in Example 2 as an example, its tensile strength is 25.7 MPa and its elongation at break is 860%, which can lift a weight of about 20,000 times its own weight, demonstrating its excellent mechanical properties.

[0065] See Figure 4 Taking the polyurethane film prepared in Example 3 as an example, the sample was first heated to 55°C. At this temperature, the soft segments of the polyurethane film are amorphous, and the crystalline regions of its internal structure can undergo a certain degree of reshaping and molecular chain rearrangement. The sample was then wrapped around a cylindrical glass rod to create a helical twisted spline, while the hard segments acted as a framework to maintain its original shape. Next, it was placed at a low temperature. Due to the decrease in temperature and deformation-induced molecular chain orientation, the soft segments of the polyurethane film transitioned from a highly elastic state to a glassy state, restricting the movement of the molecular chains and resulting in the fixation of the temporary shape. The sample was then heated to 55°C again. The temperature increase caused the crystallization and melting of the soft segments, releasing the stress, and thus the spline could return to its original shape. After three cycles of helical twisting, the sample could return to its original shape, indicating that the material has excellent shape memory function.

[0066] See Figure 5 Taking the polyurethane film prepared in Example 2 as an example, L929 cells were directly seeded onto the surface of the prepared polyurethane film and co-cultured for a period of time to evaluate the cytotoxicity of the material. It can be seen that the cells are evenly distributed and exhibit a healthy spindle-shaped morphology at different culture times. This indicates that the prepared film material has excellent biocompatibility.

[0067] See Figure 6 Five groups of polyurethane films with different ratios were placed in a 2 mol / L phosphoric acid / ethanol solution for degradation experiments, and it was found that they could all be completely degraded at room temperature.

[0068] See Figure 7Five polyurethane films with different proportions were immersed in a 2 mol / L phosphoric acid / ethanol solution for acid hydrolysis at room temperature. Due to the damage to the film surface caused by six weeks of enzymatic hydrolysis, some gaps and pores appeared on the surface of the material, which promoted the penetration of the hydrolysate into the molecular chain and caused degradation. Therefore, all five samples could be completely degraded in a relatively short time.

[0069] The above description, in conjunction with specific embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the inventive concept, and all such substitutions or modifications should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a polyurethane material with shape memory function, biocompatibility, and biodegradability, characterized in that, The synthesis reaction process is as follows: ； Its preparation method includes the following steps: (1) Take a certain amount of isosorbide and hydroxyl-terminated polyester polyol, place them in a three-necked flask, heat and melt them evenly under a nitrogen atmosphere, add diisocyanate monomer dissolved in solvent to the mixture, and react to obtain a viscous liquid. Add an appropriate amount of solvent to control the viscosity of the reaction system. (2) In the polymerization system of step (1), add hydroxyethyl hexahydrotriazine, stir and mix, and then pour the reaction mixture into a polytetrafluoroethylene mold to level it; (3) Place the mold in an oven to evaporate the solvent and cure it to obtain a polyurethane material with shape memory function, biocompatibility and biodegradability; The hydroxyl-terminated polyester polyol mentioned in step (1) is hydroxyl-terminated poly(1,4-butanediol adipate), and the diisocyanate is hexamethylene diisocyanate. In step (1), the ratio of the number of functional groups NCO:OH is 1.2:1; The reaction conditions for adding diisocyanate monomer in step (1) are: reaction at 120℃ for 10 h; The mixing time in step (2) is 30 minutes; The curing time in step (3) is 12 hours.

2. The method for preparing a polyurethane material with shape memory function, biocompatibility, and biodegradability as described in claim 1, characterized in that: The solvent mentioned in step (1) includes one or more of tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone.

3. The method for preparing a polyurethane material with shape memory function, biocompatibility, and biodegradability as described in claim 1, characterized in that: In step (3), the temperature for solvent evaporation and curing is 40-100℃.

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