Ultraviolet-curable material with shape memory and self-repairing functions and manufacturing method thereof

Abstract

This invention belongs to the field of photocurable materials, specifically relating to a UV-curable material with shape memory and self-healing functions and its manufacturing method. The process involves reacting starch, succinic anhydride, acetic anhydride, and methanesulfonic acid in glacial acetic acid to form acetate starch; reacting epoxidized soybean oil, methanol, and tetrafluoroboric acid to form soybean oil-based polyol; reacting this polyol with tert-butyl acetoacetate to form acetylated soybean oil; reacting this prepolymer with polytetrahydrofuran, diisocyanate, and isobornyl acrylate to form an acetylated soybean oil-based polyurethane photosensitive prepolymer; and finally reacting this prepolymer with acetate starch, a diluent, and a photoinitiator to form a UV-curable material with shape memory and self-healing functions. This invention features high reactivity, mild reaction conditions, high atom utilization, and the material exhibits excellent mechanical, thermal, shape memory, and self-healing properties. It is suitable for applications in adhesives, flexible electronic packaging, and advanced manufacturing.

Description

Technical Field

[0001] This invention belongs to the field of photocurable materials, specifically relating to a UV-curable material with shape memory and self-healing functions and its manufacturing method. Background Technology

[0002] In recent years, with increasingly prominent environmental issues, people have placed higher demands on energy consumption and environmental protection. Compared with traditional thermosetting, ultraviolet (UV) curing technology has the advantages of fast curing speed, high efficiency, low energy consumption, environmental friendliness, and solvent-free emissions, and has been widely used in coatings, inks, adhesives, and other fields. However, traditional UV-curable polymer materials usually have a stable cross-linked network structure. Due to the irreversible nature of double bond formation, it is difficult to recycle and reprocess the cured materials. In daily production and life, scratches or cracks will inevitably appear on the surface or inside of materials. If they are not repaired in time, the service life of the materials will be greatly shortened, resulting in economic losses and resource waste. In other situations, materials may deform after being subjected to external forces. If these deformations cannot recover naturally, they will also affect the performance of the materials and may even render them unusable.

[0003] To address this problem, researchers have made significant efforts. One highly effective approach is to introduce dynamically reversible covalent bonds during the synthesis of photocurable resins. Based on the breaking and recombination of dynamic bonds, dynamic exchange can be achieved under certain conditions, thereby repairing damaged areas of the material. This method is particularly helpful in repairing hard-to-detect microcracks and enabling multiple repairs, which is especially important for preventing catastrophic material fractures. Furthermore, constructing dynamic covalent bonds is also a key technology for achieving shape memory in materials. For example, through methods such as thermal stimulation, heating breaks dynamic bonds, softening the material, allowing it to recombine upon cooling and fix a temporary shape, and reheating restores the original shape. Photocurable dynamic covalent polymer materials, through the combination of molecular network design and stimulus-responsive units, achieve flexible shape memory functions and have received considerable attention from the industry in recent years. To date, many dynamic covalent bonds, including ester bonds, Diels-Alder additions, disulfide bonds, boron-oxygen bonds, and sterically hindered urea bonds, have been introduced into the construction of photocurable self-healing materials. However, their synthesis process is complex, requires stringent conditions, and has low atom economy.

[0004] To address this problem, a UV-curable material with shape memory and self-healing functions, along with its manufacturing method, was invented using biomass materials with excellent environmental friendliness as raw materials. This method is simple to operate and has high atom utilization, making it essential. Summary of the Invention

[0005] This invention aims to provide a method for preparing a UV-curable material with shape memory and self-healing capabilities using epoxidized soybean oil and starch as raw materials through a catalyst-free process. This material exhibits excellent mechanical properties, thermal stability, and dynamic reversibility, making it suitable for applications in adhesives, flexible electronic packaging, and advanced manufacturing.

[0006] A UV-curable material with shape memory and self-healing functions is formed by compounding and reacting acetylated soybean oil-based polyurethane photosensitive prepolymer, acetate starch, diluent and photoinitiator;

[0007] The acetylated soybean oil-based polyurethane photosensitive prepolymer is prepared by compounding acetylated soybean oil, polytetrahydrofuran, diisocyanate, and isobornyl acrylate under the action of a catalyst; the acetylated soybean oil is prepared by compounding soybean oil-based polyol and tert-butyl acetoacetate; the soybean oil-based polyol is prepared by compounding epoxidized soybean oil, methanol, and tetrafluoroboric acid.

[0008] The acetate starch is prepared by reacting corn starch, succinic anhydride, acetic anhydride and methanesulfonic acid in glacial acetic acid.

[0009] The diluent is one of hydroxyethyl acrylate, hydroxyethyl methacrylate, tripropylene glycol diacrylate, and dipropylene glycol diacrylate.

[0010] The photoinitiator is one of Darocur1173, Irgacure184, Irgacure651, and Irgacure369.

[0011] The diisocyanate is one of isoflurone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, and lysine diisocyanate.

[0012] The catalyst is one of dibutyltin dilaurate, triethylamine, and triphenylphosphine.

[0013] A UV-curable material with shape memory and self-healing functions is manufactured through the following steps:

[0014] (1) Weigh out epoxidized soybean oil, methanol and tetrafluoroboric acid according to the mass ratio of 100:129-137:0.08-0.12, add them to the reaction vessel, stir evenly, react at 60-68℃ for 45-75 min, then quench the reaction system to room temperature, extract with ethyl acetate, wash with saturated sodium chloride solution 3-5 times, and then remove the organic solvent by rotary evaporation to obtain soybean oil-based polyol;

[0015] (2) Weigh soybean oil-based polyol and tert-butyl acetoacetate according to a mass ratio of 100:50-66, mix them evenly, heat to 100-110℃, and reflux and condense under nitrogen atmosphere for 110-130 min to obtain acetylated soybean oil.

[0016] (3) Weigh acetylated soybean oil, polytetrahydrofuran, diisocyanate, isobornyl acrylate and catalyst according to the mass ratio of 100:20-30:18-24:39-43:0.63-0.71, mix them evenly, stir and react at room temperature for 170-190 min, remove excess solvent by vacuum rotary evaporation to obtain acetylated soybean oil-based polyurethane photosensitive prepolymer;

[0017] (4) Weigh corn starch, succinic anhydride, acetic anhydride and methanesulfonic acid according to the mass ratio of 100:80-90:120-126:0.45-0.49 respectively. Mix corn starch and succinic anhydride and dissolve them in glacial acetic acid. Then slowly add methanesulfonic acid dropwise. After the addition is complete, heat to 75-85℃ and stir the reaction for 50-70 min. Then add acetic anhydride to the solution and continue the reaction at the same temperature for 55-65 min. Finally, wash the reaction product with water until the washing liquid is neutral. Evaporate and dry to remove water to obtain acetate starch.

[0018] (5) Weigh out the acetylated soybean oil-based polyurethane photosensitive prepolymer, acetate starch, diluent, and photoinitiator according to a mass ratio of 100:8-12:10-20:2-4, stir well, and expose to ultraviolet light at a wavelength of 320-380 nm with an exposure intensity of 100-120 mW / cm². 2 Continue for 10-20 minutes to cure, resulting in a UV-curable material with shape memory and self-healing functions.

[0019] The diluent is one of hydroxyethyl acrylate, hydroxyethyl methacrylate, tripropylene glycol diacrylate, and dipropylene glycol diacrylate.

[0020] The photoinitiator is one of Darocur1173, Irgacure184, Irgacure651, and Irgacure369.

[0021] The diisocyanate is one of isoflurone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, and lysine diisocyanate.

[0022] The catalyst is one of dibutyltin dilaurate, triethylamine, and triphenylphosphine.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] (1) The reaction of tert-butyl acetoacetate and soybean oil-based polyol to prepare acetylated soybean oil has higher reactivity. When reacting with polytetrahydrofuran and diisocyanate to prepare acetylated soybean oil-based polyurethane photosensitive prepolymer, it can be carried out rapidly under heating conditions and can also be carried out at room temperature. The reaction conditions are much milder than those of traditional methods. The reaction can also be carried out normally without the addition of isobornyl acrylate. However, the innovative use of isobornyl acrylate in this invention can further improve the reaction rate. During synthesis, cost and efficiency factors can be considered comprehensively, and isobornyl acrylate can be selectively added or not added.

[0025] (2) Soybean oil-based polyols are prepared by reacting methanol and epoxidized soybean oil. Only a small methoxy group is introduced into the acetylated soybean oil obtained in the subsequent reaction. This results in minimal steric hindrance at the ortho position and high atomic utilization when the acetylated soybean oil reacts with diisocyanate. This is more conducive to the formation of dynamic amide bonds between the acetylated soybean oil and diisocyanate. Under heating conditions, the dynamic amide bonds of the material invented can easily undergo reversible breakage and reconstruction, thereby endowing the material with excellent mechanical properties, thermal properties, self-healing properties, shape memory ability and reprocessability, while also having higher curing efficiency.

[0026] (3) The introduction of acetate starch serves as a physical crosslinking point and stress dispersion center in the photocurable resin matrix, thereby improving the toughness of the material. When the material is subjected to impact or stress, the rigid resin matrix is ​​prone to microcracks. Starch particles can induce crazes, hinder crack propagation, and absorb energy through their own deformation, thus significantly improving the impact strength and elongation at break of the material and preventing brittle fracture. In addition, acetate starch can also promote the degradation and sustainability of the material. The addition of esterified starch introduces biodegradable components, making it possible for the material to be partially attacked and broken down by microorganisms in composting or specific biological environments, thus enhancing the environmental properties of the material.

[0027] (4) This invention uses vegetable oil as raw material to synthesize ultraviolet curable material. After adding acetate starch, the ester group on its surface has better compatibility with the resin monomer after adjusting the ratio and chemical modification. The viscosity of the resin can be controlled. If used in some high-end manufacturing fields such as 3D printing, it can prevent slurry sedimentation and improve the stability between printing layers, which is crucial for high-precision 3D printing.

[0028] (5) This invention is a green synthesis under normal pressure, with a simple and efficient process. In particular, no catalyst is required in the later resin formation stage, and the reaction time is short. The resulting material has many advantages such as being environmentally friendly, shape-memory resistant, self-healing and regenerable, and photocurable. It has a long service life, and even if it is discarded under the most unfavorable conditions, the degree of harm to the environment can be greatly reduced, providing a new way to develop environmentally friendly and recyclable high-performance photocurable materials. Detailed implementation method:

[0029] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions will be described more clearly and completely below in conjunction with embodiments. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0030] Example 1: A UV-curable material with shape memory and self-healing functions, the manufacturing steps of which are as follows:

[0031] (1) Weigh out epoxidized soybean oil, methanol and tetrafluoroboric acid according to the mass ratio of 100:133:0.1, add them to the reaction vessel, stir evenly, react at 64℃ for 60 min, then quench the reaction system to room temperature, extract with ethyl acetate, wash 4 times with saturated sodium chloride solution, and then remove the organic solvent by rotary evaporation to obtain soybean oil-based polyol.

[0032] (2) Weigh soybean oil-based polyol and tert-butyl acetoacetate according to a mass ratio of 100:58, mix them evenly, heat to 105℃, and reflux and condense under nitrogen atmosphere for 120 min to obtain acetylated soybean oil.

[0033] (3) Acetylated soybean oil, polytetrahydrofuran, toluene diisocyanate, isobornyl acrylate and triethylamine were weighed according to the mass ratio of 100:25:21:41:0.67, mixed evenly, and stirred at room temperature for 180 min. After the reaction was completed, excess solvent was removed by vacuum rotary evaporation to obtain acetylated soybean oil-based polyurethane photosensitive prepolymer.

[0034] (4) Weigh corn starch, succinic anhydride, acetic anhydride and methanesulfonic acid according to the mass ratio of 100:85:123:0.47. Mix corn starch and succinic anhydride and dissolve them in glacial acetic acid. Then slowly add methanesulfonic acid dropwise. After the addition is complete, heat to 80°C and stir for 60 min. Then add acetic anhydride to the solution and continue to react for 60 min at the same temperature. Finally, wash the reaction product with water until the washing liquid is neutral. Evaporate and dry to remove water to obtain acetate starch.

[0035] (5) Weigh out acetylated soybean oil-based polyurethane photosensitive prepolymer, starch acetate, hydroxyethyl methacrylate, and Irgacure 184 in a mass ratio of 100:10:15:3, stir well, and expose to ultraviolet light at a wavelength of 350 nm with an exposure intensity of 110 mW / cm². 2 The curing process is continued for 15 minutes to obtain a UV-curable material with shape memory and self-healing functions. Example 2: A UV-curable material with shape memory and self-healing functions, the preparation steps of which are as follows:

[0036] (1) Weigh out epoxidized soybean oil, methanol and tetrafluoroboric acid in a mass ratio of 100:129:0.08, add them to the reaction vessel, stir evenly, react at 60°C for 45 min, then quench the reaction system to room temperature, extract with ethyl acetate, wash three times with saturated sodium chloride solution, and then remove the organic solvent by rotary evaporation to obtain soybean oil-based polyol.

[0037] (2) Weigh soybean oil-based polyol and tert-butyl acetoacetate according to a mass ratio of 100:50, mix them evenly, heat to 100℃, and reflux and condense under nitrogen atmosphere for 110 min to obtain acetylated soybean oil.

[0038] (3) Acetylated soybean oil, polytetrahydrofuran, isoflurane diisocyanate, isobornyl acrylate and dibutyltin dilaurate were weighed according to the mass ratio of 100:20:18:39:0.63, mixed evenly, and stirred at room temperature for 170 min. After the reaction was completed, excess solvent was removed by vacuum rotary evaporation to obtain acetylated soybean oil-based polyurethane photosensitive prepolymer.

[0039] (4) Weigh corn starch, succinic anhydride, acetic anhydride and methanesulfonic acid according to the mass ratio of 100:80:120:0.45. Mix corn starch and succinic anhydride and dissolve them in glacial acetic acid. Then slowly add methanesulfonic acid dropwise. After the addition is complete, heat to 75°C and stir the reaction for 50 min. Then add acetic anhydride to the solution and continue the reaction at the same temperature for 55 min. Finally, wash the reaction product with water until the washing liquid is neutral. Evaporate and dry to remove water to obtain acetate starch.

[0040] (5) Weigh out acetylated soybean oil-based polyurethane photosensitive prepolymer, acetate starch, hydroxyethyl acrylate, and Darocur 1173 according to a mass ratio of 100:8:10:2, stir well, and expose to ultraviolet light at a wavelength of 320 nm with an exposure intensity of 100 mW / cm². 2 The curing process lasts for 10 minutes, resulting in a UV-curable material with shape memory and self-healing properties.

[0041] Example 3: A UV-curable material with shape memory and self-healing functions, the manufacturing steps of which are as follows:

[0042] (1) Weigh out epoxidized soybean oil, methanol and tetrafluoroboric acid according to the mass ratio of 100:137:0.12, add them to the reaction vessel, stir evenly, react at 68℃ for 75 min, then quench the reaction system to room temperature, extract with ethyl acetate, wash 5 times with saturated sodium chloride solution, and then remove the organic solvent by rotary evaporation to obtain soybean oil-based polyol.

[0043] (2) Weigh soybean oil-based polyol and tert-butyl acetoacetate according to a mass ratio of 100:66, mix them evenly, heat to 110°C, and reflux and condense under nitrogen atmosphere for 130 min to obtain acetylated soybean oil.

[0044] (3) Acetylated soybean oil, polytetrahydrofuran, lysine diisocyanate, isobornyl acrylate and triphenylphosphine were weighed according to the mass ratio of 100:30:24:43:0.71, mixed evenly, and stirred at room temperature for 190 min. After the reaction was completed, excess solvent was removed by vacuum rotary evaporation to obtain acetylated soybean oil-based polyurethane photosensitive prepolymer.

[0045] (4) Weigh corn starch, succinic anhydride, acetic anhydride and methanesulfonic acid according to the mass ratio of 100:90:126:0.49. Mix corn starch and succinic anhydride and dissolve them in glacial acetic acid. Then slowly add methanesulfonic acid dropwise. After the addition is complete, heat to 85°C and stir the reaction for 70 min. Then add acetic anhydride to the solution and continue the reaction at the same temperature for 65 min. Finally, wash the reaction product with water until the washing liquid is neutral. Evaporate and dry to remove water to obtain acetate starch.

[0046] (5) Weigh out acetylated soybean oil-based polyurethane photosensitive prepolymer, acetate starch, dipropylene glycol diacrylate, and Irgacure 369 according to a mass ratio of 100:12:20:4, stir well, and expose to ultraviolet light at a wavelength of 380nm with an exposure intensity of 120mW / cm². 2 The curing process lasts for 20 minutes, resulting in a UV-curable material with shape memory and self-healing properties.

[0047] Example 4: A UV-curable material with shape memory and self-healing functions, the manufacturing steps of which are as follows:

[0048] (1) Weigh out epoxidized soybean oil, methanol and tetrafluoroboric acid according to the mass ratio of 100:129:0.1, add them to the reaction vessel, stir evenly, react at 68℃ for 45 min, then quench the reaction system to room temperature, extract with ethyl acetate, wash 4 times with saturated sodium chloride solution, and then remove the organic solvent by rotary evaporation to obtain soybean oil-based polyol.

[0049] (2) Weigh soybean oil-based polyol and tert-butyl acetoacetate according to a mass ratio of 100:66, mix them evenly, heat to 100℃, and reflux and condense under nitrogen atmosphere for 120 min to obtain acetylated soybean oil.

[0050] (3) Acetylated soybean oil, polytetrahydrofuran, isoflurane diisocyanate, isobornyl acrylate and triethylamine were weighed according to the mass ratio of 100:30:18:41:0.71, mixed evenly, and stirred at room temperature for 170 min. After the reaction was completed, excess solvent was removed by vacuum rotary evaporation to obtain acetylated soybean oil-based polyurethane photosensitive prepolymer.

[0051] (4) Weigh corn starch, succinic anhydride, acetic anhydride and methanesulfonic acid according to the mass ratio of 100:85:126:0.45. Mix corn starch and succinic anhydride and dissolve them in glacial acetic acid. Then slowly add methanesulfonic acid dropwise. After the addition is complete, heat to 80°C and stir the reaction for 70 min. Then add acetic anhydride to the solution and continue the reaction at the same temperature for 55 min. Finally, wash the reaction product with water until the washing liquid is neutral. Evaporate and dry to remove water to obtain acetate starch.

[0052] (5) Weigh out acetylated soybean oil-based polyurethane photosensitive prepolymer, acetate starch, tripropylene glycol diacrylate, and Irgacure 651 in a mass ratio of 100:10:20:2, stir well, and expose to ultraviolet light at a wavelength of 350 nm with an exposure intensity of 120 mW / cm². 2 The curing process lasts for 10 minutes, resulting in a UV-curable material with shape memory and self-healing properties.

[0053] Example 5: A UV-curable material with shape memory and self-healing functions, the manufacturing steps of which are as follows:

[0054] (1) Weigh out epoxidized soybean oil, methanol and tetrafluoroboric acid according to the mass ratio of 100:133:0.12, add them to the reaction vessel, stir evenly, react at 60°C for 60 min, then quench the reaction system to room temperature, extract with ethyl acetate, wash 5 times with saturated sodium chloride solution, and then remove the organic solvent by rotary evaporation to obtain soybean oil-based polyol.

[0055] (2) Weigh soybean oil-based polyol and tert-butyl acetoacetate according to a mass ratio of 100:50, mix them evenly, heat to 105℃, and reflux and condense under nitrogen atmosphere for 130 min to obtain acetylated soybean oil.

[0056] (3) Acetylated soybean oil, polytetrahydrofuran, diphenylmethane diisocyanate, isobornyl acrylate and triphenylphosphine were weighed according to the mass ratio of 100:20:21:43:0.63, mixed evenly, and stirred at room temperature for 180 min. After the reaction was completed, excess solvent was removed by vacuum rotary evaporation to obtain acetylated soybean oil-based polyurethane photosensitive prepolymer.

[0057] (4) Weigh corn starch, succinic anhydride, acetic anhydride and methanesulfonic acid according to the mass ratio of 100:90:120:0.47. Mix corn starch and succinic anhydride and dissolve them in glacial acetic acid. Then slowly add methanesulfonic acid dropwise. After the addition is complete, heat to 85°C and stir for 50 min. Then add acetic anhydride to the solution and continue to react at the same temperature for 60 min. Finally, wash the reaction product with water until the washing liquid is neutral. Evaporate and dry to remove water to obtain acetate starch.

[0058] (5) Weigh out acetylated soybean oil-based polyurethane photosensitive prepolymer, acetate starch, dipropylene glycol diacrylate, and Darocur 1173 according to a mass ratio of 100:12:10:3, stir well, and expose to ultraviolet light at a wavelength of 350 nm with an exposure intensity of 120 mW / cm². 2 The curing process lasts for 10 minutes, resulting in a UV-curable material with shape memory and self-healing properties.

[0059] Example 6: A UV-curable material with shape memory and self-healing functions, the manufacturing steps of which are as follows:

[0060] (1) Weigh out epoxidized soybean oil, methanol and tetrafluoroboric acid in a mass ratio of 100:137:0.08, add them to the reaction vessel, stir evenly, react at 64℃ for 75 min, then quench the reaction system to room temperature, extract with ethyl acetate, wash three times with saturated sodium chloride solution, and then remove the organic solvent by rotary evaporation to obtain soybean oil-based polyol.

[0061] (2) Weigh soybean oil-based polyol and tert-butyl acetoacetate according to a mass ratio of 100:58, mix them evenly, heat to 110°C, and reflux and condense under nitrogen atmosphere for 110 min to obtain acetylated soybean oil.

[0062] (3) Acetylated soybean oil, polytetrahydrofuran, diphenylmethane diisocyanate, isobornyl acrylate and dibutyltin dilaurate were weighed according to the mass ratio of 100:25:24:39:0.67, mixed evenly, and stirred at room temperature for 190 min. After the reaction was completed, excess solvent was removed by vacuum rotary evaporation to obtain acetylated soybean oil-based polyurethane photosensitive prepolymer.

[0063] (4) Weigh corn starch, succinic anhydride, acetic anhydride and methanesulfonic acid according to the mass ratio of 100:80:123:0.49. Mix corn starch and succinic anhydride and dissolve them in glacial acetic acid. Then slowly add methanesulfonic acid dropwise. After the addition is complete, heat to 75°C and stir the reaction for 60 min. Then add acetic anhydride to the solution and continue the reaction at the same temperature for 65 min. Finally, wash the reaction product with water until the washing liquid is neutral. Evaporate and dry to remove water to obtain acetate starch.

[0064] (5) Weigh out acetylated soybean oil-based polyurethane photosensitive prepolymer, acetate starch, tripropylene glycol diacrylate, and Irgacure 651 according to a mass ratio of 100:8:15:4, stir well, and expose to ultraviolet light at a wavelength of 320nm with an exposure intensity of 110mW / cm². 2 The curing process lasts for 20 minutes, resulting in a UV-curable material with shape memory and self-healing properties.

[0065] Example 7: A UV-curable material with shape memory and self-healing functions, the manufacturing steps of which are as follows:

[0066] (1) Weigh out epoxidized soybean oil, methanol and tetrafluoroboric acid according to the mass ratio of 100:131:0.09, add them to the reaction vessel, stir evenly, react at 67℃ for 48 min, then quench the reaction system to room temperature, extract with ethyl acetate, wash 3 times with saturated sodium chloride solution, and then remove the organic solvent by rotary evaporation to obtain soybean oil-based polyol.

[0067] (2) Weigh soybean oil-based polyol and tert-butyl acetoacetate according to a mass ratio of 100:52, mix them evenly, heat to 109°C, and reflux and condense under nitrogen atmosphere for 114 min to obtain acetylated soybean oil.

[0068] (3) Acetylated soybean oil, polytetrahydrofuran, lysine diisocyanate, isobornyl acrylate and triethylamine were weighed according to the mass ratio of 100:26:22:40:0.66, mixed evenly, and stirred at room temperature for 177 min. After the reaction was completed, excess solvent was removed by vacuum rotary evaporation to obtain acetylated soybean oil-based polyurethane photosensitive prepolymer.

[0069] (4) Weigh corn starch, succinic anhydride, acetic anhydride and methanesulfonic acid according to the mass ratio of 100:83:125:0.48. Mix corn starch and succinic anhydride and dissolve them in glacial acetic acid. Then slowly add methanesulfonic acid dropwise. After the addition is complete, heat to 79°C and stir the reaction for 57 min. Then add acetic anhydride to the solution and continue the reaction at the same temperature for 58 min. Finally, wash the reaction product with water until the washing liquid is neutral. Evaporate and dry to remove water to obtain acetate starch.

[0070] (5) Weigh out acetylated soybean oil-based polyurethane photosensitive prepolymer, acetate starch, hydroxyethyl acrylate, and Irgacure 184 according to a mass ratio of 100:11:14:2.4, stir well, and expose to ultraviolet light at a wavelength of 340 nm with an exposure intensity of 105 mW / cm². 2 The curing process lasted for 13 minutes, resulting in a UV-curable material with shape memory and self-healing properties.

[0071] The effectiveness of Embodiment 1 of the present invention will be evaluated through actual testing.

[0072] The tensile properties of the material were determined according to ASTM D 638-22 at a tensile rate of 10 mm / min; the impact properties were determined according to GB / T1043.1-2008; the hardness of the material was determined using a Rockwell hardness tester; thermogravimetric analysis was performed using a thermogravimetric analyzer under a nitrogen atmosphere to determine the initial decomposition temperature and the peak temperature of the fastest decomposition; the deformation of the material at the deformation temperature, fixation temperature, and recovery temperature was determined using a dynamic thermomechanical analyzer to calculate the shape fixation rate and shape recovery rate; and the scratch repair efficiency was calculated by observing the reduction in scratch width before and after repair using an optical microscope.

[0073] The test results are as follows: tensile strength 11.1 MPa, tensile modulus 264.4 MPa, elongation at break 9.7%, and impact strength 23.0 kJ / cm². 2 It has a Rockwell hardness of 84, an initial decomposition temperature of 251.3℃, a peak decomposition temperature of 432.5℃, a shape retention rate of 81.2%, a shape recovery rate of 83.2%, and a scratch repair efficiency of 94.1%.

[0074] Test results show that the UV-curable material with shape memory and self-healing function of the present invention has good mechanical properties, thermal stability, strong shape memory ability and high scratch self-healing rate after curing.

[0075] The above examples are merely illustrative of the technical concept and features of the present invention, intended to enable those skilled in the art to understand the content of the invention and implement it accordingly, and should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A UV-curable material with shape memory and self-healing functions, characterized in that... It is prepared by compounding and reacting acetylated soybean oil-based polyurethane photosensitive prepolymer, acetate starch, diluent and photoinitiator; the acetylated soybean oil-based polyurethane photosensitive prepolymer is prepared by compounding and reacting acetylated soybean oil, polytetrahydrofuran, diisocyanate and isobornyl acrylate under the action of a catalyst; the acetylated soybean oil is prepared by compounding and reacting soybean oil-based polyol and tert-butyl acetoacetate; the soybean oil-based polyol is prepared by compounding and reacting epoxidized soybean oil, methanol and tetrafluoroboric acid; the acetate starch is prepared by compounding and reacting corn starch, succinic anhydride, acetic anhydride and methanesulfonic acid in glacial acetic acid.

2. The UV-curable material with shape memory and self-healing functions according to claim 1, characterized in that... The diluent is one of hydroxyethyl acrylate, hydroxyethyl methacrylate, tripropylene glycol diacrylate, and dipropylene glycol diacrylate.

3. The UV-curable material with shape memory and self-healing functions according to claim 1, characterized in that... The photoinitiator is one of Darocur1173, Irgacurel84, Irgacure651, and Irgacure369.

4. The UV-curable material with shape memory and self-healing functions according to claim 1, characterized in that... The diisocyanate is one of isoflurone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, and lysine diisocyanate.

5. The UV-curable material with shape memory and self-healing functions according to claim 1, characterized in that... The catalyst is one of dibutyltin dilaurate, triethylamine, and triphenylphosphine.

6. A method for preparing a UV-curable material with shape memory and self-healing functions according to claim 1, comprising the following steps: (1) Weigh out epoxidized soybean oil, methanol and tetrafluoroboric acid according to the mass ratio of 100:129-137:0.08-0.12, add them to the reaction vessel, stir evenly, react at 60-68℃ for 45-75 min, then quench the reaction system to room temperature, extract with ethyl acetate, wash with saturated sodium chloride solution 3-5 times, and then remove the organic solvent by rotary evaporation to obtain soybean oil-based polyol; (2) Weigh soybean oil-based polyol and tert-butyl acetoacetate according to a mass ratio of 100:50-66, mix them evenly, heat to 100-110℃, reflux and condense under nitrogen atmosphere for 110-130 min, remove n-butanol liquid, and obtain acetylated soybean oil. (3) Weigh acetylated soybean oil, polytetrahydrofuran, diisocyanate, isobornyl acrylate and catalyst according to the mass ratio of 100:20-30:18-24:39-43:0.63-0.71, mix them evenly, stir and react at room temperature for 170-190 min, remove excess solvent by vacuum rotary evaporation to obtain acetylated soybean oil-based polyurethane photosensitive prepolymer; (4) Weigh corn starch, succinic anhydride, acetic anhydride and methanesulfonic acid according to the mass ratio of 100:80-90:120-126:0.45-0.49 respectively. Mix corn starch and succinic anhydride and dissolve them in glacial acetic acid. Then slowly add methanesulfonic acid dropwise. After the addition is complete, heat to 75-85℃ and stir the reaction for 50-70 min. Then add acetic anhydride to the solution and continue the reaction at the same temperature for 55-65 min. Finally, wash the reaction product with water until the washing liquid is neutral. Evaporate and dry to remove water to obtain acetate starch. (5) Weigh out the acetylated soybean oil-based polyurethane photosensitive prepolymer, acetate starch, diluent, and photoinitiator according to a mass ratio of 100:8-12:10-20:2-4, stir well, and expose to ultraviolet light at a wavelength of 320-380nm with an exposure intensity of 100-120mW / cm². 2 Continue for 10-20 minutes to cure, resulting in a UV-curable material with shape memory and self-healing functions.