Shape memory antibacterial essential oil sustained-release tablet with multiple fixing mechanism and preparation method thereof

Abstract

The application discloses a shape memory antibacterial essential oil slow-release tablet with a multiple fixing mechanism and a preparation method thereof. In the preparation process, one or more cyclic lactone compounds are used as comonomers to prepare polyester homopolymer or random copolymer with controllable and uniform performance. Further, isocyanate compounds, chain extenders and reversible cross-linking agents are introduced into the reaction system to synthesize polyester type reversible cross-linking polyurethane. The synthesized polymer has shape memory characteristics. Finally, essential oil is added to the polymer solution, so that the antibacterial essential oil can be uniformly mixed in the polymer solution. After molding, the essential oil slow-release tablet is obtained. The prepared polymer memory material has a porous feature, so that the antibacterial essential oil is released through the porous structure, and the antibacterial essential oil can be released from the inside to the outside by using the porous structure. The whole antibacterial cycle of the antibacterial essential oil is greatly improved.

Description

Technical Field

[0001] This invention belongs to the technical field of polymer materials and their applications, and in particular relates to a shape memory antibacterial essential oil sustained-release tablet with multiple fixation mechanisms and its preparation method. Background Technology

[0002] Polyurethane, hailed as the "fifth largest plastic," is a polymer formed by the addition polymerization of polyisocyanates, chain extenders, and polyols. Due to its superior properties, it is widely used in light industry, chemical industry, electronics, textiles, medical devices, construction, building materials, and automotive industries. Because polyurethane materials can form hydrogen bonds between their molecular chains as physical cross-linking points, some polyurethane materials possess shape memory properties, making shape memory materials a newly emerging application area for polyurethane materials in recent years. In the polyurethane molecular chain, the structure and properties of the polyol often determine the polyurethane's performance and application scenarios. In the polyurethane industry, polyester-based polyurethanes are the most widely used, offering advantages such as good mechanical properties and biodegradability. Furthermore, their overall performance can be controlled by adjusting the components, resulting in excellent material designability.

[0003] However, linear polyester polyurethanes often rely solely on physical crosslinking for shape memory, resulting in poor shape memory and low shape recovery rates, thus limiting their applications. While polymers using chemical crosslinking as a fixation mechanism offer higher shape recovery rates, they often suffer from issues such as non-reusability and poor biodegradability, leading to environmental pollution. Furthermore, current preparation routes for shape memory polyurethane materials typically involve multiple steps, including the preparation and post-treatment of oligomeric polyols, chain extension reactions, casting, solvent removal, and curing, making the process complex and environmentally unfriendly.

[0004] Existing essential oil tablets often lack shape memory properties and are mostly surface-evaporizing tablets. The release time of essential oils is short and relatively concentrated, making it difficult to achieve effective evaporation over a longer period of time.

[0005] In view of this, the inventor of this case conducted in-depth research, which led to the creation of this case. Summary of the Invention

[0006] The purpose of this invention is to provide a shape memory antibacterial essential oil sustained-release tablet with multiple fixation mechanisms and its preparation method.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: A shape memory antibacterial essential oil sustained-release tablet with multiple fixation mechanisms, the preparation method of the essential oil sustained-release tablet includes the following steps: Step S1: The cyclic lactone compound, catalyst and initiator are added to the reactor for a primary reaction to obtain polyester diol; In step S1, the cyclic lactone compound is at least one of L-lactide, D-lactide, racemic lactide, caprolactone, ω-pentadecanolactone, and tridecanoic acid cycloethylene ester.

[0008] The catalyst is an organometallic compound containing any one of zinc, calcium and bismuth, or an oxide containing any one of zinc, calcium and bismuth, or an organometallic compound containing any one of zinc, calcium and bismuth, or a combination of oxides containing any one of zinc, calcium and bismuth. The molar ratio of the catalyst to the cyclic lactone compound is 1:100~5000; the molar ratio of the initiator to the cyclic lactone compound is 1:10~100. Step S2: After the temperature of the reactor drops to the set temperature, the isocyanate compound dissolved in the organic solvent is added dropwise to the reactor to carry out a secondary reaction; The molar ratio of the initiator to the isocyanate compound is 1:0.9~1.2; Step S3: The mixed solution containing chain extender / reversible crosslinking agent / isocyanate compound / organic solvent is added dropwise to the reactor for three reactions to obtain a polymer solution. The polymer is polyester-type reversible crosslinked polyurethane. In step S3, the molar ratio of the chain extender to the isocyanate compound in the mixed solution is 1:0.9~1.2; the molar ratio of the reversible crosslinking agent to the chain extender is 1:0.9~1.2. In steps S2 and S3, the isocyanate compound is any one of isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, and dicyclohexylmethane-4,4'-diisocyanate. Step S4: Add antibacterial essential oil to the polymer solution, stir for a certain time to obtain a molding liquid, pour the molding liquid into a mold, and after the solvent evaporates, obtain an essential oil sustained-release tablet containing antibacterial ingredients; The essential oil sustained-release tablet has a porous structure that forms its own pores. The essential oil sustained-release tablet has shape memory properties, and its shape memory transition temperature can be controlled within a range of 20~50 ℃, with a shape recovery rate of over 90%.

[0009] Further, in step S1, the initiator is at least one of ethylene glycol, 1,3-propanediol, and 1,4-butanediol; In step S3, the chain extender is any one of 2,5-furandiethanol, 2,5-furandicarboxylic acid, and 2,5-furandimethylamine; the reversible crosslinking agent is one of N,N′-(4,4′-methylenediphenyl)bismaleimide and N,N′-(1,3-phenylene)dimaleimide.

[0010] Furthermore, the temperature of the primary reaction is 70~150 ℃, and the time is 2~10 h.

[0011] Furthermore, the temperature of the secondary reaction is 40~100 ℃, and the time is 3~6 h.

[0012] Furthermore, the temperature of the three reactions is 40~100 ℃, and the time is 2~10 h.

[0013] Furthermore, in step S4, the stirring speed is 100~1000 r / min, and the stirring time is 10~60 min.

[0014] Furthermore, the essential oil components are Phellodendron bark: Scutellaria baicalensis: Artemisia argyi: Agarwood in a mass ratio of 3:2:2:1, and the antibacterial essential oil content is 5-80 wt% of the polymer.

[0015] After adopting the above technical solution, the essential oil sustained-release tablet of the present invention has the following beneficial effects: In the preparation of the essential oil sustained-release tablets of this invention, a cyclic lactone compound is used as a comonomer to prepare a polyester random copolymer with uniform and controllable properties. Then, a chain extender, a reversible crosslinking agent, and an isocyanate compound are introduced into the reaction system to synthesize a polyester-type reversibly crosslinked polyurethane. The synthesized polymer exhibits shape memory properties, and its material properties can be controlled by adjusting the copolymer components, with a molecular weight control range of 10~250 kg / mol. Compared to traditional linear polyester-type polyurethane, the polyester-type reversibly crosslinked polyurethane obtained in this invention incorporates both chemical and physical crosslinking fixation mechanisms, resulting in higher molecular weight and better shape memory properties. It also exhibits a higher shape memory recovery rate, and its material properties can be controlled by adjusting the copolymer components. The shape memory transition temperature control range is 20~50 °C, and the shape recovery rate is above 90%. In the polymerization process of the essential oil sustained-release tablets of the present invention, essential oils are added to the polymer solution, so that the essential oils can be uniformly mixed in the polymer solution. After molding, the porous characteristics of the polymer memory material of the present invention can be utilized to release the essential oils through the porous structure. Moreover, the essential oils can migrate and be released from the inside out through the porous structure, which greatly improves the entire antibacterial cycle of the antibacterial essential oils.

[0016] The polyester-type reversible crosslinked polyurethane of this invention is prepared by a "one-pot method", which is simple, low-cost, green and environmentally friendly, and has the prospect and potential for large-scale production. Attached Figure Description

[0017] Figure 1 Example 1: Spectra of polyester diol and shape memory polymer GPC; Figure 2 Example 1: 1H NMR spectrum of a shape memory polymer; Figure 3 Example 1: DSC spectrum of shape memory polymer; Figure 4 Example 1: Comparison of the antibacterial activity of the material with that of the blank sample; Figure 5 Example 2: GPC spectra of polyester diol and shape memory polymer; Figure 6 Example 2: 1H NMR spectrum of shape memory polymer; Figure 7 Example 2: DSC spectrum of shape memory polymer; Figure 8 Example 2: Comparison of the antibacterial activity of the material with that of the blank sample; Figure 9 Example 3: GPC spectra of polyester diol and shape memory polymer; Figure 10 Example 3: 1H NMR spectrum of shape memory polymer; Figure 11 Example 3: DSC spectrum of shape memory polymer; Figure 12 Comparison of the antibacterial activity of the material in Example 3 with that of the blank sample. Detailed Implementation

[0018] To further explain the technical solution of the present invention, the present invention will be described in detail below through specific embodiments.

[0019] The antibacterial essential oil comprises Phellodendron bark, Scutellaria baicalensis, Artemisia argyi, and Aquilaria sinensis, wherein the mass ratio of Phellodendron bark: Scutellaria baicalensis: Artemisia argyi: Aquilaria sinensis is 3:2:2:1. The specific preparation method is as follows: Select single essential oils of Phellodendron bark, Scutellaria baicalensis, Artemisia argyi, and Aquilaria sinensis. Accurately weigh each essential oil according to the mass ratio of Phellodendron bark essential oil: Scutellaria baicalensis essential oil: Artemisia argyi essential oil: Aquilaria sinensis essential oil = 3:2:2:1. Transfer all the weighed essential oils to a sterile, dry, sealed mixing container. Start a low-speed stirring device for homogenization and mixing, controlling the stirring speed at 30 r / min and the stirring time at 20 minutes to ensure that the essential oils of each component are mixed evenly, to obtain the crude compound essential oil product.

[0020] The crude compound essential oil was transferred to a clean container and placed in a low-temperature environment of 4°C for 12 hours to allow trace impurities and residual water in the system to settle and precipitate. Then, it was filtered under reduced pressure using a sterile microporous membrane with a pore size of 0.22μm to remove suspended solids and impurities. The filtrate was collected to obtain a clear, transparent, and stable antibacterial essential oil product. Example 1

[0021] This invention discloses an antibacterial essential oil sustained-release tablet. The preparation method of the essential oil sustained-release tablet includes the following steps: A 250 mL autoclave equipped with a mechanical stirrer is dried at 120 °C for more than 12 h. After vacuuming, it is cooled to room temperature and then filled with nitrogen for use. Under nitrogen protection, 2.28 g (0.02 mol) of the cyclic lactone compound caprolactone, 11.52 g (0.08 mol) of the cyclic lactone compound L-lactide, 13.8 mg (13.8 mg) of the catalyst, and 0.086 g (1.38 mmol) of the initiator ethylene glycol are weighed at room temperature and added to the reaction vessel. After sealing the reaction vessel, the reaction temperature is set to 130 °C, and the reaction is carried out for 6 hours to obtain a polyester diol. After the temperature drops to 60℃, 20 mL of the organic solvent tetrahydrofuran is added to the reactor. Once the polyester diol is completely dissolved, a solution of the isocyanate compound hexamethylene diisocyanate / tetrahydrofuran (0.23 g / 20 mL) is added dropwise to the reactor, and the reaction is maintained at this temperature for 3 hours. Then, a solution of 2,5-furandiethanol / N,N'-(4,4′-methylenediphenyl)bismaleimide / isocyanate compound hexamethylene diisocyanate / organic solvent tetrahydrofuran (0.18 g / 0.5 g / 0.23 g / 20 mL) is added dropwise to the reactor, and the reaction is maintained at 60℃ for 6 hours to obtain a polymer solution (the polymer is a polyester-type reversible crosslinked polyurethane, i.e., a shape memory polymer). Antibacterial essential oil (6.9 g, 50% of the shape memory material by mass) is added to the polymer solution, and the mixture is stirred at 500 rpm for 30 minutes. The polymer solution was poured into a polytetrafluoroethylene mold, and the solvent was evaporated at room temperature to obtain essential oil sustained-release tablets.

[0022] GPC testing results showed that the shape memory polymer had a number-average molecular weight of 52.7 kg / mol and a molecular weight distribution of 1.96. Thermal performance testing showed that the glass transition temperature of the obtained polyester-type polyurethane was 28.8℃, and the material's shape recovery rate was 90.2%. The antibacterial rate of the essential oil sustained-release tablets against Staphylococcus aureus was 55.67%.

[0023] Figure 1 The images show the spectra of the polyester diol and shape memory polymer GPC from Example 1. Figure 1 As shown, both polyester diol and polyester-type reversible crosslinked polyurethane samples exhibit a single-peak distribution. Compared with polyester diol, the molecular weight of polyester-type reversible crosslinked polyurethane samples is significantly increased, proving that the chain extension reaction was successfully carried out and polyester-type reversible crosslinked polyurethane shape memory materials were prepared.

[0024] Figure 2 The 1H NMR spectrum of the shape memory polymer in Example 1 was obtained, and the characteristic peak assignments confirmed the successful synthesis of the shape memory polymer.

[0025] Figure 3The DSC spectrum of the shape memory polymer in Example 1 shows that no obvious melting peak appeared in the secondary heating curve, proving that the material is an amorphous polymer.

[0026] Figure 4 The image shows a comparison of the antibacterial activity of the essential oil sustained-release tablets with that of the blank sample. The results indicate that the addition of antibacterial components resulted in a good antibacterial effect, with an antibacterial rate of 55.67% against Staphylococcus aureus. Example 2

[0027] This invention discloses an antibacterial essential oil sustained-release tablet. The preparation method of the essential oil sustained-release tablet includes the following steps: A 250 mL autoclave equipped with a mechanical stirrer is dried at 120 °C for more than 12 h. After vacuuming, it is cooled to room temperature and then filled with nitrogen for use. Under nitrogen protection, 1.71 g (0.015 mol) of the cyclic lactone compound caprolactone, 12.24 g (0.085 mol) of the cyclic lactone compound L-lactide, 13.8 mg (13.8 mg) of the catalyst, and 0.086 g (1.38 mmol) of the initiator ethylene glycol are weighed at room temperature and added to the reaction vessel. The reaction vessel is sealed, and the reaction temperature is set to 130 °C. The reaction is carried out for 6 hours to obtain a polyester diol. After the temperature drops to 60℃, 20 mL of the organic solvent tetrahydrofuran is added to the reactor. Once the polyester diol is completely dissolved, a solution of the isocyanate compound hexamethylene diisocyanate / tetrahydrofuran (0.23 g / 20 mL) is added dropwise to the reactor, and the reaction is maintained at this temperature for 3 hours. Then, a solution of 2,5-furandiethanol / N,N'-(4,4′-methylenediphenyl)bismaleimide / isocyanate compound hexamethylene diisocyanate / organic solvent tetrahydrofuran (0.18 g / 0.5 g / 0.23 g / 20 mL) is added dropwise to the reactor, and the reaction is maintained at 60℃ for 6 hours to obtain a polymer solution (the polymer is a polyester-type reversible crosslinked polyurethane, i.e., a shape memory polymer). Antibacterial essential oil (9.76 g, 70% of the shape memory material by mass) is added to the polymer solution, and the mixture is vigorously stirred at 500 rpm for 30 minutes. The polymer solution was poured into a polytetrafluoroethylene mold, and the solvent was evaporated at room temperature to obtain essential oil sustained-release tablets.

[0028] GPC testing results show that the shape memory polymer has a number-average molecular weight of 164.0 kg / mol and a molecular weight distribution of 3.37. Thermal performance testing shows that the glass transition temperature of the obtained polyester-type reversible crosslinked polyurethane is 31.5℃. The shape recovery rate of the material is 92.5%. The antibacterial rate (Staphylococcus aureus) is 92.10%.

[0029] Figure 5Figure 5 shows the spectra of polyester diol and shape memory polymer GPC in Example 2. Both polyester diol and polyester-type reversible crosslinked polyurethane samples show a single peak distribution. Compared with polyester diol, the molecular weight of polyester-type reversible crosslinked polyurethane sample is significantly increased, proving that the chain extension reaction was successfully carried out and polyester-type reversible crosslinked polyurethane shape memory material was prepared.

[0030] Figure 6 Example 2: The hydrogen nuclear magnetic resonance spectrum of the shape memory polymer was obtained, and the characteristic peak assignment proved that the shape memory polymer was successfully synthesized.

[0031] Figure 7 The DSC spectrum of the shape memory polymer in Example 2 shows that no obvious melting peak appeared in the secondary heating curve, proving that the material is an amorphous polymer.

[0032] Figure 8 The image shows a comparison of the antibacterial activity of the material with that of the blank sample. The results indicate that the material exhibits a good antibacterial effect after the addition of antibacterial components, with an antibacterial rate of 92.10% against Staphylococcus aureus. Example 3

[0033] This invention discloses an antibacterial essential oil sustained-release tablet. The preparation method of the essential oil sustained-release tablet includes the following steps: A 250 mL autoclave equipped with a mechanical stirrer is dried at 120 °C for more than 12 h. After vacuuming, it is cooled to room temperature and then filled with nitrogen for use. Under nitrogen protection, 13.8 g (0.12 mol) of the cyclic lactone compound caprolactone, 13.8 mg (13.8 mg) of the catalyst bismuth salicylate, and 0.086 g (1.38 mmol) of the initiator ethylene glycol are weighed at room temperature and added to the reaction vessel. The reaction vessel is sealed, and the reaction temperature is set to 130 °C. The reaction is carried out for 6 hours to obtain polyester diol. After the temperature drops to 60 °C, 20 mL of the organic solvent tetrahydrofuran is added to the reaction vessel. After the polyester diol is completely dissolved, a solution of the isocyanate compound hexamethylene diisocyanate / tetrahydrofuran (0.23 g / 20 mL) is added dropwise to the reaction vessel, and the reaction is maintained at this temperature for 3 hours. A solution of 2,5-furandimethylethanol / N,N'-(4,4′-methylenediphenyl)bismaleimide / isocyanate compound hexamethylene diisocyanate / organic solvent tetrahydrofuran (0.086 g / 3.82 mg / 0.23 g / 20 mL) was then added dropwise to the reactor. The reaction was maintained at 60 °C for 6 hours to obtain a polymer solution (the polymer was a polyester-type reversible crosslinked polyurethane, i.e., a shape memory polymer). Antibacterial essential oil (8.28 g, 60% of the shape memory material by mass) was added to the polymer solution, and the mixture was vigorously stirred at 500 r / min for 30 minutes. The polymer solution was poured into a polytetrafluoroethylene mold, and the solvent was evaporated at room temperature to obtain essential oil sustained-release tablets.

[0034] GPC testing results show that the shape memory polymer has a number-average molecular weight of 37.6 kg / mol and a molecular weight distribution of 1.88. Thermal performance testing shows that the obtained polyester-type reversible crosslinked polyurethane has a melting point of 53.8℃. The material's shape recovery rate is 91.0%. The material's antibacterial rate is 86.25%. Figure 9 The figure shows the GPC spectra of polyester diol and shape memory polymer in Example 3. Both polyester diol and long-chain branched polyurethane samples show a single peak distribution. Compared with polyester diol, the molecular weight of polyester-type reversible crosslinked polyurethane sample is significantly increased, which proves that the chain extension reaction was successfully carried out and polyester-type reversible crosslinked polyurethane shape memory material was prepared.

[0035] Figure 10 Example 3: The 1H NMR spectrum of the shape memory polymer was obtained, and the characteristic peak assignment proved that the shape memory polymer was successfully synthesized.

[0036] Figure 11 The DSC spectrum of the shape memory polymer in Example 3 shows a clear melting peak in the secondary heating curve, proving that the material is a crystalline polymer.

[0037] Figure 12 The image shows a comparison of the antibacterial activity of the material with that of the blank sample. The results indicate that the material exhibits a good antibacterial effect after the addition of antibacterial components, with an antibacterial rate of 86.25% against Staphylococcus aureus.

[0038] The above embodiments and accompanying drawings are not intended to limit the product form and style of the present invention. Any appropriate changes or modifications made by those skilled in the art should be considered as not departing from the patent scope of the present invention.

Claims

1. A method for preparing shape memory antibacterial essential oil sustained-release tablets with multiple fixation mechanisms, characterized in that: Includes the following steps: Step S1: The cyclic lactone compound, catalyst and initiator are added to the reactor for a primary reaction to obtain polyester diol; In step S1, the cyclic lactone compound is at least one of L-lactide, D-lactide, racemic lactide, caprolactone, ω-pentadecanolactone, and tridecanoic acid cycloethylene ester. The catalyst is an organometallic compound containing any one of zinc, calcium and bismuth, or an oxide containing any one of zinc, calcium and bismuth, or an organometallic compound containing any one of zinc, calcium and bismuth, or a combination of oxides containing any one of zinc, calcium and bismuth. The molar ratio of the catalyst to the cyclic lactone compound is 1:100~5000; the molar ratio of the initiator to the cyclic lactone compound is 1:10~100. Step S2: After the temperature of the reactor drops to the set temperature, the isocyanate compound dissolved in the organic solvent is added dropwise to the reactor to carry out a secondary reaction; The molar ratio of the initiator to the isocyanate compound is 1:0.9~1.2; Step S3: The mixed solution containing chain extender / reversible crosslinking agent / isocyanate compound / organic solvent is added dropwise to the reactor for three reactions to obtain a polymer solution. The polymer is polyester-type reversible crosslinked polyurethane. In step S3, the molar ratio of the chain extender to the isocyanate compound in the mixed solution is 1:0.9~1.2; the molar ratio of the reversible crosslinking agent to the chain extender is 1:0.9~1.

2. In steps S2 and S3, the isocyanate compound is any one of isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, and dicyclohexylmethane-4,4'-diisocyanate. Step S4: Add antibacterial essential oil to the polymer solution, stir for a certain time to obtain a molding liquid, pour the molding liquid into a mold, and after the solvent evaporates, obtain an essential oil sustained-release tablet containing antibacterial ingredients; The essential oil sustained-release tablet has a porous structure that forms its own pores. The essential oil sustained-release tablet has shape memory properties, and its shape memory transition temperature can be controlled within a range of 20~60 ℃, with a shape recovery rate of over 90%.

2. The method as described in claim 1, characterized in that: In step S1, the initiator is at least one of ethylene glycol, 1,3-propanediol, and 1,4-butanediol.

3. The method as described in claim 1, characterized in that: In step S3, the chain extender is any one of 2,5-furandiethanol, 2,5-furandicarboxylic acid, and 2,5-furandimethylamine.

4. The method as described in claim 1, characterized in that: In step S3, the reversible crosslinking agent is one of N,N′-(4,4′-methylenediphenyl)bismaleimide and N,N′-(1,3-phenylene)dimaleimide.

5. The method as described in claim 1, characterized in that: The temperature of the first reaction is 70~150 ℃, and the time is 2~10 h.

6. The method as described in claim 1, characterized in that: The secondary reaction is carried out at a temperature of 40~100 ℃ for a time of 3~6 h.

7. The method as described in claim 1, characterized in that: The three reactions were carried out at temperatures ranging from 40 to 100 °C for 2 to 10 hours.

8. The method as described in claim 1, characterized in that: In step S4, the stirring speed is 100~1000 r / min and the stirring time is 10~60 min.

9. The method as described in claim 1, characterized in that: The antibacterial essential oil comprises Phellodendron bark, Scutellaria baicalensis, Artemisia argyi, and Aquilaria sinensis, with a mass ratio of Phellodendron bark: Scutellaria baicalensis: Artemisia argyi: Aquilaria sinensis of 3:2:2:1; the antibacterial essential oil content added to the molding liquid in step S4 is 5-80 wt% of the polymer.

10. A shape memory antibacterial essential oil sustained-release tablet with multiple fixation mechanisms prepared by the method according to any one of claims 1-9.

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