Degradable film material and preparation method thereof

Abstract

The invention discloses a degradable thin film material and a preparation method thereof, and the preparation method comprises the following steps: mixing a gelator, a first organic solvent and a second organic solvent, heating and stirring, pouring into a mold, cooling at room temperature for a preset time, and then volatilizing the first organic solvent at a preset temperature to obtain the degradable thin film material, wherein the structural formula of the gelator is as follows: # imgabs0 # R1 is a side chain group connected to an amino acid central carbon atom except amino, carboxyl and a hydrogen atom; r2 is alkyl with the carbon atom number of 16 to 19; r < 3 > is 9-fluorenyl methoxy carbonyl or t-butyloxycarbonyl; the boiling point of the second organic solvent is greater than that of the first organic solvent, and the second organic solvent does not form an azeotrope with the first organic solvent. The method can be used for preparing the large-size, defect-free, high-strength, degradable and plasticizable hydrophobic film material.

Description

Technical Field

[0001] The present invention relates to the technical field of degradable film materials, and in particular to a degradable film material and a preparation method thereof. Background Art

[0002] With the rapid development of the plastics industry, the application of plastic products has penetrated into every corner of society, from industrial production to food, clothing, housing and transportation, plastic products are everywhere, especially the use of plastic bags, which has penetrated into every aspect of people's lives. However, since most of the plastic bags used by people in life are structurally stable and not easily degraded, they seriously endanger the ecological environment and also threaten human health. Although there are many degradable film materials that have been studied and prepared, such as starch-based plastics, polylactic acid (PLA), polyhydroxyalkanoate (PHA) and polybutylene adipate / terephthalate (PBAT), etc. However, these materials have not really replaced traditional plastics because they have certain defects in structural properties, low strength, or high production costs. Therefore, realizing the preparation of degradable film materials is a technical problem currently faced.

[0003] Supramolecular gel film materials formed by the self-assembly of small molecule gelling agents are expected to replace traditional packaging film materials due to their good degradability, safety, economy and practicality. Although supramolecular gel film materials formed by the self-assembly of small molecule gelling agents can be easily degraded by some means, supramolecular gel film materials formed by the self-assembly of small molecule gelling agents are generally soft materials, which often have the problem of too low mechanical strength, have no practical value, and cannot replace traditional plastics.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a degradable film material and a preparation method thereof, aiming to solve the problem of low mechanical strength of the existing film material formed by self-assembly of small molecule gelling agents.

[0006] The technical solution of the present invention is as follows:

[0007] The first aspect of the present invention provides a method for preparing a degradable film material, which comprises the steps of:

[0008] The gel factor, the first organic solvent and the second organic solvent are mixed, heated and stirred, poured into a mold, cooled at room temperature for a preset time, and then the first organic solvent is volatilized at a preset temperature to obtain the degradable film material;

[0009] Wherein, the structural formula of the gel factor is:

[0010]

[0011] R1 is a side chain group other than an amino group, a carboxyl group and a hydrogen atom connected to the central carbon atom of an amino acid, wherein the amino acid is selected from one of glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine, histidine, selenocysteine ​​and pyrrolysine;

[0012] R2 is an alkyl group having 16 to 19 carbon atoms;

[0013] R3 is 9-fluorenylmethoxycarbonyl or tert-butyloxycarbonyl;

[0014] The boiling point of the second organic solvent is greater than that of the first organic solvent, and the second organic solvent does not form an azeotrope with the first organic solvent.

[0015] Optionally, the first organic solvent is a liquid alkane solvent having less than 9 carbon atoms.

[0016] Optionally, the first organic solvent includes at least one of n-pentane, n-hexane, n-heptane and n-octane.

[0017] Optionally, the second organic solvent includes at least one of phytane, squalane, squalene, white oil, silicone oil, vegetable oil, poly-alpha-olefin synthetic oil, and hexadecane.

[0018] Optionally, the mass ratio of the gel factor, the first organic solvent, and the second organic solvent is 1-9:30-300:9-91.

[0019] Optionally, the mixture is heated and stirred at a temperature of 100 to 250° C., poured into a mold, cooled at room temperature for 10 to 20 minutes, and the first organic solvent is volatilized at a temperature of 40 to 90° C. for 3 to 24 hours to obtain the degradable film material.

[0020] Optionally, the preparation method of the gel factor comprises the following steps:

[0021] supply R2-NH2;

[0022] Will R2-NH2, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloric acid, 1-hydroxybenzotriazole, and a third organic solvent are mixed and stirred to react to obtain a crude product;

[0023] After purifying the crude product, the gel factor is obtained.

[0024] Optionally, the stirring reaction is carried out at room temperature for 3 to 7 days.

[0025] Optionally, after purifying the crude product, the step of obtaining the gel factor specifically comprises:

[0026] The crude product is washed with a mixed solution of ethanol and water, then recrystallized with ethyl acetate, and dried to obtain the gel factor.

[0027] The second aspect of the present invention provides a degradable film material, wherein the degradable film material is prepared by the preparation method of the present invention as described above.

[0028] Beneficial effects: The gel factor of the structure described in the present invention has a long hydrophobic alkyl tail chain, which can spontaneously aggregate and assemble into a three-dimensional network structure through hydrogen bonds, π-π interactions, and hydrophobic forces. Specifically, through a bottom-up self-assembly strategy, the self-assembled nanofibers formed by physical cross-linking can fix low-boiling point organic solvents and high-boiling point organic solvents in a very effective way to form a supramolecular gel, and then by removing the low-boiling point organic solvent, a large-size, defect-free, high-strength, degradable, plasticizable hydrophobic film material is prepared, which solves the problem of low mechanical properties of the existing film material obtained by self-assembly of small molecule gelling agents. The preparation method provided by the present invention has easy-to-obtain raw materials, low cost, and simple preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of forming a degradable film material in an embodiment of the present invention.

[0030] Figure 2 This is the hydrogen nuclear magnetic resonance spectrum of the gel factor prepared in Example 1 of the present invention.

[0031] Figure 3 (a) is a physical picture of the degradable film material in Example 2 of the present invention, (b) is a physical picture of the degradable film material in Example 3 of the present invention, (c) is a physical picture of the degradable film material in Example 4 of the present invention, and (d) is a physical picture of the degradable film material in Example 5 of the present invention.

[0032] Figure 4 This is a physical picture of the degradable film material with a thickness of 450 μm in Example 7 of the present invention.

[0033] Figure 5 This is a graph showing the load-bearing test results of the degradable film material with a thickness of 450 μm in Example 7 of the present invention.

[0034] Figure 6 This is a graph showing the tensile properties test results of the degradable film material with a thickness of 450 μm in Examples 6 and 7 of the present invention.

[0035] Figure 7 This is a graph showing the rollability of a degradable film material with a thickness of 1 mm in Example 7 of the present invention.

[0036] Figure 8 This is a diagram of the foldability performance of the degradable film material with a thickness of 1 mm in Example 7 of the present invention.

[0037] Fig. 9 This is a diagram showing the dissolution performance of the degradable film material with a thickness of 2 mm in different solutions in Example 7 of the present invention. DETAILED DESCRIPTION

[0038] The present invention provides a degradable film material and a preparation method thereof. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0039] Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0040] Through research, the inventors found that although the gel formed by small molecule gel factors (also known as small molecule gelling agents) is an ideal candidate for preparing degradable film materials, the use of small molecule gelling factors to prepare high-strength films faces such a contradiction: theoretically, when the gel factor forms a gel, the higher the gel concentration, the better the mechanical properties of the formed gel; however, in experimental tests, it was found that the better the solubility of the gel factor in the solvent, the worse the mechanical properties of the gel. This result greatly limits the use of small molecule gel factors in the preparation of high-strength films. Based on this, an embodiment of the present invention proposes a new method for preparing degradable film materials by adjusting the solvent composition and using small molecule gelling factors with specific structures. This method can overcome the above contradiction, and the film material prepared by this method can have the characteristics of high strength and degradability at the same time. Specifically, the method for preparing a degradable film material includes the steps of: mixing the gel factor, a first organic solvent, and a second organic solvent, heating and stirring, pouring into a mold, cooling at room temperature for a preset time, and then volatilizing the first organic solvent at a preset temperature to obtain the degradable film material;

[0041] Wherein, the structural formula of the gel factor is:

[0042]

[0043] R1 is a side chain group other than an amino group, a carboxyl group and a hydrogen atom connected to the central carbon atom of an amino acid, wherein the amino acid is selected from one of glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine, histidine, selenocysteine ​​and pyrrolysine;

[0044] R2 is an alkyl group having 16 to 19 carbon atoms;

[0045] R3 is 9-fluorenylmethoxycarbonyl or tert-butyloxycarbonyl;

[0046] The boiling point of the second organic solvent is greater than that of the first organic solvent, and the second organic solvent does not form an azeotrope with the first organic solvent.

[0047] As we all know, the general structural formula of amino acids is R is a side chain group other than an amino group, a carboxyl group, and a hydrogen atom connected to the central carbon atom of the amino acid. Different side chain groups of R determine different types of amino acids. For example, in this embodiment, when the amino acid is glycine, R1 is -H; when the amino acid is alanine, R1 is -CH3; when the amino acid is valine, R1 is -CH(CH3)2; when the amino acid is methionine, R1 is When the amino acid is phenylalanine, R1 is When the amino acid is threonine, R1 is When the amino acid is aspartic acid, R1 is And so on. Indicates the connection site.

[0048] R2 is an alkyl group having 16 to 19 carbon atoms, and specifically, a straight-chain alkyl group having 16 to 19 carbon atoms, such as -C 16 H 33 , -C 17 H 35 , -C 18 H 37 , -C 19 H 39 wait.

[0049] In the embodiment of the present invention, the gel factor of the structure is degradable and has a low solubility in the second organic solvent (high boiling point). In this embodiment, the first organic solvent (low boiling point) and the second organic solvent (high boiling point) are mixed to form a mixed solvent system of a low boiling point solvent and a high boiling point solvent, so that its solubility for the gel factor can be improved, and can even be improved by more than ten times, thereby greatly improving the solubility of the gel factor. The gel factor of the structure obtained by molecular design in this embodiment, i.e., the amino acid derivative small molecule, has a molecular weight of less than 600, a length of about 2-3nm, and a long hydrophobic alkyl tail chain, which can be spontaneously aggregated and assembled into a three-dimensional network structure through hydrogen bonds, π-π interactions, and hydrophobic forces through a bottom-up self-assembly strategy, such as Figure 1 As shown, the gel factor will form ultrafine fibers with a width of 2-3nm during self-assembly, and the ultrafine fibers will be spirally cross-linked to form a cross-linked network structure, so that the self-assembled nanofibers formed by physical cross-linking can fix the first organic solvent and the second organic solvent in a very effective way to form a supramolecular gel. At this time, the supramolecular gel is a soft substance with low strength. Furthermore, after removing the first organic solvent (low boiling point) by volatilization, the network structure formed between the ultrafine fibers is tighter, and the mechanical properties are fully improved, which solves the problem of low mechanical properties of thin film materials obtained by assembling small molecule gel factors.

[0050] In this embodiment, a low-boiling point organic solvent and a high-boiling point organic solvent are mixed, and the structure is fixed by self-assembly of the gel factor to achieve the preparation of supramolecular gel, and then a large-size, defect-free, high-strength, degradable, plasticizable hydrophobic film material is prepared by removing the low-boiling point organic solvent. The preparation method provided by the embodiment of the present invention has easy-to-obtain raw materials, low cost, and simple preparation process. In addition, the embodiment of the present invention can achieve the preparation of high-strength degradable film materials under the condition of low gel factor concentration.

[0051] In this embodiment, the boiling point of the second organic solvent is greater than that of the first organic solvent, and the second organic solvent does not form an azeotrope with the first organic solvent, so that the first organic solvent can be volatilized while the second organic solvent is not volatilized at a preset temperature.

[0052] In some embodiments, the first organic solvent is a liquid alkane solvent having less than 9 carbon atoms.

[0053] In some embodiments, the first organic solvent includes but is not limited to at least one of n-pentane, n-hexane, n-heptane, and n-octane.

[0054] In some embodiments, the second organic solvent includes at least one of phytane, squalane, squalene, white oil, silicone oil, vegetable oil (such as sunflower oil), polyalphaolefin synthetic oil, and hexadecane. Polyalphaolefin synthetic oil is a type of long-chain alkane obtained by polymerization of polyalphaolefin (mainly C8-C10 fraction) under the action of a catalyst (mainly trimer, tetramer and pentamer). In some specific embodiments, the polyalphaolefin synthetic oil is PAO4~PAO150 synthetic oil, such as PAO4, PAO8, PAO100, PAO150, etc. In a further embodiment, the boiling point of the second organic solvent is not less than 100°C, that is, an organic solvent with a boiling point of not less than 100°C is selected from phytane, squalane, squalene, white oil, silicone oil, vegetable oil (such as sunflower oil), polyalphaolefin synthetic oil, and hexadecane.

[0055] In the present invention, the first organic solvent and the second organic solvent can be miscible in any proportion, which can be set according to actual needs, and the amount of gel factor added can also be set according to actual needs. As an example, in some embodiments, the mass ratio of the gel factor, the first organic solvent, and the second organic solvent is 1 to 9: 30 to 300: 9 to 91. As an example, the mass ratio of the gel factor, the first organic solvent, and the second organic solvent is 1:30:9, 4:150:50, 7:250:80 or 9:300:91, etc.

[0056] In some embodiments, the mixture is heated and stirred at a temperature of 100 to 250°C, poured into a mold, cooled at room temperature for 10 to 20 minutes (for example, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 minutes), and then the first organic solvent is volatilized at a preset temperature to obtain the degradable film material. As an example, the temperature of the heating and stirring can be 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C or 250°C, etc. The temperature and time for volatilizing the first organic solvent can be set according to actual needs, so as to fully volatilize the first organic solvent. As an example, the first organic solvent is volatilized at a temperature of 40-90°C for 3-24 hours. The specific temperature may be 40°C, 50°C, 60°C, 70°C, 80°C or 90°C, etc., and the specific time may be 3h, 4h, 5h, 8h, 10h, 15h, 20h or 24h, etc.

[0057] In some embodiments, the method for preparing the gel factor comprises the following steps:

[0058] supply R2-NH2;

[0059] Will R2-NH2, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloric acid (EDC·HCl), 1-hydroxybenzotriazole (HOBt), and a third organic solvent are mixed and stirred to react to obtain a crude product;

[0060] After purifying the crude product, the gel factor is obtained, wherein the groups represented by R3 and R1 are the same as those described above and will not be described in detail herein.

[0061] In this embodiment, the amino acid with a protecting group R3 at the N-terminus is The fatty amine R2-NH2, the condensation agent EDC·HCl and HOBt react to obtain the gel factor. The use of EDC·HCl and HOBt together can effectively control side reactions, and HOBt can also prevent racemization during the synthesis process.

[0062] In some embodiments, the third organic solvent includes but is not limited to at least one of dichloromethane, toluene, n-hexane, and n-octane. Preferably, the third organic solvent is dichloromethane, and the solubility of the reactants in dichloromethane is the highest.

[0063] In some embodiments, the stirring reaction is carried out at room temperature for 3 to 7 days, such as 3 days, 4 days, 5 days, 6 days or 7 days. Unless otherwise specified, 1 day in the present invention represents 24 hours.

[0064] In some embodiments, after purifying the crude product, the step of obtaining the gel factor specifically comprises:

[0065] The crude product is washed with a mixed solution of ethanol and water (to remove unreacted condensing agent, amino acid with a protecting group R3 at the N-terminus, and fatty amine), then recrystallized with ethyl acetate, and dried to obtain the gel factor.

[0066] In this embodiment, since the gelling factor is insoluble in a mixed solution of ethanol and water, after the crude product is washed with a mixed solution of ethanol and water, the target product can be obtained by filtering.

[0067] The embodiment of the present invention further provides a degradable film material, wherein the mass content of the gel factor in the degradable film material is 10-90%, for example, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90%, etc. The present invention can realize the preparation of degradable film materials with different concentrations of gel factor (from high concentration to high concentration).

[0068] The following describes it in detail through specific embodiments.

[0069] Example 1

[0070] The raw materials used in the following examples are all commercially available products unless otherwise specified, among which PAO8 was purchased from Shenzhen Huashengyuan Petroleum Technology Co., Ltd., PAO150 was purchased from Shenzhen Huashengyuan Petroleum Technology Co., Ltd. (produced by Sinopec), and Fmoc-L-phenylalanine was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. with a brand name of F105472.

[0071] This embodiment provides a method for preparing a gel factor, comprising the following steps:

[0072] 2g Fmoc-L-phenylalanine 1.67 g of octadecylamine, 0.96 g of EDC·HCl, and 0.84 g of 1-hydroxybenzotriazole monohydrate were added to a round-bottom flask, and 125 mL of dichloromethane was added as a solvent. The mixture was stirred well at room temperature and reacted for 3 days.

[0073] The reaction product was subjected to rotary evaporation to remove the solvent, and 200 mL of a 1:1 ethanol / water mixed solvent was added, heated and stirred until boiling, filtered while hot, and the filter residue was taken. An ethanol / water mixed solvent (100 mL of ethanol and 234 mL of water) with a volume ratio of 3:7 was continued to be added, and the above operation was repeated 3 times to obtain a crude gel factor.

[0074] Add 400 mL of dichloromethane to the crude gel factor, heat to dissolve until the solution is clear, filter while hot, and take the filtrate. Cool the filtrate to room temperature and perform rotary evaporation.

[0075] The product obtained after rotary evaporation was recrystallized twice with ethyl acetate and finally vacuum dried to obtain the final product gel factor It is denoted as L-FPC18, which is a white solid powder. Its H NMR spectrum is as follows: Figure 2 shown.

[0076] Example 2

[0077] This embodiment provides a method for preparing a degradable film material, comprising the following steps:

[0078] The L-FPC18, n-octane and squalane in Example 1 were mixed in a mass ratio of 1:30:9, heated and stirred at 180°C until L-FPC18 was completely dissolved. After the solution was clarified, it was poured into a mold and cooled at room temperature for 10 minutes. After forming a stable gel, it was placed in a forced air drying oven to volatilize the n-octane, and volatilized at 80°C for 3 hours to obtain a degradable film material.

[0079] Example 3

[0080] This embodiment provides a method for preparing a degradable film material, which is different from Embodiment 2 only in that squalane is replaced by sunflower oil.

[0081] Example 4

[0082] This embodiment provides a method for preparing a degradable film material, which is different from Embodiment 2 only in that squalane is replaced by silicone oil.

[0083] Example 5

[0084] This embodiment provides a method for preparing a degradable film material, which is different from Embodiment 2 only in that squalane is replaced by PAO150.

[0085] The actual picture of the degradable film material in Example 2-5 is as follows Figure 3 As shown, it can be seen that these degradable film materials have good formability.

[0086] Example 6

[0087] This embodiment provides a method for preparing a degradable film material, comprising the following steps:

[0088] The L-FPC18, n-octane and PAO8 in Example 1 were mixed in a mass ratio of 1:100:8.31, heated and stirred at 220°C until L-FPC18 was completely dissolved. After the solution was clarified, it was poured into a mold and cooled at room temperature for 10 minutes. After forming a stable gel, it was placed in a blast drying oven to volatilize the n-octane, and volatilized at 80°C for 3 hours. By changing the amount of solution poured into the mold, degradable film materials with thicknesses of 450μm, 1mm, and 2mm were obtained, respectively, and the mass content of L-FPC18 in the degradable film materials was about 10%.

[0089] Example 7

[0090] This embodiment provides a method for preparing a degradable film material, comprising the following steps:

[0091] The L-FPC18, n-octane and PAO8 in Example 1 were mixed in a mass ratio of 1:100:4.18, heated and stirred at 220°C until L-FPC18 was completely dissolved, and after the solution was clarified, poured into a mold, cooled at room temperature for 10 minutes, and placed in a blast drying oven to volatilize the n-octane after forming a stable gel, and volatilized at 80°C for 3 hours. By changing the amount of solution poured into the mold, degradable film materials with thicknesses of 450μm, 1mm, and 2mm were obtained, respectively. The mass content of L-FPC18 in the degradable film was about 20%. The actual picture of the degradable film material with a thickness of 450μm is as shown in the figure. Figure 4 As shown, it can be seen that the degradable film material has higher transparency.

[0092] test:

[0093] The load-bearing test results of the degradable film material with a thickness of 450 μm in Example 7 are as follows: Figure 5 As shown, it can withstand a weight of about 450g and has high strength.

[0094] The tensile properties of the degradable film materials with a thickness of 450 μm in Examples 6 and 7 were tested. The results are as follows: Figure 6 As shown, the Young's modulus of the degradable film material with a thickness of 450 μm in Example 7 can reach 144 MPa, while the Young's modulus of the parafilm available on the market is 150 MPa. The degradable film material prepared according to the method provided by the present invention has excellent tensile strength, which is almost comparable to that of parafilm.

[0095] like Figure 7 As shown, the degradable film material with a thickness of 1 mm in Example 7 has excellent rollability. The degradable film materials with other thicknesses in Example 7 and the degradable materials with different thicknesses in Example 6 also have similar properties.

[0096] like Figure 8 As shown, the degradable film material with a thickness of 1 mm in Example 7 has excellent foldability. The degradable film materials with other thicknesses in Example 7 and the degradable film materials with different thicknesses in Example 6 also have similar properties.

[0097] The 2 mm thick degradable film material in Example 7 was cut into four strips of the same size, and immersed in water, ethanol, chloroform, and pepsin solution, respectively, and placed in the same environment. Fig. 9 As shown in the figure, significant changes occurred after 15 minutes. The degradable film material had almost no significant changes in water, swelled in ethanol, and the part immersed in chloroform had been decomposed, and the thickness of the gel was significantly thinned in pepsin. This shows that the film material can be slowly degraded in pepsin and completely degraded in chloroform in a short time, and has degradability.

[0098] In summary, the present invention provides a degradable film material and a preparation method thereof. The gel factor of the structure described in the present invention has a long hydrophobic alkyl tail chain, which can spontaneously aggregate and assemble into a three-dimensional network structure through hydrogen bonds, π-π interactions, and hydrophobic forces. Specifically, through a bottom-up self-assembly strategy, the self-assembled nanofibers formed by physical cross-linking can fix low-boiling point organic solvents and high-boiling point organic solvents in a very effective way to form a supramolecular gel, and then a large-size, defect-free, high-strength, degradable, plasticizable hydrophobic film is prepared by removing the low-boiling point organic solvent, which solves the problem of low mechanical properties of the existing film material assembled by small molecule gel factors. The preparation method provided by the present invention has easy-to-obtain raw materials, low cost, and simple preparation process.

[0099] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for preparing a degradable film material, characterized in that: Includes steps: The gel factor, the first organic solvent and the second organic solvent are mixed, heated and stirred, poured into a mold, cooled at room temperature for a preset time, and then the first organic solvent is volatilized at a preset temperature to obtain the degradable film material; Wherein, the structural formula of the gel factor is: R1 is a side chain group other than an amino group, a carboxyl group and a hydrogen atom connected to the central carbon atom of an amino acid, wherein the amino acid is selected from one of glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine, histidine, selenocysteine ​​and pyrrolysine; R2 is an alkyl group having 16 to 19 carbon atoms; R3 is 9-fluorenylmethoxycarbonyl or tert-butyloxycarbonyl; The boiling point of the second organic solvent is greater than that of the first organic solvent, and the second organic solvent does not form an azeotrope with the first organic solvent.

2. The preparation method according to claim 1, characterized in that: The first organic solvent is a liquid alkane solvent having less than 9 carbon atoms.

3. The preparation method according to claim 2, characterized in that: The first organic solvent includes at least one of n-pentane, n-hexane, n-heptane and n-octane.

4. The preparation method according to claim 1, characterized in that: The second organic solvent includes at least one of phytane, squalane, squalene, white oil, silicone oil, vegetable oil, poly-alpha-olefin synthetic oil, and hexadecane.

5. The preparation method according to claim 1, characterized in that: The mass ratio of the gel factor, the first organic solvent and the second organic solvent is 1-9:30-300:9-91.

6. The preparation method according to claim 1, characterized in that: The mixture is heated and stirred at a temperature of 100 to 250° C., poured into a mold, cooled at room temperature for 10 to 20 minutes, and the first organic solvent is volatilized at a temperature of 40 to 90° C. for 3 to 24 hours to obtain the degradable film material.

7. The preparation method according to claim 1, characterized in that: The preparation method of the gel factor comprises the following steps: supply R2-NH2; Will R2-NH2, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloric acid, 1-hydroxybenzotriazole, and a third organic solvent are mixed and stirred to react to obtain a crude product; After purifying the crude product, the gel factor is obtained.

8. The preparation method according to claim 7, characterized in that: The stirring reaction is carried out at room temperature for 3 to 7 days.

9. The preparation method according to claim 7, characterized in that: After purifying the crude product, the step of obtaining the gel factor specifically comprises: The crude product is washed with a mixed solution of ethanol and water, then recrystallized with ethyl acetate, and dried to obtain the gel factor.

10. A degradable film material, characterized in that: The preparation is obtained by the preparation method according to any one of claims 1 to 9.

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