Polydisulfide degradable high polymer material containing amide group and preparation method thereof

Abstract

The invention provides a polydisulfide degradable high polymer material containing an amide group and a preparation method thereof. The preparation method comprises the following steps: S100, preparing a lipoic acid polymer from a raw material comprising a lipoic acid monomer through cationic polymerization or cationic copolymerization reaction; and S200, adopting raw materials comprising a lipoic acid polymer and isocyanate or isocyanate to prepare the polydisulfide degradable high polymer material containing the amide group. According to the preparation method disclosed by the invention, the polydisulfide degradable high polymer material containing the amide group can be obtained, and a new group can be introduced to the polydisulfide, so that the polydisulfide is endowed with good performance.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a polydisulfide degradable polymer material containing an amide group and a preparation method thereof. Background Art

[0002] Polythioctic Acid (PTA or PLA) is a high molecular weight polymer synthesized from natural small molecule lipoic acid (TA or LA) through a specific chemical reaction (such as ring-opening polymerization).

[0003] Lipoic acid is an essential coenzyme in the aerobic metabolism process in animals, and has excellent antioxidant and antibacterial properties. Polylipoic acid uses naturally occurring lipoic acid as a raw material. Polylipoic acid molecules contain dynamic covalent disulfide bonds and hydrogen bonds in carboxyl groups. These dynamic chemical bonds give polylipoic acid special reactivity and self-assembly ability. Under appropriate conditions, polylipoic acid can form a transparent solid with good viscosity and elasticity. In addition, the degradation products of polylipoic acid reduced by disulfide bonds are small molecules with biocompatibility, thus having biodegradability. The carboxyl side groups in polylipoic acid can form coordination bonds, hydrogen bonds, etc., and can also be used as cross-linking points to prepare cross-linked polymers. In summary, the unique chemical structure of polylipoic acid gives it many excellent properties, such as cell permeability, processability, ductility, adhesion, etc., and it has broad application prospects in the fields of biomedical materials, smart materials, self-healing materials, recyclable materials, adhesives, electronic devices, etc.

[0004] However, the structure of polylipoic acid is relatively metastable, and the fragility of disulfide bonds may lead to polymer depolymerization, affecting the stability of the material. At present, the existing technical development of polylipoic acid is as follows: Zhang et al. reacted lipoic acid with amino-containing adamantane to generate lipoamide derivative monomers, and then thermally initiated copolymerization with lipoic acid to prepare supramolecular materials with tensile strength exceeding 1MPa (Chemical Engineering Journal, 2023, 461, 142066); Qu et al. thermally copolymerized lipoic acid and 1,3-diisopropenylbenzene (DIB), and added metal salts for coordination crosslinking. The tensile strength of the prepared supramolecular material can exceed 1.5MPa (Angewandte Chemie International Edition, 2020, 59, 5278–5283); Qu et al. converted lipoic acid into lipohydrazide derivative monomers, then thermally initiated copolymerization, and added dithiocarbamates at the same time. The tensile strength of the prepared supramolecular materials can exceed 50 MPa (Science Advances, 2022, 8, eabk3286); Qu et al. thermally initiated copolymerization of lipohydrazide derivative monomers with sulfur element, and the tensile strength of the prepared supramolecular materials can exceed 20 MPa (Nature Communications, 2024, 15, 3855); Qu et al. reacted lipoic acid with diol small molecules to generate lipoic acid ester derivatives, and then thermally or photoinitiated copolymerization with lipoic acid, and added metal salts for coordination crosslinking. The tensile strength of the prepared supramolecular materials can exceed 50 MPa (Angewandte Chemie International Edition, 2024, e202409200). The above prior art improves the strength of polylipoic acid materials by cross-linking lipoic acid derivative monomers with metal salts. In the prior art, there is no report on the research of directly modifying polylipoic acid materials by amide groups. Summary of the invention

[0005] One of the problems solved by the present invention is how to provide a polydisulfide degradable polymer material containing amide groups.

[0006] In order to solve at least one of the above problems, the present invention provides a method for preparing a polydisulfide degradable polymer material containing an amide group, the preparation method comprising:

[0007] S100, preparing a lipoic acid polymer by cationic polymerization or cationic copolymerization using a raw material including a lipoic acid monomer;

[0008] S200, using raw materials including lipoic acid polymer and isocyanic acid or isocyanate to prepare a polydisulfide degradable polymer material containing amide groups through a condensation reaction.

[0009] In any of the above technical solutions, S100 specifically includes:

[0010] S110, dissolving the lipoic acid monomer in a first organic solvent at a molar ratio of the first initiator to the lipoic acid monomer = (1-100): 5000, and then adding the first initiator to perform a cationic polymerization reaction;

[0011] S120, adding a first reaction terminator to terminate the cationic polymerization reaction, and obtaining polylipoic acid as a lipoic acid polymer.

[0012] In any of the above technical solutions, in S110, the first initiator includes a strong organic acid or an anhydride or ester corresponding to the strong organic acid; and / or in S110, the first organic solvent includes at least one of chloroform, dichloromethane, chloroform, carbon tetrachloride, dichloroethane, n-hexane, cyclohexane, n-heptane, tetrahydrofuran, acetone, butanone, ether, acetonitrile, benzonitrile, benzene, toluene, xylene, chlorobenzene, o-dichlorobenzene, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, and butyl sulfone, or a combination thereof; and / or in S110, the reaction temperature of the cationic polymerization reaction is between -90°C and 30°C; and / or in S110, the reaction time of the cationic polymerization reaction is between 5 min and 4 h; and / or in S120, the first reaction terminator includes a propylthiol solution.

[0013] In any of the above technical solutions, S100 specifically includes:

[0014] S110, firstly mixing and dissolving the lipoic acid monomer and the aromatic olefin monomer in a second organic solvent at a molar ratio of lipoic acid monomer: aromatic olefin monomer = 100: (1-10000) to obtain a reaction monomer, and then adding a second initiator to the reaction monomer at a molar ratio of second initiator: reaction monomer = (1-100): 5000 to carry out a cationic copolymerization reaction;

[0015] S120, adding a second reaction terminator to terminate the cationic copolymerization reaction, and obtaining a random copolymer of aromatic olefin and lipoic acid as a lipoic acid polymer.

[0016] In any of the above technical solutions, in S110, the second initiator includes a strong organic acid or an anhydride or ester corresponding to the strong organic acid; and / or in S110, the second organic solvent includes at least one of chloroform, dichloromethane, chloroform, carbon tetrachloride, dichloroethane, n-hexane, cyclohexane, n-heptane, tetrahydrofuran, acetone, butanone, ether, acetonitrile, benzonitrile, benzene, toluene, xylene, chlorobenzene, o-dichlorobenzene, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, and butyl sulfone, or a combination thereof; and / or in S110, the reaction temperature of the cationic copolymerization reaction is between -90°C and 30°C; and / or in S110, the reaction time of the cationic copolymerization reaction is between 5 min and 4 h; and / or in S120, the second reaction terminator includes water or an alkyl alcohol solution or a thiol solution.

[0017] In any of the above technical solutions, S200 specifically includes:

[0018] S210, mixing lipoic acid polymer with isocyanic acid or isocyanate at a ratio of carboxyl group:isocyanate group=200:(1-200), adding a catalyst at a molar amount of 0.01-1% of the isocyanate at a temperature of 40°C to 160°C, and carrying out a condensation reaction for 0.5h to 4h to obtain a polydisulfide degradable polymer material.

[0019] In any of the above technical solutions, the catalyst includes at least one of an organic metal catalyst, an amine catalyst, an organic base catalyst, or a combination thereof.

[0020] In any of the above technical solutions, the catalyst includes at least one of N,N-dimethylcyclohexylamine, pentamethyldiethylenetriamine, dimethylcyclohexylamine, bis(2-dimethylaminoethyl) ether, N,N,N',N'-tetramethylalkylenediamine, triethylamine, N,N-dimethylbenzylamine, solid amine, N-ethylmorpholine, N-methylmorpholine, N,N'-diethylpiperazine, dibutyltin dilaurate, dioctyltin dilaurate, stannous octoate, di(dodecylsulfide)dibutyltin, dibutyltin diacetate, dibutyltin dimaleate, butyltin dithiol, dioctyltin mercaptan, organic bismuth, triazine trimerization catalyst, bis(dimethylaminomethyl)benzene, triethanolamine, N,N-dimethylethanolamine (DMEA), pyridine, and N,N'-lutidine, or a combination thereof.

[0021] In any of the above technical solutions, the isocyanate includes o-toluene isocyanate, m-toluene isocyanate, p-toluene isocyanate, 4-methoxyphenyl isocyanate, 3-methoxyphenyl isocyanate, 4-chlorophenyl isocyanate, m-chlorophenyl isocyanate, o-chlorophenyl isocyanate, 2-fluorophenyl isocyanate, 2,4-difluorophenyl isocyanate, 4-fluorophenyl isocyanate, 1-naphthyl isocyanate, 1,2-phenylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-methylenebis(phenyl isocyanate), 1,5-diisocyanate. or isocyanates include at least one of isopropyl isocyanate, tert-butyl isocyanate, ethyl isocyanate, n-butyl isocyanate, cyclopentyl isocyanate, cyclohexyl isocyanate, octadecyl isocyanate, 2-ethyl chloroisocyanate, α-methylbenzyl isocyanate, phenylethyl isocyanate, benzyl isocyanate, allyl isocyanate, 2-isocyanoethyl acrylate, isocyanatopropyltriethoxysilane, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, meta-xylyl diisocyanate, L-lysine diisocyanate, and HDI trimer, or a combination thereof.

[0022] The present invention also provides a polydisulfide degradable polymer material containing amide groups, and the polydisulfide degradable polymer material containing amide groups is obtained by adopting the preparation method of any one of the above technical solutions.

[0023] Beneficial Effects

[0024] The preparation method provided by the present invention first adopts raw materials including thioctic acid monomers to prepare thioctic acid polymers through cationic polymerization or cationic copolymerization reaction; and then adopts raw materials including thioctic acid polymers and isocyanic acid or isocyanate to prepare polydisulfide degradable polymer materials containing amide groups through condensation reaction. The preparation method of the present invention can obtain polydisulfide degradable polymer materials containing amide groups, and can simultaneously introduce new groups into polydisulfide, thereby giving good performance to polydisulfide. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the H NMR spectrum of the yellow turbid solution after degradation in Example 1 measured in deuterated water. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the following is a detailed description of the specific embodiments of the present invention.

[0027] Unless otherwise specified, the reagents and raw materials used in the present invention can be purchased through commercial channels. The experimental methods in the following examples without specifying specific conditions are selected according to conventional methods and conditions, or according to the product specifications.

[0028] The embodiment of the present invention provides a method for preparing a polydisulfide degradable polymer material containing an amide group. The preparation method adopted by the present invention comprises:

[0029] S100, preparing a lipoic acid polymer by cationic polymerization or cationic copolymerization using a raw material including a lipoic acid monomer;

[0030] S200, using raw materials including lipoic acid polymer and isocyanic acid or isocyanate to prepare a polydisulfide degradable polymer material containing amide groups through a condensation reaction.

[0031] The purpose of the above S100 is to prepare lipoic acid polymer by cationic polymerization or cationic copolymerization. The lipoic acid monomer can be obtained through commercial procurement.

[0032] The thioctic acid polymer is specifically polythioic acid or an aromatic olefin and thioctic acid random copolymer. Polythioctic acid is obtained by ring-opening polymerization using thioctic acid monomer as raw material. Aromatic olefin and thioctic acid random copolymer is obtained by cationic copolymerization using thioctic acid monomer and aromatic olefin monomer as raw material. Wherein, the aromatic olefin monomer can be obtained through commercial procurement.

[0033] The following is a specific description of the preparation method of the lipoic acid polymer of the present invention, taking polylipoic acid as an example. For example, in some embodiments of the present invention, S100 specifically includes:

[0034] S110, dissolving the lipoic acid monomer in a first organic solvent at a molar ratio of the first initiator to the lipoic acid monomer = (1-100): 5000, and then adding the first initiator to perform a cationic polymerization reaction;

[0035] S120, adding a first reaction terminator to terminate the cationic polymerization reaction, and obtaining polylipoic acid as a lipoic acid polymer.

[0036] The cationic polymerization system of S110 has a variety of initiator choices. The polymerization activity of the monomer can be controlled by factors such as the initiator, polymerization reaction temperature and solvent polarity. It has the characteristics of fast reaction speed and non-termination of kinetic chain.

[0037] In S110, the reaction temperature of the cationic polymerization reaction is between -90°C and 30°C, and the reaction time of the cationic polymerization reaction is between 5 minutes and 4 hours.

[0038] The addition amount of the first organic solvent is determined according to the addition amount of the thioctic acid monomer. Preferably, the concentration of the thioctic acid monomer dissolved in the first organic solvent is 0.1mol / L to 10mol / L. In S110, the first organic solvent includes at least one of chloromethane, dichloromethane, chloroform, carbon tetrachloride, dichloroethane, n-hexane, cyclohexane, n-heptane, tetrahydrofuran, acetone, butanone, ether, acetonitrile, benzonitrile, benzene, toluene, xylene, chlorobenzene, o-dichlorobenzene, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, and butyl sulfone, or a combination thereof.

[0039] The first initiator may be a single-component initiator or a two-component initiator. Preferably, the single-component first initiator may be a strong organic acid or an anhydride or ester corresponding to the strong organic acid, and the two-component first initiator may include a small molecule initiator with an active initiation site and a salt or Lewis acid corresponding to the strong organic acid.

[0040] Exemplarily, the single-component initiator is selected from trifluoromethanesulfonic acid, trifluoromethanesulfonic anhydride, methyl trifluoromethanesulfonate, ethyl trifluoromethanesulfonate, butyl trifluoromethanesulfonate, allyl trifluoromethanesulfonate, benzyl trifluoromethanesulfonate, o-toluenesulfonate, 4-biphenyl trifluoromethanesulfonate, trifluoroacetic acid, p-toluenesulfonic acid, methyl p-toluenesulfonate, ethyl p-toluenesulfonate, perchloric acid and other strong acids and their esters, perfluorosulfonic acid resin and other strong acid ion exchange resins, phosphotungstic acid, aluminum phosphotungstate, iron phosphotungstate, potassium phosphotungstate, sodium phosphotungstate and other high concentration heteropoly acids and their salts, iron-based, aluminum-based, zirconium-based, chromium-based, titanium-based, molybdenum-based, dysprosium-based and other metal oxide solid superacids.

[0041] Exemplarily, one of the initiators in the two-component initiation system is selected from at least one of allyl chloride, allyl bromide, methylallyl chloride, methylallyl bromide, benzyl chloride, benzyl bromide, α,α-dimethylbenzyl chloride, α,α-dimethylbenzyl bromide, 1,3-di(chloromethyl)benzene, 1,3-di(bromomethyl)benzene, 1,4-di(chloromethyl)benzene, 1,4-di(bromomethyl)benzene, 1,3,5-tri(chloromethyl)benzene, and 1,3,5-tri(bromomethyl)benzene. Another initiator coinitiator in the two-component initiation system is selected from silver trifluoromethanesulfonate, trifluoromethanesulfonates of lanthanide elements (yttrium, scandium, dysprosium, samarium, gadolinium and neodymium), lithium perchlorate, potassium perchlorate, manganese perchlorate, silver perchlorate, magnesium perchlorate, calcium perchlorate, cesium perchlorate, barium perchlorate, iron perchlorate and the like, zinc dichloride, cadmium dichloride, mercuric dichloride, aluminum trichloride, aluminum tribromide, gallium trichloride, iron trichloride, tin tetrachloride, titanium tetrachloride, zirconium tetrachloride, vanadium tetrachloride, antimony pentafluoride, antimony pentachloride, tungsten pentachloride, boron trichloride, boron trifluoride, boron tribromide, AlR m X 3-m(R is an alkyl group such as methyl or ethyl, and X is a halogen) or the like.

[0042] The reaction terminator is used to terminate or slow down the rate of a chemical reaction. In a chain reaction or a free radical reaction, the reaction terminator plays a vital role. It can react with the active free radicals or intermediates in the reaction, thereby reducing their reactivity, thereby achieving the purpose of terminating the reaction. In S120, the first reaction terminator includes a propylthiol solution.

[0043] The following is a specific description of the preparation method of the lipoic acid polymer of the present invention by taking the random copolymer of aromatic olefin and lipoic acid as an example. For example, in some embodiments of the present invention, S100 specifically includes:

[0044] S110, firstly mixing and dissolving the lipoic acid monomer and the aromatic olefin monomer in a second organic solvent at a molar ratio of lipoic acid monomer: aromatic olefin monomer = 100: (1-10000) to obtain a reaction monomer, and then adding a second initiator to the reaction monomer at a molar ratio of second initiator: reaction monomer = (1-100): 5000 to carry out a cationic copolymerization reaction;

[0045] S120, adding a second reaction terminator to terminate the cationic copolymerization reaction, and obtaining a random copolymer of aromatic olefin and lipoic acid as a lipoic acid polymer.

[0046] In S110, the reaction temperature of the cationic copolymerization reaction is between -90°C and 30°C, and the reaction time of the cationic copolymerization reaction is between 5 minutes and 4 hours.

[0047] The amount of the second organic solvent added is determined according to the amount of thioctic acid monomer added. Preferably, the total concentration of thioctic acid and aromatic olefin monomer dissolved in the second organic solvent is 0.1mol / L to 10mol / L, and the concentration of the second initiator dissolved in the second organic solvent is 0.01mol / L to 1mol / L. In S110, the second organic solvent includes at least one of chloromethane, dichloromethane, chloroform, carbon tetrachloride, dichloroethane, n-hexane, cyclohexane, n-heptane, tetrahydrofuran, acetone, butanone, ether, acetonitrile, benzonitrile, benzene, toluene, xylene, chlorobenzene, o-dichlorobenzene, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, and butyl sulfone, or a combination thereof.

[0048] The second initiator may be a single-component initiator or a two-component initiator. Preferably, the single-component second initiator may be a strong organic acid or an anhydride or ester corresponding to the strong organic acid, and the two-component second initiator may include a small molecule initiator with an active initiation site and a salt or Lewis acid corresponding to the strong organic acid.

[0049] The components of the single-component initiator or the two-component initiator system are the same as those in the above-mentioned embodiment taking polylipoic acid as an example, and the present invention will not be described in detail here.

[0050] The role of the reaction terminator is the same as that of the embodiment using polylipoic acid as an example, and the present invention will not be repeated here. In S120, the second reaction terminator includes water or an alkyl alcohol solution or a thiol solution. Preferably, the second reaction terminator is precooled before use. Exemplarily, the second reaction terminator can be placed in an ice water bath at 0°C for precooling before adding the lipoic acid reaction component.

[0051] In some implementations of the present invention, S200 specifically includes:

[0052] S210, mixing lipoic acid polymer with isocyanic acid or isocyanate at a ratio of carboxyl group:isocyanate group=200:(1-200), adding a catalyst at a molar amount of 0.01-1% of the isocyanate at a temperature of 40°C to 160°C, and carrying out a condensation reaction for 0.5h to 4h to obtain a polydisulfide degradable polymer material.

[0053] It should be noted that the above steps have at least three implementation methods:

[0054] (1) In the present invention, isocyanate can be directly added to the solution of the lipoic acid polymer obtained in step S120 according to a certain proportion;

[0055] (2) The present invention can remove the solvent from the solution of the lipoic acid polymer obtained in step S120 to obtain a lipoic acid polymer elastomer, and then mix it with isocyanate in proportion, and react it in an extruder, a mixer, an injection molding machine, or other equipment;

[0056] (3) The present invention can remove the solvent from the solution of the lipoic acid polymer obtained in step S120 to obtain a lipoic acid polymer elastomer, and then add the isocyanate into a solvent in proportion to react. The solvent can be selected from at least one of acetone, butanone, toluene, tetrahydrofuran, dimethyl sulfoxide, butyl sulfone, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide) or a combination thereof according to the reaction temperature.

[0057] In some embodiments of the present invention, the catalyst includes N,N-dimethylcyclohexylamine, pentamethyldiethylenetriamine, dimethylcyclohexylamine, bis(2-dimethylaminoethyl) ether, N,N,N',N'-tetramethylalkylenediamine, triethylamine, N,N-dimethylbenzylamine, solid amine, N-ethylmorpholine, N-methylmorpholine, N,N'-diethylpiperazine, dibutyltin dilaurate, dioctyltin dilaurate, stannous octoate, di(dodecylsulfide)dibutyltin, dibutyltin diacetate, dibutyltin dimaleate, butyltin dithiol, dioctyltin mercaptan, organic bismuth, triazine trimerization catalyst, bis(dimethylaminomethyl)benzene, triethanolamine, N,N-dimethylethanolamine (DMEA), pyridine, N,N'-lutidine or at least one thereof or a combination thereof.

[0058] In the present invention, the thioctic acid polymer and isocyanic acid or isocyanate mixed reaction can generate amide groups and release carbon dioxide gas. Specifically, the carboxyl group of the thioctic acid polymer reacts with isocyanic acid to generate amide groups. The carboxyl group of the thioctic acid polymer reacts with the isocyanate group of aromatic isocyanate to first generate anhydride groups and urea groups respectively, and then the anhydride groups react with the urea groups to generate amide groups and carbon dioxide gas, or the anhydride groups continue to react with excess isocyanate groups to generate imide groups and carbon dioxide gas.

[0059] Exemplarily, aromatic isocyanates (i.e., isocyanate groups are directly attached to aromatic rings) include o-toluene isocyanate, m-toluene isocyanate, p-toluene isocyanate, 4-methoxyphenyl isocyanate, 3-methoxyphenyl isocyanate, 4-chlorophenyl isocyanate, m-chlorophenyl isocyanate, o-chlorophenyl isocyanate, 2-fluorophenyl isocyanate, 2,4-difluorophenyl isocyanate, 4-fluorophenyl isocyanate, 1-naphthyl isocyanate, 1,2-phenylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-methylenebis(phenyl isocyanate), 1,5-naphthalene diisocyanate or a combination thereof. The carboxyl group of the lipoic acid polymer reacts with the isocyanate group of the non-aromatic isocyanate to directly generate an amide group and carbon dioxide gas.

[0060] Exemplarily, the non-aromatic isocyanate (the isocyanate group is not directly attached to the aromatic ring) includes at least one of isopropyl isocyanate, tert-butyl isocyanate, ethyl isocyanate, n-butyl isocyanate, cyclopentyl isocyanate, cyclohexyl isocyanate, octadecyl isocyanate, 2-ethyl chloroisocyanate, α-methylbenzyl isocyanate, phenylethyl isocyanate, benzyl isocyanate, allyl isocyanate, 2-isocyanoethyl acrylate, isocyanatopropyltriethoxysilane, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, meta-xylyl diisocyanate, L-lysine diisocyanate, and HDI trimer, or a combination thereof.

[0061] In the present invention, when the lipoic acid polymer is polylipoic acid, the reaction formula is:

[0062]

[0063] When the lipoic acid polymer is a lipoic acid-aromatic olefin copolymer, its reaction mechanism with isocyanic acid or isocyanate is the same as that of polylipoic acid, and it is only necessary to change the polymer substrate from polylipoic acid to lipoic acid-aromatic olefin copolymer.

[0064] Example 1

[0065] This example is an example of base-catalyzed degradation, and its specific implementation method is as follows. Place 1g of a poly (N-cyclohexyl lipoamide) sample modified by cyclohexyl isocyanate in 12mL of an aqueous NaOH solution (concentration of 0.5mol / L), heat and stir at 85°C for 6h to obtain a degraded yellow turbid solution. After standing, take the upper yellow solution, add 1mol / L of an aqueous hydrochloric acid solution, acidify to pH=3-4, and a yellow powder precipitates. Vacuum filter to separate the precipitate, and continuously rinse the precipitate with deionized water, and finally dry it in a vacuum oven at 40°C to obtain a degraded and recovered monomer. The nuclear magnetic hydrogen spectrum of the degraded yellow turbid solution measured in deuterated water is as shown Figure 1 As shown, the figure marks the characteristic peaks of the degradation intermediate product sodium lipoate.

[0066] Example 2

[0067] This example is an acid-catalyzed degradation example, and its specific implementation method is as follows. 1g of poly (N-m-tolyl lipoamide) sample modified by m-toluene isocyanate is placed in 10mL N,N-dimethylformamide, 5mol% of trifluoromethanesulfonic acid is added to initiate degradation, and heated and stirred at 50°C for 4h to obtain a yellow clear solution. The solvent is removed by rotary evaporation, and finally dried in a vacuum oven at 40°C to obtain a monomer recovered by degradation.

[0068] Example 3

[0069] This embodiment is a thiol-induced degradation embodiment, and its specific implementation method is as follows. 1g of poly (N-tert-butyl lipoamide) sample modified by tert-butyl isocyanate is added to 4mL of tetrahydrofuran and heated with stirring at 70°C. 0.01mol% of propanethiol is dispersed in 2mL of tetrahydrofuran, added to the sample solution, and reacted for 4h. 0.1mol% of trifluoroacetic acid is dispersed in 1mL of tetrahydrofuran, acting as a quencher, and added to the reaction solution for 10min to terminate the reaction to obtain a clear and transparent yellow solution. The reaction solution is first diluted with dichloromethane, then washed twice with saturated Na2CO3 to remove the degradation inducer and quencher, then dried and filtered with Na2SO4, and finally dried in a vacuum oven at 40°C to obtain a monomer recovered by degradation.

[0070] The preparation method of the present invention can obtain a polydisulfide degradable polymer material containing an amide group, and can simultaneously introduce a new group into the polydisulfide, thereby giving the polydisulfide good performance. It should also be noted that although polylipoic acid has many excellent properties such as high toughness, self-repairing performance, chemical recyclability, biocompatibility and biodegradability, its disadvantage is that the strength is relatively low, and even the tensile strength of the polylipoic acid polymer material with ultra-high molecular weight is less than 0.5MPa. By adopting the technical scheme of the present invention, a polydisulfide degradable polymer material with higher strength can be obtained. The amide group has a positive effect on the improvement of the mechanical properties of the polylipoic acid material. By adjusting the content of the amide group in the polylipoic acid material, the mechanical properties of the polylipoic acid material, especially the parameters such as tensile strength and elongation at break, can be optimized, thereby helping the material to maintain better stability and durability when subjected to external forces. In addition, the polydisulfides synthesized using the prior art are actually supramolecular composite materials, not polymers with clear molecular weight and molecular chain structure, and the molecular weight of the polydisulfide molecular chain segment in such supramolecular materials is uncontrollable. By adopting the technical solution of the present invention, a polydisulfide degradable polymer material with controllable molecular weight can be obtained.

[0071] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A method for preparing a polydisulfide degradable polymer material containing an amide group, characterized in that: The preparation method comprises: S100, preparing a lipoic acid polymer by cationic polymerization or cationic copolymerization using a raw material including a lipoic acid monomer; S200, using raw materials including the lipoic acid polymer and isocyanic acid or isocyanate to prepare the polydisulfide degradable polymer material containing amide groups through a condensation reaction.

2. The preparation method according to claim 1, characterized in that: S100 specifically includes: S110, dissolving the lipoic acid monomer in a first organic solvent at a molar ratio of first initiator: lipoic acid monomer = (1-100): 5000, and then adding the first initiator to perform the cationic polymerization reaction; S120, adding a first reaction terminator to terminate the cationic polymerization reaction, and obtaining polylipoic acid as the lipoic acid polymer.

3. The preparation method according to claim 2, characterized in that: In S110, the first initiator includes a strong organic acid or an anhydride or ester corresponding to the strong organic acid; and / or In S110, the first organic solvent includes at least one of chloroform, dichloromethane, chloroform, carbon tetrachloride, ethylene dichloride, n-hexane, cyclohexane, n-heptane, tetrahydrofuran, acetone, butanone, ether, acetonitrile, benzonitrile, benzene, toluene, xylene, chlorobenzene, o-dichlorobenzene, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, and butyl sulfone, or a combination thereof; and / or In S110, the reaction temperature of the cationic polymerization reaction is between -90°C and 30°C; and / or In S110, the reaction time of the cationic polymerization reaction is 5 min to 4 h; and / or In S120, the first reaction terminator includes a propylthiol solution.

4. The preparation method according to claim 1, characterized in that: S100 specifically includes: S110, firstly mixing and dissolving the lipoic acid monomer and the aromatic olefin monomer in a second organic solvent at a molar ratio of lipoic acid monomer: aromatic olefin monomer=100:(1-10000) to obtain a reaction monomer, and then adding the second initiator to the reaction monomer at a molar ratio of second initiator: reaction monomer=(1-100):5000 to carry out the cationic copolymerization reaction; S120, adding a second reaction terminator to terminate the cationic copolymerization reaction, and obtaining a random copolymer of aromatic olefin and lipoic acid as the lipoic acid polymer.

5. The preparation method according to claim 4, characterized in that: In S110, the second initiator includes a strong organic acid or an anhydride or an ester corresponding to the strong organic acid; and / or In S110, the second organic solvent includes at least one of chloroform, dichloromethane, chloroform, carbon tetrachloride, ethylene dichloride, n-hexane, cyclohexane, n-heptane, tetrahydrofuran, acetone, butanone, ether, acetonitrile, benzonitrile, benzene, toluene, xylene, chlorobenzene, o-dichlorobenzene, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, and butyl sulfone, or a combination thereof; and / or In S110, the reaction temperature of the cationic copolymerization reaction is between -90°C and 30°C; and / or In S110, the reaction time of the cationic copolymerization reaction is 5 min to 4 h; and / or In S120, the second reaction terminator includes water or an alkyl alcohol solution or a thiol solution.

6. The preparation method according to any one of claims 1 to 5, characterized in that S200 specifically includes: S210, mixing the lipoic acid polymer with the isocyanic acid or the isocyanate in the ratio of carboxyl group:isocyanate group=200:(1-200), adding a catalyst at a molar amount of 0.01-1% of the isocyanate at a temperature of 40°C to 160°C, and carrying out the condensation reaction for 0.5h to 4h to obtain the polydisulfide degradable polymer material.

7. The preparation method according to claim 6, characterized in that: The catalyst includes at least one of an organic metal catalyst, an amine catalyst, an organic base catalyst, or a combination thereof.

8. The preparation method according to claim 6, characterized in that: The catalyst includes at least one of N,N-dimethylcyclohexylamine, pentamethyldiethylenetriamine, dimethylcyclohexylamine, bis(2-dimethylaminoethyl) ether, N,N,N',N'-tetramethylalkylenediamine, triethylamine, N,N-dimethylbenzylamine, solid amine, N-ethylmorpholine, N-methylmorpholine, N,N'-diethylpiperazine, dibutyltin dilaurate, dioctyltin dilaurate, stannous octoate, di(dodecylsulfide)dibutyltin, dibutyltin diacetate, dibutyltin dimaleate, butyltin dithiol, dioctyltin mercaptan, organic bismuth, triazine trimerization catalyst, bis(dimethylaminomethyl)benzene, triethanolamine, N,N-dimethylethanolamine (DMEA), pyridine, and N,N'-lutidine, or a combination thereof.

9. The preparation method according to claim 6, characterized in that: The isocyanate includes at least one of o-toluene isocyanate, m-toluene isocyanate, p-toluene isocyanate, 4-methoxyphenyl isocyanate, 3-methoxyphenyl isocyanate, 4-chlorophenyl isocyanate, m-chlorophenyl isocyanate, o-chlorophenyl isocyanate, 2-fluorophenyl isocyanate, 2,4-difluorophenyl isocyanate, 4-fluorophenyl isocyanate, 1-naphthyl isocyanate, 1,2-phenylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-methylenebis(phenyl isocyanate), and 1,5-naphthalene diisocyanate, or a combination thereof; or The isocyanate includes at least one of isopropyl isocyanate, tert-butyl isocyanate, ethyl isocyanate, n-butyl isocyanate, cyclopentyl isocyanate, cyclohexyl isocyanate, octadecyl isocyanate, 2-ethyl chloroisocyanate, α-methylbenzyl isocyanate, phenylethyl isocyanate, benzyl isocyanate, allyl isocyanate, 2-isocyanoethyl acrylate, isocyanatopropyltriethoxysilane, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, meta-xylyl diisocyanate, L-lysine diisocyanate, and HDI trimer, or a combination thereof.

10. A polydisulfide degradable polymer material containing an amide group, characterized in that: The polydisulfide degradable polymer material containing amide groups is obtained by the preparation method according to any one of claims 1 to 9.

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